Crank Rock Strikes

Posted by: Vikb

I bought 2 sets of carbon cranks back when they first came out and I was working in aerospace composite manufacturing...just out of professional interest and a 3rd set came on a complete bike I bought. My GF has a 4th set that came on a complete bike. Logging many years of riding on all those cranks I managed to loosen the pedal insert on the set installed on my one bike with a low BB after several seasons of use including the many crashes that happen MTBing. The damaged pair were the lightest XC/trail variant of that crank. 

While I'm not motivated to buy more carbon cranks at this point I wouldn't say no if they came on a complete bike or I got them at a discount. I expect I'll be riding the carbon cranks I have for many more years. They don't seem particularly fragile especially the later versions that were built even stronger with feed back from the lighter duty versions.

We have sooooooo many door and drawer handles at work made from failed carbon cranks.

Posted by: trumpstinyhands

We have sooooooo many door and drawer handles at work made from failed carbon cranks.

Ya I've heard the stories, but really have not had any horrible issues myself. I've had a number of droppers that, based on internet talk, were doomed to fail ASAP that ended up lasting me many years without problems.

Rock strikes can suck but for me the key is not a short crank but a better hub engagement. It's harder to time and ratchet with a sloppy engagement. Hope pro4's are fine CK is better. I had a spank wheelset that had the same engagement as a shimano and I was continuously hitting things. I'd put my efforts there personally. I run 175s on all my bikes and tbh, I don't think I'd be pedaling through rock gardens with 170s that I don't with 175's. How much does 5mm really make? I have bigger issues hitting my chainring than the actual crank arms most of the time.

Posted by: RAHrider

I run 175s on all my bikes and tbh, I don't think I'd be pedaling through rock gardens with 170s that I don't with 175's. How much does 5mm really make? I have bigger issues hitting my chainring than the actual crank arms most of the time.

5mm shorter cranks with thinner pedals can make a HUGE difference. I've tweaked bikes where they got frequent pedal strikes and making small changes to crank length, pedal thickness and size reduced the problem from near constant to occasional. Running taller tires is also something that can make a big difference for pedal strikes as well as making sure your shock is not sagging deeper than expected.

Hitting your chainring is a different problem..much bigger rocks/roots. A taco bash is useful for that.

Posted by: Vikb

I bought 2 sets of carbon cranks back when they first came out and I was working in aerospace composite manufacturing...just out of professional interest and a 3rd set came on a complete bike I bought. My GF has a 4th set that came on a complete bike. Logging many years of riding on all those cranks I managed to loosen the pedal insert on the set installed on my one bike with a low BB after several seasons of use including the many crashes that happen MTBing. The damaged pair were the lightest XC/trail variant of that crank. 

While I'm not motivated to buy more carbon cranks at this point I wouldn't say no if they came on a complete bike or I got them at a discount. I expect I'll be riding the carbon cranks I have for many more years. They don't seem particularly fragile especially the later versions that were built even stronger with feed back from the lighter duty versions.

I look at some of the scars on my (very old but still going strong) RF Turbine cinch cranks and think I made the right choice. Given they're like 60g heavier and 1/3 the price of SIXC it's a no-brainer I'm staying on alloy.

Posted by: craw

I look at some of the scars on my (very old but still going strong) RF Turbine cinch cranks and think I made the right choice. Given they're like 60g heavier and 1/3 the price of SIXC it's a no-brainer I'm staying on alloy.

I don't think alloy cranks are a bad idea at all. My fleet is split about 50/50 in terms of metal vs. carbon. I'll probably buy metal cranks next time I need some.

Posted by: craw

Posted by: Vikb

I bought 2 sets of carbon cranks back when they first came out and I was working in aerospace composite manufacturing...just out of professional interest and a 3rd set came on a complete bike I bought. My GF has a 4th set that came on a complete bike. Logging many years of riding on all those cranks I managed to loosen the pedal insert on the set installed on my one bike with a low BB after several seasons of use including the many crashes that happen MTBing. The damaged pair were the lightest XC/trail variant of that crank. 

While I'm not motivated to buy more carbon cranks at this point I wouldn't say no if they came on a complete bike or I got them at a discount. I expect I'll be riding the carbon cranks I have for many more years. They don't seem particularly fragile especially the later versions that were built even stronger with feed back from the lighter duty versions.

I look at some of the scars on my (very old but still going strong) RF Turbine cinch cranks and think I made the right choice. Given they're like 60g heavier and 1/3 the price of SIXC it's a no-brainer I'm staying on alloy.

Agreed. I am happy to pay the 60g penalty to NEVER have to worry about my cranks. I have been running Shimano cranks for years, but have a set of alloy GX cranks on the Fugitive. They seem to work fine, and I have to say I am impressed by how well the DUB BB is holding up.

Posted by: RAHrider

Rock strikes can suck but for me the key is not a short crank but a better hub engagement. It's harder to time and ratchet with a sloppy engagement. Hope pro4's are fine CK is better. I had a spank wheelset that had the same engagement as a shimano and I was continuously hitting things. I'd put my efforts there personally. I run 175s on all my bikes and tbh, I don't think I'd be pedaling through rock gardens with 170s that I don't with 175's. How much does 5mm really make? I have bigger issues hitting my chainring than the actual crank arms most of the time.

Totally agree about  better hub engagement. I didn't buy the I9 Hydras specifically for their engagement, but they definitely make pedalling up tight, technical climbs easier. It's a very noticeable improvement.   I did go from 175 to 170mm cranks, and the difference is noticeable. I still get pedal strikes, but not as many or as often even though I am riding the same bike on the same trails, and my technique hasn't changed much.  I have found that pedal thickness makes a difference too, even though the it's only a few mm.

Posted by: skooks

Posted by: craw

Posted by: Vikb

I bought 2 sets of carbon cranks back when they first came out and I was working in aerospace composite manufacturing...just out of professional interest and a 3rd set came on a complete bike I bought. My GF has a 4th set that came on a complete bike. Logging many years of riding on all those cranks I managed to loosen the pedal insert on the set installed on my one bike with a low BB after several seasons of use including the many crashes that happen MTBing. The damaged pair were the lightest XC/trail variant of that crank. 

While I'm not motivated to buy more carbon cranks at this point I wouldn't say no if they came on a complete bike or I got them at a discount. I expect I'll be riding the carbon cranks I have for many more years. They don't seem particularly fragile especially the later versions that were built even stronger with feed back from the lighter duty versions.

I look at some of the scars on my (very old but still going strong) RF Turbine cinch cranks and think I made the right choice. Given they're like 60g heavier and 1/3 the price of SIXC it's a no-brainer I'm staying on alloy.

Agreed. I am happy to pay the 60g penalty to NEVER have to worry about my cranks. I have been running Shimano cranks for years, but have a set of alloy GX cranks on the Fugitive. They seem to work fine, and I have to say I am impressed by how well the DUB BB is holding up.

I decided to go with a 165mm Shimano Crank due to availability in that length. Was looking for a Turbine at 165mm but no such thing. Also wanted something I could run a power meter on in the future and hoping there will be enough clearance on the non-drive side for that. I guess a spider based meter is also an option such as the Power2Max as was pointed out earlier. Either way it’s no biggie as it’s really all about just getting out and riding.