FSA cranks and Shimano pedals

You'll find that the thread problem has been identified way up in this thread. I'm not suggesting corrosion as an issue here. Nor is guyrwood or behindthebikeshed.

It is common practice in comment sections such as this that general advice around the key point is offered as it helps others who may have a similar issue but very little experience of their own to diagnose the issue.

On behalf of all the experienced old timers who try to contribute as positively as possible to the knowledge of the many cycling newbies who read this site, I apologise for causing you such obvious offence.

And, by the way, a little bit of copper slip WILL help to catch the first thread.

Thanks for your positive contribution. 

The use of copper grease is good advice.

Normal grease can be used but you need to periodically disassemble, degrease and reassemble to keep galvanic welding at bay in alloy cranks or carbon cranks with alloy female threading.

I bet the thread on either the pedal or crank is fubar.

Take it to your LBS so they can run a thread tap through the crank thread and restore and clean the thread

Same for the pedal.

Look a the threads on both and see if there's any damage, quite easy to do if you'd dropped the pedal. Harder to do on a crank

Also, use plenty of grease or copper grease on the threads. A mate of mine needed a new crankset and pedals after his welded themselves together. His LBS actually broke their pedal spanner (and mine!) trying to remove the pedals.

I have FSA carbon cranks and Shimano DA pedals. They are compatible. Pedal thread is universal. all the tips above are good value. Make sure you are tightening the correct direction !

i had some issues with a high end crank, some tolerence issues both with pedals and crank can cause matters to be awkward/tight.

check with other pedals, if go in ok, apply copper grease to orig pedals and try again. if still no joy return to retailer.

My Shimano SPD pedals have right and left markers and tighten arrow direction, can't go wrong with fitting.

Good question. With pedals, the drive side one screws in normally. The non-drive side screws in the 'wrong' way.

Easy way to remember the threading on pedals... They ALWAYS tighten towards the front of the bike.

eg. If you're on the right side of the bike, the direction to insert the pedal is clockwise, rotating the threading towards the front of the bike.

If you're on the left side of the bike, the direction to insert the pedal is anticlockwise, but again rotating the pedal threads towards the front of the bike.

It can however take a few seconds of fiddling to line up the threads until they catch... Even for old hands.

Will one go in but the left hand side one won't?

line up the pedal and give it 1/2 a turn or so the wrong way (you can feel it drop onto the thread) then tighten the right way.

Check that you are trying to fit the correct pedal to the correct crank arm and remember that the non-drive side pedal is reverse threaded.

They should fit, pedal threads are just about the last universal standard left in cycling.

Pedals should fit. Sometimes it takes a bit of effort for the first few threads to take. If you unsure about marring the threads I would grease them and install the pedals from the crank arms backside. 

Surely all threads are the same or Look are goinging to be pretty screwed.

Check for flush engagement, i've had the pedals slightly out of line and they won't catch the thread.

Check that you are indeed screwing in the correct direction.

No protective sheaths anywhere?

Have you checked the tighten rotation arrow? Also see if they for in a shimano crank. I always thought they had the same thread and size. You might need to tap the threads again on the crank arms to make sure they are clean.