# Safe to reshape carbon fiber frame?



## roaden (Dec 31, 2014)

I sanded down a small part of my carbon bike's chainstay just behind the bottom bracket. This was to clear the new super-compact chainring that I installed. I sanded down about 1mm or a maybe a bit more. The frame had very little clearance even with the regular size chainrings, but with the new chainrings that I got, the rings are offset 2.5mm closer to the frame. The inner ring actually contacts the frame so I thought I'd sand the paint off. Turns out I had to sand down the carbon too to clear the rings and so the cranks would fully set into the bottom bracket. I didn't sand down through the carbon completely but I sanded down at least two layers from the bands that I can see. The sanded area still seems strong; there's no give when I push hard on it with my finger.

Is this going to be safe to ride?


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## PoorInRichfield (Nov 30, 2013)

I would not have done what you did, but it's your bike. The benefit of carbon is that it can be laid-up to be strong where it needs to be and thin where it doesn't. The tube walls aren't that thick to begin with, so shaving off 1mm just to fit a chain ring sounds like a bad idea to me. I guess you'll find out if it's safe to ride or not.


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## duriel (Oct 10, 2013)

So now that it's done, your having second thoughts? That's not how it's done.


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## roaden (Dec 31, 2014)

Yeah probably shouldn't have done it. But too late now. I do have a carbon repair kit, so I can rebuild the chainstay again if needed. 

I'm thinking I could also go all the way and shave some more. Right now the chainring is still almost touching. I could shave some more for better clearance, and rebuild the carbon with a slight bend.


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## duriel (Oct 10, 2013)

That's not going to work. The material you take off is going to be way stronger than anything you could replace it with and still maintain clearance.

Just go ahead and make more room and try it. It may work! ... if it don't send it to someone. 

Why didn't you just use a spacer on the crank to clear the CS? Maybe that wouldn't work, but obviously you should reconsider all your wrenching.


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## Finx (Oct 19, 2017)

If you shaved the chainstay down enough to clear 2.5mm inwards on the chain line, you have almost certainly compromised the integrity to the point where it's unsafe to ride.

Ask yourself some questions.



If someone were selling this bike, knowing about this 'work' having been done, would you buy it? Even at a significant discount (or even 'free')?
Would you let someone you care about ride this bike? S/O, child, sibling, or your mother?
Do you honestly trust the opinion of random, anonymous people on the internet to decide if your bike is safe to ride, without so much as seeing a photograph (not that it would help much)?
Do you have good health and dental insurance? (ok, I admit, that was me being snarky, but seriously, don't ride this bike).

I am sure others reading this thread have similar questions going through their minds as I have. Namely, 'WHY?' But the answer to that doesn't really matter.

On the bright side, you now have sufficient justification to go out and purchase yourself a shiny new bike (or frameset)...


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## roaden (Dec 31, 2014)

I agree shaving 2.5mm would compromise the carbon. In fact, it would not be a question at that point because I don't think carbon walls would be 2.5mm thick, so you'd really end up with a hole in the carbon tube.

I sanded around 1mm deep about an inch diameter area. The chainstay is really beefy though. That's part of the reason why there's so little clearance because they made the chainstay tubes so large. It's actually more rectangular cross section rather than circular cross-section (tube).

I'm thinking the design was for extra stiffness around the bottom bracket. So thinning out a small section probably would not be catastrophic. There's still the other chainstay intact. I would not try to sand down a fork or a downtube. But if a chainstay breaks, that shouldn't be any worse than getting a rear spoke break or a rear tire flat. I mean it's not going to throw you over the bars I don't think.


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## roaden (Dec 31, 2014)

duriel said:


> Why didn't you just use a spacer on the crank to clear the CS?


There's no room for a spacer on the bottom bracket.


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## ogre (Dec 16, 2005)

roaden said:


> I sanded around 1mm deep about an inch diameter area. The chainstay is really beefy though. That's part of the reason why there's so little clearance because they made the chainstay tubes so large. It's actually more rectangular cross section rather than circular cross-section (tube).


Did you ever think that the BB area is really beefy because that's where the frame has the most torsional forces acting against it? While the cross section of the tube is huge, the wall thicknesses aren't necessarily huge.



roaden said:


> I'm thinking the design was for extra stiffness around the bottom bracket. So thinning out a small section probably would not be catastrophic. There's still the other chainstay intact. I would not try to sand down a fork or a downtube. But if a chainstay breaks, that shouldn't be any worse than getting a rear spoke break or a rear tire flat. I mean it's not going to throw you over the bars I don't think.


See what I said above. Yeah, the other chainstay is intact, but no one has made a 'Lefty' version of a rear triangle. I agree, you may not get thrown over the bars when failure occurs, but please post vids. I sure wouldn't want to experience a chainstay snapping from the BB shell at 25 mph and sending my rear tire into the chainstay.

To steal a quote, 'Dibs on your stuff'


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## Jay Strongbow (May 8, 2010)

The only real answer is 'maybe'.

I can tell you I wore a gouge maybe that deep in a chain stay from breaking a spoke and riding home with the tire rubbing and subsequently rode about 30K miles on the frame. But that's a far cry from meaning sanding off 2.5mm from any bike would be no problem.


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## Opus51569 (Jul 21, 2009)

If it were me, that bike would be relegated to the trainer... permanently.


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## craiger_ny (Jun 24, 2014)

Might as well have stuck some grip-tape to the chainring and let it sand it's own clearance. I think you're into 'test of faith' territory at this point. Ride at your own peril, just don't sell it.


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## cxwrench (Nov 9, 2004)

OP have you heard of the 'Darwin Awards'? 

I know I shouldn't be surprised at what people think is ok to do but then things like this happen.


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## velodog (Sep 26, 2007)

I ain't afraid...

I ain't smart enough to be afraid.


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## SPlKE (Sep 10, 2007)

Pics, please.


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## Srode (Aug 19, 2012)

I really can't imagine how anyone would think this was a good idea.


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## No Time Toulouse (Sep 7, 2016)

After reading this, I wasn't sure if you were either a genius or incredibly stupid. I'm tending towards the latter, though......


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## nova_rider (Sep 23, 2005)

How lucky do you feel? Just go hop off the curbs few times and see if it holds up. If it lets go, at least it won't catch you by surprise.

There's no repair that will restore the original structural integrity, just make sure the area is properly protected from moisture. I believe you provided the depth, but not the length of your handiwork, which I believe is the more critical value.


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## Kerry Irons (Feb 25, 2002)

cxwrench said:


> OP have you heard of the 'Darwin Awards'?
> 
> I know I shouldn't be surprised at what people think is ok to do but then things like this happen.


You can always fix it with some EEEEpoxy Raysun!


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## roaden (Dec 31, 2014)

Jay Strongbow said:


> The only real answer is 'maybe'.
> 
> I can tell you I wore a gouge maybe that deep in a chain stay from breaking a spoke and riding home with the tire rubbing and subsequently rode about 30K miles on the frame. But that's a far cry from meaning sanding off 2.5mm from any bike would be no problem.


