Roypercy

I'm putting the finishing touches on a bike with a Spidel crankset threaded for French pedals. I found a great pair of Spidel (Maillard 700) pedals that I'm awaiting delivery on.

I've been advised to install washers between the pedals and the crank arms to prevent scratching. When I look a pedal washers a lot of them say "for 9/16 pedals". Can I ignore this and just use any pair of pedal washers? Or is there something specific I should be looking for? Any recommendations?

Brad L 

French spindles are ever so slightly smaller so the 9/16" will be fine.

non-fixie 

Sure, but we'll all know, whenever we see that vélo, that is hasn't the correct 14 x 1.25 pedal washers, won't we?

Roypercy

I won’t tell if you won’t.

romperrr 

I've never heard of pedal washers on any bike. Is this a common practice?

tiger1964 

Me neither, but it was quick to see them available for purchase online. Hmm, seems like a way to lose 3/4 of one thread of engagement between pedal and crank arm.

daka

I don't know that it is common, but the idea is to reduce fretting at the junction where the pedal spindle (hard) works against the crankarm (soft). On a used aluminum crankarm a "ring" around the threads is usually visible - this is the fretting damage. Placing a thin washer there will spread the load around and slow the process. Not much of an issue with steel crankarms, obviously.......

Roypercy

As it was explained to me, French threaded pedals tend to cause more wear on the crank arms than English-threaded just because of the way the spindles are made. The Spidel cranks I have are shiny and minty, so I figured it couldn't hurt.

oneclick 

I'd be wary of any other mechanical suggestions from the same source.

JohnDThompson 

A washer helps prevent fretting damage between the pedal axle and the crank arm, which can lead to failure at the crank arm's pedal eye.

daka

Might be true if French-threaded pedals were screwed into an English-threaded crankarm?

Chombi1 

I never installed washers between my pedals and my crankarms. I want my pedal spindles to be anchored directly to the crsnkarms as much as they can be. Introducing a washer between the two components just makes for more chances (Even minute as they can be.) that the pedal spindles can loosen from the crank, while riding.....

tiger1964 

That makes a lot of sense, but...

Anyway, not only all the bikes I've owned over the years, but the years I worked in bikes shops while in college... never saw them. Perhaps a more recent invention?

daka

I think you will find that your policy here disagrees with most everything else you own. Look under the hood of your car, you will find washers beneath the bolts that hold most everything on including the cylinder heads - and, trust me, with thousands of combustion events happening every minute underneath them those pieces are trying a lot harder than your pedals to come off!

And what other critical attachment on your bike doesn't have a washer? Crank bolts?, Brake blocks? Calipers? Washers are used because they help keep things secure, not vice-versa.

non-fixie 

I am sensing a non-issue here. Not using pedal washers with aluminum cranks hasn't been a problem for 75 years or so, so why would it be a problem now?

I am guessing some practical joker at SRAM suggested on a Friday evening over a beer to "let's add a couple of washers to the bag and see what happens".

daka

Jobst Brandt likely spent more time thinking about this than most of us. He was also a strong rider who did a tremendous number of miles and spent a bunch of money replacing failed crankarms (more than two dozen according to him in March of 2000, and he was an active rider until his death in 2015). He experimented with other ways of securing pedals, bevels like automobile lug nuts and collets. He went after the source of the fretting rather than "pushing the problem down the road" as one does by using washers.

There was a discussion on this topic just a year ago: https://www.bikeforums.net/bicycle-m...c-reasons.html

While aluminum alloy crankarms were developed in the 1930s I think it is safe to say that they leveraged the design of pedal attachment from the steel parts that preceded them. Steel crankarms, being a harder material, don't often display the same level of fretting one sees on an aluminum part.

gugie 

At the risk of this turning into a 10 page thread, here's a pic from Rivendell's website:


Pedal on the left needs a washer, one on the right, maybe not

Note that the pedal on the left has two flats. These can dig into an aluminum crank arm - it's a stress riser. I'd definitely use a pedal washer if you had this type of pedal. The one on the right we can argue about.

bulgie 

TA started making cranks in the early '60s and pedal washers (ref.137) came with each and every TA crank. Back then TA cranks had "blind" holes; not really a bottoming hole but a thru-hole that had a blanking plug pressed in to the backside. Those were held in only by a tight press fit, and a pedal would often push them out if its threads were too long. I wonder if the ones missing their blanking plug were simply assembled without the supplied washer, which let the pedal come thru too far?

Mark B

JohnDThompson 

It can be a problem:

gugie 

Thanks for posting that pic. Pedal washers are cheap insurance for something that happens from time to time.

reroll

Pedal washers are usually made of thin steel and having a pedal washer between a steel spindle and an aluminum crankarm can help prevent them from loosening. Without a washer when they get tightened the spindle and the crankarm twist against each other and the harder spindle could then damage the softer crankarm by turning its smooth contact surface into a rough contact surface which in turn reduces the ability of the spindle and the crankarm to stay tight, but with a washer the softer aluminum "grips" the washer which prevents it from twisting and the spindle then twists smoothly on the washer as it tightens.

base2 

^^^^
Yep. And every carbon crankset ever made () has a recommendation to use pedal washers to save the aluminum insert & thus avoiding any shape change or stress that would affect the inserts bond to the carbon fiber structure. Most also have a max torque recommendation, too for the same reason. Some as low as 20nm.

tiger1964 

The "blanking plugs" I've run into over the years, without thinking much about them; never the washer. Anyway, I bookmarked a bag of washers and maybe I'll be willing to add 2.7g of rotating weight to each bike.

OK, there's a problem I doubt I'll ever have.

reroll

The best and only good practice is to always use washers beginning with the very first time a spindle gets connected to a crankarm.

JohnDThompson 

Jobst Brandt had a better solution: conical seats as used on automobile lug nuts. But that requires retrofitting cranks and pedals, and retooling pedal manufacturing. Pedal washers do help, and are much easier to utilize.