the ever shifting stable loaded with comfortable road bikes and city and winter bikes
what's on there right now, and how much clearance do you have? add mms to within about 3 mm of the fender, and you have max width. Double check at chainstays, under fork, and at seatstays.
the more recent treks had limitations at the fork clearance, but this clearance appeared to be improved on the last couple of years. in mid 2000s you couldn't usually get more than a 35 under the fork unless you filed down the steerer tube!