You're the 2nd person who thought I sanded off 2.5mm. I sanded off only 1mm (approx.; i didn't measure it). The 2.5mm is how much the new super-compact chainring offsets the rings towards the frame compared to normal chainrings. Regular chainrings don't rub on the chainstay, but there's so little clearance, that moving the chainrings 2.5mm inward contacts the frame. I was able to make the new chainrings clear the frame by sanding off 1mm from the chainstay.


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## roaden (Dec 31, 2014)

SPlKE said:


> Pics, please.


Will post a pic later. I realized I can't leave the bare carbon unsealed, so I'll have to take off the cranks again, and spray paint the carbon. Will take pics.


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## roaden (Dec 31, 2014)

craiger_ny said:


> Might as well have stuck some grip-tape to the chainring and let it sand it's own clearance. I think you're into 'test of faith' territory at this point. Ride at your own peril, just don't sell it.


I actually thought I'd just let the chainring gouge it's own clearance. But maybe a better idea would have been to sand the chainring instead. That probably would have been less risky because you would be putting stress on the small chainring only when you're climbing during which you would be going at slower and therefore safer speeds.


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## roaden (Dec 31, 2014)

nova_rider said:


> How lucky do you feel? Just go hop off the curbs few times and see if it holds up. If it lets go, at least it won't catch you by surprise.
> 
> There's no repair that will restore the original structural integrity, just make sure the area is properly protected from moisture. I believe you provided the depth, but not the length of your handiwork, which I believe is the more critical value.


The sanded area is about 1.5-2 inches diameter. I originally estimated 1 inch diameter but that was too low estimate. I'll measure it when i take off the crank again and take a pic.


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## cxwrench (Nov 9, 2004)

roaden said:


> I actually thought I'd just let the chainring gouge it's own clearance. But maybe a better idea would have been to sand the chainring instead. That probably would have been less risky because you would be putting stress on the small chainring only when you're climbing during which you would be going at slower and therefore safer speeds.


You should give up cycling and find something very, very safe to occupy your time. Possibly meditation, you can think about not doing stupid things.


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## MMMhills (Jan 13, 2016)

As a mechanic I would NEVER ride that frame again and recommend you dont either. Carbon is strong or flexy or weak depending on how it is layered. The fame could last and never fail BUT it also could have a catastrophic failure at any time.

Question is how lucky do you feel when cruising downhill at speed and that is the point the frame brakes in half where you did your work????? Hope it works out but I would not ride it!


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## Finx (Oct 19, 2017)

roaden said:


> I actually thought I'd just let the chainring gouge it's own clearance. But maybe a better idea would have been to sand the chainring instead. That probably would have been less risky because you would be putting stress on the small chainring only when you're climbing during which you would be going at slower and therefore safer speeds.


Even less risky would be to run chainrings that don't interfere with the chain stay. Or, if you really really really needed those chainrings, find a frame they work on without compromising the integrity of your bike.


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## roaden (Dec 31, 2014)

MMMhills said:


> As a mechanic I would NEVER ride that frame again and recommend you dont either. Carbon is strong or flexy or weak depending on how it is layered. The fame could last and never fail BUT it also could have a catastrophic failure at any time.
> 
> Question is how lucky do you feel when cruising downhill at speed and that is the point the frame brakes in half where you did your work????? Hope it works out but I would not ride it!


The frame breaks in half while cruising downhill? You paint a much scarier picture than what Jay Strongbow's experience suggests. As he said:



> _I can tell you I wore a gouge maybe that deep in a chain stay from breaking a spoke and riding home with the tire rubbing and subsequently rode about 30K miles on the frame._


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## ngl (Jan 22, 2002)

This is only ONE of the reasons I recommend a 'novice' person take any 'used' bike to a LBS for inspection before buying it.


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## ngl (Jan 22, 2002)

roaden said:


> . But maybe a better idea would have been to sand the chainring instead.


At what location were you planning to sand on the chainring?


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## cxwrench (Nov 9, 2004)

roaden said:


> The frame breaks in half while cruising downhill? You paint a much scarier picture than what Jay Strongbow's experience suggests. As he said:
> 
> [/I][/COLOR]


Good god you are truly not smart enough to take the advice you've been give, are you? No one here has seen the damage you've done. No one here is a composite engineer. The ONLY advice worth a damn anyone can give you is to play it safe and not ride the frame. This has been done repeatedly and yet you reply like this? I hope you don't have kids.


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## ogre (Dec 16, 2005)

I'm not sure which is worse, this remedy or the thread you made making your integrated seatpost mast higher.


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## duriel (Oct 10, 2013)

ogre said:


> I'm not sure which is worse, this remedy or the thread you made making your integrated seatpost mast higher.


OMG, I missed that one... give us a link!

Can the OP post any engineering support/education/classes/work he has done that would qualify u as to capable of re-engineering a CF frame? 
Besides making a mud pie in the backyard once?


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## Opus51569 (Jul 21, 2009)

I'm starting to suspect there's a troll afoot...


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## ogre (Dec 16, 2005)

duriel said:


> OMG, I missed that one... give us a link!
> 
> Can the OP post any engineering support/education/classes/work he has done that would qualify u as to capable of re-engineering a CF frame?
> Besides making a mud pie in the backyard once?


Here you go. That thread is just a couple down from this one.

https://forums.roadbikereview.com/components-wrenching/isp-seat-post-cut-fit-measurement-strategy-371607.html

edit: watch the second video


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## roaden (Dec 31, 2014)

ogre said:


> Here you go. That thread is just a couple down from this one.
> 
> https://forums.roadbikereview.com/c...post-cut-fit-measurement-strategy-371607.html
> 
> edit: watch the second video


sorry to disappoint you, that wasn't me. so you just see 2 guys trying to fix carbon and assumed they are the same person? i feel bad for that other guy, my mad tinkering is giving him a bad reputation. his fix is actually not bad, but I would sand down the glued seatmast pieces first before applying 2 layers of carbon, or else the whole thing would be too thick for the seatmast topper.


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## ngl (Jan 22, 2002)

roaden said:


> sorry to disappoint you, that wasn't me. so you just see 2 guys trying to fix carbon and assumed they are the same person? i feel bad for that other guy, my mad tinkering is giving him a bad reputation. his fix is actually not bad, but I would sand down the glued seatmast pieces first before applying 2 layers of carbon, or else the whole thing would be too thick for the seatmast topper.


I'm still interested to know where you were going to sand on that chainring.


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## roaden (Dec 31, 2014)

ngl said:


> I'm still interested to know where you were going to sand on that chainring.


i thought i answered your question, but i checked and it's not there. maybe i didn't post the reply. anyway, it's a moot point because I'm not sanding the chainring now that i've already sanded the frame. but it would have been on the side of the small chainring where it's contacting the frame. Not the teeth of the rings, but the thick part below the teeth where the bolt holes are. This is a special chainring where the holes are threaded, it doesn't use the normal chainring slot-style bolt nut.

