Discuss light weight issues concerning road bikes & parts.
Really? Because currently the Trek website lists all the Emonda SL disc 2019 as having clearance for 25mm, while the 2020 are listed at 28mm.
If I'm not mistaken, the fork is shared with the Emonda ALR disc. Here's a picture of mine with 25mm tires (measured at 26mm on the stock rim, 25mm high). You can see that it's already pretty tight in there. I can fit a 5mm hex key, but a 6mm won't pass on the crown and sides. I'd say actual clearance is about 5.5 mm on both sides and the crown.
If I were to put 28mm tires, that would mean an increase in width of 1.5 mm on each side, bringing side clearance to 4mm (which is ok), but the 3mm increase in height would leave me with only 5.5-3=2.5 mm of clearance at the crown, which seems to be way to little and probably explains why the 2019 SL discs are only rated for 25mm.
If you compare with the new fork design (2nd pic, from Trek website), there seems to be way more crown clearance. I'm actually super bummed I didn't get the new design, as I ordered the bike last week - I was really expecting it and now I'm not sure if it's a good idea to stick gp5000 28mm in there.