Can't get freeplay out of Truvativ/SRAM Elita cranks

Discuss light weight issues concerning road bikes & parts.
Post Reply
Rossin67
Posts: 10
Joined: Sat Feb 16, 2019 8:01 pm

by Rossin67

I recently bought a 2008 Raleigh RX 1.0 CX bike. It has Elita cranks. The bike had few miles but the bottom bracket bearings were fried on the DS, so I bought a new GXP BB.

I installed everything correctly. It's a road crank and a 68mm shell so I did not use the spacers. When I torque it to specs it has a lot of freeplay. Not a little, a LOT. The only way to get rid of the freeplay is to crank the bolt down as tight as I can, but then the bearings pop loudly from too much load. I even tried a spacer on the NDS for the heck of it and no go.

From the instructions:

Check the assembly for play by rocking the crank arms back and forth away from frame.
If the crank moves, tighten crank arm bolt until no play is detected. If maximum torque
of 54 N•m (478 in-lb) has been achieved, remove the crank arm from the spindle, apply
additional grease and repeat installation proceedures until play is eliminated.


When I tighten the crank arm too much the bearings pop loud when I ride and will no doubt fry them in short order. Can't ride it like that. It states to add grease to eliminatre freeplay. Although making no sense to me, I still added tons of grease and it did nothing. Like I said, it has A LOT of freeplay.

I didn't check for freeplay with the original BB, but I suspect the seller knew something was wrong because the DS bearing (the fried one) had fresh grease, and he didn't know what he was doing because he just put it on top of the seal that covers the bearings so it did nothing.

I have thought about buying a wave washer, but those are only used on the pressfit cranks. Please help!

by Weenie


Cosmo
Posts: 88
Joined: Sun Feb 25, 2007 5:05 pm
Location: Netherlands

by Cosmo

GXP is a pretty simple system-some basics:

-68mm threaded shell and road crank = no spacers/wave washers/anything else anywhere. As a confirm pull the crank and make sure the axle doesn't have "wide axle" printed on it. If nothing on the axle then you've got a standard road crank.
-Cups installed correctly? As in with greased threads and properly tight? I didn't check but if the frame is alum a wrap of plumber's tape on the threads makes most noises go away.
-All shields in place? There should be a seal on the NDS which matches the spindle spline pattern (it's loose so easy to have it drop off when you push the axle thru); on the drive side there should be a plastic sleeve shield which is pressed into the bearing bore (can be removed but not going to happen on it's own). Without the NDS shield the system doesn't work and be sure it's on in the right direction.
-Axle isn't damaged in some way? As in obviously worn down or something else? Takes a lot to do this but it's a used bike so anything is possible.

For install grease the splines and with a standard length 8mm wrench tight as you can; 50 odd ft/lbs is a lot with a standard length wrench. The way the axle captures the NDS bearing it's basically impossible to overload the bearing without breaking/stripping the crank bolt; the drive side isn't loaded at all. Play (as in you can rock the arms laterally) is the result of the NDS arm not being tight enough assuming nothing wrong with the arms themselves-the torque spec is based on the NDS arm being bottomed out first (when bottomed there is no play in the system but it's not tight enough to keep the crank on the taper). Since this isn't a new crank unlikley it needs an extra remove/regrease to bottom out as some new ones do-the extra grease allows the NDS arm to go all the way up the splines. Typically people are afraid to tighten the bolt fully.

If you've got "popping" noises then either the BB isn't a GXP (if you put a GXP crank into a Shimano BB you'll end up with exactly as described-either a lot of play or binding with a popping noise), missing NDS shield or there is something else beyond grossly wrong. At that point have a shop mechanic take a look.
after 2 drinks I'm a loser, after 3 a star

Rossin67
Posts: 10
Joined: Sat Feb 16, 2019 8:01 pm

by Rossin67

Cups are installed, everything is installed correctly. In summary, the problem is loud clicking like bad bearings when the crank bolt is tightend until all freeplay is removed. But I think I found the fix. On another forum someone had the exact same problem. It was said to put gobs and gobs of grease (not a light coat like I had) on the threads of both cups and BB shell and 3-4 wraps of teflon tape over that. I guess it's a SRAM BB thing, I don't know this is my first crank with the brand. I held off on the teflon tape and put a massive ridiculous amount of grease on all the threads. Took it for a spin through the neighborhood and it clicked a few times at first then was totally quiet, so I think I'm good. Before it was so loud it was unrideable. When I go on a ride in the morning if it still clicks some then I'll try the teflon tape but hopefully I'm ok now.

mikemelbrooks
Posts: 97
Joined: Wed Jun 16, 2010 10:58 pm

by mikemelbrooks

Rossin67 wrote:
Sun Oct 06, 2019 11:51 am
I recently bought a 2008 Raleigh RX 1.0 CX bike. It has Elita cranks. The bike had few miles but the bottom bracket bearings were fried on the DS, so I bought a new GXP BB.

