Play in cranks

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Play in cranks
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O+ FL
Posted: Feb 22, 2017 at 0:22 Quote
Hello,

I have a set of SRAM X01 11 speed cranks (GXP type axle) and also a set of RaceFace Ride single chainring cranks (24mm axle).

Both are the self extracting type using an 8mm allen key (They also both have this 'dust cap' which can be removed using a 10mm allen key).

When I'm installing both sets I'm left with a few mm of play forward and back, as if they are not done up tight enough! There's nothing side to side.

If I tighten these up any more I'm sure I'm going to shear the bolt or something. What am I missing here? I've been having this issue pretty much all the time I've owned them. Do they need to go tighter still or have I dropped and lost a spacer or something and that's where the play is coming from?? Maybe they're designed like this but I doubt it...

Thanks,

Tom

Posted: Feb 22, 2017 at 2:25 Quote
hi there.

is your bike a pressfit bb?

O+ FL
Posted: Feb 22, 2017 at 5:58 Quote
lepak1corner wrote:
hi there.

is your bike a pressfit bb?

PF92 on one, threaded 73mm on the other

O+
Posted: Feb 22, 2017 at 8:29 Quote
Even if they are loose there shouldn't be a couple mm of play front and back. Can you see where the movement is happening? The only thing I could guess is that the bearings/cups are completely shot. If the gxp one is in the wrong BB it would have play, but the race face wouldn't fit in the wrong one.

O+ FL
Posted: Feb 22, 2017 at 9:01 Quote
Just to clarify, by front to back play I mean movement from drive side to non-driveside.

The PF BB is brand new so definitely isn't an issue with the bearings.

Arphia, the BB types are correct.

Posted: Feb 22, 2017 at 12:39 Quote
On the RaceFace cranks, you have a number of small spacers (white, black and red, check the RaceFace website for the actual number you need and position) that you can use to either adjust the chain line, or actually compensate for that side to side play along the axle.

Not sure about the GX crankset though, never had one and don't plan on getting a SRAM crankset ... :/

O+
Posted: Feb 22, 2017 at 15:21 Quote
Either spacers on the crank spindle then, or the spacers behind the BB would probably be a good thing to start with on the race face.

The Gxp crank arm is supposed to clamp down on the non drive side bearing, the drive side should have a spacer and a spring washer but even without those it shouldnt be able to move if its clamped down tight. You could take off the non drive side and clean the splines on the spindle and crank arm then re grease it and see if it will clamp all the way down.

Posted: Feb 23, 2017 at 4:39 Quote
sounds like it could be a couple different things. Based on the amount of play though, I'd first ask if you have the correct amount of BB spacers. If your BB shell is 68mm wide then you'll need 2 ea. 2.5mm spacers to make the effective width 73mm which is what a threaded GXP is meant to fit. If that's right, then all you should really need is the "top hat" spacer on the drive side.

If that isn't the problem, then the next question I'd ask is "Are you sure you have the right crank for the BB you're using?" If you're using an X01 crank that's intended for a THREADED GXP BB in a press fit BB frame I would expect the spindle length to be too long. Your post isn't real clear on this, so I'm wondering if that's the problem...

Posted: Feb 23, 2017 at 5:58 Quote
Did you get the DH model crank with the 83mm spindle?

I've done it

O+ FL
Posted: Feb 23, 2017 at 9:04 Quote
RunsWithScissors wrote:
sounds like it could be a couple different things. Based on the amount of play though, I'd first ask if you have the correct amount of BB spacers. If your BB shell is 68mm wide then you'll need 2 ea. 2.5mm spacers to make the effective width 73mm which is what a threaded GXP is meant to fit. If that's right, then all you should really need is the "top hat" spacer on the drive side.

If that isn't the problem, then the next question I'd ask is "Are you sure you have the right crank for the BB you're using?" If you're using an X01 crank that's intended for a THREADED GXP BB in a press fit BB frame I would expect the spindle length to be too long. Your post isn't real clear on this, so I'm wondering if that's the problem...

Thanks for your help.

On the first bike, BB shell is 73mm (SC Nomad C). I've got a Hope BB and run a 2.5mm spacer on the driveside then Truvativ/GXP cups on non-driveside before installing SRAM X01 11-speed chainset. I'm 99% that everything up to this point is correct. Now then, what is the "top hat" spacer?

On the second bike, BB shell is 89.5mm, 41mm internal (Canyon Exceed SLX). I've got a Hope PF41 BB and run a 2.5mm spacer on the driveside (To make PF92) before installing RaceFace 24mm single chainring chainset. Again, pretty certain I've not got an issue with incorrect BB sizing. Perhaps I'm missing a spacer on the RaceFace cranks too!?

Cheers,

Tom

Posted: Feb 23, 2017 at 9:50 Quote
jenksy wrote:
RunsWithScissors wrote:
sounds like it could be a couple different things. Based on the amount of play though, I'd first ask if you have the correct amount of BB spacers. If your BB shell is 68mm wide then you'll need 2 ea. 2.5mm spacers to make the effective width 73mm which is what a threaded GXP is meant to fit. If that's right, then all you should really need is the "top hat" spacer on the drive side.

If that isn't the problem, then the next question I'd ask is "Are you sure you have the right crank for the BB you're using?" If you're using an X01 crank that's intended for a THREADED GXP BB in a press fit BB frame I would expect the spindle length to be too long. Your post isn't real clear on this, so I'm wondering if that's the problem...

Thanks for your help.

On the first bike, BB shell is 73mm (SC Nomad C). I've got a Hope BB and run a 2.5mm spacer on the driveside then Truvativ/GXP cups on non-driveside before installing SRAM X01 11-speed chainset. I'm 99% that everything up to this point is correct. Now then, what is the "top hat" spacer?

On the second bike, BB shell is 89.5mm, 41mm internal (Canyon Exceed SLX). I've got a Hope PF41 BB and run a 2.5mm spacer on the driveside (To make PF92) before installing RaceFace 24mm single chainring chainset. Again, pretty certain I've not got an issue with incorrect BB sizing. Perhaps I'm missing a spacer on the RaceFace cranks too!?

Cheers,

Tom

Too buried at work at the moment to look deeply into the second bike, but on the first bike I'd strongly suspect that the problem is due to mixing BB cups. Without being able to put a set of calipers on it I can't really tell for sure, but I'd suspect that the Hope BB cup has a different inset distance for the bearings than the SRAM GXP. As for the top hat, I mis-spoke. It's actually a bearing shield. I happened to have a new GXP sitting on my desk so I shot you a pic. This is the only thing on the Drive side of my GXP crank outboard of the bearing and it fits perfect with a 68mm BB shell and two 2.5mm spacers.

If your SC has a true 73mm wide BB shell and your crank is spec'ed for a THREAD IN GXP you shouldn't need any BB spacers at all. The fact that you have one on the DS and it's still loose makes me wonder about your BB shell's actual dimensions and your crank spindle length...

Top hat bearing shield

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