Horizontal vs. Sloping top tubes - what do we think?

[betty swollocks]

I prefer the aesthetics of a horizontal top tube and have specified this requirement in my upcoming handbuilt, steel bicycle.
Here's a preliminary drawing the builders sent me, which I have approved.

 

[simongt]

I suspect that most women would probably find that an 'eye watering experience' too!

Though less likely to experience a 'squelch' as they come in contact with the top tube - !

 

[samsbike]

out of curiosity what is the geometry?

 

[GrumpyGregry]

I ride a frame with a 57cm horizontal top tube (centre to centre) and a 61cm seat tube (centre to top). I have about 18cm of seatpost showing.

A different frame from the same manufacturer has a effective top tube of 57cm and a seat tube of 53cm, so I'd need about 26cm of seatpost showing.

From a purely aesthetic point of view I much prefer the horizontal top tube and not too much seatpost showing, but if I'm looking for a new frame that severely limits the choice.

Why are sloping top tubes so prevalent at the moment? Is it just fashion or are there practical reasons?

Why? Because with sloping top tubes it means the manufacturers can get away with making a more limited number of frame sizes and still cover all the bases
-plus-
On an aluminium alloy frame a good length of seatpost showing can go an awful long way to taming some of the frame zing as the saddle is free to flap about in the breeze
-plus-
Lots of folk came to road biking from mtb backgrounds in the States and were used to the aesthetics of sloping top tubes because mtb's tended to have huge amounts of standover compared to road frames.

Me? Give me a steel frame with only a fist of seatpost, tops, showing, and I'm a happy rider.

 

[GrumpyGregry]

I prefer the aesthetics of a horizontal top tube and have specified this requirement in my upcoming handbuilt, steel bicycle.
Here's a preliminary drawing the builders sent me, which I have approved. View attachment 125828

Some would argue that is still too much seatpost and too big a stack on the headset but it is a good compromise between classic and contemporary.

 

[alecstilleyedye]

a lot of budget frames with a sloping top tube are not true compacts but have just been designed with a sloping top tube without the true compact geometry.

i've got both compact and horizontal top tubed bikes (see sig), and can ride both for a good distance. the carbon compact is a smaller (50cm) frame than the alu horizontal (57cm), and while a lot of seatpost is visible with the former, it's barely enough to mount a couple of lights on with the latter…

 

[Stinboy]

My Scott expert bought in 2000 was my first sloping top tubed bike.

(Not my bike but 95% like it) The colour scheme looks a bit dated, don't you think?

I prefer sloping but don't mind horizontal top tubes.

That's the same colour scheme on my Scott MTB (pretty much anyway)

 

[Accy cyclist]

That's the same colour scheme on my Scott MTB (pretty much anyway)

How old is your mountain bike? Is it something like this?

 

[slowmotion]

My Spesh Secteur has a sloping, bent and tapered top tube. It's just so wrong that it's silly.

 

[Blue Hills]

Yes, seen those.

What's the theory?

 

[betty swollocks]

Some would argue that is still too much seatpost and too big a stack on the headset but it is a good compromise between classic and contemporary.

They are only preliminary drawings. I like these proportions, but agree with your comment about the head tube stack. This will disappear during the bike fitting stages. It is very important to me that the bike should look beautiful as well as be fully functional.

 

[Fab Foodie]

Yes, seen those.

What's the theory?

Marketing ....

 

[winjim]

My Spesh Secteur has a sloping, bent and tapered top tube. It's just so wrong that it's silly.
View attachment 125936

It wouldn't look quite so daft if it wasn't for that brake cable.

 

[Blue Hills]

Marketing ....

yes, did wonder. I'm no engineer, but doesn't the bend make the tube weaker?

 

[Profpointy]

The original argument for sloping frames was the smaller triangle provided a stiffer structure whilast the longer seatpost dulled vibration mre effectively. I can see the point.

For what it's worth, I like both.

I've always been a bit skeptical of value of that argument. Just to be clear I rather think it may be literally true, it seems odd to simultaneously claim a stiffer rear triangle is a good thing whilst at the same time having a longer wobblier seat post supporting the heaviest part of the bike (80kg rider) is perfectly OK. I'd have though the sear post should be as short as possible if overall stiffness was so important.

I suspect the reason for slopping top tube is to allow fewer fram sizes to fit A wider range of riders. It does reduce the risk of walloping your bollocks though.

Aestheticall I prefer the "trad" look -horizontal preferably with pretty lugs.

Anyhow, what's all this "top tube" malarkey - it was a cross-bar in my day