I guess i didn't think of sanding the chainring because it was easier to sand carbon, and if i change my mind and want to go back to regular chainrings, the carbon is repairable. You can't rebuild back a sanded down chainring.


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## ljvb (Dec 10, 2014)

The frame is basically trash. Others have said it.. and there is a huge difference between a gouge and sanding a part of the frame away. There are some possible occasions where you could get away with it (seat tube for example is the only one I can think of), areas that are vertical that take no lateral stress. On the chainstay, you have a tone of lateral stress.. Carbon is layered in perpendicular layers impregnated with resin in a vacuum chamber, even if you use a carbon fiber patch and resin, it will not be truly bonded and will will not provide structural support. At most, you should only have removed the clear coat. If you cannot use a part, then it was not designed to fit that part, don't use the part, get a different part, don't compromise the structure of the frame to fit a part, that is just stupid.

You are literally taking your life into your hands there at best, at worst, and you sell it, you are risking someone elses life. Take the lesson learned, suck it up, it's a big financial hit, and get a new frame, and trash the current one, don't be that guy.


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## roaden (Dec 31, 2014)

Some of you guys make it sound like there is no carbon repair industry that do all sorts of repairs all the time. Take a look at Calfee, for example, who give a 10-year warranty on their repairs. 

https://calfeedesign.com/repair-examples/


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## tlg (May 11, 2011)

roaden said:


> Is this going to be safe to ride?


Might want to invest..... https://www.deltadental.com/us/en/dental-insurance.html


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## ljvb (Dec 10, 2014)

roaden said:


> Some of you guys make it sound like there is no carbon repair industry that do all sorts of repairs all the time. Take a look at Calfee, for example, who give a 10-year warranty on their repairs.
> 
> https://calfeedesign.com/repair-examples/


That is not the same thing as a patch repair you mentioned further up in the thread. They actually cut and remove the affected section, and lay out essentially an entirely new piece of a part and tie it into the frame structurally. Since you are familiar with them, send your frame to them to repair.

Seriously, you asked a question, you got an answer, basically every response gave you the same answer, don't do it, you should not have done it, it's a bad idea... and yet you are still arguing.. I could see if maybe one or 2 people here agreed with what you did, but there is a solid consensus that it was dumb... life threateningly dumb.


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## jetdog9 (Jul 12, 2007)

Still no pictures?


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## duriel (Oct 10, 2013)

Come on, if caffee can do so can he! ... or her!

I think his next project should be a trip to the MOON!


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## cxwrench (Nov 9, 2004)

roaden said:


> Some of you guys make it sound like there is no carbon repair industry that do all sorts of repairs all the time. Take a look at Calfee, for example, who give a 10-year warranty on their repairs.
> 
> https://calfeedesign.com/repair-examples/


There definitely is a carbon repair industry. The thing is _they know what they're doing..._unlike you. 



Who is totally clueless. 




And refuses to acknowledge the fact despite it being brought up by many members.


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## rideit (Feb 8, 2005)

Why in the hell didn’t you just get a crankset with a wider, adjustable bottom bracket?


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## No Time Toulouse (Sep 7, 2016)

cxwrench said:


> There definitely is a carbon repair industry. The thing is _they know what they're doing..._unlike you.
> ...


If even CX wouldn't attempt it, you shouldn't either. I wonder what sort of 'kludge' repairs you've done on your car.....


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## OldChipper (May 15, 2011)

roaden said:


> There's no room for a spacer on the bottom bracket.


A) sorry, but that was an exceptionally stupid thing to do. Do you really think frame designers put a ton of extra material anywhere just for the heck of it? B) your statement above makes no sense. You put a 1-2mm spacer on the crank spindle, re-install, job done. I had to do this when I put eTap on my TT bike to get the drive side crank arm to clear the adjusting screws. I guess by your logic I should have just filed a groove in the crank arm.


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## roaden (Dec 31, 2014)

OldChipper said:


> B) your statement above makes no sense. You put a 1-2mm spacer on the crank spindle, re-install, job done. I had to do this when I put eTap on my TT bike to get the drive side crank arm to clear the adjusting screws. I guess by your logic I should have just filed a groove in the crank arm.


Just because your crankset has room for spacers on your bike doesn't mean all cranks have room for spacers. What does not having room look like? It means when the cranks are installed, both cranks are flush to the bottom bracket bushings. There is no side-to-side leeway.


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## velodog (Sep 26, 2007)

roaden said:


> Just because your crankset has room for spacers on your bike doesn't mean all cranks have room for spacers. What does not having room look like? It means when the cranks are installed, both cranks are flush to the bottom bracket bushings. There is no side-to-side leeway.


Did you attempt to apply a spacer or just assume that it wouldn't work?


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## roaden (Dec 31, 2014)

velodog said:


> Did you attempt to apply a spacer or just assume that it wouldn't work?


I like the way you think. Some people here just assumed sanding a frame wouldn't work without even attempting it.


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## OldChipper (May 15, 2011)

roaden said:


> Just because your crankset has room for spacers on your bike doesn't mean all cranks have room for spacers. What does not having room look like? It means when the cranks are installed, both cranks are flush to the bottom bracket bushings. There is no side-to-side leeway.


You need to sell or give away any tools you have and never touch a bike again. Guess what, if you shim your crank spindle and re-install, your crank+shim will be flush up against your BB bushings again - just this time it will be 1-2mm farther away from the chainstay so your chainrings won’t rub. There isn’t and shouldn’t ever be any dead space between your crank and the BB bushings - with or without shims. 

I’m actually starting to think this might be a troll. No real person could be this dumb. 


Sent from my iPhone using Tapatalk Pro


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## velodog (Sep 26, 2007)

roaden said:


> I like the way you think. Some people here just assumed sanding a frame wouldn't work without even attempting it.


I wouldn't try and create clearance by removing material from the frame myself, what I asked is if you tried spacers before taking your sandpaper to frame.


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## roaden (Dec 31, 2014)

OldChipper said:


> Guess what, if you shim your crank spindle and re-install, your crank+shim will be flush up against your BB bushings again - just this time it will be 1-2mm farther away from the chainstay so your chainrings won’t rub. There isn’t and shouldn’t ever be any dead space between your crank and the BB bushings - with or without shims.


Hmm. Now, that doesn't make sense. If your cranks were flush to the BB bushings to begin with and you added 2mm of spacers, where did you take 2mm away from to create the space? Does that mean the bushings are compressible and you just forced them to compress 2mm in width? Or does that mean the non-drive side crank is now clamping on the BB spindle with 2mm less bite. (I have Shimano hollowtech II crankset, by the way). Since there's a pin on the non-drive crank to slot into a hole in the bb spindle, does this mean the pin is no longer pushed in? Is this even safe?

