Anyone ever worn a hole in a crank arm?

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7/16/2021 11:24pm Edited Date/Time 7/27/2021 7:48pm


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metadave
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7/16/2021 11:51pm
Dang. Nope. Looks like it's time for your.... Next set though.
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joelsman
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Ferndale, WA US
7/19/2021 2:03pm
Some protective wrap would have been a good idea and replace often.
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TEAMROBOT
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Los Angeles, CA US
7/19/2021 2:22pm
Wowza. Never seen that in a carbon crank. I've worn a hole just like that through a carbon frame from cable rub under the bottom bracket, but I wasn't nearly as worried about structural integrity as you should be.

Either that or say F it and go do some "structural testing" by overshooting all your local jumps to flat.
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7/19/2021 5:31pm
joelsman wrote:
Some protective wrap would have been a good idea and replace often.
They did come with some protective film, but I can’t remember whether it covered this part of the crank. And it peeled off after a few months anyway.

I mean it’s pretty clear that it was being worn down, but Im still surprised at how thin it is.
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dirtyberd
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Manchester, MA US
7/19/2021 6:30pm
joelsman wrote:
Some protective wrap would have been a good idea and replace often.
They did come with some protective film, but I can’t remember whether it covered this part of the crank. And it peeled off after a few...
They did come with some protective film, but I can’t remember whether it covered this part of the crank. And it peeled off after a few months anyway.

I mean it’s pretty clear that it was being worn down, but Im still surprised at how thin it is.
wow. literally looks like a sandpaper job. id be very interested to see the material that did this fine work! do you actively push on the crank for stabilization or something? maybe in corners?
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jasbushey
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7/19/2021 7:36pm
What does your shoe look like?!
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FqqTBawL
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AU
7/19/2021 8:37pm
I had worn a hole through the underside of the top tube of a Trance Advanced from the water bottle rubbing. Was not impressed, but it was a good reason for a new bike though.
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sharpy212
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7/19/2021 8:49pm
What kinda footwear do you ride in? That’s high on the crankarm… I’m guessing boots of some kind?
adamdigby
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San Juan Capistrano, CA US
7/19/2021 8:54pm Edited Date/Time 7/19/2021 8:56pm
It doesn't have to be high, could be and is most likely when the cranks are level. If he rides left foot forwards while descending steeper terrain, that part of the crank will be lower than the pedal and would be right around the point of the heel where it moves up and down as you ride over rough terrain.


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StudBeefpile
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Peninsula Livin, WA US
7/19/2021 9:01pm
sharpy212 wrote:
What kinda footwear do you ride in? That’s high on the crankarm… I’m guessing boots of some kind?
30mm cranks. Just like those little bicycles the bear rides at the circus.
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7/19/2021 9:09pm
sharpy212 wrote:
What kinda footwear do you ride in? That’s high on the crankarm… I’m guessing boots of some kind?
Maybe he’s got shoes where the grip that goes all the way up the side. Crazy. Never seen that
T-Dawg
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Portland, OR US
7/19/2021 9:29pm
I would be making some calls looking for a mfg defect warranty claim ….. a reputable brand with limited lifetime- would replace or upgrade with one or two calls
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7/19/2021 9:35pm
metadave wrote:
Dang. Nope. Looks like it's time for your.... Next set though.
What you did there..Grinning
coyoterun
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San Francisco, CA US
7/19/2021 10:09pm
sharpy212 wrote:
What kinda footwear do you ride in? That’s high on the crankarm… I’m guessing boots of some kind?
not necessary wearing by boots. My set of Hope Cranks, the color of the cranks and crank caps have been worn out slightly. I wear the Shimano DH shoes. AM9, something like that.. Just not yet to the point having a gouge on the crank that far yet.

The reason might have to be combination of foot position and angle on the pedals, riding style, muddy condition will only make it worst if rider have the foot push against the crank for stability while going down rough terrain.


I do wrap around my frames' upper and lower swingarms on both sides, because in the past, my shoes would wear out the frame's paint. I use cut out inner tube strip for wrapping. While I was doing that, I also wrap the housing, brake and derailluer, to eliminate additional movement from the hoses.
FuzzyL
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IT
7/19/2021 10:54pm
Never wore a hole in a carbon crank - it did happen to me with a XTR aluminium crank, though.
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lev
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Leighton Buzzard GB
7/20/2021 2:30am
I had some Next carbon cranks develop stress cracks along the length of the arm. Never crashed, just my 100kg heft and pedalling. RF (siverfish in the UK) didn't want to know to begin with, but I kept pressing them. They ended up swapping for some SIXC under warranty in the end. They were nice until I took the end of them off with a pedal strike! I'm now on Turbines, probably like I should have always been!

Moral - keep pushing these manufacturers. They sell expensive stuff that should last. You should minmum get a replacement at cost..
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7/20/2021 4:14am
Funnily enough I didn’t think to look at my shoe.
It’s quite obvious now though.

I ride left foot forward and I guess I twist my heel into the crank arm a lot. No signs of wear on the other side.

Lots of sand in the dirt where I live too and it creates a perfect sandpaper when damp.

I already ordered another set, don’t think it’s a defect, just neglect. Race Race deserve credit for being one of the few original parts on my bike prior to death by sandpaper shoe though

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eRod
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AZ US
7/20/2021 8:04am
I've actually seen that a few times on Next SLs. I stopped running them because of that and people breaking them a lot. Went back to metal.
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ddspaz
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Bellingham, WA US
7/20/2021 8:24am
I've gotten to that point on a set of e13 carbon cranks, and had a riding buddy do the same on some X01s. Neither failed because of it, just figured that was enough miles on chunk of carbon to retire anyway.
7/20/2021 2:42pm
You've almost worn the head of the bolt too.
How old are the cranks?
metadave
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7/20/2021 6:21pm
Are you running the standard axle Mallet E's
1
7/20/2021 6:38pm
Nzdinosaur wrote:
You've almost worn the head of the bolt too.
How old are the cranks?
I think almost 5 years.
Normally that’s long enough to become incompatible in the bike industry but I was pleasantly surprised that this isn’t the case.
filmdrew
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Northern California coast, CA US
7/21/2021 12:30pm
Perhaps move up to some steel cranks like Profiles?? I've just seen so many issues with carbon cranks. but wearing a hole seems pretty extreme. Good luck and safe trails!
Falcon
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Menifee, CA US
7/27/2021 8:41am
I don't know about you guys, but my new favorite phrase is, "death by sandpaper shoe." It sounds vaguely Japanese.
Big Bird
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7/27/2021 7:48pm
filmdrew wrote:
Perhaps move up to some steel cranks like Profiles?? I've just seen so many issues with carbon cranks. but wearing a hole seems pretty extreme. Good...
Perhaps move up to some steel cranks like Profiles?? I've just seen so many issues with carbon cranks. but wearing a hole seems pretty extreme. Good luck and safe trails!
Going straight to steel Profiles seems pretty extreme. There are plenty of alloy cranks out there that are more appropriate. I love Profiles and have them on several bikes. But not a trail bike.

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