Broken profile crank

I’m still puzzled over why it broke. I was riding down a rocky hill on
my Muni when my left foot slipped off the pedal. I fell backwards
and my right foot continued on the down forward stroke on the other
pedal. I got up and started back up the hill for a retry when I hear
a “klank”. I look down and the right crank is on the ground!

don’t go buy a new set! they’re under lifetime warranty, you can get them replaced! that’s one heck of a break there…

I had a Profile crank do the same thing. used to grind down the chain sprocket bolt area on the right-hand crank so there would be more clearance between that protrusion and the frame. Some got a little more grinding than they should and ground away too much of the weld.

If you got it from just contact them and find out how to return it. You’ll get it replaced under warranty.

Don’t grind down the replacement crank any more than absolutely necessary (preferably none at all).

Did you hear any strange creaking from your unicycle before the crank finally cracked?


You know exactly why it broke: Look at all that corrosion, and on top of it the nub was ground down. Next time spray some WD-40 inside the crank, or squirt some oil (30W or heavier is better) in the crank before a long ride.

yeah but it all started with the grinding…hopfully those days are close to being over as Profile fades into the past.

The Profile cranks have a rust preventative coating inside. Unfortunately it looks like the coating is sprayed inside before the hole is drilled and the nub for the chainwheel is welded in. Since that nub doesn’t get the rust preventative treatment at the factory, a spray with some after market rust preventative would still be a good idea around the area of the nub inside the crank.

I plugged the chainwheel hole with a large set screw to help keep water and dirt and junk from getting inside the crank. I also Loctited it in so it wouldn’t manage to fall inside the crank. I can’t remember the thread size for that hole. I’m pretty sure it’s an imperial size rather than metric. I was able to find the right size set screw at a local hardware store.

I was thinking about the corrosion, but where it broke it was all metal as far as I can tell. There is quite a bit of chrome pitting. And the nub, while it looks heavily corroded from the surface, doesn’t provide any support because it’s attached on one edge of the hole only. It would provide structural support if there was a bolt screwed in there and the bolt was attached to something else.


When did you become an industry analyst? Where’s the “buzz” about Profile closing down their operations? …and what company will step up in their place? Who’s stealing their business?

It’s important to remember that in JC’s case, it wasn’t rust that led to the break, it was pure rage.

This might be considered OT, but have anyone broken the 05 KH cranks yet?

I suspect they are just as sturdy and strong as the Profiles. Only cheaper.

never said i was, Profile is fading…fading out of the unicycle end of things.

My question still stands… who’s going to step up and warranty their equipment? I know its costly, maybe I’m old fashioned, but I’m more than willing to pay extra money for a product that comes with a warranty. Granted, the uni parts market is quite small, but why is it so hard for a company to stand behind their product? Until I see other companies taking their lead, Profile gets my money.

Funny pic!