I installed everything correctly. It's a road crank and a 68mm shell so I did not use the spacers.
Which spacers do you mean? The spacers that fit between the cup and the shell? some bottom brackets come with two 2,5mm spacers you use these if you have a 68mm shell and leave out if you 73mm bottom bracket. Some of my bikes I have had to use an additional NDS shield. You should not need gobs of grease, wavey washers or Teflon tape.

TobinHatesYou
Posts: 5729
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I don't even understand how there can be freeplay or too much preload to bind the bearings on a GXP BB.

The entire system is anchored to the NDS bearing's inner race. The only way there can be binding is if the outer to outer width in the BB is greater than the spindle length. The only way there can be freeplay is if there is play in the NDS bearing and/or cup.

joejack951
Posts: 819
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE
Contact:

by joejack951

I would check the bottom bracket shell. It could be that the two faces are far from parallel causing the binding.

mikemelbrooks
Posts: 97
Joined: Wed Jun 16, 2010 10:58 pm

by mikemelbrooks

TobinHatesYou wrote:
Sun Oct 06, 2019 8:26 pm
I don't even understand how there can be freeplay or too much preload to bind the bearings on a GXP BB.

The entire system is anchored to the NDS bearing's inner race. The only way there can be binding is if the outer to outer width in the BB is greater than the spindle length. The only way there can be freeplay is if there is play in the NDS bearing and/or cup.
If you use the wrong 68mm cups in a 73mm bottom bracket it will bind (ask me how I know). If you use the omit the two 2.5 mm spacers on a 68mm you will have a 5mm gap If you omit the plastic sleeve you will get free play on the drive side. If you omit the serrated washer from the non drive side you can get free play in the whole thing.

TobinHatesYou
Posts: 5729
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

mikemelbrooks wrote:
Sun Oct 06, 2019 8:59 pm
TobinHatesYou wrote:
Sun Oct 06, 2019 8:26 pm
I don't even understand how there can be freeplay or too much preload to bind the bearings on a GXP BB.

The entire system is anchored to the NDS bearing's inner race. The only way there can be binding is if the outer to outer width in the BB is greater than the spindle length. The only way there can be freeplay is if there is play in the NDS bearing and/or cup.
If you use the wrong 68mm cups in a 73mm bottom bracket it will bind (ask me how I know). If you use the omit the two 2.5 mm spacers on a 68mm you will have a 5mm gap If you omit the plastic sleeve you will get free play on the drive side. If you omit the serrated washer from the non drive side you can get free play in the whole thing.
On a SRAM GXP external BB, the crank spindle and NDS crankarm capture the NDS bearing inner race. There cannot be lateral play unless the NDS bearing is also moving side to side. This can only happen if there is play in the bearing itself, play in the bearing seat, or play in the external cup.

On some third-party GXP BBs, the bearings might not be held in place by a C-clip and they might be more likely to develop lateral play in the seat/bearing interface. Since you mention a serrated washer, I assume you're using a third-party BB like a Chris King. SRAM threaded BBs don't use that washer or a wave washer. For SRAM pressfit BBs, a wave washer is supplied, not the serrated style.

It would take a very shitty BB cup design not to be cross-compatible between 68mm and 73mm shells.

mikemelbrooks
Posts: 97
Joined: Wed Jun 16, 2010 10:58 pm

by mikemelbrooks

TobinHatesYou wrote:
Sun Oct 06, 2019 9:11 pm
mikemelbrooks wrote:
Sun Oct 06, 2019 8:59 pm
TobinHatesYou wrote:
Sun Oct 06, 2019 8:26 pm
I don't even understand how there can be freeplay or too much preload to bind the bearings on a GXP BB.

