# Just installed SRAM GXP BB



## csneom4a1 (Mar 12, 2012)

I just installed my sram gxp bb on my english threaded bb for the first time and didn't use any spacers, even though the directions said to. There is a small gap between the crank arms and the externel cups now.

I tried with the spacers also, but the crank locked up tight with them on.

Is the gap in this picture too much? I used a torque wrench also, so it is the correct torque. This picture is without spacers.


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## csneom4a1 (Mar 12, 2012)

Kristatos said:


> You are correct that you don't need any spacers. That gap looks similar to what I observe on my setup but it's hard to tell for sure. If the crank spins and there is no play side-to-side then you should be good to go.


Cranks seems to spin fine and there is no side to side movement from the cranks arms, even when I pull on them pretty hard. So I figured it was good to go, but when looking at other bikes, the gap on mine just seems bigger.


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## Kristatos (Jan 10, 2008)

You are correct that you don't need any spacers. That gap looks similar to what I observe on my setup but it's hard to tell for sure. If the crank spins and there is no play side-to-side then you should be good to go.


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## svard75 (Jun 10, 2011)

I used 1 spacer. Did you notice the spindle is tapered? You probably want all of that larger part of the taper fully inside the BBC cup.

You used a spacer and it was so tight you had drag?! See if you can find a smaller spacer.


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## csneom4a1 (Mar 12, 2012)

svard75 said:


> I used 1 spacer. Did you notice the spindle is tapered? You probably want all of that larger part of the taper fully inside the BBC cup.
> 
> You used a spacer and it was so tight you had drag?! See if you can find a smaller spacer.


I used both spacers and it locked up the cranks. I never tried one spacer. Now that I look at the extra space on both sides of the crank arms, I think one spacer may take up the gaps on both sides. What side did you put the single spacer on?

Edit: Would putting a spacer just on one side cause anything to be off, as far as balance in regards to the other side?


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## svard75 (Jun 10, 2011)

csneom4a1 said:


> I used both spacers and it locked up the cranks. I never tried one spacer. Now that I look at the extra space on both sides of the crank arms, I think one spacer may take up the gaps on both sides. What side did you put the single spacer on?
> 
> Edit: Would putting a spacer just on one side cause anything to be off, as far as balance in regards to the other side?


My spacer went on the drive side. When i inserted the crank it wouldn't slide all the way in because the spindle on the nds has a larger tapered section. I initially thought i needed to force it in but closer inspection i discovered its designed that way. I have a seam red black compact crankset 2011 model year and my BB installation sheet told me for a 68mm KB width use one spacer on DS.


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## csneom4a1 (Mar 12, 2012)

Mine is 2012 Force. I will go try one space and take another pic.


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## forge55b (Jan 30, 2011)

The arms would be slightly offset, maybe 1mm depending on the spacer.


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## cxwrench (Nov 9, 2004)

svard75 said:


> I used 1 spacer. Did you notice the spindle is tapered? You probably want all of that larger part of the taper fully inside the BBC cup.
> 
> You used a spacer and it was so tight you had drag?! See if you can find a smaller spacer.


did either of you guys ever read the directions that come w/ the parts you installed? you don't use spacers w/ road bikes. your bb shell would have to be insanely out of spec (like over 2mm) for a spacer to be needed. in 20 years of working on bikes for a living i've never seen that. why did you think you needed a spacer? play? because it didn't 'look' right?


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## csneom4a1 (Mar 12, 2012)

cxwrench said:


> did either of you guys ever read the directions that come w/ the parts you installed? you don't use spacers w/ road bikes. your bb shell would have to be insanely out of spec (like over 2mm) for a spacer to be needed. in 20 years of working on bikes for a living i've never seen that. why did you think you needed a spacer? play? because it didn't 'look' right?


The instructions that came with my SRAM GXP BB indicated that I should use both spacers. I tried that and when it didn't work I read online that no spacers was the correct way, despite the instruction sheet. 

The reason I entertained the idea of one spacer was that there was still a gap between the crank arms and the external cups. When I say gap, look at my picture, as that is the size I am referring too. Some of the bikes I have seen have much smaller gaps between the crank arms and the cups. Couple that with the fact that this is my first time building a bike, I wasn't sure.

Well I tried one spacer, and figured out rather quickly that it is wrong also. So no spacers, with the proper torque gets me a small gap like in the previous picture, and also a small gap about the same size on the other side.


