I've seen 2 sets of these break locally (all the DH ones), and there is a pic in pinkbikes broken parts photos this month of another broken set. I think they should be fine for XC/Trail but using them for DH doesn't seem to be the best idea...
I was wondering about that too. There were a lot of downed trees across the trail that day and I think a trail crew was tagging downed trees that were to be cut. That's my story and I'm sticking with it.
in Leicestershire, United Kingdom - photo by Big-daves-remedy - Pinkbike
Looks a little different but close enough. I think the biggest problem is that SRAM rates these as "Downhill" and they're not. They really need a XO level downhill/enduro/free-ride aluminum crank that can take multiple high impact hits and uses the same splined system for multiple or single ring set-ups.
Good luck with your replacement cranks.
I too am a composites specialist and the first photo in this thread is very telling. Like Mr.Magura I like to figure out why a failure occurs.
At the failure point there is de-lamination which indicates layup voids and or material contamination. With these items made in a fast pace work shop I can see shortcuts being made at several levels.
On the second photo at entry #7, the pedal insert completely separated from the composite. Mr.Magura may be correct, galvanic reaction - the aluminum corrodes due to an electrical current between the aluminum and carbon. This breaks the bond between the two. I don't see any measures to insulate the carbon from the aluminum.
The photo in #28 looks the same - complete insert separation.
No aircraft quality work on this stuff!
Wipp you are correct, pre-impacts would weaken and compromise the part before the big impact and it's demise. Especially upon water ingress in the pedal insert area.
You are lucky you physically came out without a scratch.
These products are more than strong enough for downhill, but cannot take the kind of repeated strikes that aluminum can.
INSPECT YOUR EQUIPMENT OFTEN.
15 Enduro Expert 29, SW build - 27.6 lb
14 SW Epic WC - 21.8
12 Niner Air9RDO -16.4
Just sent a set back for a different faliure, I had the non drive side crank crack and seperate all around the alloy insert that connects to the axle (through bb). 95kg rider on a hardtail, hopefully will be sorted through warrenty quickly. Cranks are 2 months old.
95K + hardtail seems to be the the magic formula for those cranks!
Originally Posted by thrower78
It says "11 speed crankset". Does it really matter how many speeds are on the rear if it has 1 speed up front that you plan to use on a 1x10?
Broken XO Crank
Incredible. First time seeing this thread. I didn't know this was a problem with the SRAM carbon crank.
gnar, you can use this crank for whatever. Doesn't have to be 1x11. In fact, this crank is the same exact crank that SRAM has been using for years on their 2x10 X0 systems. Even the XX1 crank is the same exact thing (this also includes the SRAM 2200 crank that comes on Specialized bikes). Exact same crank every time, just different paint job.
I've had 3 of these cranks now on a variety of bikes. I've never had one break on me and I live in a very rocky area. I always use the Race Face crank boots. Always. I usually have to put new ones on halfway through the season as I eventually tear right through them with multiple pedal strikes. I also weigh 225lbs. I'm hard on my equipment. I guess I'll consider myself lucky from now on as these cranks have been perfect for me thus far.
I think it's important to note that broken carbon is increasingly less common as time goes by. They would not spec downbill and AM bikes with carbon now if it wasn't tough. Bike companies put their reputation on the line for it.
My buddy's aluminum Yeti frame crack near the bottom bracket recently. No wrecks or anything. Just cracked. So all material can fail.
I know this is a older thread but thought I would add a little to it.
I broke these XO cranks 2 weeks ago.
They are 2 years old and I have ridden them about once a week.
I have them on a fully rigid Black Cat 29er.
It turns out my right heel wore through the carbon so thin that it caused them to snap.
This was during a short track race in Portland. I am lucky because 4 days prior I had been riding Tiger Mtn near Seattle and if they had snapped on one of the DH sections I may not be typing this.
XO by gearlessinseattle, on Flickr
^ That sucks, man. Glad you're okay. I imagine these cranks take more of a beating on a fully rigid bike like this.
Do you have a pic of the non drive side arm? Is it worn like the DS arm? I'm just curious to see how worn the crank arm is. I have an XX1 crank and my shoes do rub the arms.