Anyway, this sounds interesting. I admit I didn't try the spacers solution since I didn't have spacers to begin with on the non-drive side that I could have moved to the drive side. I'll try adding spacers. If I could shift the cranks at least 2mm to the drive side that would be great and would put the chainline back close to the original. I have a crank power meter on the non-drive side and the non-drive crank is also pretty close to the chainstay, but i think 2mm further in won't be a problem.


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## 202cycle (Sep 13, 2011)

roaden said:


> Hmm. Now, that doesn't make sense. If your cranks were flush to the BB bushings to begin with and you added 2mm of spacers, where did you take 2mm away from to create the space? Does that mean the bushings are compressible and you just forced them to compress 2mm in width? Or does that mean the non-drive side crank is now clamping on the BB spindle with 2mm less bite. (I have Shimano hollowtech II crankset, by the way). Since there's a pin on the non-drive crank to slot into a hole in the bb spindle, does this mean the pin is no longer pushed in? Is this even safe?
> 
> Anyway, this sounds interesting. I admit I didn't try the spacers solution since I didn't have spacers to begin with on the non-drive side that I could have moved to the drive side. I'll try adding spacers. If I could shift the cranks at least 2mm to the drive side that would be great and would put the chainline back close to the original. I have a crank power meter on the non-drive side and the non-drive crank is also pretty close to the chainstay, but i think 2mm further in won't be a problem.


None of this matters now. You have ruined your frame.


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## cxwrench (Nov 9, 2004)

roaden said:


> Hmm. Now, that doesn't make sense. If your cranks were flush to the BB bushings to begin with and you added 2mm of spacers, where did you take 2mm away from to create the space? Does that mean the bushings are compressible and you just forced them to compress 2mm in width? Or does that mean the non-drive side crank is now clamping on the BB spindle with 2mm less bite. (I have Shimano hollowtech II crankset, by the way). Since there's a pin on the non-drive crank to slot into a hole in the bb spindle, does this mean the pin is no longer pushed in? Is this even safe?
> 
> Anyway, this sounds interesting. I admit I didn't try the spacers solution since I didn't have spacers to begin with on the non-drive side that I could have moved to the drive side. I'll try adding spacers. If I could shift the cranks at least 2mm to the drive side that would be great and would put the chainline back close to the original. I have a crank power meter on the non-drive side and the non-drive crank is also pretty close to the chainstay, but i think 2mm further in won't be a problem.


Let me try to explain this in a way that you might be able to understand. 

Shimano makes all their cranks to the same dimensions. ALL of their crank axles are the same length. The axle on the drive side is supposed to go into the non drive side crank arm a certain amount, you know this because of the safety tab w/ the pin that goes into the hole in the axle. 

There are different bottom brackets that adapt various frames to work w/ the very much standardized Shimano axle. If your frame/bottom bracket/crank combination doesn't work properly w/ the parts as they come out of the box something is wrong. You shouldn't add shims to make it work _nor should you remove material from your damn frame_. I would think for most people this would be obvious. I have a feeling that your frame/bb/crank combination is not compatible but can't say for sure w/o seeing it. You need to stop what you're doing and take your bike to a reputable bike shop. After they stop laughing at you for trying to sand the frame away to get necessary clearance they might be able to fix things for you.


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## 202cycle (Sep 13, 2011)

cxwrench said:


> Let me try to explain this in a way that you might be able to understand.
> 
> Shimano makes all their cranks to the same dimensions. ALL of their crank axles are the same length. The axle on the drive side is supposed to go into the non drive side crank arm a certain amount, you know this because of the safety tab w/ the pin that goes into the hole in the axle.
> 
> There are different bottom brackets that adapt various frames to work w/ the very much standardized Shimano axle. If your frame/bottom bracket/crank combination doesn't work properly w/ the parts as they come out of the box something is wrong. You shouldn't add shims to make it work _nor should you remove material from your damn frame_. I would think for most people this would be obvious. I have a feeling that your frame/bb/crank combination is not compatible but can't say for sure w/o seeing it. You need to stop what you're doing and take your bike to a reputable bike shop. After they stop laughing at you for trying to sand the frame away to get necessary clearance they might be able to fix things for you.


Would you work on that bike? I wouldn't touch it with a 10 foot pole. I'm not going to be liable for anything that happens to that frame after I touched it. No way.

I would have a good laugh though.


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## cxwrench (Nov 9, 2004)

202cycle said:


> Would you work on that bike? I wouldn't touch it with a 10 foot pole. I'm not going to be liable for anything that happens to that frame after I touched it. No way.
> 
> I would have a good laugh though.


True, I wouldn't touch it either. 'Fix it' could mean selling him a new bike in this case.


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## duriel (Oct 10, 2013)

I think he just likes to 'work' on bikes, probably not planning on riding that thing, are you crazy?


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## jetdog9 (Jul 12, 2007)

Please please post a picture.


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## nova_rider (Sep 23, 2005)

As bad as what OP's description of what he did, it may not be as bad as one might think for the following reasons: 1) Built-in Factor of Safety 2) Structural component involved, and 3) The location/orientation of the breach. I won't bore you with the technical details, but even if the chainstay experience a complete shear failure, I do not believe it would lead to a catastrophic collapse of the rear triangle. Having said that, this would have a very different outcome if say this involved the seatstay.

Found this posting related to the topic:
https://forums.roadbikereview.com/g.../ever-seen-carbon-frame-fail-like-253975.html

Here's a video of a chainstay failure during a ride:
https://www.youtube.com/watch?v=7zoJ4fhJmO0


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## OldChipper (May 15, 2011)

cxwrench said:


> Let me try to explain this in a way that you might be able to understand.
> 
> Shimano makes all their cranks to the same dimensions. ALL of their crank axles are the same length. The axle on the drive side is supposed to go into the non drive side crank arm a certain amount, you know this because of the safety tab w/ the pin that goes into the hole in the axle.
> 
> There are different bottom brackets that adapt various frames to work w/ the very much standardized Shimano axle. If your frame/bottom bracket/crank combination doesn't work properly w/ the parts as they come out of the box something is wrong. You shouldn't add shims to make it work _nor should you remove material from your damn frame_. I would think for most people this would be obvious. I have a feeling that your frame/bb/crank combination is not compatible but can't say for sure w/o seeing it. You need to stop what you're doing and take your bike to a reputable bike shop. After they stop laughing at you for trying to sand the frame away to get necessary clearance they might be able to fix things for you.


Come on CX a 1 or 2 mm shim isn't going to fatally compromise anything. I've had to do this on both the DS and NDS on several bikes with Shimano cranks, ridden each 1000's of miles and never a problem and all the safety tabs inserted properly with no problem. With all the different cranks, frame and BB designs, CRs, FDs, etc. some combinations are going to have issues and a small tweak like this isn't going to cause problems.


