Wheel size

[KDean]

Using a 2.5" tire on a 26" wheel , That's got to be quite close to a 650B with a 47mm tire hasn't it size wise ?

[Danneaux]

Using a 2.5" tire on a 26" wheel , That's got to be quite close to a 650B with a 47mm tire hasn't it size wise ?

This thread may be helpful...
http://thorncyclesforum.co.uk/index.php?topic=3893.msg20016#msg20016

To do a self-quote...

...to equal the outside diameter of my 26x2.0 tires (Schwalbe Duremes), I would need to run 650x38B tires (within 1mm of the same outside diameter). The tire of choice to do that at present would be the 650B x 38mm Grand Bois Lierre.

For reference, the EWD for a 26in wheel is 559mm vs 584 for 650B...a difference of 25mm...roughly 1in. Halved, that is a 12.5mm difference in radius. It is fairly easy to figure the outside tire diameter equivalency from those baseline rim diameters.

Best,

Dan.

[JohnR]

Here's a useful table https://www.cyclinguk.org/cyclists-library/components/wheels-tyres/tyre-sizes although actual diameter / circumference depends on actual tyre size / rim combination and pressure.