Do cranks have a lifespan?

It’s come to the time where I need to replace some drivetrain bits (currently 2×9) and I’m toying with the idea of going 1×10 after surprising myself at what I could get up with a 32t front this weekend. The swap is going to be fairly expensive, and a fairly big chink of that is going to be the cranks (£100 for an XT double).

So my question is do cranks have a lifespan? There’s no obvious sign of wear on my current ones apart from a bit of heel rub, but they must be coming up to five years old and I’d sooner replace them before they break for obvious reasons. They’ve been in pretty much constant use, though they are pretty meaty FSA Gravity jobbies.

So can I use that as an excuse to buy new shiny things?

Wait till the heel rub gets close to wearing out the crank arm. That could take ages and ages though.

http://singletrackworld.com/forum/topic/xt-crank-fail/page/2#post-5118861

My old square taper cranks are still going strong. I have a Suntour XC Pro which is 22 years old and is used twice a week as it is on my single speed and a middleburn RS7 which was purchased in 2000 so making it 14 years. I do have a youthful LX HT11 which is six years old so I’m not a complete old fart!!

jam bo – that was the kind of thing I was worried about! Don’t think there’s that much rub but I’ll certainly be having a check.

I have probably six sets of cranks dating from 1989 to 1993 in the garage, some very well used. All work fine. If you look after your kit it should last longer then you need it to.

My 92 Ritcheys have a crack.

I broke some Cook Bros.

The Suntours from my ’92 Hardrock are still going strong after 20 years in daily use.

I snapped a Shimano Exige Crank arm back in the 90’s. Went to set off across a road and as I did the 1st crank turn I thought the chain had come off. Looked down and my spd/half a crank arm were still attached to my shoe.

I’d really like to know how they make hollowtech cranks now!

I think Hollowtech cranks are cold forged, starting with something tube like to get the hollow bit.

It is perfectly possible to wear through the side, but I think you need a very wonky pdealling style to do it. Ash (off of Trans Provence) clearly does…

http://singletrackworld.com/forum/topic/worn-cranks-word-of-warning

I’ve seen quite a few broken cranks, but usually it’s either at the hands of serial component destroyers (very high mileage and very high power) or of lioghtweight construction (eg 90s era Middleburns). Never broken any myself, but I’m generally not a breaker of bits!

Only Cranks I ever broke were Cooks Brothers Racing ones after doing a big drop – it actually snapped the Shimano bottom bracket but the reamaining axle jutting out was sharp and took a chunk of crank metal out and a crack formed. I wept as £230 of a CNC’d bike jewellery died…

Unless you do big big jumps I can’t see the heavy duty cranks you’ve got ever wearing out.

I do little jumps and big rocks badly, mostly! I’ll keep an eye on the rub but save the money for now I reckon. I like the idea of 1×10, but not so much the cost (and I rarely drop a chain with 2×9 and a roller).

Why not just use your existing cranks?

various square tapers in use – must be ‘quite old’ and the cranks on my M2 (1998) are still original (only thing bar frame that is, mind)..

Hmm. Y’know, I never thought about that. Would I need to run it with a bash or could I just get super short chainring bolts?

My 1992 Cook Bros are fine, apart from the logos being a bit worn. Unless there is significant damage or wear I wouldn’t worry.

you can get super short chainring bolts at velosolo, the singlespeed shop.

Sweet. I probably have some outer bolts kicking around, they might even fit. Not that some bolts is going to break the bank 😉

Not trying to be funny, but cranks last until they fail. I had a pair of Deore that I had 4 years with heavy use and no trouble, and are still going strong AFAIK. Sold them in the classifieds on here.

I switched to 1x a couple of days ago, I uses the original bolts but with washers in place of the outer ring.
Seems ok so far!

No funniness taken patriotpro, that was kind of what I thought.

I had a DEORE fail this weekend, bought them second hand on here though, need to see if I can find out who had them. If any of you remember I can be found in Ward 7 Edinburgh RI…

I had a DEORE fail this weekend, bought them second hand on here though, need to see if I can find out who had them. If any of you remember I can be found in Ward 7 Edinburgh RI…

Oh ‘DEORE’…

Oh ‘DEORE’…

J’DEORE