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## forge55b (Jan 30, 2011)

Wait wait wait, by gap do you mean because the arm isn't flush with the cup? It is supposed to be like that if that is what you are referring to. If it were too close it would scrape up against your frame and mess up your ****.


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## Kontact (Apr 1, 2011)

csneom4a1 said:


> The instructions that came with my SRAM GXP BB indicated that I should use both spacers. I tried that and when it didn't work I read online that no spacers was the correct way, despite the instruction sheet.
> 
> The reason I entertained the idea of one spacer was that there was still a gap between the crank arms and the external cups. When I say gap, look at my picture, as that is the size I am referring too. Some of the bikes I have seen have much smaller gaps between the crank arms and the cups. Couple that with the fact that this is my first time building a bike, I wasn't sure.
> 
> Well I tried one spacer, and figured out rather quickly that it is wrong also. So no spacers, with the proper torque gets me a small gap like in the previous picture, and also a small gap about the same size on the other side.


I don't see a gap. If there was a gap, you'd be looking at the 22mm spindle, and I don't see anything as narrow as 22mm in your photo. There would also be lateral play.

GXP cranks work by clamping onto the left bearing between the step on the spindle and the left crank arm. The right bearing doesn't touch the right crank arm at all - the spindle just floats through the bearing, which is what allows for variations in BB shell width. It also completely avoids any concerns about bearing preload, because GXP cranks don't push on both bearing. (Shimano deals with it a completely different way, which is why there have 3 bolts, not one.)

For road bikes, don't use spacers. The instructions say that if you have any lateral play, grease the spindle end and try it again. Do not try to fill in the gaps that are there by design.


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## cxwrench (Nov 9, 2004)

csneom4a1 said:


> *The instructions that came with my SRAM GXP BB indicated that I should use both spacers.* I tried that and when it didn't work I read online that no spacers was the correct way, despite the instruction sheet.
> 
> The reason I entertained the idea of one spacer was that there was still a gap between the crank arms and the external cups. When I say gap, look at my picture, as that is the size I am referring too. Some of the bikes I have seen have much smaller gaps between the crank arms and the cups. Couple that with the fact that this is my first time building a bike, I wasn't sure.
> 
> Well I tried one spacer, and figured out rather quickly that it is wrong also. So no spacers, with the proper torque gets me a small gap like in the previous picture, and also a small gap about the same size on the other side.


wrong. read them again...


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## Kontact (Apr 1, 2011)

cxwrench said:


> wrong. read them again...


I think the instruction sheet that incorrectly suggest using the spacers is pretty well established. It comes in the BB box, but is not in any of the online manuals.

I recall reading it and finding it misleading, but can't find a copy of it anywhere to look at again.


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## svard75 (Jun 10, 2011)

Well regardless my spacer neither put preload on the bearing nor did it screw up the driveline offset. I've been building a few bikes over the years and a friend of mine suggested i use one on the nds but that would have put the chainrings too close. Just sharing my experiences. 
It makes sense that if its too tight to not use one but mine had a gap on the drive side similar in size to the OP and it concerned me that the tapered part which fits snugly into the bB cup was not completely seated ESP the drive side.


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## csneom4a1 (Mar 12, 2012)

forge55b said:


> Wait wait wait, by gap do you mean because the arm isn't flush with the cup? It is supposed to be like that if that is what you are referring to. If it were too close it would scrape up against your frame and mess up your ****.


This is exactly what I mean. I had the thought that I did something wrong because on friends bikes, there gaps are much smaller. However, they are also using shimano groups, so that may be the reason for the difference.

EDIT: The drive side has a similar size gap between the cup and the crank "spider" ( for lack of knowing the real term).


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## csneom4a1 (Mar 12, 2012)

Here is the instructions that came with my gxp bb.


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## Kontact (Apr 1, 2011)

svard75 said:


> Well regardless my spacer neither put preload on the bearing nor did it screw up the driveline offset. I've been building a few bikes over the years and a friend of mine suggested i use one on the nds but that would have put the chainrings too close. Just sharing my experiences.
> It makes sense that if its too tight to not use one but mine had a gap on the drive side similar in size to the OP and it concerned me that *the tapered part which fits snugly into the bB cup was not completely seated ESP the drive side*.


There is no tapered part on the drive side. The drive side spindle is straight where it interfaces with the drive side bearing. 


I have to wonder if the bad rep GXP has with some people is because they are wedging spacers on the drive side and ruining the bearings. These aren't Shimano BBs, and don't work anything like Shimano.


