Tyre Sizes

[Tonislegs]

Hi everybody,
After 15 months my rear tyre exploded like a rifle shot and consequently I went to my LBS with the tyre and asked them to give me one the same as the old one (But without the hole) The size on the tyre was 26" x 1.38" and they sorted one out for me. However I said to the assistant "A blind man on a galloping horse could see that those two tyres are not the same size" the one they were trying to sell me was much bigger than the original in spite of it having 26" x 1.38" on it! They got a 26" wheel and sure enough the wheel passed straight through the tyre, they then tried umpteen tyres with the same result - I came home without a new tyre.
I then tried another shop and ended up with the same problem and after a lot of tooing and frowing the supplied me with a tyre that fitted but the size on the side is 26" x 1.50" Can anyone explain this as the people in both shops couldnt.
The bike is a Ladies Dawes Red Feather and was bought new in December 2007 so it only 15 months old.

 

[Tynan]

Google says a 26" wheel, width to suit the rims

Perhaps the old tyre was damaged enough to have deformed, it seems odd that an LBS couldn;t work it out, what sort of LBS were they?

 

[Randochap]

Sounds like confusion here with 26X1 3/8 (590 ISO) -- common on old Raleighs, etc. -- and the now more common 26" MTB tyre/wheel (559 ISO) -- though I've never seen a 559/1.38.

Usually they would be 1.3, or 1.5, like the one you finally bought.

 

[tyred]

There is also an American size 26 x 1 3/8 which is totally different from the size used on old Raleighs. How this would find it's way onto a Dawes is a very good question.

 

[Randochap]

There is also an American size 26 x 1 3/8 which is totally different from the size used on old Raleighs. How this would find it's way onto a Dawes is a very good question.

That's right -- 597 ISO. Neither 590, nor 597 ISO would find their way onto a Dawes -- presumably w/ 559. They'd be too big, like the OP said.

BTW, the other '26"' tyre is 584 ISO -- 26X1 1/2 ... 0r 650B

 

[ufkacbln]

The CTC guide to tyre sizes

More information than you will ever need, but a superb guide to the reasoning behind tyre sizes.

 

[Seamus]

Thers's about 3 diferent size of 26" tryes

26" 26 x1 3/8 597 Schwinn
650a 650 x28a 590 3 speeds
650b 650 x 28b 584 French tandems
650c 650 x 20c 571 Triathlon bikes
26" 26 x1.5 559 Mountainbikes