SRAM GXP BB help (Wheelsmfg)

Discuss light weight issues concerning road bikes & parts.
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TimW
Posts: 480
Joined: Sat May 09, 2009 1:52 pm
Location: England, UK

by TimW

Hi all

I'm building a new bike and for the first time using a SRAM groupset with Quarq DZero Red GXP cranks. The frame is a BMC RoadMachine 01 - PF86 Bottom Bracket shell.

I've gone and bought (and partly fitted) a Wheels MFG BB86/92 Shimano 24mm compatible threaded bottom bracket since PF is known to creak and this should solve that...

However I noticed (too late) that WheelsMFG make a specific SRAM version for 22/24mm systems.

When I use calipers to measure the DZero spindle it is 24mm so I can't see it will be a problem...but what am I missing? Why does the SRAM version exist?

TIA

by Weenie


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bikerjulio
Posts: 1901
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

You should have done a little more research. And looked at the crankset a little harder.

GXP spindles are 24 mm except at the NDS end where there is a shoulder and then they step down to 22 mm.

Therefore the NDS bearing on GXP is either:

1. smaller

or

2. has a sleeve that reduces it to 22 mm. (this was the early years of GXP)

You cannot use a regular Shimano BB.
Last edited by bikerjulio on Mon Aug 07, 2017 1:51 am, edited 2 times in total.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

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fa63
Posts: 2274
Joined: Mon Feb 19, 2007 7:26 am
Location: Atlanta, GA, US

by fa63

bikerjulio wrote:You cannot use a regular Shimano BB.

+1. Return the other one if you can and get a SRAM specific one.

sungod
Posts: 1565
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

as above, get the gxp

this is a gxp spindle, 24mm all the way except for the step at the end where is goes to 22mm...

Image

TimW
Posts: 480
Joined: Sat May 09, 2009 1:52 pm
Location: England, UK

by TimW

Thank you. Will source the SRAM version.

topflightpro
Posts: 819
Joined: Tue Jan 13, 2009 2:35 am

by topflightpro

There used to be a little sleeve you could buy to run GXP cranks in a Shimano BB. I've not actually ever seen one, but I have seen reference to it. It might be worth looking into if you've already pressed the BB into the frame. I'm pretty sure you can't return them after they've been pressed in.

benhama
Posts: 50
Joined: Fri Aug 09, 2013 1:10 pm

by benhama

Something like this should do the trick: http://www.ebay.com/itm/J-L-BB-Bottom-B ... 1668785933

I think that Hope may do something along these lines as well.

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bikerjulio
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Location: Welland, Ontario

by bikerjulio

benhama wrote:Something like this should do the trick: http://www.ebay.com/itm/J-L-BB-Bottom-B ... 1668785933

I think that Hope may do something along these lines as well.


The flanges on those look really thick - 2 mm at least. That means that the NDS spline engagement is less than designed, and the cranks is pushed 2 mm to the right.

The Hope is similar, but I don't think available any more.

FWIW the original sleeve was a tight press fit with no flanges - just a plain sleeve. But again that style is long gone.

I'd just get the right BB.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

Hexsense
Posts: 462
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

So what do you guys think about Sram's own current version of BB86 to GXP Bottom bracket?
Does plastic press in sufficient for the task while not damaging the frame as much as a tight aluminum press in?

Would Wheels mfg thread together version, which is like "snug but can be push in by hand" right side and loose fit left side so we can turn it to thread both side together, fit better or worse than Sram's tight press fit on both side?

i wouldn't want to use aluminum tight fit press in right now so here are two approach i think make sense but don't know which one is better.

glepore
Posts: 1119
Joined: Thu Mar 28, 2013 4:42 pm
Location: Pa USA

by glepore

Sram's is fine. If you've not installed a gxp crank its a little different, take a look at the instructions...the nds arm gets torqued really darn tight as it doesn't preload the bearing so much as clamp the step against the inner race. You need the appropriate seal and shims for it to work as intended. Its kind of counter intuitive.
Cysco Ti custom Campy SR mechanical (6.9);Cannondale SS Evo Di2 7970 (5.79); Willier Cento Uno Air Di2 9070 (7.0); C40 Mk2 DA 7800 ; Anvil Custom steel Etap;1996 Colnago Technos Record

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bikerjulio
Posts: 1901
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

GXP and also Campy's UT were designed back in the days when bearing cups were screwed in and therefore provided a solid anchor to prevent lateral movement.

The GXP design locks the spindle to the NDS bearing. Therefore if the bearing is pressed in, the crank has a tendency to work it out.

As long as the bearing cups are nice and secure, all should be well. The screwed together solution is a little more solid IMO.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

pdlpsher1
Posts: 1543
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

A bit off topic but I'm getting a custom Ti frame built. I spoke to my frame builder today. I asked him if he has the tooling for the new T47 BB standard. He said yes. Without hesitation I told him I want T47

T47 is basically a threaded PF30. It has the same dimensions as a FP30 BB shell except it's threaded. I'm going to get a Chris King T47 BB. I also like Chris King's neat grease injector tool. I've have had some issues in the past with regards to water intrusion on both Praxis and Wheels Mfg BBs. The CK grease injection tool will solve that problem.


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by Weenie


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