Truvativ GXP External type BB mounting - spacers for 73mm?
dynamis_dk
Posts: 428
Can someone clear a little issue up for me as i'm not 100% on what the setup should be. Unfortunatly the sram / truvativ website's technical manuals only seem to list for press fit where i'm on external type screw in.
To fit to a 73mm BB width 2009 Heckler, do I need to add a spacer when installing the GXP BB or do I just install the BB cups alone? The BB came with the X0 Cranks.
I've always had hollowtech and installed spacers so I'm not sure what the difference is (if any). bought 2nd hand so don't have a install manual and like above, I can't find anything on there website.
To fit to a 73mm BB width 2009 Heckler, do I need to add a spacer when installing the GXP BB or do I just install the BB cups alone? The BB came with the X0 Cranks.
I've always had hollowtech and installed spacers so I'm not sure what the difference is (if any). bought 2nd hand so don't have a install manual and like above, I can't find anything on there website.
0
Comments
-
http://www.sram.com/sites/default/files ... nksets.pdf
As can be seen from the manual above.
No spacers."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
I must have just downloaded the wrong PDF's then - doh...
cheers for that quick reply as always
0 -
I'm just on with this now. One quick thing I want to check is that the drive-side crank arm when pushed through the cups bottoms on the non-drive side bearing, leaving a few milimeter gap between the drive side seal and the drive-side arm.
Is this how it should be?0 -
Yes, this is normal. They changed the design a while back and the new GXP cups leave a gap on the drive side.
Drove me nuts trying to resolve it but then worked out it's as designed. All the face loading is on the non drive side and it doesn't matter about the other side.
See also http://forums.mtbr.com/drivetrain-shift ... 28751.html0 -
Cheers for that. Thought I was going a little crazy for a minute.0
-
there is no preloading on GXP cranks and never has been. there has always been a gap on the drive side."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
That be as it may, I've never ran GXP cranks before - only hollowtech in recent years so it wasn't something I was aware of.
Cheers for the quick updates tho - means I have at least managed something on the bike build today.0 -
Yeah, they never had preloading, but on my GT (from 2009) it had no obvious gap, went flush. Okay there may have been a very tiny gap, but I never noticed. Definitely a bigger gap on the current GXP. Measured the drive side cup and they are a few mm deeper than the one I had on the GT.nicklouse wrote:there is no preloading on GXP cranks and never has been. there has always been a gap on the drive side.0 -
Derailment here but related, if i don't have any spacers installed, running a GXP on a 73mm BB with no ISCG mounts, can i still add a double chain device to the setup to convert from triple to double?0
-
No, 73mm requires no spacers, so nowhere for the BB mount plate to go.0
-
Well sometimes. But for some reason SRAM never mention this possiblity."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Hmm? How else would it work?nicklouse wrote:Well sometimes. But for some reason SRAM never mention this possiblity.0
