#1
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Wheel Sizes
Bit of a numpty question this but here goes.
Many moons ago I used to cycle a bit and am considering getting a bike again to help keep fit and general riding. I have with guidance almost written off mountain bikes as I have no intention of of riding accross really rough terrain, my intended being roads, canal towpath and forest roads etc so believe that a hybrid type bike will be a better choice for me. In the past bikes had wheel sizes that were easy to understand like 27 x 1, or 26 x 1 and 3 eighths etc. I am now faced with sizes like 700c 25 etc. What does all this mean? I guess that it is metric with this meaning 700mm x 25mm but chat do the letters stand for. Any help as I am still in imperial measurements. Dave UK |
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#2
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Wheel Sizes
On Wed, 7 Sep 2005 15:53:01 +0100, "Dave"
wrote: In the past bikes had wheel sizes that were easy to understand like 27 x 1, or 26 x 1 and 3 eighths etc. I am now faced with sizes like 700c 25 etc. What does all this mean? I guess that it is metric with this meaning 700mm x 25mm but chat do the letters stand for. Any help as I am still in imperial measurements. Trust in Sheldon, for he is The One: http://www.sheldonbrown.com/tire_sizing.html "Bob" -- Email address is spam trapped, to reply directly remove the beverage. |
#3
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Wheel Sizes
Dave wrote:
What does all this mean? I guess that it is metric with this meaning 700mm x 25mm but chat do the letters stand for. The basic summary would be: 700c - road bike size wheels 25mm - width of tyre. So 700c x 38 would be big tyres suitable for the sort of thing you are proposing Tyres labelled 26 x 1 1/4" etc are for old roadsters Tyres laballed 26 x 1.25" are for MTBs. Note that these last two examples are not the same size tyre even though 1 1/4 = 1.25! Arthur -- Arthur Clune |
#4
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Wheel Sizes
in message , Dave
') wrote: Bit of a numpty question this but here goes. Many moons ago I used to cycle a bit and am considering getting a bike again to help keep fit and general riding. I have with guidance almost written off mountain bikes as I have no intention of of riding accross really rough terrain, my intended being roads, canal towpath and forest roads etc so believe that a hybrid type bike will be a better choice for me. In the past bikes had wheel sizes that were easy to understand like 27 x 1, or 26 x 1 and 3 eighths etc. I am now faced with sizes like 700c 25 etc. What does all this mean? I guess that it is metric with this meaning 700mm x 25mm but chat do the letters stand for. The nominal overall diameter is 700mm. In fact it isn't but never mind; the actual diameter of the rim is 622mm (or maybe that's the bead seat diameter). Doesn't matter. It's a smidgin smaller than an old 27" and a smidgin bigger than a 26", and it's the current default size for road bikes and road-oriented hybrids. Tyres range from 20mm (similar to an old 3/4" - razor thin for racing on - through 23mm which is default fast roadbike tyre, 28mm which is about 1 1/4" up to 38mm fat touring tyres (and indeed you can get '29"' mountain bike tyres which are even fatter, which also fit a 700c rim). Any help as I am still in imperial measurements. Think of it as being 27", give or take. -- (Simon Brooke) http://www.jasmine.org.uk/~simon/ ;; All in all you're just another nick in the ball -- Think Droid |
#5
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Wheel Sizes
In article , Call me Bob wrote:
On Wed, 7 Sep 2005 15:53:01 +0100, "Dave" wrote: In the past bikes had wheel sizes that were easy to understand like 27 x 1, or 26 x 1 and 3 eighths etc. I am now faced with sizes like 700c 25 etc. What does all this mean? I guess that it is metric with this meaning 700mm x 25mm but chat do the letters stand for. Any help as I am still in imperial measurements. Trust in Sheldon, for he is The One: http://www.sheldonbrown.com/tire_sizing.html But this being a UK group, you want his English page: http://www.sheldonbrown.com/tyre_sizing.html |
#6
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Wheel Sizes
