Is it possible to buy a single crank arm. I was riding today and my left pedal came loose, stripping the threads in my crank arm.

Usually, it it's a current crank.Think there are also repairs for hosed pedal threads.

pedals are fine...why is it that they make the cheap pedals so much harder than the expensive cranks?

Aluminium is softer than steel. They both have roughly the same strength-to-weight ratio. However, size-to-strength is 3x better with steel. In the limited size available to make a pedal-axle, steel is the better material. A 1/2" diameter aluminium pedal-axle won't last long, especially with continually hitting it on the ground.

If the threads aren't too damaged, you can often re-tap it and re-install the pedal as is. Otherwise, you can use various thread inserts. Personally, I don't like Helicoils, they are among the weakest thread-repair solutions. It's actually possible to strip a Helicoil upon re-assembly if the hole was badly damaged. Time-serts are much, much better and more permament solution. They do cost about twice as much as a $3 Helicoil. I've repaired engine-blocks threads taking over 120 lb*ft of torque with Time-serts before, definitely not something a Helicoil can handle. EZ-locks or Keenserts work well too. You can get them all from Barnhill Bolt.



As mentioned, proper installation is of vital importance. Most holes can be drilled with a drill-press in proper alignment if they are perpendicular to the crank-arm (assuming the crank-arms are flat). Also the correct sealant/threadlocker must be also used to prevent galvanic corrosion with dissimilar metals as well. Count on 30-minutes of labor minimum, so buying a new crank-arm is often the easiest solution.

what make and size arm do you need? is it the drive side or the chain ring side? try ebay or aebike.com go to the parts and do a search. btw, I have a non drive campy 172.5 sitting around...make me an offer!

Yes, check out https://aebike.com/site/page.cfm?Page...ory=576&type=C. I found their price for Ultegra 6600 parts better than Performance even with the discount. Another option would be to buy used via Ebay and get the whole crank...

It was kind of a rhetorical question but thanks for the great info.

It's not campy and as I stated before it's the left side.

There's actually a funny story that goes along with it. I noticed the pedal had come loose after coming down the hill in Prospect Park, so I decided to go to the nearest bike shop to put it back in. I got about halfway there riding with only my right leg then decided to stop and hand tighten the pedal.
It didn't want to go back in so I gave it some grunt and loosened it, that's when I saw that the crank was stripped. That's when I began the long trip home, again riding with one leg. I got quite a few stares from people, they must have thought I was on some new training routine.
Anyway, I got about halfway home and some random guy whom I have never seen before comes up to me and calls me by my first name. I'm new to Brooklyn and NYC so this is a little weird. It turns out that he is the guy who wants to buy my bike. Quite a coincidence, huh? Apparently he recognized me by the bike and thinks "there can't be to many 6'5" guys riding F70's around Brooklyn". So here I am pedal in hand trying to convince him that this is a great bike.
He didn't seem too phased by the need for a new crankarm and after straddling the bike he said he'd get back to me. Once again I headed home, this time walking as the one pedal method just wasn't doing it for me anymore.
I get a few hundred yards from my dorm, when I hear a loud bang. I mean really loud, it could've been a gunshot...no. When I felt the cool rush of air on my right leg I knew it was only my brand new tube. Come on, I've had flats before but never while walking my bike.
That's pretty much how my day ended, sorry for rambling but looking back it was a rather peculiar day.

Gotta hate the bad days! That's so unlucky! At least it didn't happen WHILST you were riding one-pedalled, that could have been nasty. I'd try to re-tap the thread first, using the second gadget mentioned above if possible. Failing that, I guess it's a new crank arm. Good luck though, especially after that day!