Bicycle Mechanics - Tyre problems: 700 35C / 700 38 B

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View Full Version : Tyre problems: 700 35C / 700 38 B

pistolpedro
02-19-09, 12:40 PM
Hi Guys

New tyres arrived today,

Currently: Schwalbe 700 38B

New tyre: Dutch perfect 700 35C

Tried to fit the new tyre tonight and it wouldnt go on, new ones seem much to small (diameter) are these sizes compatible?

Squeazel
02-19-09, 12:59 PM
I'm sorry to inform you that your new tire won't fit. 700B is 635 mm bead seat diameter and 700C is 622 mm. Here's what Saint Sheldon says about it:

http://www.sheldonbrown.com/tire-sizing.html

You may be able to wedge on a 27 inch tire (630 mm), but I would be scared about the consequences of the wrong BSD...
demoncyclist
02-19-09, 01:00 PM
700C is 622mm BSD (bead seat diameter). 700B is 635mm BSD. Completely different animals.

tatfiend
02-19-09, 06:14 PM
Schwalbe USA lists 3 tires in 635mm BSD on their web site per the check I just made. A rare size here but originally used on English roadster utility bikes and it may still be used in India and China on some bikes.
pistolpedro
02-22-09, 08:44 AM
Thanks guys, going to ring the supplier in the morning and see if i can exchange them for the correct size
jgedwa
02-22-09, 09:08 AM
You may be able to wedge on a 27 inch tire (630 mm), but I would be scared about the consequences of the wrong BSD...

Are you sure this has any chance of working? I have always worked under the assumption that there was NO room to fudge bead size on a tire. I am tempted to declare this advice (even in the cautious form you gave it) bogus, but I will have to admit I have never actually tested this particular permutation of it.

Failing someone saying that it does stand a chance of working, I have to disagree firmly on it.

jim
Grand Bois
02-22-09, 09:13 AM
Are you sure this has any chance of working? I have always worked under the assumption that there was NO room to fudge bead size on a tire. I am tempted to declare this advice (even in the cautious form you gave it) bogus, but I will have to admit I have never actually tested this particular permutation of it.

Failing someone saying that it does stand a chance of working, I have to disagree firmly on it.

jim

I would have said the same thing, but way less tactfully.