Potentially daft q. Re sizing and fit on a non compact frame

pigman

Senior Retro Guru
Re:

Sorry, I didnt know how to pitch it, I wasnt meaning to be patronising, hope you read it in the spirit it was intended. Its not always easy to know who knows what.
Anyway, back to your dilema.

As a (very) rough guide, horizontal frames are built square, that is seat and top tubes are built to the same lengths. So, if you are looking for something with a 535mm top tube, I would expect your frame to be 53-54 cm. It can vary a bit, eg Colnagos are bit short in the top tube and some of mass produced raleighs of old are a bit longer. I wouldnt expect a 50-52cm frame to have a 55 top tube. Maybe that was a custom special that the customer wanted like that
 

M_Chavez

Dirt Disciple
Pigman - yes, I am questioning that 2cm of stem length will make a noticeable difference to handling.

Cornholio - I think bike sizing guidance is generally rubbish. Or I am a freak and have disproportionately short legs and long torso.

For road bike I went almost a size up (compared to "recommended", made it fit and it was weird for the first couple hundred miles but now fits like a glove. For cx I went half a size down, made it fit and it's still not as good as the "oversized" road bike.
Keep in mind - the lower the handlebars and the wider the handlebars, the "longer" the bike feels, as you have to stretch. Always an option of installing the bars a bit higher.
 

Holiocornolio

Devout Dirtbag
Re: Re:

pigman":getowgf4 said:
Sorry, I didnt know how to pitch it, I wasnt meaning to be patronising, hope you read it in the spirit it was intended. Its not always easy to know who knows what.
Anyway, back to your dilema.

As a (very) rough guide, horizontal frames are built square, that is seat and top tubes are built to the same lengths. So, if you are looking for something with a 535mm top tube, I would expect your frame to be 53-54 cm. It can vary a bit, eg Colnagos are bit short in the top tube and some of mass produced raleighs of old are a bit longer. I wouldnt expect a 50-52cm frame to have a 55 top tube. Maybe that was a custom special that the customer wanted like that
You weren't at all, I just didn't make it particularly clear that was what I was measuring :) no offence taken. I guess in the end, my question is really - should I expect to be able to replicate my normal riding position (on a compact frame) on a frame with a horizontal TT?
 

Holiocornolio

Devout Dirtbag

foz

Gold Trader
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Re:

In simple terms, your riding position should be the same on both bikes. So BB to saddle, then saddle to bars. How you get there will be different, depending on bike age, geometry, make, etc... The frame, stem and seatpost are just what join the contact points.
But then again, not all bikes are exactly the same, and some difference in position isn't usually a problem.
Most racing bikes have geometry designed for that, and are designed to be used with a longish stem. If I put an 80mm stem on my 58cm frames, the handling would probably be worse than with the 130mm stems I usually use, weight distribution and steering angle being the main reasons. But it wouldn't necessarily be unrideable or even bad.
 
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