Crank Length/ Bike fit

[HLaB]

I had knee problems last year the physio said it was to do with tightness of my IT band or something. At the same time I got a bike fit for my roadbike, at the same time they printed out my ideal dimensions for a hybrid bike. So both my bikes have been set up to these specs. After a year however the problem has returned and although I rested from my road bike for the last fortnight, followed the physio exercises, spinning lower gears and the knee pains went away the tightness round the lower left thigh seems to reappear when I'm on the hybrid.
I'm trying to rule out things and the biggest difference I can see is the bike fit reccomended 175mm cranks for the hybrid and 170mm for the road bike. I'm using 175 on the hybrid and 172.5 on the road bike; should I consider putting shorter cranks on the hybrid? Or has anybody any other ideas?

 

[spandex]

2.5mm is not going to change it to much I would have a look at the BB hight, your seat hight and the stem length 1st.

 

[spandex]

And even the seat can change the ride hight.

 

[HLaB]

Thanks, the hybrid (ridgeback velocity) came with a suspension seat post, I've swapped that with the old post of my Spesh Sirrus its suspension too however. I set it 5mm over the bike fit specs to allow for deflection due to my weight, perhaps I should have allowed for more. Even better I think I'll remove it and pop up to the lbs at lunchtime and get a fixed post.