Joined: Jul 2015
Posts: 7,379
Likes: 3,222
From: NW Oregon
Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike
advertised tire width is not always the Actual width, and the rim internal width figures into it too...
your research is solid.
the SL8 model can handle a 40, but the older models are limited to 30s.