Hi there, I have just bought a late 70's bike with unnamed Campagnolo crankset. I then bought some touring pedals with 9/16th axles and they are slightly too large/tight to go in the cranks. Can someone shed a bit of light on the size? Maybe 1/2 inch or strange metric size? I am thinking the next stop is a bike shop to have the cranks tapped to the correct size.
9/16th pedals too large?
- Thread starter Paulus
- Start date
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T.M.H.N.E.T
Rainbows aren't just for world champions
- Location
- Northern Ireland
Is the thread size stamped onto the crank? There is a french standard of 14mm/ 0.55in which would certainly make 9/16th or 14.2875mm tricky
Easiest solution is tap out for English thread
Easiest solution is tap out for English thread
Last edited:
accountantpete
OAP
Old Campy crank threads were cut at a slightly different angle to most others - so you still have the same TPI but the fit is a bit tight.
I seem to recall that the proper solution (apart from a ret-tap) was to slowly thread the pedal on from the back although I have just threaded them on normally in the past using some anti-seize so that they will come off again.
I seem to recall that the proper solution (apart from a ret-tap) was to slowly thread the pedal on from the back although I have just threaded them on normally in the past using some anti-seize so that they will come off again.
Yellow Saddle
Guru
- Location
- Loch side.
Measure twice, tap once.
But why not try a 1/2 inch pedal from a kiddies bike? There are plenty of them lying about rusting in the rain. Kidnap one and borrow a pedal.
But why not try a 1/2 inch pedal from a kiddies bike? There are plenty of them lying about rusting in the rain. Kidnap one and borrow a pedal.
And do what with it? It is a set of touring/road pedals with toe straps that i need to fit the cranks.
Yellow Saddle
Guru
- Location
- Loch side.
Well, you have some advice here that it may be a strange thread that goes in with a bit of force and copper compound. This leaves you with a question: is it a 1/2 inch thread in there or a slightly "off" 9/16th of an inch thread.
If the kiddies bike pedals, which are all 1/2 inch, fits in there you can be sure that no 9/16th pedal, no matter how tight, will also fit in there.
I assumed you did not have the equipment to measure the eye hole and thread pitch.
Use it, don't use it.
Gravity Aided
Legendary Member
- Location
- Land of Lincoln
http://www.parktool.com/blog/repair-help/basic-thread-concepts
I believe the Campy threads may be Whitworth profile. I've heard of the screw the pedal in from the back as a solution, but are you using MKS pedals? MKS and Shimano seem to have the threads cut a little prouder than the other brands. This may be the cause of your problem. You could follow the screw in from the backside method as mentioned above, or have a machine shop tap the threads to the SAE spec. Maybe a little thread cutting oil may help as well.
I believe the Campy threads may be Whitworth profile. I've heard of the screw the pedal in from the back as a solution, but are you using MKS pedals? MKS and Shimano seem to have the threads cut a little prouder than the other brands. This may be the cause of your problem. You could follow the screw in from the backside method as mentioned above, or have a machine shop tap the threads to the SAE spec. Maybe a little thread cutting oil may help as well.
Thanks for all the info. The cranks were stamped with 9/16th 20 F. What that meant I do not know. I screwed the pedals in from the back, and with some loud clicks they went in, albeit tightly. The pedals that were on the cranks originally fitted my other bikes, but the pedals from them were still very tight?. However, all done, thanks again .
Gravity Aided
Legendary Member
- Location
- Land of Lincoln
F is for filetti, or threads.
Yellow Saddle
Guru
- Location
- Loch side.
That's interesting. Would 20 F then be 20 TPI (Threads Per Inch?). The Italians are such big metric patriots it would almost be Italian sacrilege if that were the case.
Gravity Aided
Legendary Member
- Location
- Land of Lincoln
I don't know about that, because they may have been using American machine tools,which were once, along with German machine tools, pretty common everywhere. Used to be a large part of the economy of Cincinnati, Ohio,IIRC. Filettare mostly means thread in Italian. ( I grew up in an Irish family, in a Czech neighborhood, bordered by a much larger Italian and French area of town. Only in America.)