----------



## ROAD&DIRT (Mar 27, 2009)

roaden said:


> i sanded down a small part of my carbon bike's chainstay just behind the bottom bracket. This was to clear the new super-compact chainring that i installed. I sanded down about 1mm or a maybe a bit more. The frame had very little clearance even with the regular size chainrings, but with the new chainrings that i got, the rings are offset 2.5mm closer to the frame. The inner ring actually contacts the frame so i thought i'd sand the paint off. Turns out i had to sand down the carbon too to clear the rings and so the cranks would fully set into the bottom bracket. I didn't sand down through the carbon completely but i sanded down at least two layers from the bands that i can see. The sanded area still seems strong; there's no give when i push hard on it with my finger.
> 
> *Is this going to be safe to ride?*


Who in there right mind sands down a carbon from well into carbon... and then ask's _"is this going to be safe to ride"?_ .... NO!  :mad2:


----------



## velodog (Sep 26, 2007)

ROAD&DIRT said:


> Who in there right mind sands down a carbon from well into carbon... and then ask's _"is this going to be safe to ride"?_ .... NO!  :mad2:




By sanding it down before asking he didn't have to ignore any advice that suggested he didn't do what he was going to do anyway.


----------



## cxwrench (Nov 9, 2004)

OldChipper said:


> *Come on CX a 1 or 2 mm shim isn't going to fatally compromise anything.* I've had to do this on both the DS and NDS on several bikes with Shimano cranks, ridden each 1000's of miles and never a problem and all the safety tabs inserted properly with no problem. With all the different cranks, frame and BB designs, CRs, FDs, etc. some combinations are going to have issues and a small tweak like this isn't going to cause problems.


No, it won't. That said I have never seen a frame w/ the correct bottom bracket and a Shimano crank need a shim of any kind. Not once. I've seen them the opposite, nearly wide enough that the safety tab won't engage, but not loose. When people talk about needing to use shims that aren't supplied w/ whichever component they're using it always leads me to thinking the same thing...I'm sure you can guess what that is.


----------



## roaden (Dec 31, 2014)

cxwrench said:


> No, it won't. That said I have never seen a frame w/ the correct bottom bracket and a Shimano crank need a shim of any kind. Not once. I've seen them the opposite, nearly wide enough that the safety tab won't engage, but not loose. When people talk about needing to use shims that aren't supplied w/ whichever component they're using it always leads me to thinking the same thing...I'm sure you can guess what that is.


Is everything alright? You seem uncharacteristically restrained today.


----------



## roaden (Dec 31, 2014)

before and after painting pics


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## cxwrench (Nov 9, 2004)

roaden said:


> Is everything alright? You seem uncharacteristically restrained today.


All good.  The weather is global climate change wonderful for Feb, can't wait to get on the Fuel EX this weekend. Maybe even play some tennis and start working on my tan a bit early this year.


----------



## Opus51569 (Jul 21, 2009)

roaden said:


> before and after painting pics


I owe you an apology. I really thought you were just trolling us. But, no, you actually are just that ridiculous. Best of luck.


----------



## ljvb (Dec 10, 2014)

Dude.. that is not a little sanding.. you went through 3 layers of carbon, in what is more than likely 5 or so layers, in a very high stress area.......


----------



## velodog (Sep 26, 2007)

Seeing as it's painted, have you built it back up and ridden it yet? How about a ride report? 

Maybe report back every 500 miles or so, after the initial ride report, I'm sure everyone is anxious to hear how things work out for you.


----------



## roaden (Dec 31, 2014)

I read somewhere 7 layers is minimum recommended, and can go as high as 12 to 16 layers in high stress areas.


----------



## roaden (Dec 31, 2014)

No, not ridden yet. It's touching again after painting, but I have spacers on order. Will add some spacers before I ride it. Hopefully I can fit 1mm, but even 0.5mm should be enough. I need to bring the chainline back out also since right now the derailleur is still very slightly rubbing the chain when in the lowest gear (low limit is completely open).


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## ROAD&DIRT (Mar 27, 2009)

Sounds like it's time to make some room for wall art


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## DrSmile (Jul 22, 2006)

No guarantees but unless you're a Clydesdale I'd say that's probably safe to ride. People freak out here over cracks in clearcoat... Most of the stress is probably on the top and bottom of that chain stay not on the side. Ride it in a soft grassy field and sprint all out throwing the bike back and forth. Make sure to video tape it just in case for our amusement.


----------



## roaden (Dec 31, 2014)

DrSmile said:


> No guarantees but unless you're a Clydesdale I'd say that's probably safe to ride. People freak out here over cracks in clearcoat... Most of the stress is probably on the top and bottom of that chain stay not on the side. Ride it in a soft grassy field and sprint all out throwing the bike back and forth. Make sure to video tape it just in case for our amusement.


video tape? you're dating yourself.

You've hit on something important - rider weight (and power) matters. Nobody has asked and I haven't even mentioned it, but I'm 145 lbs. If a frame has tolerances to handle the likes of Peter Sagan sprinting, it probably can handle me with 2 plies of carbon tied behind its back so to speak.


----------



## DrSmile (Jul 22, 2006)

roaden said:


> video tape? you're dating yourself.


Sorry about that, let me fix it.

Please Betamax it.


----------



## roaden (Dec 31, 2014)

Just finished a 40 mile ride with climbing. Bike feels absolutely fine. Did sprints, bunny hops, out-of-saddle climbs. 

I was able to add 1mm spacer on the drive side. It was the max possible. I tried 1.5mm and could not lock the safety tab pin on the non-drive crank. I have sufficient clearance now between the chainring and the frame. No problems with shifting.

I consider the question answered - whether the bike is safe to ride. Yes, it is. 

Thanks to all who offered their advice and opinion.


----------



## cxwrench (Nov 9, 2004)

roaden said:


> Just finished a 40 mile ride with climbing. Bike feels absolutely fine. Did sprints, bunny hops, out-of-saddle climbs.
> 
> I was able to add 1mm spacer on the drive side. It was the max possible. I tried 1.5mm and could not lock the safety tab pin on the non-drive crank. I have sufficient clearance now between the chainring and the frame. No problems with shifting.
> 
> ...


FTFY. That's all you really know. It might hold up for years, it might not. You have absolutely no idea.


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## roaden (Dec 31, 2014)

The good thing about carbon is that it has practically infinite fatigue life. That means that if you have verified that it can withstand a certain amount of force/stress once, it will not fail with repeated application. You cannot say that about metal. 

The only way carbon will fail is if you subject it to higher force/stress above the level you have already tested; or if it gets additional damage. But you can say that about any frame material.

I googled the info above.


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## duriel (Oct 10, 2013)

I suggest you ride over a brick in the road at 15 mph, make sure you use plenty of safety gear!


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## xxl (Mar 19, 2002)

roaden said:


> The good thing about carbon is that it has practically infinite fatigue life. That means that if you have verified that it can withstand a certain amount of force/stress once, it will not fail with repeated application. You cannot say that about metal.
> 
> The only way carbon will fail is if you subject it to higher force/stress above the level you have already tested; or if it gets additional damage. But you can say that about any frame material.
> 
> I googled the info above.



