# Shimano R700 Compact Crank HELP!



## Vargas026 (Dec 29, 2006)

I just recently put on a compact crank....its great on the hills but I lost a lot of speed on the flats (spin out on the 34T), I end up Switching to the large gear 50T =/ I have to do a lot of shifting around my area ( lots of hills). My setup that I have right now is 50/34 and rear 12/25 9 speed. If I change the cassette 11/23 10 speed will it make a difference or should I go out and get a 53/39 crank?


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## TurboTurtle (Feb 4, 2004)

Vargas026 said:


> I just recently put on a compact crank....its great on the hills but I lost a lot of speed on the flats (spin out on the 34T), I end up Switching to the large gear 50T =/ I have to do a lot of shifting around my area ( lots of hills). My setup that I have right now is 50/34 and rear 12/25 9 speed. If I change the cassette 11/23 10 speed will it make a difference or should I go out and get a 53/39 crank?


Do the math. Only you can figure out what you need. Find the gear ratios you use and find the best crankset (there are more choices than just the two you mentioned) and cassette that gives you those gears in the most convenient package. - TF


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## estone2 (Sep 25, 2005)

Vargas026 said:


> I just recently put on a compact crank....its great on the hills but I lost a lot of speed on the flats (spin out on the 34T), I end up Switching to the large gear 50T =/ I have to do a lot of shifting around my area ( lots of hills). My setup that I have right now is 50/34 and rear 12/25 9 speed. If I change the cassette 11/23 10 speed will it make a difference or should I go out and get a 53/39 crank?


I don't see why you wouldn't want to switch onto the big gear. Climb in the little gear, do the flats in the big gear. There's nothing wrong with that. It's what most people do...
-estone2


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## kwyer (May 7, 2004)

A lot of people are going the compact crank rout and having the same problem. I took a different approach and am very happy with it and it might be a better solution for you. Instead of the compact crank go back to the standard 53-39 (really cheap right now on many web outlets) and put an XTR rear derallier with an 11-32 or 11-34 XT casette in the rear. It works great and you end up with a lower gear than the compact can give you and all the way up to the 11 for high speed stuff. Almost all tandems run this type of rear setup in either 9 or 10 speed and it works great.


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## Qstick333 (Jul 21, 2004)

You could switch out the 34 inner ring for a 36 or 38 and have an extra gear or two on the flats and only sacrificing the extreme lowest gear.....


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## dover (Apr 5, 2007)

Qstick333 said:


> You could switch out the 34 inner ring for a 36 or 38 and have an extra gear or two on the flats and only sacrificing the extreme lowest gear.....


and you would get really sh!*ty shifting!!!!


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## Qstick333 (Jul 21, 2004)

what would cause the poor shifting? If anything - wouldn't keeping the 14 tooth jump between rings (53-39 50-36) as opposed to the 16 tooth (50-34) jump make shifting a bit better? I know several riders who prefer the 50-36 combo and am considering it myself - not one of them has complained about shifting issues.....


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## dover (Apr 5, 2007)

*shift ramps*



Qstick333 said:


> what would cause the poor shifting? If anything - wouldn't keeping the 14 tooth jump between rings (53-39 50-36) as opposed to the 16 tooth (50-34) jump make shifting a bit better? I know several riders who prefer the 50-36 combo and am considering it myself - not one of them has complained about shifting issues.....


When a crank is designed to use 50-34 chain rings the big ring has ramps placed in the correct place to pick up the chain from a 34t ring. If you change the ring to 36 or 38 you will not get the benefit of the shift ramps and your shifting will suffer for it.

Remeber in the old days when shift ramps were'nt invented and the chain would just scratch the inside of the big ring because there was nothing to help it climb the big ring


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## Qstick333 (Jul 21, 2004)

I'm not claiming to be an expert on componentry - I will probably need a basic explanation as to why.......but, why wouldn't rings like this work without a problem?

http://www.competitivecyclist.com/z...RD&PRODUCT.ID=1194&CATEGORY.ID=199&MODE=&TFC=

These are shimano compatible and ramped......


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## Dr_John (Oct 11, 2005)

It's the outer chain ring that ideally should be ramped/pinned to accommodate the specific inner/small ring.

I run a 50/36 FSA set up. The original outer ring was marked "50/36." I couldn't find a replacement. All the outer rings I could find were "50/34." I ordered one, and sure enough the ramp/pins are different on the "50/36" and "50/34" 50-tooth outer chainrings. To be honest, I notice absolutely no difference in shifting on my 36/50 between the "50/36" and "50/34" outer chainring. I have no idea about the Shimano set up, even though I have an R-700 crank on one of my bikes. It's still the stock 34/50. Hope this makes sense.


