Too much slope?

[TAW]

Saw this ebay auction:

http://cgi.ebay.com/Titus-Modena-Road-Bike-with-Powertap-Very-low-miles_W0QQitemZ120271333177QQihZ002QQcategoryZ9808 4QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I have to admit that I've grown to accept and even like a little slope on the top tube, but this seems a little extreme to me. How much slope is too much? Do you like this?

[eddief]

but so light and so fast.

[Sandy]

I don't like the looks of it. I agree- too much slope to be pleasing to look at. But it is all a personal opinion.


Sandy

[flickwet]

left brain says it makes engineering sense, right brain says sloping toptubes can be visually challenging. A little slope can look good.IMHO Too much is too much, esp when someone has rolled the bars to far up or forward.

[soulspinner]

On medium bikes my eye likes 7 degrees or so YMMV...

[pdxmech13]

no more than 7 degrees.
anything else needs to go back to the drawing board.

Just talking looks here though.

[Lifelover]

I have mixed feeling about extreme slopers like this. Part of me likes they way they look. To me they look faster. However, with the wrong body atop them they look a little silly.

I had a pre-Pacifica Schwinn Fastback that was a sloper similar to the Titus. I LOVED the way it rode. However, for my setup there was almost 2 feet of seat post showing. With my 250 lb build I just felt a little silly riding it. I envisioned that I looked like a circus bear riding a bike.

When my skinny 15 y/o rode it, it looked great. Too me slopers reflect the younger generation of cyclist.

[Mr. Butterworth]

Most of the Titus road bikes I've seen have a large amount of slope. Must be an homage to their MTB roots...

[capybaras]

I like it - looks fine on a small bike like that. A lot of slope looks weird with a long head tube.

[Ti Designs]

left brain says it makes engineering sense

It does? Explain.

[flickwet]

but based on the many friends I think I have I could probably play one on TV. Tubing diameter aside, Doesn't a smaller main triangle with thusly shorter main tubes result in a "stiffer" configuration based on moment arm length from joint to joint and axial stiffness down the due to a reduced "twisting" coefficient. What Im trying to say "Its easier to twist and bend a long tube than a short one if the tubes are the same material, diameter and wall thickness". Also at a given frame size wouldn't a sloping or compact frame be lighter both for the reduced amount of material and the reduced size of the tubes to achieve the same stiffness as a comparable conventional and dare I say aesthetically more pleasing frame set. About the right vs left brain I can never remember which side is supposed to be what. All I know is I'm right handed yet take pictures with my left eye, and FWIW I always get on my bike from the left, not mostly, always.

[Ti Designs]

Tubing diameter aside, Doesn't a smaller main triangle with thusly shorter main tubes result in a "stiffer" configuration based on moment arm length from joint to joint and axial stiffness down the due to a reduced "twisting" coefficient. What Im trying to say "Its easier to twist and bend a long tube than a short one if the tubes are the same material, diameter and wall thickness".

Thusly shorter main tubes or tube? The seat tube is shorter, the top tube doesn't change very much and the down tube doens't change at all. Kinda blows the explaination out of the water as the down tube takes most of the torsional stress. My concern is more of the twisting of the frame front to back. In sprinting bars are used to generate power at the pedals by pulling up on the same side that the pedal is pushing down. This puts a twisting force on the frame, which you hope it resists. As the top tube gets closer to the down tube it loses it's ability to resist the twisting force and you wind up with wheels that don't stay in-line.

[WadePatton]

me no like

looks like a mtb.

me no like mtb's with huge slope either.

[keevon]

Here's a sloper for ya...
http://www.rideonbicycles.com/roadbikes/vgreen1.JPG

[flickwet]

Thusly shorter main tubes or tube? The seat tube is shorter, the top tube doesn't change very much and the down tube doens't change at all. Kinda blows the explaination out of the water as the down tube takes most of the torsional stress. My concern is more of the twisting of the frame front to back. In sprinting bars are used to generate power at the pedals by pulling up on the same side that the pedal is pushing down. This puts a twisting force on the frame, which you hope it resists. As the top tube gets closer to the down tube it loses it's ability to resist the twisting force and you wind up with wheels that don't stay in-line.
I didn't think about that, but it sure makes sense, And your answer is why I love this forum, you tested me and then presented a view point I hadn't considered. Now I wonder this, aesthetics aside, what is the engineering ideal? Large diameter down tube (to compensate for torsional stresses) compact or smaller diameter conventional tube horizontal TT? My guess is the answer is given by the number of frame builders and manufacturers who can't decide either, I want to like compact frames but its difficult, personally I think racing frames reached their aesthetic zenith in the late 80's early 90's and their nadir today.

[Fixed]

me no like

looks like a mtb.

me no like mtb's with huge slope either.
iam likein you bro +1
cheers

[Kirk Pacenti]

Thusly shorter main tubes or tube? The seat tube is shorter, the top tube doesn't change very much and the down tube doens't change at all. Kinda blows the explaination out of the water as the down tube takes most of the torsional stress. My concern is more of the twisting of the frame front to back. In sprinting bars are used to generate power at the pedals by pulling up on the same side that the pedal is pushing down. This puts a twisting force on the frame, which you hope it resists. As the top tube gets closer to the down tube it loses it's ability to resist the twisting force and you wind up with wheels that don't stay in-line.

I would agree with this. Less triangulation = less stiffness.
A friend of mine (Boeing Eng. type) explained it to me once, about 10 years ago like this (I'm paraphrasing here):

"Imagine the HT was rigidly fixed to a wall and you grasped the saddle and bb shell in your hands and started twisting the frame. All other things being equal, the horizontal TT bike will be able to resist the torsional forces better than the sloping frame."

Since my friend is much, much smarter than me and also race(d) at a Pro level on the track (1/2 on the road); I figured he knew what he was talking about and put the matter to rest, at least in my own mind. I like the looks of Horizontal TT's better anyway so his explanation was justification enough for me.

That being said, I have grown accustomed to looking at slopers and they don't bother me much anymore. Same goes for integrated headsets and a bevy of other supposed 'improvements' most mass produced bikes come with today. ;)

[Ti Designs]

Now I wonder this, aesthetics aside, what is the engineering ideal? Large diameter down tube (to compensate for torsional stresses) compact or smaller diameter conventional tube horizontal TT?


I gave this a little thought back when I tested out the IF ultralight prototype and found it was the worst sprinting bike in the world. The rear hub was on the axis of rotation so the bike basicly crab-walked down the road under hard effort out of the saddle. There are too many parameters in bike design to talk about an engineering ideal, let's just say it depends on the rider. There are plenty of riders out there who never generate and force from the bars and would have loved that IF...