Can I shorten carbon cranks?

[TheoG]

1 minute ago, stefmeister said:

Whenever I read something about Raceface carbon cranks, it's about them failing. 

I have mine for a while now (bought used) and zero issues so far.

[MudLark]

42 minutes ago, JA-Q001 said:

And PS, stop using crank boots.

 

Why? 

[TNT1]

2 hours ago, mountainfun said:

 

What I was thinking is whether I can go extreme and shorten the cranks to say 162,5.  This would involve cutting etc.. It would need to be done by a very seasoned carbon expert.  

I'm sure the right answer is "no", for various reasons, but I thought worth a shot.

Thanks

JL

Send them to me. I have an angle grinder and a drill. I'm a seasoned expert too. Well, not in carbon, but I'll give it a shot anyway.

[Jewbacca]

18 minutes ago, MudLark said:

Why? 

Bea cause just stop! 

I also want to know why. I don't use them, but I'm dying to know the science behind why we shouldn't use crank boots.

 

[TNT1]

2 hours ago, mountainfun said:

 

What I was thinking is whether I can go extreme and shorten the cranks to say 162,5.  This would involve cutting etc.. It would need to be done by a very seasoned carbon expert.  

I'm sure the right answer is "no", for various reasons, but I thought worth a shot.

Thanks

JL

Send them to me. I have an angle grinder and a drill. I'm a seasoned expert too. Well, not in carbon, but I'll give it a shot anyway.

[Veebee]

Yeah Graeme Kidson aka Carbon Ninja will be able to sort this out for you.

He posted new contact details yesterday, here we go.

 

[Mountain Bru]

Possibly a more relevant question than "Can I cut these shorter?" is do you want shorter cranks? If they're currently 170mm, you'll probably have to go down to like 160mm, which is maybe not a good idea in itself and so it's irrelevant if they can be cut shorter. 

I'm also interested to hear why crank boots are a bad idea though. I've never heard anything bad about them. 

[Jewbacca]

14 minutes ago, Mountain Bru said:

Possibly a more relevant question than "Can I cut these shorter?" is do you want shorter cranks? If they're currently 170mm, you'll probably have to go down to like 160mm, which is maybe not a good idea in itself and so it's irrelevant if they can be cut shorter. 

I'm also interested to hear why crank boots are a bad idea though. I've never heard anything bad about them. 

I present to you, the 145..... Used to be 175

Bit of tooling, tapping and boom! Cranks for ants!

[SwissVan]

4 hours ago, mountainfun said:

Hi

I have RaceFace SIXC carbon cranks, 170mm.  Awesome, except that the pedal insert has come loose.  (Thread not stripped.)  Apparently that cannot be fixed, but any comments on that also welcome.

What I was thinking is whether I can go extreme and shorten the cranks to say 162,5.  This would involve cutting etc.. It would need to be done by a very seasoned carbon expert.  

I'm sure the right answer is "no", for various reasons, but I thought worth a shot.

Thanks

JL

Can you claim warranty due to the loose insert, and then ask for a shorter length 162.5 (if available)?

 

 

[wessie12]

1 hour ago, TNT1 said:

Send them to me. I have an angle grinder and a drill. I'm a seasoned expert too. Well, not in carbon, but I'll give it a shot anyway.

No no no please no...you need to be delicate with carbon cranks. All you need is a proper hammer en beitel with a soft touch. 

[Mountain Bru]

3 minutes ago, wessie12 said:

No no no please no...you need to be delicate with carbon cranks. All you need is a proper hammer en beitel with a soft touch. 

I've heard carbon is much easier to carve if you heat it up with a blow torch first.... 

[shaper]

Just wondering the cost for repair and not knowing if it will last....in comparison to getting a new crank?

[porqui]

18 minutes ago, SwissVan said:

Can you claim warranty due to the loose insert, and then ask for a shorter length 162.5 (if available)?

 

 

This  ^^^

I would say that it is a manufacturing defect.

[droo]

2 hours ago, Mountain Bru said:

Possibly a more relevant question than "Can I cut these shorter?" is do you want shorter cranks? If they're currently 170mm, you'll probably have to go down to like 160mm, which is maybe not a good idea in itself and so it's irrelevant if they can be cut shorter. 

I'm also interested to hear why crank boots are a bad idea though. I've never heard anything bad about them. 

I'm 1.82 and ride 165mm cranks on my MTB. Much preferring them to the 175mm I was on before, although they take a bit of getting used to on steeper climbs.

[Mountain Bru]

1 hour ago, droo said:

I'm 1.82 and ride 165mm cranks on my MTB. Much preferring them to the 175mm I was on before, although they take a bit of getting used to on steeper climbs.

For sure. I'm sure there are loads of people that have chosen to ride short cranks for a number of reasons. My point is trying to figure out if the OP actually wants shorter cranks, or is only wanting short cranks because he doesn't want to bin his "broken" 170mm cranks, I think that's a really bad reason to switch to 160mm cranks. 

Edited August 24, 2021 by Mountain Bru

[JA-Q001]

3 hours ago, Jewbacca said:

Bea cause just stop! 

I also want to know why. I don't use them, but I'm dying to know the science behind why we shouldn't use crank boots.

 

Those crank boots get dust between the boot and the crank. I have seen more failed cranks because of that dust than any other reason.

It grinds the carbon away around the insert and creates a weak spot. That black dust all over the tip of his crank, thats carbon dust.

Edited August 24, 2021 by JA-Q001