I have campagnolo pista cranks and gr-9 pedals, both of them are 9/16, but the pedals will not thread into the crank arms. Are they different thread pitches? If so what kind of pedals do i need to get to fit into the crank arms?!

left threads in left. lefty tighty. did you do this?

yeah man. they fit in my sugino 75's perfectly.

shoot, im sorry.. this is where i am no longer useful.

Shouldn't be a problem - Campy don't use any unusual threading on their cranks. Grease the threads thoroughly, fit the end into the crank arm, reverse it round with the wrench til you hear a click, then go forwards. And don't forget that the left hand pedal is left hand thread.

If this doesn't help, try telling us a bit more about the problem. Do the threads engage but then you can't tighten them? Will they not engage at all? Are the cranks new, or used? Have you had any other pedals in them?

Here's some details:
- The cranks are older style fluted pista cranks from the 80's
- I'm the second owner.
- The threads do engange.
- I can only finger tighten them one turn
- I can tighten them all the way in with a pedal wrench, but it takes maximum effort and results in a high pitch sqeaking sound. (I'm assuming that's the threads.)
- I have never put any other pedals in them.

Can you see the threads in the cranks? They may be damaged. Like the other guy said, grease them up and try again if the threads look ok and the pedals can be threaded in.
Good luck, hopefully the first owner didn't mess the threads up.

Grease is your friend. If you can advance them, the chances are either there's some corrosion in there (from where someone didn't grease them before), or the threads have been damaged. Either way, getting the pedals in there will help sort things out, but the grease will help you be sure you can get them out again!

Sounds like you either cross threaded them or put the pedals on the wrong side. The cranks are probably aluminum which is pretty soft and pretty easy to cross thread with a steel pedal. If so, oh well, everyone screws up threads once in a while.

Can you tell if the threads in the crank are okay?

Or, are the threads on the crank or pedal dirty? If they're old cranks or pedals, they could have some crap in the threads. If so, I usually use a pipe cleaner to clean female threads, and a wire wheel or wire brush on male threads.

You've crossthreaded and have now pretty much screwed your cranks by forcing them in that way.

Apparently, the cranks were never used. So you're saying i cross threaded both pedals? Doubt it.