The diagram posted is designed to tell you how to mount a MTB crank - the spacers make a 68mm shell act like the normal 73mm MTB BB shell. SRAM failed to note that those instructions are for the MTB cranks, only. Road cranks have spindles that are 5mm shorter than MTBs.


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## svard75 (Jun 10, 2011)

Kontact said:


> There is no tapered part on the drive side. The drive side spindle is straight where it interfaces with the drive side bearing.
> 
> 
> I have to wonder if the bad rep GXP has with some people is because they are wedging spacers on the drive side and ruining the bearings. These aren't Shimano BBs, and don't work anything like Shimano.
> ...


There is a taper on my compact cranks. I don't want to disassemble everything now just for sake of posting pictures here but I specifically remember this being an issue during assembly.

here is a good shot I found of what I am taking about.









But hey mine work fantastic and roll soo smooth. Again there's absolutely no play nor is there side loading. I'll take a pic of my DS spindle one day and post it here.

Just to add. I found a CK BB installation document which is much more detailed in it's installation procedure and Kontact is correct for road double we shouldn't use any spacers. I'm gonna keep mine on anyway just because I seem to recall there was a slight bit of play without. Maybe it's the FM-015 Chinese frame?!

Installation of bearing cups
Note BB cup orientation marking on BB threads before greasing
threads, as marking may be obscured when grease is applied to
threads. Apply a generous coating of waterproof grease to the threads
on the BB cups, as well as on the BB shell threads on the bicycle
frame.
Make sure that the double O-ring side of the center sleeve is pressed
into either BB cup, seating the inner O-ring on the inner edge of the
BB cup.
If installing a MTB-style BB and crankset into a 68 mm BB shell, install
one 2.5 mm BB cup spacer onto each bearing cup. No spacers are required for all other setup configurations.
With proper BB spacers installed on BB cups, thread BB cups into frame using a compatible BB cup spline tool (see below) and torque to
40 Nm (30 ft/lbs).
BB cups are compatible with the following external BB cup spline tools: Chris King External BB Cup Tool, Park™ BBT-9 and Shimano™ TLFC32/
TL-FC33. The Chris King External BB Cup Tool features an optimized spline interface that minimizes the chance of marring BB cup
anodization and is compatible with 3/8” socket wrenches and torque wrenches.
Preparation and fitting of crank spindle
Remove BB bearing spindle sleeves (black plastic pieces) from the inner diameter of both bottom bracket bearings by hand. If not removable
by hand, carefully insert the tip of a small screwdriver or penknife under outer flange of BB bearing spindle sleeve and gently pry it out of the
bearing using alternating prying locations.
Clean crank spindle and spline interface and apply grease to splines
Slide adaptor sleeve over the spindle splines until it sits flush with the shoulder on the spindle shaft.
Tech tip: if resistance is encountered when sliding adaptor sleeve onto spindle, slide adaptor washer onto splines and apply even pressure to
the top of the washer to slide the sleeve up the splines until it sits tightly and evenly against the shoulder on the spindle shaft. Then remove
the washer from the spindle before proceeding.
Determine the recommended number of spindle spacers required for your crankset/BB shell interface by referring to the Spindle Spacer Guide

24mm Stepped BB Spindle Spacer Guide
crankset BB shell width 1 mm spindle spacers
road double 68 mm 0
road triple 68 mm 5
mtn triple and double 68 mm 4
mtn triple and double 73 mm 4
mtn triple and double 73 mm with E-type FD 1
tandem captain 68 mm 0
tandem stoker 68 mm 8


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## Kontact (Apr 1, 2011)

svard75 said:


> There is a taper on my compact cranks. I don't want to disassemble everything now just for sake of posting pictures here but I specifically remember this being an issue during assembly.
> 
> here is a good shot I found of what I am taking about.


I don't see a Drive Side taper that you should be engaging. The right bearing should be in contact with the polished section, not the part that goes into the spider. Period. Anything else risks side loading that bearing.

If you had play, you should find out why rather than masking the problem with incorrect installation.


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## Kontact (Apr 1, 2011)

I just installed a GXP and looked at the instructions. It comes with two sets - one with a MTB graphic in the top left corner and pictures of a MTB crankset, and the other set shows a road bike and crank. The spacer graphic is only on the MTB instructions.

So CX is right - if you read the *right* instructions, you'll get the right answers.


