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GXP bottom brackets...
 

[Closed] GXP bottom brackets and Truvativ cranks... are they garbage ?

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[#3623599]

Following on from a couple of other threads, i seem to have a bike with Truvativ stylo cranks and GXP BB. I've had plenty of issues with GXP's in the past... but wondering if that's becasue tehy're rubbish... or because they were badly fitted and tensioned ?

I 'think' they need to be fitted a little more precisely than Shimano ones, which even a monkey like me can do...

So, is that the case ?

If so, you have 2 nuts on the end, 1 i a tightening nut, the other a lock type nut... What sort of tension/torque on them ?


 
Posted : 30/01/2012 2:59 pm
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w,

I have a GXP and it is very smooth and free-running.
I have stripped and repacked the bearings so they are full of grease.

GXP needs the BB to be exactly 68 or 73mm and square (faced) for the seals to work properly and not be exposed or compressed/tight.
Shimano knew this is not simple, so use a spline with a loading nut before you tighten the 2x 5mm clamping bolts.

The smaller of the nuts needs to be tightened fully to bottom-out the crankarm on the axle.

The larger one is to be pinched up, not more.
It is the One-Allen-Key (8mm) extractor nut.

PaulD


 
Posted : 30/01/2012 3:07 pm
 Del
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garbage, yes, IMHO.


 
Posted : 30/01/2012 3:09 pm
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I ran a set of Stylo cranks and GXP BB for a while, they're on the missus' bike now.

They're a little maligned I think. Compared with the RaceFace Evolve cranks I had before, the Stylos are much lighter, stiffer and the spline interface is much better designed. They shift well and on my set at least (mirror black), the finish is intact.

The minus points are the BBs, which aren't the longest lasting and the fact that Shimano's offerings are so darned good these days. Even Deore cranks these days are well worth a punt.


 
Posted : 30/01/2012 3:15 pm
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I've been running GXP BB's on 3 bikes for the last 4 years. Tighten them up to 54nm and they're fine, easy to get cranks off for maintenance, cheap to replace, and spin freely.

Top banana as far as I'm concerned.


 
Posted : 30/01/2012 3:16 pm
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Liking the GXP offerings. Mine all seem to be more free running than HT2s.
The SRAM Red version is excellent.


 
Posted : 30/01/2012 3:24 pm
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the one on my roadbike has been fine for 2+ years. the one on my mtb chewed bbs at a rate of 1/ 3 months or so. replaced it for shimano and get about 1 year out of a BB.

YMMV.


 
Posted : 30/01/2012 3:27 pm