What does 700c mean ?

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spinner_43
Posts: 50
Joined: 2 Sep 2008, 2:45pm
Location: Bolton

What does 700c mean ?

Post by spinner_43 »

As a newbie, I am confused about the '700c' jargon/buzzword. Does it refer to a wheel size, tyre size, wheel specification, or what? Is it important to know?

I've tried the search engine, but couldn't find what I wanted.

And, while I'm logged in- what the devil are eggbeater pedals !

Regards, Alan.
thirdcrank
Posts: 36776
Joined: 9 Jan 2007, 2:44pm

Post by thirdcrank »

700C (Capital C) is a tyre size roughly the same as 27" but a bit smaller. It's now the standard for so-called road bikes. Although it is generally assumed by UK riders to have superseded the British standard 27" wheel, I understand that 700C came first and either Raleigh or Dunlop wanted to protect their market with a size of their own and introduced 27 x 1 1/4", so 700C just really made a comeback in the UK starting about 25 years ago. It's usually expressed as 700 x 32C or similar where the second number is the tyre size in millimetres - the equivalent of the 1 1/4" bit in 27 x 1 1/4".

See http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3802 for chapter and verse

Eggbeaters are a type of clipless pedal that look a bit like foodmixers
GeoffL
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Joined: 28 Feb 2007, 7:47pm
Location: SE Cornwall

Post by GeoffL »

As usual, Sheldon Brown had light to shed on the subject. http://www.sheldonbrown.com/tire-sizing.html gives a little more depth and information of how the industry got into such an unholy mess with wheel and tyre sizing!

HTH,

Geoff
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cranky
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Joined: 3 Jul 2008, 11:28pm
Location: Glasgow

Post by cranky »

Eggbeater pedals...

Image
Iain

Ridgeback Genesis Day 2
Surly Long Haul Trucker
spinner_43
Posts: 50
Joined: 2 Sep 2008, 2:45pm
Location: Bolton

Tyre sizes

Post by spinner_43 »

Thank you 'thirdcrank', 'GeoffL' and 'cranky' for taking the time and touble to direct me to the information sites. I have found the ISO tyre spec (37-622) for the tyres on my bike and can now try to digest the data.
One important piece of advice I noticed is that the tyre pressures should be checked every few days. It's obvious really, with such high pressures nowadays, that the tyres will be leaky- and that I'll have to invest in a track pump, rather than the tichy little thing I currently use.
Again, I'm very grateful for your help,
Alan
thirdcrank
Posts: 36776
Joined: 9 Jan 2007, 2:44pm

Post by thirdcrank »

spinner43

I think general experience is that modern (OK fairly modern :oops: ) butyl tubes retain the air much better than latex which generally needed pumping up before every ride.

One problem about maintaining pressure is that nobody seems sure what is a properly calibrated gauge. I have a Topeak Twister (now obsolete, I think with a digital gauge) but the suggestion is that even though they appear to show to the nearest psi, that is spurious accuracy.

The eproblem of valves becoming detached from the tube comes up here quite often, and a track pump is ceratinly a good way to maintain high pressure without riving the valve out with a push on adaptor in the end of a frame fitting pump or similar.
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