Originally Posted by
Maro
Will the 1.2cm difference on the TT make a huge difference?
Yes. You will definitively have to make adjustments. Check frame angles and fork length because everything will have an effect. As far as setback, I do not know if you should adjust it to compensate a change in angles. I do know that should not move it forward to compensate reach:
"...It is generally considered a Bad Idea to tinker with saddle position to adjust the reach to the handlebars; it is better to adjust this by replacing the handlebar stem with one with a different reach, or by buying a bicycle with a different length top tube..." (Sheldon Brown,
www.sheldonbrown.com/saddles.html)