Chinertown

Chinese Carbon MTB => 29er => Topic started by: Jerryno on May 28, 2015, 08:42:03 AM

Title: SRAM 1x11 drivetrain in BB92 frame
Post by: Jerryno on May 28, 2015, 08:42:03 AM
Couple nice frames have BB92 option only (YFY-BM-01: http://www.yfy-carbon.com/en/pro_detail.php?id=20 (http://www.yfy-carbon.com/en/pro_detail.php?id=20), CS-041: http://www.xmcarbonspeed.com/Productinfo.asp?f=1327 (http://www.xmcarbonspeed.com/Productinfo.asp?f=1327), and others), but I would like to run XX1 or X01 1x11 SRAM drivetrain.

The crank in both has options for BB30 bracket (30mm crankshaft) or GXP bracket (24mm stepped crankshaft). So there are 2 options how to fit it:
Which solution should I go with and which is better? Any experience and thoughts would be highly appreciated (I hate squeaking cranks!)

Other thing is I want to use 38T or even 40T front chainring in the 1x11 setup. Would there be enough room between the frame and the huge ring?
Title: Re: SRAM 1x11 drivetrain in BB92 frame
Post by: Ramborage on May 30, 2015, 02:15:35 PM
I'm running the BB92 option with the XX1 gxp cranks and have no issues.  I would say that's your best bet.  On another note though 38-40 on that frame might now work.  Highest I've heard on most xx1's is 36.  You must have some serious leg power!!!  In that case maybe think about a fixed gear bike!!!
Title: Re: SRAM 1x11 drivetrain in BB92 frame
Post by: Jerryno on May 30, 2015, 02:38:30 PM
This is good to hear that BB92 with GXP has no issues! I live in a flat land with some hills around so I need gear ratios from 4.0 down to 1.0 as the bike will be like a cyclocross but a mtb which is stronger frame..

With 1x11 I ran into issues with frame clearance around the chainring, you are correct, so it looks like I'll use a 2x10 with 42T biggest ring which should fit. There is a thread about this from me with some frame pics.
Title: Re: SRAM 1x11 drivetrain in BB92 frame
Post by: cmh on June 05, 2015, 09:04:33 AM
Quote from: Jerryno on May 28, 2015, 08:42:03 AM
Couple nice frames have BB92 option only (YFY-BM-01: http://www.yfy-carbon.com/en/pro_detail.php?id=20 (http://www.yfy-carbon.com/en/pro_detail.php?id=20), CS-041: http://www.xmcarbonspeed.com/Productinfo.asp?f=1327 (http://www.xmcarbonspeed.com/Productinfo.asp?f=1327), and others), but I would like to run XX1 or X01 1x11 SRAM drivetrain.

The crank in both has options for BB30 bracket (30mm crankshaft) or GXP bracket (24mm stepped crankshaft). So there are 2 options how to fit it:
  • Directly pressed bearings into frame (for BB30 crank): http://www.rotorbike.com/products/mtb/bb89-bb92_98 (http://www.rotorbike.com/products/mtb/bb89-bb92_98) or http://wheelsmfg.com/bottom-brackets/bb86-92/bb86-92-bottom-brackets/bb86-to-30mm-ceramic-hybrid-sealed-bearing.html (http://wheelsmfg.com/bottom-brackets/bb86-92/bb86-92-bottom-brackets/bb86-to-30mm-ceramic-hybrid-sealed-bearing.html). The downside is some spacers might be needed because the shaft lenghts migh not fit precisely (is this the case and true?).
  • GXP BB92 press-fit bearing cups (for GXP crank): http://www.tredz.co.uk/.SRAM-GXP-Team-Press-Fit-MTB-BB92-Bottom-Bracket_43299.htm (http://www.tredz.co.uk/.SRAM-GXP-Team-Press-Fit-MTB-BB92-Bottom-Bracket_43299.htm). This should be less hack-ish solution and one I favour so far (but have zero experience with). Shimano BB92 brackets are not compatible with stepped SRAM crankshafts so I can't use one.
Which solution should I go with and which is better? Any experience and thoughts would be highly appreciated (I hate squeaking cranks!)

Other thing is I want to use 38T or even 40T front chainring in the 1x11 setup. Would there be enough room between the frame and the huge ring?

Scott Scale has a BB92, but no experience with SRAM cranks there. BB92 is pretty common, plus the Scales are available with SRAM drivetrains, so SRAM has to have a solution.

One really nice option is Race Face's awesome Cinch cranks, either the aluminum turbine or the gorgeous and super spendy Next SLs.  Got those on the wife's bike and 36t Wolf Tooth spiderless fits with no problem, and I'm pretty sure a 38 could clear, but that's with the Scale frame. No idea on the Chiners.