I have the Tarmac SL7 with 28mm tires and would like to upgrade to 30mm tires (Conti AS GP5000) (I saw from another post that the SL7 is rated up to 32mm, but unsure if the model year matters? I have the one from 2021). My wheel’s inner width is 21mm and outer is 28mm. Will going to 30mm tires be less aero dynamic since it will be wider than the outer width of my wheel?
Thanks
Probably, but the thing I also consider in these situations is road surface condition and rolling resistance. In some cases, the lower RR and better cornering and comfort outweighs the small penalty of increased cda
You really need to know the actual width the tire is once inflated. What Spec sent on the bike was what they deemed was the most aero on those rims. A 28 cotton turbo will inflate to a different width than a 28 GP tire at the same pressure. You will prob run the 30 at a bit less pressure than the 28. ………..
If you’re going wider for comfort reasons that could offset any aero loss, as stated above.