I’ve been working on a Falcon lately and wanted to complete the bike with a set of Campagnolo pedals. I removed the pedals that were on the bike, there were French made Atom pedals. Put a little anti-seize on the Campy pedals;s and no go.
Being a novice, I thought that Campy pedals would fit a Campy crank set. The Atom pedals screw in easily and tighten without issue, the Campy pedals won’t do the same.
The Campy pedals have 9/16x20 stamped on them. Should they fit or are their different pedals for different crank sets in the Campy world.

Zoomed and cropped.




It looks like some threads are damaged. They can be dressed with a thread file. Maybe I'm just seeing the anti-seize. Could there be old thread locker in the thread recesses?

I should have cleaned the threads before posting, that is the anti-seize. Should they fit?

From Sheldon- RIP
https://www.sheldonbrown.com/pedals.html

Thread Sizes

• Most pedals have 9/16" x 20 tpi threads.
• Pedals for one-piece cranks are 1/2" x 20 tpi.
• Older French bicycles used a 14 mm x 1.25 mm thread, but these are quite rare. French-threaded pedals are commonly labeled "D" and G" (French for "droite" and "gauche" (right and left). A French pedal will start to thread into a 9/16 x 20 crank (and vice versa), but will soon bind. Do not force it, or it will damage the crank. Aluminum French cranks can be rethreaded to 9/16" x 20 TPI. You should ask in advance whether a shop is able and willing to rethread cranks. Better bike shops have the special taps, but some are reluctant to subject them to wear, and prefer to use them only to chase threads that are already 9/16" x 20.

Pedal Threading

Type of cranks Pedal threading, inches Pedal threading, metric One-piece (American) Cranks 1/2" (0.50") x 20 tpi 12.7 x 1.27 mm Standard-3-piece cranks 9/16" (0.56") x 20 tpi 14.28 x 1.27 mm Old French 0.55" x 2032 tpi 14 x 1.25 mm Dyna Drive 1" x 24 TPI 25.4 x 1.06 mm

French threads are metric, and take a slightly smaller hole in the crank than do BSA pedals, which are 9/16. Campagnolo made cranks and pedals with both threads, so you'll either have to find a pair of Campy pedals in metric threading, or tap the crank for 9/16 threads.

I just looked at my '71 Gitane Super Corsa. With original crankset and pedals.
The crankset markings indicate 9/16 x 20 F, while the pedals simply show 9/16 x 20.
Makes me wonder if the shop forced the pedals on. Many years ago, I removed and rebuilt the pedals without issues.
I own a good set of Park taps for English threads. Hardened steel that easily cleans up aluminum threads.
Possibly a good time to deploy soon.

‘Thank you, that makes sense as to why the French Atom pedals fit but the Campy pedals don’t. As a novice, working on a French bike and English bike at the same time is certainly a learning experience.
Maybe easier to get a new crank set than find the correct Campy pedals.

Thanks for everyone’s help and patience, I’d certainly be lost without the support.

I've tapped a LOT of French thread alloy cranks to the BSA standard. It's pretty straightforward and works fine. And from the description, that is pretty much the issue here: French threaded cranks. The OP could hold the pedal threads next to each other and see the difference. A simple caliper measure of the pedal thread diameter would confirm.

You are exactly correct. I did check with a caliper and they are different sizes. I don’t know where to get the crank arms tapped and I’m not up to the task. Thanks.

I looked up "9/16 X 20 tap" on line and found many vendors, some of whom specify theirs is a pair, including R and L taps, for bicycle repair. Prices started in the teens dollars. It might be helpful to also have a tap handle (to help get it started and keep going in straight) and be sure to use plenty of light oil to lubricate the tool. Back it out partway from time to time to help clean out built up metal chips that could clog and mess up the newly cut threads.

Others here may have more experience with this job. It's more than chasing and reshaping messed up 9/16 X 20. You are using the existing pedal threads as a guide and then cutting new threads of a slightly larger diameter, so keeping it going straight may be a bit more challenging.