I Googled this: 

Steel and titanium frames have a ‘fatigue limit’ below which a repeated load (frame flex) can be applied an infinite amount of times without causing failure. Aluminium, on the other hand, has no fatigue limit, meaning that it will eventually fail after enough load cycles. 

https://www.cyclingabout.com/frame-materials-for-bicycle-touring-aluminium-vs-steel-vs-titanium/


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## roaden (Dec 31, 2014)

Why don't you do the same on your bike.


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## roaden (Dec 31, 2014)

xxl said:


> I Googled this:
> 
> Steel and titanium frames have a ‘fatigue limit’ below which a repeated load (frame flex) can be applied an infinite amount of times without causing failure. Aluminium, on the other hand, has no fatigue limit, meaning that it will eventually fail after enough load cycles.
> 
> https://www.cyclingabout.com/frame-materials-for-bicycle-touring-aluminium-vs-steel-vs-titanium/


Yeah, the thing is that the fatigue limit of steel is substantially below its yield strength. So you can apply force above the fatigue limit but below the yield strength and it won't break the first 10 times. But repeat it enough times and eventually it will break.


----------



## Opus51569 (Jul 21, 2009)

roaden said:


> Just finished a 40 mile ride with climbing. Bike feels absolutely fine. Did sprints, bunny hops, out-of-saddle climbs.
> 
> I consider the question answered - whether the bike is safe to ride. Yes, it is.


A bit like saying... '_I put one round in the chamber, spun the cylinder, held the pistol to my head, pulled the trigger and nothing happened. Therefore, it should be safe to spin that cylinder and pull that trigger as much as I like._'

That logic will hold true... right up to the moment it doesn't.


----------



## Finx (Oct 19, 2017)

roaden said:


> Just finished a 40 mile ride with climbing. Bike feels absolutely fine. Did sprints, bunny hops, out-of-saddle climbs.
> 
> I was able to add 1mm spacer on the drive side. It was the max possible. I tried 1.5mm and could not lock the safety tab pin on the non-drive crank. I have sufficient clearance now between the chainring and the frame. No problems with shifting.
> 
> ...


Posting this here is incredibly dangerous and irresponsible.


----------



## tlg (May 11, 2011)

roaden said:


> The good thing about carbon is that it has practically infinite fatigue life. That means that if you have verified that it can withstand a certain amount of force/stress once, it will not fail with repeated application. You cannot say that about metal.
> 
> The only way carbon will fail is if you subject it to higher force/stress above the level you have already tested; or if it gets additional damage. But you can say that about any frame material.
> 
> I googled the info above.


Your 'understanding' of fatigue is misplaced. 

The carbon fibers and resins have been compromised. Your bunny hops and out of saddle climbs are a meaningless. They have no bearing on how your compromised frame will perform after 10, 100, or 1000 hours. 


During your google search, did you research the fatigue life of compromised structures?


----------



## xxl (Mar 19, 2002)

roaden said:


> Yeah, the thing is that the fatigue limit of steel is substantially below its yield strength. So you can apply force above the fatigue limit but below the yield strength and it won't break the first 10 times. But repeat it enough times and eventually it will break.




You might want to read this, re thinking of CF and fatigue life: https://www.velonews.com/2018/12/gear/technical-faq-derailleurs-brakes-and-frame-fatigue_481933

I also Googled this, from the founder of Calfee, and it speaks directly to the overarching topic of this thread:

Composites are very different when it comes to fatigue failure. Theoretically, because the strength of carbon fiber is so high, designed stresses would never approach the yield strength, (which is almost the same as the ultimate tensile strength because carbon fiber is so brittle). A well-designed (and well-built) carbon fiber component will never fail under normal loading. But a stress concentration can be built into a poorly made component, rendering that area prone to a fatigue crack. The failure mechanism starts with the epoxy matrix, which starts microcracking in the high-stress area. That starts rendering the epoxy ineffective as a matrix for the carbon fiber and soon results in the fiber starting to break. This is when the fracture starts to be visible on the surface. Note that the vast majority of composites failures make their appearance on the surface because that is where the maximum stress is located when caused by a stress riser. Once the fiber starts to break, the component will soon fail catastrophically, not giving nearly as much warning as metals do.

If a component is designed for lowest possible weight without margin for typical abuse, minor manufacturing errors, or subtle changes to the design, a very small gouge will become a stress riser that will lead to a failure. This is why we stay quite busy with our carbon repair service. A component designed with a margin for this type of real-world experience will last a lot longer because a small, unnoticed gouge will not progress into a full-blown crack.
_— Craig Calfee_
_Founder and President, Calfee Design_

https://www.velonews.com/2018/11/gear/tech-faq-universal-brakes-and-frame-fatigue_481577

Of course, that dude is trying to sell CF repair services, and you've already _shown_ your frame isn't compromised, so go out and ride!:thumbsup:


----------



## tlg (May 11, 2011)

xxl said:


> A well-designed (and well-built) carbon fiber component will never fail under normal loading. But a stress concentration can be built into a poorly made component, rendering that area prone to a fatigue crack. The failure mechanism starts with the epoxy matrix, which starts microcracking in the high-stress area. That starts rendering the epoxy ineffective as a matrix for the carbon fiber and soon results in the fiber starting to break. This is when the fracture starts to be visible on the surface. *Note that the vast majority of composites failures make their appearance on the surface because that is where the maximum stress is located *when caused by a stress riser. Once the fiber starts to break, the component will soon fail catastrophically, not giving nearly as much warning as metals do.


Goes directly with my post above.

OP no longer has a (well designed / well built) component. He effectively has a flawed component. All bets are off in terms of 'fatigue'. And of course his carbon fibers are compromised.... on the surface.


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## nova_rider (Sep 23, 2005)

roaden said:


> The good thing about carbon is that it has practically infinite fatigue life. That means that if you have verified that it can withstand a certain amount of force/stress once, it will not fail with repeated application. You cannot say that about metal.
> 
> The only way carbon will fail is if you subject it to higher force/stress above the level you have already tested; or if it gets additional damage. But you can say that about any frame material.
> 
> I googled the info above.


The issue with composite is HOW it fails. A metal frame can fail by bending(or yielding) when it's loaded beyond its limit. The same cannot be said for composite frames, it does not undergo plastic deformation and simply fails by surrendering all of its structural integrity nearly instantaneously.

If there is an unavoidable giant pothole while descending at speed, would one rather be in a steel or composite frame? Perhaps this guy knows:
https://www.instagram.com/p/BepNGgwHyPu/?utm_source=ig_embed


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## roaden (Dec 31, 2014)

tlg said:


> The carbon fibers and resins have been compromised.


Seriously? I didn't do anything to the resins or carbon fibers remaining on the bike. What I did was remove 2 layers in one small area. You know carbon bikes have different numbers of layers all over, right? So what's the effect of having 10 layers instead of 12 let's say on that one area? The most that I did was reduce the ultimate strength of the area that I sanded. It's not like I was on the limit of the strength tolerance of the frame to begin with. I'm sure the frame has enough tolerance to handle much heavier and much stronger riders than me.


