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Broken XO Crank

35K views 45 replies 18 participants last post by  Erock503 
#1 ·
Broke my drive side crank arm today doing some groomed drops at Duthie Hill in WA. Weird that they list them in their free ride category:madman:
 

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#4 ·
I'll take some more pics tomorrow. I'm sure it will (should) be covered, the cranks are less than a year old. The damage was all at once, I landed a clean drop onto an easy transition with my right foot back and the cranks parallel to the ground and the insert just popped right through the crank arm. It felt like I broke my peddle spindle. I was really surprised to see that the crank arm had exploded, and thankful that it didn't happen back country!
 
#8 · (Edited)
Ha I've been waiting 2 1/2 weeks on my X0 shifters. Glad this worked out for you man. Lame when something spendy does that, hope it doesn't occur again. That really does seem unusual.

Consider ordering some crankskins, you seem to ride hard and it looks like your shoes scratched up your cranks real nicely. I know my five ten freeriders were doing that to my X0 cranks and now it isn't an issue. Crank boots by race face are also nice. The bottom of my crank struck a rock, so I got them after that and it has since helped. I don't subscribe to full on skins, I even saw a bike wrapped in helicopter tape once. My bike is proudly scratched, but like your chainstay, I think it is one of those places worth protecting. Keeps it fresh,

or something.

Sent from my Desire HD using Tapatalk 2
 
#11 ·
Right foot back, landing a groomed jump and the pedal tears out in a downward and inward direction and the crank ends up looking like a car drove onto it. Not saying the crank is unbreakable, but that looks like the crank was driven into something large, hard and muddy, like a log taking out the pedal and the crank. Or maybe a car drove onto it?

Landing a smooth and simple jump and destroying a top of the food chain crank which you now get replaced and will never use again for fear - I call BS. Smells to high heaven. Just saying.:skep:
 
#15 ·
Out of curiosity, how many cranks how often would you estimate a crank fails because of galvanic corrosion? bike parts, in general-really.

It still is surprising this happened. OP, if you're going to part out your X0 cranks-let me know; but seriously that doesn't happen twice. I got my X0 drivetrain in July of 2011 and I've beat the high hell out of my cranks and I know a number of other riders with them too. I'd recommend Saint if you were really concerned. X0 usually doesn't do this.
 
#16 ·
Out of curiosity, how many cranks how often would you estimate a crank fails because of galvanic corrosion? bike parts, in general-really.
I'd guesstimate quite a few products suffers this type of failures.
Often the issue is not even considered, and the end user also often does his part to make the issue worse.
Currently there is a thread about failing carbon rims here on MTBR.
I am 99.8% sure that they fail cause people use aluminum nipples.
Once the nipple head corrodes, at some point the load per mm2 is exceeded.

I have made carbon cranks in the past (like 15 years ago). Those cranks died a couple of years ago due to galvanic corrosion, since back then I didn't know I had to take that into account.
Ibis had some Mojo frames loose the nut rivets lately, for the very same reason.

More on the matter :

MIL-STD-889B

Magura :)
 
#18 ·
I'm all for great CS, but the guy puts **** all over the crank, won't use it again and manages to break it in a way that should not be even slightly possible. No tinfoil hat and no cave - it sounds like ********.

If you think the XO crank is really that piss-poor Mr Mag, then please enlighten us so we can all avoid buying the product ever. Looks like at least 5 layers of composite have been torn open on the crank - all from landing a smooth jump??? If that's the risk you really take buying the crank, then I may be on the OP's side. Right now I am on SRAM's side, but if they are selling a product with such a manufacturing fault and you can identify that from the pics, then that is negligence and good customer service would be a product recall.

Sorry for any interest taken.
 
#19 ·
I'm all for great CS, but the guy puts **** all over the crank, won't use it again and manages to break it in a way that should not be even slightly possible. No tinfoil hat and no cave - it sounds like ********.

If you think the XO crank is really that piss-poor Mr Mag, then please enlighten us so we can all avoid buying the product ever. Looks like at least 5 layers of composite have been torn open on the crank - all from landing a smooth jump??? If that's the risk you really take buying the crank, then I may be on the OP's side. Right now I am on SRAM's side, but if they are selling a product with such a manufacturing fault and you can identify that from the pics, then that is negligence and good customer service would be a product recall.

Sorry for any interest taken.
Try some comprehension classes :madman:

Based on wild guessing, you accuse the OP of lying, and thus fraud for asking for a warranty replacement.
Unless you have exact knowledge of the OP not telling the truth, those are pretty far out accusations.

I have as far as I can see, not said anything about the crank in question, be that positive or negative, besides that I found it interesting to see the broken part close up, and that it must have been a manufacturing defect, for things to go that bad under normal circumstances.
There are thousands of those cranks out there, so if they failed left and right, I'm sure we would have heard of it.

If there is a defect in the layup, composites fails, that's pretty common knowledge, and a common failure mode. This happens to any manufacturer, and that's about all there is to it.
This goes for just about any high performance part, as the room for minor manufacturing defects gets smaller.

Magura :)
 
#21 ·
Personally I think the cranks failed from taking occasional peddle strikes in rock gardens and technical sections. There are a few blemishes on the bottom side of the crank arm but I think that the combination of peddle strikes and a slight flaw in manufacturing probably led to a stress fracture that I didn't catch or could see durring normal maintenance.

I also suspect that because they were run on a hardtail vs a FS bike, whatever flaw they had or that was put upon them by yours truly in the course of normal (re: aggressive) riding in our local bike park accelerated the cranks demise.

Long story short: I was stunned at first that they broke, I've always had very good luck with SRAM parts. SRAM came through right away with a fix (thank you) and my Yelli Screamy is now happily running forged aluminum cranks again. In retrospect I think running carbon cranks was a total weight weenie move on my part when I know that through a year of aggressive riding my cranks are usually full of battle scars from rock and peddle strikes. I'n my eyes, it's just not a good application for carbon. If I were to run them again I would definitely grab some of those rubber crank boots from RaceFace and protect them with some helo tape.
 
#28 ·
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.
 
#30 ·
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.
 
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#33 · (Edited)
I STRONGLY advise not to purchase :nono:. See the reviews on chain reaction
SRAM X01 11 Speed Crankset | Chain Reaction Cycles

UPDATE AND EDIT:
I emailed SRAM and got an instant response that they would be in touch with CRC regarding my issue. :thumbsup: AMAZING SRAM CUSTOMER SERIVCE.

Also had a further response from CRC, saying that as a 'gesture of good will' they will give me vouchers to the value of the chainring. :thumbsup: AMAZING CHAINREACTION CUSTOMER SERIVCE (just took them a while to come around to my predicament).
 

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#35 ·
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.
 
#36 ·
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.
 
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