24 Inch tire won't fit 24 inch wheel?

[af557]

i'm trying to fix a late 70s triumph bicycle that's in need of tires and tubes, but the 24in tires i have don't fit the 24in wheels
what could be causing this and where would i find the correct tires?

 

[mjr]

Are one set 24 inch American (decimal) and the other 24 inch Imperial (fractions)? American is smaller.

 

[Tigerbiten]

Read up on tyre sizing here -> https://www.sheldonbrown.com/tire-sizing.html
Then measure the bead seat diameter and get that size tyre.

Luck .........

 

[fossyant]

Keep researching..

It's geting harder for us with 26" mountain bike wheeled bikes too. And they aren't as OLD.

 

[FrankCrank]

i'm trying to fix a late 70s triumph bicycle that's in need of tires and tubes, but the 24in tires i have don't fit the 24in wheels
what could be causing this and where would i find the correct tires?

I think Triumphs were just rebadged Raleighs, so as well as obscure tyre sizes, you have to contend with proprietary thread sizes for the bottom bracket and headset. Would be no fun if it was easy eh

 

[Chris S]

Did you get 24 inches by measuring the rim diameter with a tape measure? If you did then you've got 26 inch wheels as they included the nominal tyre width in the calculation.
You will probably need 26 x 1 3/8" tyres (ETRTO 590) as you have an old British bike. There is a small chance that they are 26 x 1 1/4 (ETRTO 597) which are rather scarce these days.
Take a close look at the rims for any size markings. If there aren't any then measure the bead diameter with a tape measure. Hopefully it will be 590mm.

 

[midlife]

What bike is it? My memory is not what it used to be but 24" wheels were usually on junior not adult bikes?

 

[af557]

it's a small triumph, on 24x1 3/8th dunlop tires
conventional modern 24in tires do not fit the wheels

 

[T4tomo]

it's a small triumph, on 24x1 3/8th dunlop tires
conventional modern 24in tires do not fit the wheels

look at the sheldon link above, there are many versions of 24" you need to identify which BSD it is, anything from 520mm-547mm.

most common is 540mm "wheelchair" but see what is on current tyres that do fit. A Puch of a similar era I once sorted out had 540mm

 

[mjr]

it's a small triumph, on 24x1 3/8th dunlop tires
conventional modern 24in tires do not fit the wheels

There is no conventional modern 24 inch tyre. There are only competing sizes with confusing inch names. Go for the ISO mm measurements, as mentioned above.

 

[T4tomo]

There is no conventional modern 24 inch tyre. There are only competing sizes with confusing inch names. Go for the ISO mm measurements, as mentioned above.

ahem.....Isla bikes, amongst others, do a 24" wheel version of most junior bikes 507mm iSO BSD, which almost certainly wont fit a 70's triumph

 

[Chris S]

it's a small triumph, on 24x1 3/8th dunlop tires
conventional modern 24in tires do not fit the wheels

Your tyres should have a size in millimeters on them beside the 24 x 1 3/8. It will be something like 37-540. Use that.

 

[mjr]

ahem.....Isla bikes, amongst others, do a 24" wheel version of most junior bikes 507mm iSO BSD, which almost certainly wont fit a 70's triumph

Just one of the competing sizes. It has no real claim on being the modern convention.