tyler12 said:
Am I missing something guys? Its all about Standard vs. Metric. 1 inch is equal to 2.54 cm. 1 cm is equal to 10 mm. 700 mm/10=70 cm. 70 cm / 2.54 = 27.56 inches. I think this explanation makes alot more sense, don't you?
Yes, tyler12, you ARE missing something. It's NOT about standard vs. metric in a lot of cases. Please don't get me wrong. I am not picking on you or anything of the sort. Your question is classic and there IS a very good reason for asking it. If you take a few minutes and read the Sheldon Brown article that I referred to earlier, he explains why (for example):
(26x1.75) DOES NOT EQUAL (26x1 3/4), as far as bicycle tires are concerned.
Unless you grew up in the bicycle business, you will never understand some of the quirks of bicycle measurements without referring to some of the articles written by those who "know". Sheldon Brown's site is loaded with sage advice about cycling's oddities. If it were as simple as "standard vs. metric" then why do are just about all new bikes all metric, except, of course for the bottom brackets and headsets, and head tubes? Why aren't they just all metric? It's a perplexing and often confusing issue of legacies. Tires are amongst the most confusing of all (lack of consistent) measurement standards. Fortunately, Sheldon has taken pity on people that have not made the mistakes enough times to learn the hard way and has published a very nice compilation of what tire size markings really mean. Here's the link again:
http://www.sheldonbrown.com/tire_sizing.html
I can tell you, from personal experience, that the example I used above does not work. I was helping a friend with his bike and he says "I need a new tire". So, we go off to Wallyworld and get him a 26 x 1 3/4" tire. Well, we fought that damn thing for an hour and could not get it on his 26 x 1.50" rim (you should always be able to go a size, or two bigger with the tire, right?). In this case, it was not a "metric vs. English" issue, but a "decimal vs. fractional" issue. Arrrgh!!! Now, thanks to Sheldon Brown, I understand why this does not work.
If you want to understand bikes, sometimes you have to just accept the fact that things don't necessarily make sense and refer to the experts. Life gets easier once you do.