Quote Originally Posted by TheReverand View Post
I am about to upset some riders on here. I have been riding a single speed, fixed wheel bike for a few month now, so this is a relatively new 'cycling experience' for me, I love my singlespeed bike, love cruising round on it and boy does it move like a rocket!! And its sexy as........
But as ive started to do some longish rides on it, about 20 - 30 mile it has led to me developing injurys Ive never had, my knees are getting done in by it, and I have got a problem in my thigh which only hurts when im getting on and off my bike. Ive had to lay off riding it for a week or two to give my self chance to recover, any one else found riding fixed wheel to cause injury problems?
I've been riding fixed through the winter on the road for the last five years and have never had any problems. I also ride SS off-road in the winter too now.

Sounds as if you might have done too much too quickly... the thigh thing might well be due to the extra eccentric loading of riding fixed (your muscles lengthen under load as you apply resistance when slowing down or going downhill). With regards to the knees, check saddle height/fore-aft and maybe cleat position too. Also, consider backing the gearing off a bit and finding some flatter routes for a while.