Difference between "classic" or "sloping&quot

drumon

Whats the difference and benefits of either a traditional road frame with level top tube versus a sloping top tube road frame?

morrisje

I have got both - a Look KG 361 and a Kinesis TK.
Basically the type of top tube doesn't cause any difference. Wheels, frame material, group set, geometry are the main things that make bikes feel different. When I say geometry I mean distance between wheels, etc.
I suppose that if you have more seat post showing on a sloping bike then you may get some more vertical compliance for comfort.
It seems to be mainly for cosmetic reasons. Sloping new, horizontal old.

JC.152

A lot of bike companies nowadays do a sloping top tube sportive model with big head tube and a race bike , more horizontal top tube, shorter head tube.But even then a lot still have slightly sloping top tubes as well

JC.152

Sorry about the second picture it broke a bit.

neeb

This is the way I see it:

A sloping top tube combined with a tall head tube allows you to have a more upright, "sportive" position without having to have either 1) loads of spacers under the stem, or 2) an uncomfortably small distance between crotch and top-tube. When quill stems were common and all bikes had straight top tubes, an upright position could be achieved simply by raising the stem.

If you want a more aggressive position with handlebars significantly lower than the saddle and a relatively short headtube, there is no real difference between a straight and sloping toptube other than the length of seatpost you will need, plus any minor differences in stiffness/weight/flexibility that may result from a more compact frame and the properties of the seatpost.

huggy

I can't speak for others so don't criticize me but I do find horizontal top tubes far comfier.

neeb

I can't speak for others so don't criticize me but I do find horizontal top tubes far comfier

To be sure about that you'd have to have ridden a lot of different bikes or else two bikes that were the same in all other respects other than the slope of the top tube... Could it be that the sloping TT bikes you've ridden are mainly Alu and the straight TT ones steel or something like that? Don't worry I'm not being critical, you could be right!

I sometimes wonder where the cut-off point between compact and "semi-compact" is. Maybe 6 degrees? I reckon the Wilier above has an 8-10 degree slope on the TT aprox., while the cannondale must be about 4-5. I'd Call the Wiliert compact and the 'dale semi-compact.

cannonfodder

Sloping top tubes were not an attempt to change the geometry of a bike - they were designed to give you smaller triangles for the same geometry. Sloping TTs were popularised by mountain bikes before they hit the mainstream road bikes to give better stand over height and stiffer frames whilst giving the rider the same position. Another advantage on a road bike can be a better ride as you have more (flexible) seat post showing.

McBain_v1

It's an aesthetic thing with me, I just don't like sloping top tubes - it's got to be horizontal. This was a major factor in my choice of my best bike, it had to have that "classic" frame geometry 8)

neeb

It's an aesthetic thing with me, I just don't like sloping top tubes - it's got to be horizontal. This was a major factor in my choice of my best bike, it had to have that "classic" frame geometry Cool

My bike's an Enigma too (Esprit) but I went for a slightly sloping TT!

You are right about the aesthetic thing though and the subjective element. I don't like an extremely sloping toptube, but I think 4-6 degrees looks nice. Some frames just look "right" and some don't. Probably there are certain mathematical ratios in the proportions that reflect the golden mean or other historically & culturally favoured proportions (e.g. 1 to the square root of two).

bill57

Agree entirely with Neeb. Semi-compact, fine, I would definitely have one, but compact just does not appeal aesthetically. Having said that all my bikes have horizontal top tubes. Call me a cynic, but personally I doubt if it makes any difference at all to the ride - it's more about current trends and fashions.
But I'm not about to advocate blind testing on a bike.

meagain

"This is the way I see it: ....."

Me too, Neeb!

I prefer sloping both aesthetically and practically. The more seat post the better for comfort IMO/E - and with a horizontal that puts bars where I want them in relation to saddle means only 2-3" of post out. Also, as I age, hoisting my leg over a horizontal 22" frame is not, shall we say, entirely convenient! My most "comfortable" bike once moving at the moment happens to be horizontal, but that has nowt to do with the top tube, simply the wheelbase, front-centre and stay lengths.