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## dover (Apr 5, 2007)

*small ring is not as important*



Qstick333 said:


> I'm not claiming to be an expert on componentry - I will probably need a basic explanation as to why.......but, why wouldn't rings like this work without a problem?
> 
> http://www.competitivecyclist.com/z...RD&PRODUCT.ID=1194&CATEGORY.ID=199&MODE=&TFC=
> 
> These are shimano compatible and ramped......



The inner ring is not the important part of this equation. The ramping is on the inside of the outer ring. You can change the inner ring to whatever brand you want but if you go up or down in size you will need to change to the corresponding outer ring as well. Shimano does not make different size inner rings for compact cranks. The FC-R700 is the best shifting compact crank around and it because shimano puts lots of time and engineering into making the rings work perfectly together.


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## Mark McM (Jun 18, 2005)

*Pins and ramps*



dover said:


> Remeber in the old days when shift ramps were'nt invented and the chain would just scratch the inside of the big ring because there was nothing to help it climb the big ring


You make it sound like the front derailleur was useless in the 80 or so years between the invention of the front derailleur and the invention of shifting pins. Reliable shifting without pins and ramps is not a problem for a competent operator.

I still haven't gotten around to putting a pinned outer ring on any of my three road bikes (well, four bikes if you count the cyclocross bike), and yet I am able to shift the front derailleur at any time, whether seated or standing, sprinting or climbing.


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## Mark McM (Jun 18, 2005)

*Moving pins*



dover said:


> The inner ring is not the important part of this equation. The ramping is on the inside of the outer ring. You can change the inner ring to whatever brand you want but if you go up or down in size you will need to change to the corresponding outer ring as well.


I think the word "need" here is a little strong. True, Shimano does move the pins around a bit in an attempt to "optimize" shifting with different size small rings. But the differences in performance are subtle at best, and most people notice no degradation in performance mixing and matching big rings and little rings.


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## dover (Apr 5, 2007)

Mark McM said:


> I still haven't gotten around to putting a pinned outer ring on any of my three road bikes (well, four bikes if you count the cyclocross bike), and yet I am able to shift the front derailleur at any time, whether seated or standing, sprinting or climbing.


If you have not even used a bike with pinned and ramped chain rings you don’t know what you are missing. Your arguement is like saying a "horse and buggy" is a great form of transportation, why do we need cars to get around. Yes, "horse and buggy" worked, but the automobile is a vast imporvement.
I never said shifting in the past was impossible, but I guaranty you it has improved with leaps and bounds with the invention of shift ramps. 
Technology can be your friend:thumbsup: give it a try!


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## Mark McM (Jun 18, 2005)

dover said:


> If you have not even used a bike with pinned and ramped chain rings you don’t know what you are missing. Your arguement is like saying a "horse and buggy" is a great form of transportation, why do we need cars to get around. Yes, "horse and buggy" worked, but the automobile is a vast imporvement.
> I never said shifting in the past was impossible, but I guaranty you it has improved with leaps and bounds with the invention of shift ramps.
> Technology can be your friend:thumbsup: give it a try!


Of course I've used pinned and ramped chainrings. That's what came with my MTB, so that's what I use on that bike. They've also been on a few road bikes I have ridden, but I just haven't put them on the road bikes I own. I just don't see what the big deal is - there hasn't been any particular performance improvement for me, so why bother buying new chainrings for my bikes?

But, on the other hand, I probably don't need them, because I already know now to shift a front derailleur. It's become an instinctive reaction to synchronize my pedal stroke with the shift lever (I hit the lever just as my right foot approaches BDC of the stroke) and modulate the following left foot power stroke as the chain climbs up to the big chainring. At most, I lose half a power stroke when shifting.

But, you're right, maybe they are necessary for those who never mastered proper shifting technique.

(Oh, just in case you're wondering - yes, there are times when I need to and can shift just as fast as everyone else. Although it is common practice to start criteriums in the big chainring to avoid having to do a front chainring shift, I usually start in my small chainring because I get better intial acceleration in a smaller gear, and then shift up to the big ring after a dozen pedal strokes or so. Even still, I usually manage to get into the front part of the pack by the first corner. And on the occasional uphill standing sprint, if I start in the little chainring and find I run out of gears, I just pop it into the big chainring, mid-sprint)


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## RoadCube (Nov 22, 2006)

How Hilly is hilly?

I run a 50/42 compact in the flatlands. This gearing is great for me. When I run a 53/39, the 53 is a bit biggish and the 39 is a bit smallish in the flats. Just swap out the 34 for a 42 or 39 inner ring. Salsa makes a 42 in 110. It is actually an outer and you will have to turn it around to get it to shift properly but it will shift fine. You are running 9 speed now correct? 10 speed, it should work too. When you do ride in the mountains, swap to the 34.
RC


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