Hi there. I'm going to provide some numbers and I'd be very grateful if some of you could consider them and tell me what you think about the kind of frame sizes I "should" be riding?
Or, more specifically, the kind I should be buying - because I have no usable bike at the moment.
I am 6ft (183cm) and my inside leg measurement is 35-36" (89-91.5cm)
I have had three bikes in recent years, all cheap second-hand things which I just tried and decided fit me alright. Their measurements are as follows:
Centre of BB to top of seat tube (flush with top tube) = 24" (61cm)
Top of top tube to the floor, vertically = 33.25" (84.5cm)
This is an old racing bike, very nice to ride and feels like it fits me well.
Centre of BB to top of seat tube (0.5" above the top of the top tube) = 24" (61cm)
This is a Dawes Galaxy from the late 70's most likely, and again it fit me well and in fact I completed 130mi on it two weeks after purchase, with no training (10mi commuting per week) and no experience over 30mi on a bike - it fit well and I had no discomfort.
Centre of BB to top of seat tube (1" above the top of the top tube) = 22" (61cm)
Top of top tube to the floor, vertically = 31.5" (80cm)
This is a junky old hybrid I bought for £10. It fits alright - in the past when I've had to ride this as my primary bike I have got used to it and the others seemed wrong and uncomfortable. And vice versa.
When I was in a bike shop recently I couldn't remember how big my Dawes was, and I said I think maybe 24" - the guy was shocked and said no, no, that must be far too big for me. Perhaps 21" would be more suitable.
Anyway, as I've discovered, bikes with a large BB-to-ground clearance like 3) above can end up with a fairly similar "size" overall to bikes lower to the ground but with a longer seat tube, like 1) and 2).
I will be buying something second hand and may not have a chance to ride it before I pay (there aren't many nice bikes for sale around here). Do you think I'd be safe going for a 24" Galaxy again?
p.s. the bike I will be getting will be used for commuting sometimes (a few miles per day), occasional touring and camping trips, and very occasional intercity rides of 100-150mi/day.