Originally Posted by Rowan

Because the Trek is aluminium, and you're light, I would run the rear around 100 or even 95 rather than 120. That might soften the ride up through the seat tube and post and make the ride less stressful. I haven't exceeded 95psi on any of my bikes in years, and I run 23C tyres on my titanium and CF rides, and 25C on the fixie.