----------



## roaden (Dec 31, 2014)

xxl said:


> If a component is designed for lowest possible weight without margin for typical abuse, minor manufacturing errors, or subtle changes to the design, a very small gouge will become a stress riser that will lead to a failure.


Assuming my frame was indeed designed with margin for the things mentioned above, then my subtle change to the design will not be a problem. Agree?


----------



## tlg (May 11, 2011)

roaden said:


> I didn't do anything to the resins or carbon fibers remaining on the bike.
> 
> What I did was remove 2 layers in one small area.


Seriously?
You do realize those two statements are completely contradictory. 




> The most that I did was reduce the ultimate strength of the area that I sanded.


Uhhhh no. You also compromised all the carbon fibers you severed by sanding through them.


----------



## roaden (Dec 31, 2014)

tlg said:


> Seriously?
> You do realize those two statements are completely contradictory.


I think you're assuming all the carbon fibers have to be continuous all over the bike. This is not the case. The BB area for example might have 12-16 plies of carbon including around the chainstay closes to the BB. The rest of the chainstay might have 7 plies. Also repairing a carbon frame requires only patches of carbon plies to be applied to the local damaged area. For example if you have a cracked downtube, repairers don't lay up the entire downtube with carbon fiber to repair it, they only lay up carbon fiber around the cracked area. They don't even lay up completely around the downtube if the crack was on 1 side only.

This means that the strength of a carbon component depends mainly on the local fiber and resin and the direction of the plies of carbon fibers glued together on that area. If you sand down a carbon tube you only reduce the strength of that part where you sanded. In my case, the carbon fibers than I sanded probably only extended an inch further down the chainstay anyway, certainly not the entire chainstay. So the strength of the rest of the chainstay is not compromised. The strength of the BB is not compromised. The BB itself probably has more plies of carbon too. The other side of the chainstay tube where I sanded is also not compromised. And the other chainstay is also not compromised. Basically, the carbon fibers and resin remaining on the bike not near the immediate area where I sanded is not compromised.



> Uhhhh no. You also compromised all the carbon fibers you severed by sanding through them.


Right. Of the area that I sanded!


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## OldChipper (May 15, 2011)

OK seriously guys... he did it - even though he didn’t have to and everyone here says it was a dumb idea. He obviously doesn’t want to hear that was a dumb and unnecessary thing to do and is happy with his result. 

We obviously won’t convince him it was dumb and he will never convince us it was fine. 

Can we stop now? 


Sent from my iPhone using Tapatalk


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## velodog (Sep 26, 2007)

OldChipper said:


> OK seriously guys... he did it - even though he didn’t have to and everyone here says it was a dumb idea. He obviously doesn’t want to hear that was a dumb and unnecessary thing to do and is happy with his result.
> 
> We obviously won’t convince him it was dumb and he will never convince us it was fine.
> 
> ...


You must spread some Reputation around before giving it to OldChipper again.


----------



## 202cycle (Sep 13, 2011)

velodog said:


> You must spread some Reputation around before giving it to OldChipper again.


Got that for you.


----------



## velodog (Sep 26, 2007)

202cycle said:


> Got that for you.


I appreciate that. I wanted to thank you, but...

You must spread some Reputation around before giving it to 202cycle again.


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## xxl (Mar 19, 2002)

roaden said:


> ...What I did was remove 2 layers in one small area....


Exactly.




roaden; said:


> Assuming my frame was indeed designed with margin for the things mentioned above, then my subtle change to the design will not be a problem. Agree?
> 
> I think the more pertinent question is how hard you want to hit the road with an assumption.


----------



## OldChipper (May 15, 2011)

Legit question for the OP though... why did you come here to ask AFTER you already sanded it down? A more logical approach would be to ask BEFORE. Or did you have an: "Oh crap, what did I just do" moment and come here hoping everyone would say it was just fine and now you're actually ticked at yourself for doing something dumb? (pretty sure the latter is the case)


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## roaden (Dec 31, 2014)

OldChipper: "Can we stop now?"

Also OldChipper: "Let's go back to the beginning. Why did you do it?"

I was trolling. Then people started asking for pictures. So I took my old bike that I was using as wall art and sanded it. Installed a greasy bottom bracket too to make it look real.


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## 202cycle (Sep 13, 2011)

roaden said:


> OldChipper: "Can we stop now?"
> 
> Also OldChipper: "Let's go back to the beginning. Why did you do it?"
> 
> I was trolling. Then people started asking for pictures. So I took my old bike that I was using as wall art and sanded it. Installed a greasy bottom bracket too to make it look real.


Aaaaand We're done.


----------



## duriel (Oct 10, 2013)

... and OP, your on ignore.


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## SPlKE (Sep 10, 2007)

We're not done.

Clearly, this is a double-meta troll. He's trolling us now by saying he *was* trolling us, when he was serious (not trolling) and is now trying to get us off of his back.

Think outside the trollbox.

OP: Do you have dental insurance? After your frame explodes, you'll need it. New incisors are expensive.


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## OldChipper (May 15, 2011)

SPlKE said:


> We're not done.
> 
> Clearly, this is a double-meta troll. He's trolling us now by saying he *was* trolling us, when he was serious (not trolling) and is now trying to get us off of his back.
> 
> ...


Haha, yeah that occurred to me too.  Nonetheless, I down-repped him, whether for being a troll or recalcitrant idiot, and reported the thread.


----------



## SPlKE (Sep 10, 2007)

Fun will not be had!!


----------



## 202cycle (Sep 13, 2011)

Not sure if CX beat me to it, but shouldn't this be in Frames and Forks forum? Maybe if it gets moved to the Lounge it will die quickly.

Nice chatting with you all.


----------



## jetdog9 (Jul 12, 2007)

If this was trolling, at least kudos for doing a better job of acting sincere than ASFOS. Although he was much more entertaining...


----------



## ogre (Dec 16, 2005)

jetdog9 said:


> If this was trolling, at least kudos for doing a better job of acting sincere than ASFOS. Although he was much more entertaining...


Dammit, I thought I would win the ASFOS award this month with my ‘Tire pressure myths’ thread posted in General. I did put evidence of my troll baiting in the OP and exposed it quickly cause, well, I’m not a troll and I wasn’t double meta-trolling. But I’m going to have to step up my game. Pretty soon someone is going to post that they have stage 3 cancer and they’ll be accused of trolling.


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## Opus51569 (Jul 21, 2009)

SPlKE said:


> We're not done.
> 
> Clearly, this is a double-meta troll. He's trolling us now by saying he *was* trolling us, when he was serious (not trolling) and is now trying to get us off of his back.
> 
> ...


...and he installed a greasy bottom bracket just for appearances? Pretty sure "dumbass" applies both ways... if he rides the bike or trolled us and hangs it on a wall.


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## flatlander_48 (Nov 16, 2005)

roaden said:


> I read somewhere 7 layers is minimum recommended, and can go as high as 12 to 16 layers in high stress areas.


