Originally Posted by
jeffwhitfield
Based on what I’ve read when researching gravel tires, the big difference between a 700c and a 650b tire is the volume. Considering there’s at least an inch difference in the wheel sizes, a 650b tire will give you more volume since the tire has to have a bit larger profile to provide the same overall wheel size as a 700c. So, yeah, wouldn’t surprise me in the least that a 650x47 will provide more control over a 700x45. I’m running on 47’s myself and love them. The extra flex in the tire does indeed allow for more glide over rougher surfaces, thus the reason why the 650b wheel size is becoming so popular. Not sure how much of a difference it makes with speed though. Personally, I prefer a smoother ride with more control.
Just to note that a 700c 45mm has a larger diameter than a 650b 47mm. 650b 47mm is roughly the same diameter as a 700c 28mm. It is interesting because you can change between wheels for road and gravel without affecting the geometry of the bike. If the bike can take both wheels and has enough tire clearance.