The entire system is anchored to the NDS bearing's inner race. The only way there can be binding is if the outer to outer width in the BB is greater than the spindle length. The only way there can be freeplay is if there is play in the NDS bearing and/or cup.
If you use the wrong 68mm cups in a 73mm bottom bracket it will bind (ask me how I know). If you use the omit the two 2.5 mm spacers on a 68mm you will have a 5mm gap If you omit the plastic sleeve you will get free play on the drive side. If you omit the serrated washer from the non drive side you can get free play in the whole thing.
On a SRAM GXP external BB, the crank spindle and NDS crankarm capture the NDS bearing inner race. There cannot be lateral play unless the NDS bearing is also moving side to side. This can only happen if there is play in the bearing itself, play in the bearing seat, or play in the external cup.

On some third-party GXP BBs, the bearings might not be held in place by a C-clip and they might be more likely to develop lateral play in the seat/bearing interface. Since you mention a serrated washer, I assume you're using a third-party BB like a Chris King. SRAM threaded BBs don't use that washer or a wave washer. For SRAM pressfit BBs, a wave washer is supplied, not the serrated style.

It would take a very shitty BB cup design not to be cross-compatible between 68mm and 73mm shells.
The top right serrated spacer/ shield whatever is used in all GXP bottom brackets threaded and press fit if it is left out you may not clamp the NDS bearing.

Image
If the plastic sleeve on the crankset is missing you will get play between the axle and the drive side bearing.
Image
Come on Eugene I am trying to help the guy but you OCD is really annoying me

TobinHatesYou
Posts: 5729
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Use the right terminology them. You're confusing everyone. That is a bearing seal/shield, not a spacer. It is not serrated...it is splined.

This is a serrated washer on the far right below.

Also nope, current GXP BBs do not have that reducer on the DS...they just use bearings with an ID of 24mm instead of 25mm and a seal/cap. Also that kind of radial play is probably not what the OP is talking about since he mentions binding.

Re: OP. It might be possible your BB threads are ovalized, the shell needs some facing, or the cups aren't being installed to the right torque.
Attachments
download.jpg
download.jpg (6.65 KiB) Viewed 418 times

mikemelbrooks
Posts: 97
Joined: Wed Jun 16, 2010 10:58 pm

by mikemelbrooks

TobinHatesYou wrote:
Sun Oct 06, 2019 10:44 pm
Also nope, current GXP BBs do not have that reducer on the DS
Since the OP stated that his bike was from 2008 and that the plastic sleeve I mentioned comes with the crankset, not the bottom bracket. What the current bottom brackets come with is completely irrelevant.
It was you who stated that they didn't know how a GXP bottom bracket could be installed incorectly "I don't even understand how there can be freeplay or too much preload to bind the bearings on a GXP BB."
Do you understand the more times say an incorrect thing it doesn't make them correct?

by Weenie


TobinHatesYou
Posts: 5729
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

mikemelbrooks wrote:
Mon Oct 07, 2019 4:51 am
TobinHatesYou wrote:
Sun Oct 06, 2019 10:44 pm
Also nope, current GXP BBs do not have that reducer on the DS
Since the OP stated that his bike was from 2008 and that the plastic sleeve I mentioned comes with the crankset, not the bottom bracket. What the current bottom brackets come with is completely irrelevant.
It was you who stated that they didn't know how a GXP bottom bracket could be installed incorectly "I don't even understand how there can be freeplay or too much preload to bind the bearings on a GXP BB."
Do you understand the more times say an incorrect thing it doesn't make them correct?

????

He bought a new GXP BB. A GXP spindle is 24/22mm...period. It does not need a reducer to fit in a new GXP BB...it does not matter if a reducer comes with one part or another. It is irrelevant unless he bought old stock or some bizarre third-party BB that doesn't come with everything he needs to install bare GXP crankset. Personally every GXP crankset I have ever purchased has been completely bare, no reducers, no spacers, not even a wave washer.

And yes, I still don't understand unless the combined width of the shell+cups is much greater than the length of the spindle. This is extremely unlikely. There is no other way he can put too much preload on the system without somehow crushing the inner race of the NDS bearing. The entire combined BB+crank system is anchored around one fixed point...the NDS bearing. This is not something that can be argued. The DS bearing does not experience significant axial or deflective loads.

I've already mentioned what it might be. The BB cups aren't threaded in as far as they should be. If they're loose, they will probably make a clicking noise. The overall face-to-face width of the BB will also be beyond spec, allowing for "binding."

But sure, OK, you win and the OP doesn't need my help since I'm wrong.

Post Reply