Forum menu
SRAM gxp crank ques...
 

[Closed] SRAM gxp crank question

Posts: 0
Free Member
Topic starter
 
[#7427217]

Will gxp cranks fit my Trance 650b with pf92 bottom bracket

Running hollowtech at the moment assuming as a minimum I will need to change the bottom bracket


 
Posted : 01/11/2015 1:10 pm
Posts: 781
Free Member
 

pretty sure sram do a pf92 bottom bracket for the gxp range ... think i
saw one on crc ?


 
Posted : 01/11/2015 1:33 pm
Posts: 0
Free Member
Topic starter
 

Cheers just seen it thanks


 
Posted : 01/11/2015 1:44 pm
 mboy
Posts: 12651
Free Member
 

One thing I'll add is that SRAM's GXP BB's are notoriously short lived. It's worth spending the extra on something like a Wheels MFG or even a Hope IMO as the extra cost is well rewarded with a much longer service life...


 
Posted : 01/11/2015 4:18 pm
Posts: 0
Free Member
 

Can back up boy's comment about the gxp bb boing short lived. Get a better after market one and save yourself the pain.


 
Posted : 01/11/2015 10:11 pm
Posts: 3828
Full Member
 

Or just stick with HTII where you actually have control over the preload applied to the BB.


 
Posted : 01/11/2015 10:13 pm
Posts: 34530
Full Member
 

You can run a gxp crank in a shimano bb92 with a little adaptor thingy


 
Posted : 01/11/2015 10:16 pm
Posts: 759
Free Member
 

Hope BB did not fit in my Anthem as the BB shell is stepped, not sure if the Trance is stepped or not but worth checking.


 
Posted : 01/11/2015 10:30 pm
Posts: 52609
Free Member
 

For one tool fitting, removable spiders, interchangeable spiders and a generally nicer cranks sells it beyond the gxp (fitted hope) and 2 1/2 years of maintenance free riding.


 
Posted : 01/11/2015 10:50 pm
Posts: 4389
Full Member
 

Or just stick with HTII where you actually have control over the preload applied to the BB.

GXP cranks/BB setups don't put any lateral preload on the bearings like HTII. They are held in place from either side of the non drive side bearing's inner race. Thats why the cranks are available for different length BB Shells.

Agree that Sram's GXP BB don't last long. I bought a Hope with the GXP converter.


 
Posted : 01/11/2015 11:01 pm
 aP
Posts: 681
Free Member
 

I had a Hope BB that lasted 40 minutes before the bearings collapsed. The cheap SRAM BB that replaced it has lasted 600 miles so far.


 
Posted : 02/11/2015 1:03 am
Posts: 52609
Free Member
 

Sounds like a defect ap did you warranty it? I would have.
As I said for reference one did about 3 years before being swapped back for another 2 in ht2 duties the other is going well after 2 1/2 years so something sounds very wrong there.


 
Posted : 02/11/2015 1:09 am
Posts: 3828
Full Member
 

"GXP cranks/BB setups don't put any lateral preload on the bearings like HTII. They are held in place from either side of the non drive side bearing's inner race. Thats why the cranks are available for different length BB Shells.

Agree that Sram's GXP BB don't last long. I bought a Hope with the GXP converter."

That's the intention of the design, but due to BB shells rarely being exactly 68 or 73mm wide especially after being painted, they do experience sideload. Worse on PF BBs as they are more prone to being out of spec it seems.

If the BB is marginally too wide, the DS bearing is side loaded. If the BB is marginally too narrow, the NDS bearing experiences side loads in both directions as it is all that holds the cranks in place laterally.


 
Posted : 02/11/2015 10:12 am