Classic Geometry - diff frame size needed?
Classic Geometry - diff frame size needed?
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Discussion

mikees

Original Poster:

2,891 posts

202 months

Sunday 14th July 2013
quotequote all
There seem to be loads of what I would call classic geometry road bikes on the bay (level top tube, rather then dropping a couple of cms at the seat tube) that are 60cm frame size or more.

I can't recall riding one of these (or more to the point the size) so in general are they a "larger" frame size for the same size person ?

Cheers
Mike

itsnotarace

4,685 posts

239 months

Sunday 14th July 2013
quotequote all
Assuming the effective (horizontal) top tube length is the same on the sloping and classic, then reach will be the same. However, if you have shorter legs, you won't have as much seatpost showing. Classic geometry also means short headtubes (generally speaking) so if you are flexible and can manage a reasonable saddle to bar drop thats's fine, otherwise you will need to run with a stload of spacers under the stem to bring your bars up to the right height.

gazza285

11,167 posts

238 months

Sunday 14th July 2013
quotequote all
60 cm would equate to a 23&1/2" frame, which is a large. Frames used to be sized from 19&1/2, 21&1/2, 23&1/2 and 25&1/2". The head stock was in direct proportion to the seat tube, to keep the top tube horizontal, there were no spacers to worry about because the stem could adjust up and down and tightened at the required height.

How quickly people forget. I used to ride on a 23&1/2" but am now on a 59.