SRAM 2×10 Questions Answered: Q-Factor, Weights and GXP Press Fit

A couple of questions surfaced over the weekend about SRAM’s new 2×10 drivetrains, so we took advantage of having SRAM’s entire marketing and product management staff at our disposal to get some answers.  The following info is also being added to the main post so it’s all in one place, but here are the updates:

Q-FACTOR: Only XX will have multiple Q-Factor options.  X0, X9 and X7 will all have standard Q-Factors, which means they should work on pretty much any mountain bike frame made in the last decade or so.

X0 CRANK WEIGHT: Their website and PR has supposedly been updated, but the original (erroneous) number was 198g.  While that would have been great, it also would have meant bending the laws of physics and such.  Actual weight for the X0 2×10 crankset is 736g for BB30 and 790g for GXP.

GXP PRESS FIT: You may have noticed that GXP PF is a new bottom bracket offering.  So did we, but there wasn’t any info on it, so here’s the deal:  Much like a BB30 press fit, GXP PF uses a bearing set that’s pressed into the frame with no external bottom bracket shell component.  This should save weight, and it allows frame designers the ability to stiffen the frame by running wider tube sections at the BB juncture.  What it also means is yet another standard, and for those unfamiliar with GXP, it looks like your standard outboard bearing BB…like those from FSA, RaceFace and Shimano, etc…but the driveside bearing has a larger ID (Inside Diameter) than the non-driveside bearing, so it’ll only work with GXP cranksets.  In otherwords, those from SRAM and Truvativ.  So far, I think Scott’s the only manufacturer that’s using it, but it’s only been “available” for a couple months, so look for more brands to start incorporating it in the future.

Comments

Jerrylikesbikes - 04/20/10 - 12:21pm

Trek uses PF bb’s on a few of their mountain bikes and their cross bikes. It is the same press-fit standard that Shimano invented a couple years ago, just different bearings in the cups.

Dave - 04/20/10 - 1:00pm

Trek/Fisher are using press-fit GXP right now also, in their X0 cross bikes [wider BB shell lets you pull the chainstays out a bit for more clearance] and on the new Hi-Fi 29ers, as well as some others.

Tyler (Editor) - 04/20/10 - 1:40pm

Dave and Jerry, Thanks…I had a hunch that was the case, but didn’t want to say so without confirming and hadn’t received a return call from anyone before you guys commented.

ohioguy - 04/20/10 - 6:31pm

Where does the Specialized Oversized BB91 Bottom Bracket fit into the new XO / 2×10 stuff?
What solutions have come out of the new “lower cost” offerings?

I know the only things right now that everyone has found to work are the XX Spider on Speci carbon cranks or the Lighting Carbons cranks (Super $$$$).

Thanks Tyler!

michael - 04/21/10 - 5:50am

The Sram’s “press-fit BB” is refering to the BB92 standard, which Scott and Pivot Cycles use.
It isn’t exactly new either, I have been using a Truvativ branded GXP pressfit BB92 on my Pivot Mach 4 for a year now.

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