Just started going out on the road on a CX type bike and was wondering how much tyre width is affecting me. I swapped the Kenra small block for Halo Twin Rails I had lying around and not a great difference (although it was windy as hell today and I probably act like a sail). Really just trying to use it to get miles in and get fit for once in my life. Currently it has 38mm tyres but was wondering how much quicker a narrower tyre would be. Also any recomendations.

If you are using it to get fit then don’t go for a faster tyre.

Valid point and I probably am not in a rush to change anything, even gritted through the wind today and looked on it as extra resistance training! But still interesting for reference and in the future when I do want to eek out a little more speed. Happy with the tyres at the minute as I can come back down towpaths that I would destroy the wheels on a road bike.

Conti are saying after test you get less roll resistance with a wider tyre. The BMC pro team are gonna be running 28 I think it is for racing

im using 32c kenda small block 8’s on my CX, i think they are fairly fast for a knobly tyre, only using them as they were well cheap at crc last year.

would love to know how much faster a slick like a michelin pro 4 would be at about 100g lighter per wheel