Wilkinson's is quite useful in a town with no bike shop, except out of town Halfords, but I've always been puzzled by the selection of tyre sizes. Here is what was available in their Barking branch today. I'm only quoting ISO sizes, formerly known as ETRTO sizes. Although unfamiliar to any, they are the only ones that are reliable. The British, European and US sizes can seem similar whilst being very different.This guide converts between the different standards.
ISO uses width in mm, dash, bead circumference in mm. Obviously the latter is critical. The former doesn't make that much difference, especially with a few mm of course
Wilkinson's had 47-406, 47-507, 47-559, 37-622 and 32-630 sizes. I believe the most popular size in the world is 37-590, which British (Empire) people know as 26 x 1 3/8. 37-622 is a common size amongs my LCC friends.
I once encoutered someone who had his Brompton folding bike stolen shortly after he bought some new tyres for it. Brompton tyres are 37-349 typically, commonly called 16 x 1 3/8. Unfortunately he had bought 16" USA sized tyres, of a mere 305mm diameter (probably 47-305), almost an inch and three quarters too small in diameter.
Showing posts with label iso tyre sizes. Show all posts
Showing posts with label iso tyre sizes. Show all posts
Saturday, 28 May 2011
Tuesday, 27 May 2008
Air free tyres, tyre sizes
http://www.airfreetires.com/
Such things as air free tyres always - rightly - attract a lot of interest. I can't comment on the quality of the products here, but be very careful of the sizing information here - much of it is wrong. I've come across someone who bought 37-305 tyres fro his Brompton. The only reason he didn't realise they won't fit is that the poor so-and-so has had his bike nicked. I found out about it when he tried to sell his tyres.
The website claims that 37-305 tyres are a substitute for 16 x 1 3/8 tyres. Nonsense! This can be clearly seen if we stick to the only reliable yet undeservedly least familiar tyre sizing system - the ISO one, in which 16 X 1 3/8 tyres are 37-349. The large number is the diameter at the bead and as is obvious they are 44mm larger that the 305s. The smaller number is the width of the tyre - not so critical, but its probably best to buy the same size
Such things as air free tyres always - rightly - attract a lot of interest. I can't comment on the quality of the products here, but be very careful of the sizing information here - much of it is wrong. I've come across someone who bought 37-305 tyres fro his Brompton. The only reason he didn't realise they won't fit is that the poor so-and-so has had his bike nicked. I found out about it when he tried to sell his tyres.
The website claims that 37-305 tyres are a substitute for 16 x 1 3/8 tyres. Nonsense! This can be clearly seen if we stick to the only reliable yet undeservedly least familiar tyre sizing system - the ISO one, in which 16 X 1 3/8 tyres are 37-349. The large number is the diameter at the bead and as is obvious they are 44mm larger that the 305s. The smaller number is the width of the tyre - not so critical, but its probably best to buy the same size
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