Mountain Biking - Crank Question

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View Full Version : Crank Question


CycleAloha
04-03-07, 12:39 AM
As mentioned in earlier posts...today while installing my new pedals I managed to stripe my crank arm...ie the pedal won't stay on. My question is can (or should I) buy a new crank arm or look for a whole new crank set. The one's on are TruVativ ISOFlow 3.0 175mm (22/32/42). Does the replacement have to be exact specs or just make sure it's compatible w/BB (Power Spline)? Appreciate any help....and yes I know I'm a moron!!!!


metabike
04-03-07, 04:45 AM
Before you give up on what you have, track down an auto shop in your area who can try installing a helicoil thread insert for you. Don't mean to insult you but just in case you are wondering, "Heli-CoilŪ inserts are precision formed screw thread coils of stainless steel wire having a diamond shaped cross section.When they are installed into Heli-CoilŪ tapped holes, they provide permanent conventional 60' internal screw threads that accommodate any standard bolt or screw."

Good luck and welcome to the International Federated Brotherhood & Sisterhood of Amalgamated Mistake Makers! (I've attained journeyman status so don't feel bad.):)

pinkrobe
04-03-07, 07:58 AM
Oh, and a word of advice - start threading your pedals by hand. Once you've got a few threads engaged, feel free to break out the tools. Don't force it - most pedals can usually be screwed pretty much all the way in without needing tools.


dminor
04-03-07, 08:38 AM
In my experience, Heli-Coiled pedal threads do not last. There is often not enough material removed from the pedal hole to get a clean bore to tap for the coil. There are more heavy-duty thread inserts made by Eldi; but good luck finding a shop that actually stocks them AND has the Eldi tools to do the job. Plus, your TruVativ crank is probably not worth the expense of going that route.

Try the more economical Heli-Coil if you want but be prepared to have to replace it eventually anyway.

CycleAloha
04-03-07, 09:13 AM
All, I'll make some calls but limited resources here in Hawaii.....thanks for the info and advice on doing it by hand.

Thanks again.

CycleAloha
04-03-07, 09:31 AM
I've been shopping around and have a few possible replacements, guess my question now is do the new cranks have to be 175mm and have 22/32/42, exactly what I have now? I can't find my current crankset online or I'd just buy it.

....and yes I'm a full card carrying member of the Brotherhood now.

santiago
04-03-07, 09:37 AM
I've been shopping around and have a few possible replacements, guess my question now is do the new cranks have to be 175mm and have 22/32/42, exactly what I have now? I can't find my current crankset online or I'd just buy it.

....and yes I'm a full card carrying member of the Brotherhood now.

Sometimes you can just buy the crank arm. At that point the only thing you have to try to match up is the 175mm length. Not sure if this applies for the crank arms you have.

ZeCanon
04-03-07, 10:58 AM
if you are replacing the whole crankset, you don't need to buy the exact same thing. Just make sure it goes with your BB, and you'll be fine. If you are only replacing one arm, it needs to be the same length. BCD (bolt hole diameter) and tooth count do not need to be the same, though 90% of all mtb cranks are damn close to 22/32/42. Some may have 24's, or 44's, but that doesn't really matter (though if you like your current gear ratios, try to find one that is the same).
Powerspline BB? You mean ISIS?

CycleAloha
04-03-07, 02:40 PM
if you are replacing the whole crankset, you don't need to buy the exact same thing. Just make sure it goes with your BB, and you'll be fine. If you are only replacing one arm, it needs to be the same length. BCD (bolt hole diameter) and tooth count do not need to be the same, though 90% of all mtb cranks are damn close to 22/32/42. Some may have 24's, or 44's, but that doesn't really matter (though if you like your current gear ratios, try to find one that is the same).
Powerspline BB? You mean ISIS?


Sounds good, think I'm tracking all.

Yes, I believe it is ISIS.

I've got my eye on a crank arm but waiting on seller to get back w/me but it should be 175mm.

alumrock12
04-03-07, 07:03 PM
dang. you stripped the pedal threads on your crank? i wouldn't want to get into a fight with you... hehe.

CycleAloha
04-03-07, 08:43 PM
dang. you stripped the pedal threads on your crank? i wouldn't want to get into a fight with you... hehe.


That's one thing I couldn't figure out....thought I'd jack up the pedals first, which would have been much more cool b/c they were cheap platforms.