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## Kontact (Apr 1, 2011)

forge55b said:


> I think this discussion comes up once a month with no spacers being right and some that randomly use a spacer with it working. I'll just put up the pdf link from SRAM......again......
> http://cdn.sram.com/cdn/farfuture/l...hdocs/95-6115-012-000_rev_b_red_cranksets.pdf
> 
> I think I know what people are thinking is a spacer now. It is the dust cover that Sram has for their cranks with the teeth and what not.


No, they're talking about the 2 2.5mm spacers that go over the cups threads for installation of MTB cranks.


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## forge55b (Jan 30, 2011)

Kontact said:


> I just installed a GXP and looked at the instructions. It comes with two sets - one with a MTB graphic in the top left corner and pictures of a MTB crankset, and the other set shows a road bike and crank. The spacer graphic is only on the MTB instructions.
> 
> So CX is right - if you read the *right* instructions, you'll get the right answers.


I think this discussion comes up once a month with no spacers being right and some that randomly use a spacer with it working. I'll just put up the pdf link from SRAM......again......
http://cdn.sram.com/cdn/farfuture/l...hdocs/95-6115-012-000_rev_b_red_cranksets.pdf

I think I know what people are thinking is a spacer now. It is the dust cover that Sram has for their cranks with the teeth and what not.


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## svard75 (Jun 10, 2011)

Kontact said:


> I don't see a Drive Side taper that you should be engaging. The right bearing should be in contact with the polished section, not the part that goes into the spider. Period. Anything else risks side loading that bearing.
> 
> If you had play, you should find out why rather than masking the problem with incorrect installation.


I'm following what you're saying and during my installation I could see about 3mm of that shiny part of the spindle once I had the NDS arm and bolt secured. I measured the BB width on the frame and it was 68mm so technically according to those numbers I shouldn't need a spacer but I used one anyway. There is still a small amount of space between the DS and the cup on the DS. I don't see how anyone could sideload the NDS because the inside of the NDS cup stops the spindle at that tapered part so unless you're over torquing your crankarm bolt.


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## Kontact (Apr 1, 2011)

forge55b said:


> I think this discussion comes up once a month with no spacers being right and some that randomly use a spacer with it working. I'll just put up the pdf link from SRAM......again......
> http://cdn.sram.com/cdn/farfuture/l...hdocs/95-6115-012-000_rev_b_red_cranksets.pdf
> 
> I think I know what people are thinking is a spacer now. It is the dust cover that Sram has for their cranks with the teeth and what not.


The spacers are included with the BB and go over the threads, 2.5mm thick. They are also shown in the MTB diagram I mentioned. If you pulled up the equivalent document from SRAM's MTB tech files you'd see them.


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## Kontact (Apr 1, 2011)

svard75 said:


> I'm following what you're saying and during my installation I could see about 3mm of that shiny part of the spindle once I had the NDS arm and bolt secured. I measured the BB width on the frame and it was 68mm so technically according to those numbers I shouldn't need a spacer but I used one anyway. There is still a small amount of space between the DS and the cup on the DS. I don't see how anyone could sideload the NDS because the inside of the NDS cup stops the spindle at that tapered part so unless you're over torquing your crankarm bolt.


There was 3mm of spindle showing because if you had installed the cranks on a 70mm Italian BB bike there would have been 1mm showing.


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## tconrady (May 1, 2007)

Kontact is correct. The first time I installed a SRAM BB the spacers confused the crap out of me. I finally found some installation videos by SRAM on youtube that showed no spacers for road bike installation.


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## bon_gabs (Feb 2, 2010)

anyone here used the Chris King BB with sram crank? what is the meaning of stepped 24mm? is this means I need to use the sleeves?


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## Kontact (Apr 1, 2011)

bon_gabs said:


> anyone here used the Chris King BB with sram crank? what is the meaning of stepped 24mm? is this means I need to use the sleeves?


SRAM cranks have 24mm spindles that step down to 22mm where the enter the left bearing and crank arm. The cranks are held in place by clamping the left bearing between the step and the left arm. 


There are some BBs that include adapters to be used with either kind of crank, but my experience with the Enduro model was that it was not well thought out and didn't work.


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## svard75 (Jun 10, 2011)

Just thought it would be fair to update my gxp bb installation. I took it all apart as I was cleaning the bb cover and removed the spacer on the ds. Re-installed and the gap doesn't look so bad now. I might have been a bit too concerned and in all fairness didn't read up on it prior to installing. 

Thanks Kontact. 

Sent using my retarded blackberry


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