Originally Posted by
coasting
...The new tyres (michelin lithium) were same 23mm width as old ones (pro2 race) so shouldn't have caused the harshness. I changed them because the pro2 were getting cut up and worn so quickly. If the new wheels are stiffer isn't that the whole point of upgrading wheels? I'll give the tyre pressure a go first before deciding if the wheels need to be changed back to old ones.
The back problem was weird since the saddle was not moved and I'm pretty sure the levers look like similar position to the old ones. I never had serious back pain before and the set-up was pretty comfortable. I think Vibes has a good point about staying stretched out more with STI. I used to move to the tops while reaching down to shift gears so was varying my position a lot more without consciously changing hand positions. I'll try rotating the bars up a bit...
Tyre carcass can vary in stiffness too.
Just keep the tyre pressure high enough to avoid pinch flats. 150psi is for people that need every last fraction of a second as a competitive advantage.
Back problems when cycling are usually related to a weak core and, slightly less so, to being too stretched out. Do plank exercises 3 times a day and in a few weeks you sheould feel an improvement in core strength and a resulting decrease in back pain. If it continues and you've tried rotating the bars and doing the exercises definitely go and see either your doc or a physio/chiro.
keep those gut muscles sucked in hard
