[BadgerOne]

Talk about a solution looking for a problem. Twice in a single week, on two different bikes, I damaged carbon cranks. Once picking my way through a line and glancing the non-driveside crank arm on a rock outcropping, leaving two nice deep gashes in the arm. The other just trucking down a line with some scrabble, a good sized rock popped up and I heard that dreaded dead-plastic thunk and felt it through my feet and frame. The rock hit the spindle end of the crank and took out a nice little chunk of material. Neither was catastrophic, but now every time I ride I'll be thinking about that damage. With the frequency of nasty rocks and rock impacts where I ride, these cranks make no sense. I have boots on both sets, one is X01 and one is Descendant.

I didn't buy them, they came on a couple of bikes so I used them. There was never a problem and a million advantages with a good set of 7000-series forged cranks like Turbines or something similar, which would have laughed this stuff off for the next 20 years. I guess carbon cranks were developed to save, what....100 grams low on the bike where it will never be noticed anyway and to separate us from more of our dollars for no advantage?

Rant off.

Admin Edit: Add photo for Featured Thread

 

[Jayem]

Maybe if we lower the BB some more?

 

[Gym123]

This is almost as bad as the headline in this review-

$2,500 Ethernet Switch Effectively Isolates Audiophiles From Cash

Faraday Rage

www.tomshardware.com

I don't think a solid metal crank has ever been damaged by a small rock, other than a slight ding.

 

[BadgerOne]

Maybe if we lower the BB some more?

I like it! That way the rock would have sailed over the spindle and smashed my ankle. Chicks like dudes that limp.

On a related note it gives me pause about carbon rims too, though I'll bet they are tougher since to some degree they are designed for impacts. The way a rock occasionally nails my AL rims and leaves a gash, I'd be curious how carbon holds up.

 

[FrankS29]

This is almost as bad as the headline in this review-

$2,500 Ethernet Switch Effectively Isolates Audiophiles From Cash

Faraday Rage

www.tomshardware.com

I don't think a solid metal crank has ever been damaged by a small rock, other than a slight ding.

It's crap like this that made me take a BIG step back from audio.

Granted, I took that step right into cycling.

But hey, my wife gets far less angry about bike purchases than my audio stuff since cycling is the only hobby that I have that is even remotely healthy for me.

 

[Prognosticator]

I have never even thought about my cranks when I had good ol' Shimano aluminum ones. Four months into owning a bike that came with carbon cranks, the epoxy fusing the carbon to the aluminum insert broke on my XO cranks.

SRAM was great about replacing them but I am like you...worried. But when I posted about my dilemma, multiple people responded that they had been running carbon cranks for many years with no problems.

As for carbon rims, I am new to them also. They make more sense to me because they are rotating weight, but I still worry about them.

 

[BillyBicycle]

ok.. i'll bite. I've own twelve high end mtb bikes of various sizes, shapes, specs - all with carbon cranks. Not one single failure. Over the last three years, i've owned twenty six high end bikes, no failures of carbon cranks.

 

[Zguitar71]

They have their place but it’s not around rocks.

 

[834905]

ok.. i'll bite. I've own twelve high end mtb bikes of various sizes, shapes, specs - all with carbon cranks. Not one single failure. Over the last three years, i've owned twenty six high end bikes, no failures of carbon cranks.

You've owned 26 different mountain bikes in 3 years?

 

[FrankS29]

ok.. i'll bite. I've own twelve high end mtb bikes of various sizes, shapes, specs - all with carbon cranks. Not one single failure. Over the last three years, i've owned twenty six high end bikes, no failures of carbon cranks.

A lot of this is depending on your personal riding and trails you ride.

Example, if I only rode light xc and flow trails I wouldn't be worried about carbon cranks.

But I ride in a lot of rocky and chunky places that end up with crank strikes pretty regularly. So, carbon cranks are pretty much a non-starter for me.

 

[Monty219]

ok.. i'll bite. I've own twelve high end mtb bikes of various sizes, shapes, specs - all with carbon cranks. Not one single failure. Over the last three years, i've owned twenty six high end bikes, no failures of carbon cranks.

And I’ll bite on this… you have owned 12 high end mtb and 26 high end bikes? 26 as in inches of wheel size? Regardless, that is a lot of bikes!

 

[RickBullottaPA]

Talk about a solution looking for a problem. Twice in a single week, on two different bikes, I damaged carbon cranks. Once picking my way through a line and glancing the non-driveside crank arm on a rock outcropping, leaving two nice deep gashes in the arm. The other just trucking down a line with some scrabble, a good sized rock popped up and I heard that dreaded dead-plastic thunk and felt it through my feet and frame. The rock hit the spindle end of the crank and took out a nice little chunk of material. Neither was catastrophic, but now every time I ride I'll be thinking about that damage. With the frequency of nasty rocks and rock impacts where I ride, these cranks make no sense. I have boots on both sets, one is X01 and one is Descendant.

I didn't buy them, they came on a couple of bikes so I used them. There was never a problem and a million advantages with a good set of 7000-series forged cranks like Turbines or something similar, which would have laughed this stuff off for the next 20 years. I guess carbon cranks were developed to save, what....100 grams low on the bike where it will never be noticed anyway and to separate us from more of our dollars for no advantage?

Rant off.

Never had an issue with Next SLs despite much, much abuse. I do put rubber protectors on the ends, but that's about it.

 

[jeremy3220]

Only issue with cranks I've had in the 5 years I've been riding have been Shimano XT cranks coming loose. No problems with the carbon X01 set I've had twice as long (as the XT set).

 

[MudderNutter]

I don't mind carbon cranks on other types of bikes like cx/gravel/road.... Buuttt I'll never leave any on a mountain bike even if they come with em. One 12 mile walk out of the backcountry was all it took for me to decide they are very stupid.

Honestly selling a nice new set of carbon cranks and replacing with aluminum is a good way to fund some upgrades that positively impact ride quality.

 

[mack_turtle]

no one that I know in central Texas is dumb enough to put carbon cranks on a mountain bike. that would last a few rides with all the exposed rock here.

 

[fmendes]

I've seen very few failures on carbon cranks. On the other hand, I've never seen a failure on aluminum cranks. And I've seen many more aluminum cranks than carbon cranks.

 

[slapheadmofo]

And I’ll bite on this… you have owned 12 high end mtb and 26 high end bikes? 26 as in inches of wheel size? Regardless, that is a lot of bikes!

Looks like the secret behind not having to worry about carbon cranks is has been revealed: simply buy new ones every 6 weeks.

 

[Gym123]

I like it! That way the rock would have sailed over the spindle and smashed my ankle. Chicks like dudes that limp.

On a related note it gives me pause about carbon rims too, though I'll bet they are tougher since to some degree they are designed for impacts. The way a rock occasionally nails my AL rims and leaves a gash, I'd be curious how carbon holds up.

You mean, like Esmerelda and Quasimodo?

 

[834905]

Looks like the secret behind not having to worry about carbon cranks is has been revealed: simply buy new ones every 6 weeks.

Fail rate is astronomically low when each set only sees 3 miles.

 

[dir-T]

I've seen very few failures on carbon cranks. On the other hand, I've never seen a failure on aluminum cranks. And I've seen many more aluminum cranks than carbon cranks.

I snapped an aluminum LX crankarm in half while sprinting away from a stop sign. Upon inspection, the arm had a little ding in it that must have acted as a stress-riser over time. The crank was pretty old.

Anything can break.