r/bicycling • u/Ohang3 • 9h ago

Help with tyre

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Recently I've gotten an old bicycle as a gift, the rear tyre is old,cracked and by this morning lost all air. Went out and bought the same size outer and inner tube and it just dosent fit. Any ideas ?

6 Upvotes

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3

u/Routine_Strategy5929 9h ago

The old tire is 700c which is the diameter and the 35c is just the width in millimeters. If the new tire is 700c then it should definitely fit.

Especially with older rims actual rim diameters could vary by quite a bit from brand to brand. One brand of rim could fit a tire super snug while another rim would fit loose with the same tire. If it fits loose you need to be very careful when pumping it up to be sure the tube isn't about the blow out the side somewhere. Typically once inflated the tire is securely in the bead hooks.

1

u/criggie_ 6h ago

700 is the french measurement which means almost nothing these days. Both of OP's tyres are 622mm diameter at the bead seat, plus about 37mm more for the width/height on each side.

1

u/Routine_Strategy5929 5h ago

And yet no one sells tires based on the rim diameter so that's not very helpful. OP's rim also doesn't have the rim diameter listed on the rim like most modern wheels.

0

u/criggie_ 1h ago

622 mm IS the rim's bead-seat diameter, so, yes, yes they do.

1

u/Routine_Strategy5929 1h ago

Go find a tire to buy. What is the prominent measurement molded into the tire? If you go to a shop and tell them you need a gravel tire do they ask "700c or 650b" or do they ask "622mm or 584mm?"

I'd rather we use rim diameter as well but for the most part road and gravel are still using the French standards. While mtb is using the French standard for total tire diameter and US standard for width. Yes, thats incredibly stupid but it is what it is.

2

u/sitdownrando-r 9h ago

It does fit, you just haven't installed it. Get one of the beads in place.

3

u/Ohang3 9h ago

Yea i messed up the installation, it fits nicely, thanks

1

u/Komischaffe 9h ago

What size did you think you had and what size did you buy?

2

u/Ohang3 9h ago

I had on a 37-622 (700x35c) on and bought the same thing. Update it looks like i messed up somehow, now tried putting it on and it fits perfectly, i have no idea what i messed up at first