The English 760 x 90 looks mighty close to the American 30 x 31/2, but slightly smaller. Will it fit on the same rim and function just as well?
Steve, The tyre size you posted is a metric size, not necessarily English. Last time I had English tyres they were still on 4.50 x 21" type measurements.
Using an approximate 25mm to 1" the size you post would be approx. 10mm larger in diameter and a bee's bum wider than 3.5"
Hope this helps.
Allan from down under.
Steve,
From this not close enough, I think
George shows rim sizes in mm, and modern car tires has used the rim diameter for size since the wire reinforced bead was introduced in the mid 20's, but I guess the tire you found was a clincer and the 760mm size would then be the nominal outside diameter. Allan uses 25, but the correct conversion is 25.4mm per inch which gives 760mm = 29.92 => close enough to 30 inches, I'd say.
With a tire width of 90mm (=3.54"), the rim size should be 760-90-90= 580mm (=22.83") - the inside rim diameter in George's table for 30x3.5" tires is given as 579mm. So yes, sounds like a 30x3.5" tire in metric.
(In Sweden we converted to the metric system in 1879 but still use inches in daily speech for things like tire rim diameter (but not width), lumber and nails.)
Funny how this discussion is almost the reverse of one a year or so ago, on a Rover forum. A U.S. enthusiast was searching for 760 x 90 tyres for a veteran (IIRC about 1912) Rover, and I suggested that he check a tyre retailer for 30 x 3.5 tyres instead. He found that they fitted properly and were much cheaper than the 760 x 90 ones he had been hunting.
The reason I asked is that I've been offered some Dunlop clinchers, 760 x 90. A good deal if they fit, but a bad deal if they don't.
The rim fit is the important part, and 22.83" sounds too tight for an already tight situation on a 23" rim.
That's what I thought just looking at the two tires together. The inside diameter of the metric tire is almost an inch smaller. I think I'd better pass on this offer.
If it really is much smaller than your regular 30x3.5" (& I doubt that referring to George's table).. There's always the possibility to put a smaller deflated regular wheel inside the clincher and fill with air to expand it some. Heat works too.