Pedal Problem

[brother nathaneil]

Hi,
I bought a road bike last Friday and set it up with SPD pedals. On Saturday I went out for a 16 mile ride (a couple of hills nothing too strenuous). Loved it.
On Sunday I got on the bike again and started pedalling only to feel something wrong with the right hand pedal, I pulled over and saw that the pedal had come loose and found that it had stripped the thread in the FSA Gossamer crank. Gutted.

It won’t be covered by warrantee as I’m sure that they will say I didn’t tighten the pedals but I just don't understand why or how this has happened. As I said, I didn’t touch the pedals between the 16 mile ride on Saturday and the 300 yards on Sunday. Any Ideas?

Gutted, £1,000 for 16.33 miles = £61.24 per mile! And now it'll cost £100+ to buy and change the crankset!

Still, lesson learnt, I will always check them before every ride from now on, and at least it didn’t happen at John O’ Groat’s on day 1 of a JOGLE.
Nathan

[MikewsMITH2]

Hi Nathan,
the pedals don't need to be particularly tight as they will naturally tighten as you ride, which is why there is a LH thread on the LHS. It doesn't seem logical at first glance as it appears that they would loosen themselves. However due to a phenomenon called precession, the balls have a tightening effect. BUT if the pedal bearings are set up too tight, they will unscrew themselves from the cranks. I know this because it happened on my wife's bike miles from anywhere and she had to ride home with one pedal! So check if the pedal concerned has a tight or notchy bearing. If it has provided you bought the pedals from the same source as the bike then you could have a case.

Before you scrap the cranks, try an LBS to get the thread chased with a tap, as it may not be damaged beyond repair. Also there is a system called helicoil, which can repair stripped threads. A local engineering works or motor engineer may be able to help with this.

[cycleruk]

Highpath advertise a crank repair service.
http://www.highpath.net/
£25 for a thread insert.

My own personal thought is if the thread has stripped due to NO misuse then I would be wondering about the crank metal?
Can the thread be cleaned up or has it gone to far?

[gilesjuk]

I suspect the bearing locked up and as you pedalled the axle turned and stripped the thread.

[Wesh-Laurence]

I had the same problem recently.

I was lucky that when the pedal came off the crank it only took a small piece of thread out of the cranks.

I fitted a different pedal into the other side of the crank (from the inside) in order to try and "recut" the stripped part of the the thread in the crank.

I was lucky that I then just managed to get the pedal to thread back onto the crank from the correct side (the outside) of the crank.

[brother nathaneil]

I'm being told "You can't have tightened the pedals enough". It’s going to be very hard to argue with them as I don't have a way of proving otherwise!

About half of the thread in the crank has been stripped, strangely I was told that this was evidence that the pedal was loose! I pointed out that when the pedal was only just loose, it couldn’t cross thread.

I also got told “The other pedal was only finger tight” and that this was also evidence that the damage was my fault. I pointed out that after the incident I took both pedals off to check that I hadn’t put them on wrong (yes I know you can’t “put them on wrong” but I had to check anyway).

I’ll let you know when I get any information, hopefully later today.
Nathan

[Deckie]

Am I alone in being amazed that someone sold you a £1,000 bike but didn't set it up for you?

[brother nathaneil]

It came boxed and I just had to bolt on the SPD pedals, seat and handle bars and couldn't even manage to do that!
As I said before... Lesson Learnt

[[XAP]Bob]

As mentioned above pedals will do themselves up if there is any play.

A grands worthof bike - I'd insist on them replacing both cranks and pedals. How can you be expected to trust the originals?

[brother nathaneil]

All sorted, all replaced and back as good as new.... and didn't cost me a penny.
Now all I need to is find the time to get out there and ride it