Tyre circumference

mrcheez

I don't have a ruler with me, but my Schwalbe tyre reads:

"32-622 28 x 1.25 700 x 32C"

So is this tyre circumference 28" or 32" ?

What do the other figures represent?

thanks

Tenzor07

One's Imperial and other Metric I'm sure..

White Clover

mrcheez wrote: »

I don't have a ruler with me, but my Schwalbe tyre reads:

"32-622 28 x 1.25 700 x 32C"

So is this tyre circumference 28" or 32" ?

What do the other figures represent?

thanks

I take it you mean diameter? It's 32"

cython

White Clover wrote: »

I take it you mean diameter? It's 32"

Ah here lads, I know it's Friday, but no need to be leading the OP astray! :pac:

To come back to the OP's values:
"32-622 28 x 1.25 700 x 32C"
32-622, as was mentioned, is metric. The 622 corresponds to the rim diameter, while the 32 is the cross sectional diameter of the tyre in mm, not inches. 700x32c is another metric way of saying the same thing in terms of the tyre's approximate external diameter, and 28x1.25" is indeed imperial speak for the same.

mrcheez

cython wrote: »

Ah here lads, I know it's Friday, but no need to be leading the OP astray! :pac:

To come back to the OP's values:
"32-622 28 x 1.25 700 x 32C"
32-622, as was mentioned, is metric. The 622 corresponds to the rim diameter, while the 32 is the cross sectional diameter of the tyre in mm, not inches. 700x32c is another metric way of saying the same thing in terms of the tyre's approximate external diameter, and 28x1.25" is indeed imperial speak for the same.

Cheers, it says "tyre circumference" on the instructions for my Lidl bike computer so I just repeated what it said

It has an inch to mm conversion table on it which only goes up to 28" so it would be odd if my tyre is over that as it's not abnormally large I would have thought.

The bike computer takes mm values, so I put in the value for 28" (2237mm) ?

mrcheez

The instructions say "multiply tyre diameter by 3.1416 to get the tyre circumference mm"

I doubt it's 32 x 3.1416, so probably 622 x 3.1416 = 1955 (which corresponds to ATB26 x 1.4) in their table.

so...eh... I guess I go with 1955


EDIT: Actually looking again I think it's the 27" (700 x 32C) figure I use which they say is "2155 mm"

confuzzled

cython

mrcheez wrote: »

Actually the instructions say "multiply tyre diameter by 3.1416 to get the tyre circumference mm"

I doubt it's 32 x 3.1416, so probably 622 x 3.1416 = 1955 (which corresponds to ATB26 x 1.4) in their table.

so...eh... I guess I go with 1955

Nope, go bigger. 622 is the rim diameter, and your tyre diameter will be that plus a good chunk of the diameter of the tyre, if that makes sense? Many bike computers would actually have a conversion chart, whereby you look for rim/wheel size on 1 axis, and tyre diameter on the other and it gives you the resulting circumference - does yours not? If not, then Sheldon can always help. From that page:

700c/29er 32 mm 622 32.00 686.00 2155.13

That means a 32mm diameter (cross-sectional) tyre, on a 622 rim will have a wheel/tyre diameter of 686mm (remember, the 700 in 700c refers to approx 700mm, not exactly - different sized tyres will result different diameters, after all), and a circumference of 2155.13mm. Does that make sense to you?

mrcheez

cython wrote: »

That means a 32mm diameter (cross-sectional) tyre, on a 622 rim will have a wheel/tyre diameter of 686mm (remember, the 700 in 700c refers to approx 700mm, not exactly - different sized tyres will result different diameters, after all), and a circumference of 2155.13mm. Does that make sense to you?

Does indeed, so 2155 it is, thanks again!

Beasty

Don't forget to take away the number you first thought of......