Simon Brooke wrote: in message , Dave ') wrote: Bit of a numpty question this but here goes. Many moons ago I used to cycle a bit and am considering getting a bike again to help keep fit and general riding. I have with guidance almost written off mountain bikes as I have no intention of of riding accross really rough terrain, my intended being roads, canal towpath and forest roads etc so believe that a hybrid type bike will be a better choice for me. In the past bikes had wheel sizes that were easy to understand like 27 x 1, or 26 x 1 and 3 eighths etc. I am now faced with sizes like 700c 25 etc. What does all this mean? I guess that it is metric with this meaning 700mm x 25mm but chat do the letters stand for. The nominal overall diameter is 700mm. In fact it isn't but never mind; the actual diameter of the rim is 622mm (or maybe that's the bead seat diameter). Doesn't matter. It's a smidgin smaller than an old 27" and a smidgin bigger than a 26", and it's the current default size for road bikes and road-oriented hybrids. Tyres range from 20mm (similar to an old 3/4" - razor thin for racing on - through 23mm which is default fast roadbike tyre, 28mm which is about 1 1/4" up to 38mm fat touring tyres (and indeed you can get '29"' mountain bike tyres which are even fatter, which also fit a 700c rim). European sizes were traditionally the overall diameter of the tread with a letter to indicate the tyre width, so 700c was nominally a 700mm diameter wheel and tyre with a tyre of width 38mm (about 27x1 1/2) So a 650B and a 650A tyre would be incompatible though the same overall diameter becasue the rim was a different size. Fortunately tyres have now standardised on the size of rim they fit onto. The thing to look for is the ETRO number. This is the bead seat diameter, ie the size of the rim the tyre fits on and the width of the tyre, and looks like 622-25 (622mm diameter rim and 25mm cross section tyre, broadly equivalent to the 27 x1" but not quite the same.) Here is an abbreviated list of sizes ETRO traditional description 635 28" Policemans bike 630 old 27" road 622 700c (also known as 29" for off road) 597 Another 26" 590 Old 26" roadster 584 650B 571 650c 559 26" mountain bike 547 24" 541 600A 540 24" 520 24" 507 24" 501 22" 490 550A 451 many 20" folding bikes 440 500A 438 Dutch 20" 406 20" BMX 400 18" 390 450A 387 Dutch 18" 369 17" Moulton 355 Another 18" size 349 16" 340 400A 305 16" 298 14" 254 14" 222 11" 203 12 1/2" As you can see it is a bit of a minefield, but armed with the ETRO number, you will get the right tyre for your bike, ie one that fits the rims. Hope this helps. A 700c wheel will be about a quarter inch or so smaller than a 27" wheel, not enough to worry about for riding the bike but quite important when it comes to replacing tyres. Most modern bikes are either 622 (700c) or 559 (MTB 26") ...d |
#7
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Wheel Sizes
David Martin wrote:
The thing to look for is the ETRO number. I think there should be another letter in there... ETRTO? ISO size is the same thing. This is the bead seat diameter, ie the size of the rim the tyre fits on and the width of the tyre, and looks like 622-25 (622mm diameter rim and 25mm cross section tyre, broadly equivalent to the 27 x1" but not quite the same.) Here is an abbreviated list of sizes ETRO traditional description 635 28" Policemans bike 630 old 27" road Well, not *that* old... it's post-WW2 (there was a pre-war 27 x 1-1/4; that's ETRTO 622!) 622 700c (also known as 29" for off road) 597 Another 26" That's 26 x 1-1/4 590 Old 26" roadster 26 x 1-3/8 or 650A 584 650B 26 x 1-1/2 in UK 571 650c 26 x 1-3/4 (ie: trade bike size) 559 26" mountain bike and it's round about here that my memory fails 547 24" 541 600A 540 24" 520 24" 507 24" 501 22" 490 550A 451 many 20" folding bikes 440 500A 438 Dutch 20" 406 20" BMX 400 18" 390 450A 387 Dutch 18" 369 17" Moulton 355 Another 18" size 349 16" 340 400A 305 16" 298 14" 254 14" 222 11" 203 12 1/2" -- Andrew |
#8
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Wheel Sizes
Naqerj wrote:
David Martin wrote: The thing to look for is the ETRO number. I think there should be another letter in there... ETRTO? European Tyre and Rim Technical Organisation -- --- Marten Gerritsen INFOapestaartjeM-GINEERINGpuntNL www.m-gineering.nl |
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