tetonrider

Every set of instructions or manual I see indicates to use a washer between pedal and crank. However, I have 5 sets of pedals between MTB & road bikes for me and my wife. Of them, I can remember only one that has washers -- and I remember that set as having been zip-tied to the cranks.

I just got a new set of road cranks, and they didn't have washers. A while back, I got a new set of XT MTB cranks....no washers either. None of my pedals have come with them.

Are they necessary or even "highly" recommended? Should I be heading to the hardware store ASAP?

Thank you!!!!

jacerab

the fsa cranks i've used have come with washers. any shimano cranks i've used haven't come with nor called for the use of washers.

huytheskigod

If a crank comes with washers, I use them. If they don't I don't. The FSA cranks I've had have recesses for the washers while the Shimano cranks do not.

umd

It depends, the specialized cranks (that's what you have, right?) don't need washers because they have a metal facing already in place. I have some other carbon cranks that need washers otherwise the pedal shaft would rub the carbon.

markwebb

MY FSA carbon cranks have recesses for washers. I have always used washers. I got in habit of using washers 30 years ago with Campy quill pedals and Campy cranks. Washers and grease, so I could remove the pedals later

terrymorse 

The washer is supposed to help prevent fatigue cracking of the crank arm, caused by the pedal spindle rocking against the face of the crank's threaded hole. Hardened steel rolling against soft aluminum.

No idea if it works, but that's the reasoning I've heard.

iareConfusE

The washers help protect the cranks from being scratched from the pedal bolts. When you tighten the pedal bolts down on carbon cranks without the washers, it will end up scratching them and probably weakening them as well.

tetonrider

thanks for the replies. in parallel, i posed the question to a friend who is an engineer (and also works with carbon).

umd: i do have specialized carbon cranks on my roadbike. i've also got fsa cranks and shimanos around here, too. i recall the FSA came with pedal washers.

the specialized manual is very clear on the use of washers and yet.....none are included.

here's what my friend had to say on the matter:
If the pedal flange is smaller than the counterbore, then you will have really high load peaking right at the threads. This is bad. You want to distribute this load as much as possible, especially on carbon crank with a metallic pedal insert.