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Post by cusqueno on Jul 11, 2016 22:17:59 GMT
It might be interesting to share some information on frame dimensions. The most important are the seat tube and top tube. I assume that Viscounts were built to Imperial measurements (adverts bear this put), so perhaps we should stick to inches? Do people normally measure seat tubes centre to centre (ctc) or to top (ctt)? I prefer the latter but it should be to the top of the top tube, not the top of the seat tube as Viscount seem to have random amounts of seat tube above the top tube. I'll refine this later, but all the Viscounts I measured this evening had top tubes 22.5" ctc. The seat tubes were from 22 to 23.5 ctt. I think.
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Post by velocipete on Jul 12, 2016 18:28:42 GMT
I prefer the the measurement to be to the actual top of the seat tube. This is on account of being a tad short in the leg department. I then know if the bike would actually fit me. I've been caught out with ctc seat tube measurements when the tube actually finishes about 1 1/2" above ctc measurement. Cheers, Pete.
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Post by cusqueno on Jul 12, 2016 19:16:18 GMT
You have a good point Pete. It doesn't matter too much as long as everyone uses the same. Centre to top of seat tube it is. I'll do some better measurements later this week.
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Post by kickstandman on Jul 13, 2016 1:01:28 GMT
It might be interesting to share some information on frame dimensions. The most important are the seat tube and top tube. I assume that Viscounts were built to Imperial measurements (adverts bear this put), so perhaps we should stick to inches? Do people normally measure seat tubes centre to centre (ctc) or to top (ctt)? I prefer the latter but it should be to the top of the top tube, not the top of the seat tube as Viscount seem to have random amounts of seat tube above the top tube. I'll refine this later, but all the Viscounts I measured this evening had top tubes 22.5" ctc. The seat tubes were from 22 to 23.5 ctt. I think. That's quite an interesting observation on the top tube and sounds about correct.
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Post by 54roadie on Jul 18, 2016 7:21:48 GMT
Nice idea, John. My Gran Prix, as well as I can measure, comes out like this: Head tube: 6 5/8" Seat tube: 23 5/8" center to top of top tube, 23 5/16 c to t of seat tube Top tube: 22 1/2" Chain stays: 17" +/- 1/2" measured from BB center to rear axle center. Varies by where I set the wheel in the drop outs. Seat stays: 21 1/4" measured from rear axle center to where stays are brazed to seat tube. Currently the rear axle is centered along the centerline of the seat stays. Front center: 24" exactly. Wheelbase 40 1/2" =/- 1/2" Rake: 2" (least trustworthy measurement, I think).
I find this sufficiently fascinating that I may break out the old geometry book and calculate the BB drop from the centerline of the wheelbase. I don't trust myself to measure that accurately.
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