Anyone else confused by this?: the Campi R pedal shaft has 9/16X20 on one side and D on the other. Usually D indicates French (metric, 14X1.25 MM) thread as well as droit (right.) I guess I haven't seen enough old Campi pedals up close to have noticed this labeling.

D for Destra is Italian for "right" and S for Sinistra is Italian for "left," so you can keep R/L and D/G and D/S in mind while you work on your bike and your foreign languages simultaneously.

I would make absolutely sure using a couple different methods. If the crank arm is marked 9/16x20, it would be really bizarre that someone fit French pedals. Maybe try another 9/16" pedal like a Japanese one.

ime, Campy pedals were always extremely tight in Campy arms that were new to me. I often had to start the pedal axle from the other side of the crank arm and work it in slowly and with some force.

[QUOTE ime, Campy pedals were always extremely tight in Campy arms that were new to me.[/QUOTE]

I remember them being like that, too, the times I worked with them back in the 1970s and early 80s. Worried the crank arm would crack! A smear of Campi grease and some patient back-and-forthing got the job done, resulting in the stiffest truest and smoothest running crankset in my experience.

Falcon is a British brand, and I would expect English thread throughout.
Metric thread Lyotard pedals should be markd "G" (gauche, "left") and "D" (droit, "right"). If yours are marked L and R, they are English thread. Similarly, your Campagnolo crank should have the pedal thread indicated next to the pedal eye, "9/16 x20F" = English; "14 x 100" = metric.

Interlock the threads of the two different pedals together and see how well they match up. Make certain to compare the left pedal to the left pedal and right to right.

Pay attention to the fit of the angled sides of the thread and not so much whether they meet at the bottom of the valleys. Also double check that the major diameter of both are the same. And if also the minor diameter if you have the tools to measure that. Even just calipers will measure the minor diameter well enough if the points of it's jaws are beveled to a fine enough edge.

Of course they do make thread gauges. But I doubt that you want to spend that money for just this application. And even they don't tell you any of the stuff you really need to know about whether a thread is correct or not.

I did measure them and found the Atom pedals are slightly smaller than the Campy pedals. The Atom are 14mm.


You are correct. I just checked, the crank arms are marked 9/16 x20F which makes sense. The pedals that are on the bike are Atom and have a “Made in France” marking. I’m guessing at this point there is an issue with either the threads in the crank arms or Campagnolo pedals. I guess it’s time for the tap and die set. Again, I’m a novice at these bikes so again, thanks for the assist.

i just measured the campy pedals which were .557

They are marked L/R and measure 13.78mm.

So both Campy cranks and current non-Campy pedals are labeled 9/16, and your new Campy pedals won't thread in. Been there. Every time.

I guess I’ll run the pedals and crank arms through a 9/16x20 tap and die to make sure the threads are sharp and clean and go from there.

These old bikes certainly test one’s ability to work on them, ability which I’m in short supply.

Thanks for the assistance

Just chase the crank arms with taps. I wouldn't bother with using a die on the pedal threads. Pedal axles are hardened steel and will not be kind to your dies. Just make sure the threads are clean. If the threads are damaged, use a thread file on the damaged places.

I measured the Campy pedal 14.2mm, Atom pedal 14mm and a pedal from my Trek MB 14.2

The atom screws in easily and even tightens down. The Trek pedal started nicely but became very snug. I ran the pedal in/out until it was completely in the crank arm. Removed it, cleaned and greased the crank opening and then tried the Campy pedal. It started but got a bit snug. I started working the pedal in/out again and eventually it was seated properly.
Thanks for the assistance with this.



Trek pedal on drive side

The LENGTH of threads on the Atom pedals is mighty short; That alone may allow them to thread in with a slight mismatch in pitch, which there probably isn't. More importantly, the thread length is way too short for threading into aluminum; They were probably originally designed for a steel crankset. You should limit them to that.

It'd be nice to see a picture of the threads of the two different pedals interlocked together. That will tell quickly if there is any difference at all in the pitch of the thread.

Though not the two in the photo above since that obviously are opposite threading directions.