Noticed pedal feeling a bit odd while pedaling, after 3km of pedaling it got really bad. I am unable to remove the pedal, it seems to be spinning freely inside the crank arm socket. Bike is fairly new, have cycled around 500km max. But I have been riding in winter, there’s quite a bit of salt on the road. Also what caused this issue? Is it that crank arm is made of some alloy that couldn’t handle corrosion, or the metal on the pedal caused a reduction reaction on it?
Do I need a new crank arm? or just the pedal?
byu/komalnaath inbikewrench
by komalnaath
11 Comments
Both
Losh dosh
The threads in the crank arm are ruined, so at the least you need a different crank or to get a helicoil installed in the crank, which can often cost more than just getting a crank. The pedal threads might also be bad, but they’re steel vs the aluminum of the crank, so they’re probably fine.
I doubt corrosion ruined the threads in such a short time. What’s more likely was poor pedal installation caused the damage.
Yes, you need new crank arm, and maybe new pedals, because thread on crank arm 100% gone, and maybe thread on pedal damaged too
Looks like you need a new crank and pedal.
Low torque causes this.
The pedal didn’t unscrew itself though. What happens is the low binding force of the threads causes the spindle to move ever so slightly, gradually increasing in movement as the threads get obliterated.
It doesn’t happen overnight.
It’s why pedals require 35-40 Nm. Most people are mistaken in thinking all you need to do is get it finger tight and that since pedaling is in the direction of the threads, that it will be enough.
The weigh of the rider and the little bit of extra leverage created by the length of the spindle is enough to literally pry and rip the pedal out of the cranks.
Either get a helicoil installed or replace the crankarm.
The pedal threads have a good chance of not being damaged, since the pedal is steel and the cranks are aluminum.
Wellgo, buy a new crank and pedal
Pedals mounted on the wrong sides or misaligned threads while mounting is what generally causes this. You’ll at the very least need a new arm, and maybe new pedals. The threading on the pedals is generally much stronger.
Bro this is the equivalent of swinging a broken ankle around, it’s toast, I had the same issue once which was a low quality pedal and must have accidentally cross threaded
Both
Both.