I suspect those numbers are very generalized as the the type of carbon fiber and the weave Of the matting comes into play. Clearly though, the ultimate strength of the chainstay has been compromised but we can’t say how much. Carbon fiber structures are designed as a unit. Each layer of carbon fiber matting and resin is there for a reason. It appears that you have sanded through 3 layers of matt and resin. That makes those layers ineffective as the loads can’t be passed through them. The removed material creates a discontinuity.

As I said, it’s been compromised but we don’t know to what degree...


----------



## roaden (Dec 31, 2014)

flatlander_48 said:


> I suspect those numbers are very generalized as the the type of carbon fiber and the weave Of the matting comes into play. Clearly though, the ultimate strength of the chainstay has been compromised but we can’t say how much. Carbon fiber structures are designed as a unit. Each layer of carbon fiber matting and resin is there for a reason. It appears that you have sanded through 3 layers of matt and resin. That makes those layers ineffective as the loads can’t be passed through them. The removed material creates a discontinuity.
> 
> As I said, it’s been compromised but we don’t know to what degree...


I think at this point we know the ultimate strength has been reduced to an insignificant degree, given that I have already ridden the bike 200 miles in varied terrain, including hills, gravel, and indoor trainer, and I'm still alive and have all my front teeth.


----------



## 202cycle (Sep 13, 2011)

roaden said:


> I think at this point we know the ultimate strength has been reduced to an insignificant degree, given that I have already ridden the bike 200 miles in varied terrain, including hills, gravel, and indoor trainer, and I'm still alive and have all my front teeth.


I think at this point we (I think I can speak for may here) wish you the best. I hope the next 200 miles go as well as the first. I would recommend next time you have trouble fitting components to your bike, you visit with someone who knows what they are doing.


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## Opus51569 (Jul 21, 2009)

roaden said:


> I think at this point we know the ultimate strength has been reduced to an insignificant degree, given that I have already ridden the bike 200 miles in varied terrain, including hills, gravel, and indoor trainer, and I'm still alive and have all my front teeth.


Sooo... are you lying about it being wall art... or are you lying about riding it? Either way, you've strayed beyond your bridge...


----------



## roaden (Dec 31, 2014)

Opus51569 said:


> Sooo... are you lying about it being wall art... or are you lying about riding it? Either way, you've strayed beyond your bridge...


I was lying about wall art. It was a joke. It was obvious to at least one person anyway.


----------



## 202cycle (Sep 13, 2011)

roaden said:


> I was lying about wall art. It was a joke. It was obvious to at least one person anyway.


Yes, to the one who came for advice after sanding layers of carbon from his chainstay and refuses to accept the advice he's been given.


----------



## Finx (Oct 19, 2017)

roaden said:


> I think at this point we know the ultimate strength has been reduced to an _*insignificant degree*_


You know nothing of the sort.


----------



## 202cycle (Sep 13, 2011)

Finx said:


> You know nothing of the sort.


I think at this point _*I THINK*_ the ultimate strength has been reduced to an insignificant degree.

I went ahead and fixed that statement for him as I don't think anyone else here (we) think or know that to be true.


----------



## duriel (Oct 10, 2013)

202cycle said:


> I think at this point _*I THINK*_ the ultimate strength has been reduced xx an insignificant degree.


I'm going to go ahead and fix your fix. Insignificant is true, until you hit a pot hole, then it becomes significant!


----------



## roaden (Dec 31, 2014)

duriel said:


> I'm going to go ahead and fix your fix. Insignificant is true, until you hit a pot hole, then it becomes significant!


Dude, I've bunny-hopped multiple times on the bike. I know how to bunny hop over potholes. That's a shock to the frame as much as hitting a pothole would be (except your front wheel doesn't take the brunt of the impact) and the frame is fine.


----------



## roaden (Dec 31, 2014)

202cycle said:


> I think at this point _*I THINK*_ the ultimate strength has been reduced to an insignificant degree.
> 
> I went ahead and fixed that statement for him as I don't think anyone else here (we) think or know that to be true.


200 miles is not enough proof for you? How about 2000 miles? I'll come back here and post after I've ridden 2000 miles and will you concede that I'm right then?


----------



## 202cycle (Sep 13, 2011)

roaden said:


> 200 miles is not enough proof for you? How about 2000 miles? I'll come back here and post after I've ridden 2000 miles and will you concede that I'm right then?


After 2,000 miles I will concede that your frame is not broken. I will never concede that you are right about this. What you did was really stupid and your inability to accept that fact is equally stupid.


----------



## roaden (Dec 31, 2014)

202cycle said:


> After 2,000 miles I will concede that your frame is not broken.


Good enough for me. See you after 2k miles.


----------



## 202cycle (Sep 13, 2011)

202cycle said:


> What you did was really stupid and your inability to accept that fact is equally stupid.





roaden said:


> Good enough for me. See you after 2k miles.


I can't wait.


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## Opus51569 (Jul 21, 2009)

roaden said:


> I was lying about wall art. It was a joke. It was obvious to at least one person anyway.


Thanks for admitting it publicly.


----------



## cxwrench (Nov 9, 2004)

roaden said:


> Dude, I've bunny-hopped multiple times on the bike. I know how to bunny hop over potholes. That's a shock to the frame as much as hitting a pothole would be (except your front wheel doesn't take the brunt of the impact) and the frame is fine.


This means absolutely nothing when you've removed material that was put there on purpose by an engineer. I sincerely hope you don't have or ever want to have any kids. Darwin Award contestants shouldn't mess around w/ kids.


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## 202cycle (Sep 13, 2011)

cxwrench said:


> This means absolutely nothing when you've removed material that was put there on purpose by an engineer. I sincerely hope you don't have or ever want to have any kids. Darwin Award contestants shouldn't mess around w/ kids.


OP: So I did a really questionable thing to my frame. Do you guys think it's safe?
Forum consensus: NO!
OP: Thanks anyway, It will be safe and I have successfully trolled your eyes out.
Forum consensus: But your frame is compromised and cannot be trusted as safe.
OP: I'll prove you all wrong. See you in 2,000 miles.
Forum consensus: K


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## roaden (Dec 31, 2014)

Didn't want to bring back an old thread, but I promised to come back after 2k miles. Well, I just passed 3k miles now for this year. 122 rides, 174k feet of climbing. I didn't bother to calculate my exact mileage since the beginning of March, but most of the mileage were after that. Probably 30% of the mileage were indoors on Zwift.

I can report absolutely zero, zip, zilch, nada issues with the frame.


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## DaveT (Feb 12, 2004)

roaden said:


> Didn't want to bring back an old thread, but I promised to come back after 2k miles. Well, I just passed 3k miles now for this year. 122 rides, 174k feet of climbing. I didn't bother to calculate my exact mileage since the beginning of March, but most of the mileage were after that. Probably 30% of the mileage were indoors on Zwift.
> 
> I can report absolutely zero, zip, zilch, nada issues with the frame.


...so far.


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