Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

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webber
Posts: 267
Joined: 2 May 2012, 3:48pm

Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by webber »

are sram gxp and shimano the same as ive got sram apex 10 speed and would like to fit shimano bb ita bottom bracket and not much choice from sram
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: bottom brackets

Post by gxaustin »

Shram GXP is notthe same as Shimano Hollowtech 2. The GXP axle has a reduced diameter on the non drive side where it goes through the non drive side bearing. That bearing therefore has a smaller diameter than the drive side. Shimano HT 2 has a constant diameter axle. They are incompatible. Sorry
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by Brucey »

Italian thread GXP BBs are readily available. Like it says above, a shimano one won't fit.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by mattsccm »

Adaptors exist. Mine worked fine. It shims out the thinner left end of the GXP to 24mm
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by Brucey »

mattsccm wrote:Adaptors exist. Mine worked fine. It shims out the thinner left end of the GXP to 24mm


Q. How was a small/consistent preload on the bearings achieved?

One of my issues with the GXP system is that the preload on the RH bearing is not well controlled; it appears to rely on the BB shell being the exact right width (within a few microns) and there being no axial movement in the bearings. If this is not maintained it is quite usual for the RH bearing to work itself slack, and when you take everything apart, you find that the top hat has been moving around and has worn; the bearing itself might be fine.

I would imagine that there would be a similar issue with a conversion of this type; the LH crank pulls up to a shoulder and unless the width of the shimano BB is exactly correct (unlikely), or there is a spring element introduced in the system, there will be an uncontrolled preload on the bearings.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by mattsccm »

Better than the crappy GXP and that's all that matters!
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by gxaustin »

Hi Brucey
My GXP cranks have a wavy washer between the RH crank and the bearing. That's not much prelaod, admittedly. As you say the LH bearing is sandwiched between the groove on the axle and the LH crank. It's OK but I prefer Shimano on balance.
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by Brucey »

gxaustin wrote:Hi Brucey
My GXP cranks have a wavy washer between the RH crank and the bearing. That's not much prelaod, admittedly. As you say the LH bearing is sandwiched between the groove on the axle and the LH crank. It's OK but I prefer Shimano on balance.


is that a pressfit version? I see the wave washer listed for those but not with the cups that fit 68mm BSC threaded versions.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by gxaustin »

is that a pressfit version? I see the wave washer listed for those but not with the cups that fit 68mm BSC threaded versions.


My BB is a BSA type. It came with a Mekk bike. The cranks are branded Mekk but may be Truvative sourced?
mattsccm
Posts: 5101
Joined: 28 Nov 2009, 9:44pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by mattsccm »

Wavey washer on my BSA. Came on the bike. Blasted nuisance as it hides during reassembly then pops up as you are tidying up.
gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by gxaustin »

Wavey washer on my BSA. Came on the bike. Blasted nuisance as it hides during reassembly then pops up as you are tidying up.


New ones can be had for a reassuring expensive price so worth hanging on to.
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Bottom bracket replacement for Sram Apex 10-spd ( will Shimano fit ?)

Post by Brucey »

these

https://www.sjscycles.co.uk/bottom-brackets/sram-wave-washer-for-gxp-to-pressfit-adapter-245-mm-pack-of-5/

would presumably do the trick. However I do wonder if the water can get in more easily with one of these fitted; it is unlikely to be squashed flat completely.

I confess I recently assembled a GXP bottom bracket without such a thing. I had a nest of shims but none of the possible combinations of shims seemed to provide a suitable preload leave alone might be likely to maintain it. Thus in a fit of improvisation I made a flat rubber washer and that did seem to nip up (in such a way as the preload might be maintained in service) as the LH crank went home. Only time will tell if this is a good arrangement or not; one of my chums is going to be using it and he will soon find out one way or another.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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