Tech Gravel Tyre Size

Aug 23, 2009
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Kawasaki
I can run 700x32mm in my disc brake bike. I have ridden my CX bike on single track without issue, so I feel ok with 32mm. But I noticed the gravel crowd often run bigger... 40mm+. I think I could fit a 650b with 38mm~40mm. My question is if it makes that much difference between 32mm and 38mm for Japanese off-road as I would prefer to stay with 700c? Thanks...
 

OreoCookie

Maximum Pace
Dec 2, 2017
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Yes, it should make a huge difference. The reason is that you can run much lower pressures when you keep the surface tension of the tire constant. That means you have a lot more “suspension” on your bike — a lot of people focus on the frame when talking about ride quality, but the most important factor are the tires. You can think of tires + bike as a collection of soft and hard springs. The soft tires will deform first before the harder frame “spring” compresses.

You can get great tires these days that strike a good balance between being fast on- and off-road. One example are Schwalbe's G-One Speed and their gnarlier siblings, the G-One Bite and G-One Ultrabite. (They also had a goldilocks tire, the G-One Allround, but apparently it has been discontinued.)
 
Last edited:
Aug 23, 2009
16
9
13
Kawasaki
Thanks mate!

Yes, my other concern was finding tyres, whilst the Schwable links show a variety of sizes I only seem to find 35mm or 40mm. Just not sure if 40mm will fit. 38mm should be OK however all the 650b x 38mm tyres are slicks. I assume some tread is preferable when off-road here?

Will need to ponder this a little more and perhaps take some more accurate measurements of my bike.