Crank threading
 

Friends - I have a Gipiemme crank with same brand pedals on a project I am putting back together. Early to mid 80s FWIW and both pedals measured 9/16 x 20tpi with my calipers and thread gauge. The pedals don’t thread in easily like most stuff I have worked with. For a test ride I was going to slap on some MKS Sylvans and they would thread in by hand maybe 1/8 of a turn and stop. Here comes the science;

Said Gipiemme pedal easily threaded into an SR crank I had laying around and the MKS did too, naturally.

I cleaned the Gipiemme pedal and crank arm threads and little difference spinning in/out. The MKS was still a no-go. Not cross threading.

My theory - the crank arm threading is kinda marginal from new. Low mile components, I believe. Zero rust on anything, very clean bike.

Do I lean on my pedal wrench with the MKS pedal? I’m reluctant to do that but I believe this era was the twilight years for Gipiemme so maybe the machinery was a bit tired and QC was lax?

Input appreciated!

I would suggest a 9/16” hand tap to clean/chase the threads, then enjoy the smooth threading thereafter.

What you describe sounds exactly like this description of old French pedal threads:
https://www.sheldonbrown.com/pedals.html

So the question is really, was your crank made with optional French pedal threads? Just because Gipiemme also made cranks and pedals with English thread doesn't mean they didn't have other options. Just like Shimano still makes Italian BBs.

Does the inside of the crank have any markings, or around the pedal holes?

And that won't destroy the crank if the threads are French?

Edit: It sounds like Sheldon is saying that works.

Sadly, not in my toolbox though they have been under consideration.

Pedals are these;

https://www.velobase.com/ViewCompone...=109&AbsPos=90

No marks on crank arms except length and pedals have D and S followed by a triangle(?).

Well, I took OP at his word that 9/16” was confirmed, but it’s worth investigating the French if it’s in question. Since French is smaller diameter than English, worst case scenario is that you end up with a functioning crank that is now converted to English, bit I know whether that constitutes an upgrade is contentious.

A bike shop has them.

The pedals are confirmed. The crank is the one that consistently doesn't match different pedals.

Since the cranks are unmarked, I don't think converting them to a different factory threading damages their collectability.

Italian markings destra and sinistra, but still not sure what threading that might mean.

Doesn't that just mean left and right?

Well, FWIW - Velobase states the pedals are 9/16 x 20

I think a thread chasing is the most logical solution

Exactly — I know it’s sort of short hand that when you have French marking D/G it’s a likely indication that you have French threads, but I don’t know of any such short hand for Italian marking. In other words, just because these markings show left/right, we still don’t know the threading based on these markings alone. At least I don’t. There is no “Italian” pedal threading that I know of like there is Italian bottom bracket threading.

Correct

According to VeloBase, these Gipiemme cranks came in both English and French threads: https://velobase.com/ViewComponent.aspx?ID=2D6B7107-DAC8-472B-A274-06CED61CC544&Enum=115&AbsPos=3
https://velobase.com/ViewComponent.aspx?ID=e7ef5f1b-e1c1-469f-8768-91356ded694d&Enum=115

Up in OR it can’t be too terribly difficult to find a confirmed French thread pedal set to try, either at a co-op, buddy, or member of a local coffee klatsch. It’s likely worth the effort if you want to make sure you’re not altering French threads accidentally, if that matters to you.

I doubt French threads means that French words are going to be used on the pedals. But the pedals are English and the crank is French.

That's what I'd do! Half the time I'm threading in pedals to new-to-me Italian crank arms (usually Campy), it takes a lot of force. Scary, but it always works out. :thumb:

Sometimes it helps to thread 'em in the backside of the arm to clean 'em up.

I know a guy with an Atelier in your neighborhood...and he's retired.

You and I are kindred spirits.

Heh, heh…I have bigger fish for you to fry my friend.

I tried a 4th set of pedals - Suntour Cyclones with a touch of grease. They went in about as well as the Gipiemmes so I’m thinking case is closed. 9/16 x 20.

Pics will be coming soon in a separate thread.

This is either a joke or just really questionable advice. "A lot of force" is what leads to "I stripped my vintage crankset". If your threads are tight (or French) - they should be cleaned up with a tap. That extra material in there is just as likely to make the threads blow out as anything else.

https://cimg4.ibsrv.net/gimg/bikefor...4aa806a4e.jpeg

The only thing questionable is how much smarter he thinks he is.

I had a recent crank fail and the good folk at Cycle Path fixed it right up for $30 and 1day.

That is if stripping occurs.

Actually, at least with Stronglight, Nervar, and Spécialités TA cranks, the marks D and G (droit et gauche) do signify French threads. Those cranks use R and L for English threaded arms.