I wanted to swap tires. Left tire is 24×1 3/8 and the right is marked 24×1.95.
I was struggling to fit it.
Then I placed the rims side by side and the rim on the right is smaller in diameter compared to the left rim.
I compared the tire inner dimension and are enough the one on the right is smaller in dimension. So, consistent with the rim issue.
I initially proceeded with the swap because when I checked the tire marking they are both 24”.
Does that mean the tire on the left is erroneously marked 24” or am I missing something?
Thanks
by Frankie1234567890
8 Comments
Fractional wheel/tires. It’s a different size all together
Welcome to the world of bicycle standards.
https://www.sheldonbrown.com/tire-sizing.html
A [decimal tire and a fractional tire](https://sheldonbrown.com/tire-sizing.html) are not the same diameter.
See our Lord Sheldon.
Sheldon nay have the bottom of that rabbit hole https://www.sheldonbrown.com/tire-sizing.html
https://preview.redd.it/xtq675yr4loh1.jpeg?width=1220&format=pjpg&auto=webp&s=dfba7df03ea9e8f2b8263a34e3a84b8941d5bd04
Different standards of tire measurements are confusing. The are 5 different “26 inch” tire sizes for example lol. Look at the metric measurements and you will never mess it up
A 24 x1 3/8 wheel measures 540 mm, a 24 inch mtb wheel measures 507 mm. So you’re trying to stretch a tire that is over an inch too small for your rim.
The metric measurement are always acurate, where as the imperial sizes are more of a size name than a true measurement.
Edit for wierd autocorrect
There is 3 24″ tire sized
507 mtb size
520. Mini bmx size and
540 specialty and wheelchair
As was explained to me, some of this is from standards that refer to the outer diameter of the tire not the rim. To have consistent outer diameters for bmx racing for example a narrower tire would need a larger diameter rim to keep a consistent outer diameter for all sizes as required by some regularion.