Road Frame Size

I ride and 18" mountain bike - but I would like to buy a road fame for a little tinkering around with - but what size? I'm guessing that a 45cm road frame would be pretty small?

Any thoughts?

Thanks

Ollie

Get down to your LBS and try some out. The length of the top tube is the critical factor in road bike sizing and this varies quite a lot for any given size between manufacturers. The size of MTB you ride will have little input to the skinny wheel bike that will fit you best.

Good advice there. The bike shop is your best bet. Sit on the saddle with youe hands on the hoods. Look down. Can you see the front hub? Yes? Too short or long. No? It's about right for length.

I'd guess around the 21" mark but all depends on your appendages vs torso length ratio

Just like with MTBs different manufacturers measure their frames differently. Even before there were compact frames there were those who measured centre to centre and those who measured centre to top. And since compacts came along there are even more ways to measure a frame. Let's not even get started on the XS,S,M,L,XL nonsense.

It's the TT or VTT length that matters so ignore the classic table based on height or inside leg. if you've got short legs for your height you'll probably need a larger frame than your height would suggest because you'll have a longer torso. And a rider who is all leg will need a smaller frame than his inside leg would suggest because they will have a short torso for their leg length. It must be a bitch for those circus chimpanzees to choose the right frame.

And don't take as gospel the advice of somebody who is a similar height to you. It's amazing how many people ride the wrong size bike.