Loz150693

Hi,

I've recently acquired an old town bike (Sun Bicycles). No idea when it dates from but it is fitted with 26 x 1.25 tyres. I'd like to fit them with white wall tyres, as I like the look of them, but can only find these in a 26 x 1 3/8 size. Anyone have any advice on whether these would fit the rims?

Thanks
Laurence

randyjawa 

Be careful if ordering tires. Your rims might be old school and difficult to find proper tires for. Look at the rims carefully, even with a magnifying glass if your eyes are like mine. Report everything you see stamped into the rim - everything. There is, most likely, a number there that will define what kind of tire to get.

SJX426 

Welcome to C&V. You need to measure between the fork legs, chain and seat stays to make sure there is enough room, which is likely.

JohnDThompson 

As noted above, there are several mutually incompatible nominal 26" rim sizes. Look on the current tire sidewall for the ETRTO size designation, it should look something like this: 32-550 or 28-584. The second number is the bead seat diameter, and your replacement tire must match this or the tire will not seat on the rim. The first number is the tire width, and is far less crucial as long as the tire is narrow enough to pass through your frame and fork.

bmthom.gis

In short, it depends on the 26 x 1 3/8 size. There are two ETRO sizes, 597 (S-6) - for Schwinn, and 590 for British 3 speeds. Yours is the 597 size (British club racer), so it *would* fit a 26 x 1 3/8 (S-6), or, "Schwinn sized" tire, but not a 590, or English 3 speed tire.
Tire Sizing Systems

That mm sizing is what you want to go off of. Also important is a picture of your bike!

bmthom.gis

Also, I don't see any white walls out there in that size, but there are gumwalls. If you are dead set on whitewalls, you'll most likely have to build up new wheels with 590 mm rims instead of 597 mm rims (or even as low as some 650B rims), or you could see if you have the clearance to .go up to 700C.

SkyDog75

Confusingly, there are a number of different 26" tire & rim size specifications that are incompatible with one another. In general, 26" tires and rims with a decimal-notated width (like 1.25") are not interchangeable with 26" tires and rims whose width is expressed as a fraction (e.g 1 3/8"). Even tires with similar fractional or decimal sizes might not be compatible.

Just a sampling of 26" tire sizes to illustrate the point:
26" x 1.0" through 5.0" is a common mountain bike size with a rim diameter of 559 mm.
26" x 1.25" and 26" x 1.375" were sizes used on American "lightweights" with a rim diameter of 599 mm.
26" x 1 3/8" can denote the S-6 size used on Schwinn "lightweights" with a rim diameter of 597 mm.
26" x 1 3/8" can also denote the E.A.3 size used on British three-speeds with a rim diameter of 590 mm.

Sheldon Brown lists even more tire sizes, 26" and otherwise, on his web site.

To ensure you get the right 26" size, follow JohnDThompson's advice above and look for an ETRTO size designation on your original tires, which will tell you specifically which 26" standard you're looking for by identifying the rim diameter.

sailorbenjamin

If it's a 559 you've got, just get some 26x 2.0s or something like that. If it's a 599 you have then you really must post pictures.

rhm

I'm with @bmthom.gis in guessing @laurence has EA1 rims, that is 26 x 1 1/4, not 26 x 1.25 (don't convert the fraction to a decimal; we're talking bike tires here, not math). If there's an ETRO number, it will be 597-32.

tcs

If it's a Sun, I bet they're ISO559.

rhm

Well, you make a good point! On the other hand, since OP says it's an old bike, and is looking for a "tyre" rather than a "tire," I suspect it's a Sun with ISO 559.

Loz150693

Thanks for the advice everyone, I will check the rims and find the ISO/ERTRO and go from there. And yes it is a British 3 speed