So... 710, 730?

You *might* be able to fit a 32 in there... but for sure a 28.

I have Pasela 28s on my 730- 32s wouldn't fit, but mines' a 78 and it's the "racing" 730. Yours has eyelets and a lot of room behind the seat tube. I'd guess 32s would fit.

Like several others- I find the Compass tires to be AMAZING. Two things suck about the Compass tires- the price and then you get spoiled by these fantastic tires. So then you have no choice other than to really really consider Compasses from here on out.

Just looking at your bike, I'm just imagining how nice it would be to ride... I know you get a lot of really sweet bikes go through your stable- maybe some people think 700 series Treks are "whatever," I just know a Trek designed and made 531 long frame and fork will just glide over the road. I'd throw down the money for the Compass 32s.