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How does one measure wheel diameters?
My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? Alan |
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#2
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How does one measure wheel diameters?
Alan Holmes wrote:
My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? Alan It might, measure from the bottom of the brake block to the middle of the front fork dropout in millimeters. Multiply by 2, and compare to common wheel sizes (406, 451, 507, 559, 571, 622 or 630) Warning! It might be that your son's bike is not a common size. The above are just the commonest. For a full list see http://sheldonbrown.com/tire-sizing.html But probably the easiest way is to try some of his friends' bike wheels in his frame and read the size off the tyre. Hope this helps Tom -- Return address is dead. Real address is at http://www.happy-penguin.info/address.jpg |
#3
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How does one measure wheel diameters?
Alan Holmes wrote:
My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? When you say brake ring do you mean the position of the pads on the rim? If yes, then measuring that will give you a rough idea of the ERTRO size of the wheel. 622 mm is 700C 559 mm is 26" mountain bike. -- Phil Cook looking north over the park to the "Westminster Gasworks" |
#4
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How does one measure wheel diameters?
In article
Alan Holmes wrote: My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? Brake ring? I guess you mean the braking surface on the side of the rim. Measuring the distance from the middle of the axle to the middle of the brake block in millimetres and doubling it will give a fair approximation of the actual wheel diameter. The actual tyre diameter is measured where the tyre fits against the inside of the rim, but the nominal size will be different from that so you need to check a tyre size chart like the one at the bottom of this page: http://www.users.globalnet.co.uk/~pa...cc/arc0307.htm to find the nominal size. The ETRTO number in the first column is the width and diameter in millimetres in the format ww-ddd. There is usually a choice of tyre widths to fit a particular rim, so the width isn't particularly critical, although a very narrow tyre won't work on a very wide rim and vice-versa. What sort of bike is it? |
#5
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How does one measure wheel diameters?
"Rob Morley" wrote in message ... In article Alan Holmes wrote: My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? Brake ring? I guess you mean the braking surface on the side of the rim. That's right, couldn't think of the right term. Measuring the distance from the middle of the axle to the middle of the brake block in millimetres and doubling it will give a fair approximation of the actual wheel diameter. Can't I do it in inches? The actual tyre diameter is measured where the tyre fits against the inside of the rim, but the nominal size will be different from that so you need to check a tyre size chart like the one at the bottom of this page: http://www.users.globalnet.co.uk/~pa...cc/arc0307.htm to find the nominal size. The ETRTO number in the first column is the width and diameter in millimetres in the format ww-ddd. There is usually a choice of tyre widths to fit a particular rim, so the width isn't particularly critical, although a very narrow tyre won't work on a very wide rim and vice-versa. What sort of bike is it? An Elwick Sovereign folding bike, had a sturmey archer gear. Alan |
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How does one measure wheel diameters?
Alan Holmes said the following on 20/12/2006 16:44:
Can't I do it in inches? No necessarily. A measurement given in inches can have a different meaning to the apparently equivalent dimension in mm. Again, see the Sheldon Brown website. Strange things, tyre sizes! -- Paul Boyd http://www.paul-boyd.co.uk/ |
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How does one measure wheel diameters?
Paul Boyd wrote:
Alan Holmes said the following on 20/12/2006 16:44: Can't I do it in inches? Yes but you will need to convert to mm so measure in mm. Not necessarily. A measurement given in inches can have a different meaning to the apparently equivalent dimension in mm. Again, see the Sheldon Brown website. Strange things, tyre sizes! Very. But getting a wheel diameter from a brake isn't going to be an exact science. The numbers you are looking at from Tom's post (406, 451, 507, 559, 571, 622 or 630) are the bead seat diameters for the common wheel sizes. Given that the bead seat of the rim is pretty close to where the brakes are you should end up with what size wheel you need when you compare with the wheel sizes. 20 x 1.5-20 x 2.125 406 mm Most BMX, folders, some recumbents 20 x 1 3/8 451 mm Juvenile lightweights 24 x 1.5-24 x 2.125 507 mm Juvenile mountain bikes 26 x 1.00 through 2.3 559 mm Most Mountain bikes 650 C 571 mm Road bikes for smaller riders 700C 622 mm Modern road bikes 27 x anything 630 mm Older road bikes. -- Phil Cook looking north over the park to the "Westminster Gasworks" |
#8
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How does one measure wheel diameters?
In article
Alan Holmes wrote: "Rob Morley" wrote in message ... In article Alan Holmes wrote: My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? Brake ring? I guess you mean the braking surface on the side of the rim. That's right, couldn't think of the right term. Measuring the distance from the middle of the axle to the middle of the brake block in millimetres and doubling it will give a fair approximation of the actual wheel diameter. Can't I do it in inches? You can measure it in cubits if you want but you'll have to convert it to millimetres because that's how the ISO/ETRTO size is given in tyre size tables. The actual tyre diameter is measured where the tyre fits against the inside of the rim, but the nominal size will be different from that so you need to check a tyre size chart like the one at the bottom of this page: http://www.users.globalnet.co.uk/~pa...cc/arc0307.htm to find the nominal size. The ETRTO number in the first column is the width and diameter in millimetres in the format ww-ddd. There is usually a choice of tyre widths to fit a particular rim, so the width isn't particularly critical, although a very narrow tyre won't work on a very wide rim and vice-versa. What sort of bike is it? An Elwick Sovereign folding bike, had a sturmey archer gear. If it's from the mid 80s or later it's probably 20 x 1.75, but ISTR Elswick did some 24" wheel bikes as well, and an older 20" wheel could be 20 x 1 3/8". |
#9
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How does one measure wheel diameters?
"Rob Morley" wrote in message ... In article Alan Holmes wrote: "Rob Morley" wrote in message ... In article Alan Holmes wrote: My son had the wheels stolen off his bike and I'm trying to find replacements, if I measure the diam of the brake ring will this help? Brake ring? I guess you mean the braking surface on the side of the rim. That's right, couldn't think of the right term. Measuring the distance from the middle of the axle to the middle of the brake block in millimetres and doubling it will give a fair approximation of the actual wheel diameter. Can't I do it in inches? You can measure it in cubits if you want but you'll have to convert it to millimetres because that's how the ISO/ETRTO size is given in tyre size tables. The actual tyre diameter is measured where the tyre fits against the inside of the rim, but the nominal size will be different from that so you need to check a tyre size chart like the one at the bottom of this page: http://www.users.globalnet.co.uk/~pa...cc/arc0307.htm to find the nominal size. The ETRTO number in the first column is the width and diameter in millimetres in the format ww-ddd. There is usually a choice of tyre widths to fit a particular rim, so the width isn't particularly critical, although a very narrow tyre won't work on a very wide rim and vice-versa. What sort of bike is it? An Elwick Sovereign folding bike, had a sturmey archer gear. If it's from the mid 80s or later it's probably 20 x 1.75, but ISTR Elswick did some 24" wheel bikes as well, and an older 20" wheel could be 20 x 1 3/8". Thanks, when the weather warms up I'll go into the garage and check the size. Alan |
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