Originally Posted by
Mike T.
Sogood, so what's your suggestion of how we should state our gear sizes? And how do you propose to get the whole of the English speaking cycling world to change to your method?
I don't understand the "hands" measurement in horse circles. "15 hands" means nothing to me but I'm sure 5' would, compared to a 5' 5" horse. But if I got into horses I'll bet the "hands" measurement would make sense in time.
Yes I'm sure 48 div by 16 (which equals 3) would make sense in time and just as much sense as 48 div by 16 x 27 (which equals 81) but Gear Inches has been around for a little while (like a hundred years) and almost everyone who's really into cycling understands it.
Sorry if you don't agree with the majority of the English speaking cycling world. We're happy with the present system but then I'm happy with Imperial measurement even though I live in Canada and some stuff is measured in Metric. Try going to the lumberyard and asking for a ten foot 2x4 in metric. Hell a 2x4 doesn't even measure 2x4 but we ALL know how relative that is to a 2x6 that doesn't measure 2x6 either.
Mike, you seem to be completely missing the point as to why people use gear inches over gear ratios. Gear inches (and development meters) take into account your wheel/tire size which allows you to compare how "hard" or "easy" a gear/wheel combo is to another. If a mountain biker, a roadie, a BMXer and a guy on a folding bike wanted to compare their gearing, using gear inches (or development meters) would be a far superior method to just gear ratios, because riding a 48x16 with 20" tires is a lot easier than riding a 48x16 with 700x23C tires.
Sogood isn't suggesting we stop using gear inches but that people use the correct tire measurement when doing the calculations. 27" maybe be "close enough" when comparing 700C tires but it's not accurate and makes comparisons with other wheel sizes difficult.
So for the record, a 700C wheel is 622mm in diameter, or 24.5". Add on a 23C tire (which is 23mm thick, adding a total of 46mm to the diameter of the wheel) and you get a diameter of 668mm or 26.3".
My track gearing is 48x15 so that would give me the following gear inches:
27" tire: 86.4"
700x23C tire: 84.2"
700x20C tire: 83.4"
So if I'm using a 20C tire and do the calculates with 27", I'm off by 3 gear inches, which is significant.