Why compact your geometry??

[Inner Peace]

The classical style of a horizontal top tube is the most visually pleasing part of a frame, in my humble opinion.

What is the point of the compact/sloping geometry, and why are so many carbon fibre bike manufacturers adopting this style?

Is it a weight saving thing? (i.e. making a compact geometry would literally use less materials than the traditional geom. - bigger triangle)

I think compact geometry/sloping top tubes are the most ugly thing going around on a a road bike, and I would love if someone can explain the non image based reasons as to why they are making them?

Also, time trial bikes, in general, use a horizontal top tube? But the same bike manufacturer might use a sloping top tube for their road bike... Why?

Enlighten me!!

 

[lostintime]

The classical style of a horizontal top tube is the most visually pleasing part of a frame, in my humble opinion.

What is the point of the compact/sloping geometry, and why are so many carbon fibre bike manufacturers adopting this style?

Is it a weight saving thing? (i.e. making a compact geometry would literally use less materials than the traditional geom. - bigger triangle)

I think compact geometry/sloping top tubes are the most ugly thing going around on a a road bike, and I would love if someone can explain the non image based reasons as to why they are making them?

Also, time trial bikes, in general, use a horizontal top tube? But the same bike manufacturer might use a sloping top tube for their road bike... Why?

Enlighten me!!

There are no valid reasons, unless you're a very small rider, then I can see some validity. Mostly, it's monkey see ..... monkey copy in the bike biz.

I agree, the sloping tubes look like he!!, especially for tall bikes with extra long seat posts. But hey, I grew up as a teen in the 70's..... so all the carbon frames today look like they were designed in a cartoon! The high profile wheels with the huge advertising look like he!! too.

That's ok though ..... I don't have to buy the junk Steel frames and Aluminum rimmed handbuilt wheels for me!

 

[Ad Rock]

There are two reasons that I can think of...
1)Compact geometry can be ONE WAY to make a frame stiffer and more responsive (NOT the only way, obviously)
2) It allows some frame manufacturers to reduce the cost of production, making maybe 4-5 frame sizes instead of 7-10+


As for why TT bikes generally have horizontal TTs, that is entirely for aerodynamics.... Then the tube is perfectly horizontal, all the wind sees is the cross-sectional area of that tube.... wind goes around it once and the main source of drag is only surface drag along the tube (minimal).... If the tube slopes then the air will leave the headtube, have to fill the gap behind that, and then at some point re-contact the top tube and (depending on the slope) have to flow from one side of the TT to the other, causing form drag- which is more of a concern!

 

[RDV4ROUBAIX]

Compact geometry came about because it's simply a way for the mfg's to save money. I think it was Giant that first started this. They figured out that by effectively reducing the size of the main triangle it cuts, in some cases, two thirds of the sizes needed to cover everybody compared to traditionally fit frames. This is typical big company thinking and they disguised it as some technological wonder of the age using BS marketing catch phrases like "stiffer, and lighter" to mask the real reason for going compact. The only "improvement" that came from compact geometry was a lower standover from the sloping and semi-sloping top tube so you can throw your leg over it easier, that's it, but the apologists will claim "lower center of gravity", also BS. I also stick to the classic steel frame and sensible wheels idea, but I also roll a full carbon rig with that really ugly compact geometry because I've always kept up with tech, or so-called tech for my job, prefer the steel for everyday riding though. You know there's actually a generation of cyclists now that doesn't get it because they've been brainwashed by these big corps into believing whatever they say or do must be right.

"Don't believe the hype"
~Chuck D

 

[Big GMaC]

CAAD9 FTW!

Actually most Cannondale Road bikes (except the Synapse) have kept the horizontal top tube. Any reason they haven't followed suit in going compact?

 

[Black Dog]

RDV is 100% correct. There is no technical advantages to compact geometry. Lighter frame = longer heavier seat-post etc... It is all marketing and now has become the fashion. There is one distinct disadvantage. Getting the water bottle out of the seat tube is more difficult because of the lowered top tube.

 

[usedtobefast]

Compact geometry came about because it's simply a way for the mfg's to save money. I think it was Giant that first started this. They figured out that by effectively reducing the size of the main triangle it cuts, in some cases, two thirds of the sizes needed to cover everybody compared to traditionally fit frames. This is typical big company thinking and they disguised it as some technological wonder of the age using BS marketing catch phrases like "stiffer, and lighter" to mask the real reason for going compact. The only "improvement" that came from compact geometry was a lower standover from the sloping and semi-sloping top tube so you can throw your leg over it easier, that's it, but the apologists will claim "lower center of gravity", also BS. I also stick to the classic steel frame and sensible wheels idea, but I also roll a full carbon rig with that really ugly compact geometry because I've always kept up with tech, or so-called tech for my job, prefer the steel for everyday riding though. You know there's actually a generation of cyclists now that doesn't get it because they've been brainwashed by these big corps into believing whatever they say or do must be right.

"Don't believe the hype"
~Chuck D

i think Specialized was the manufacture, not Giant.

 

[Wallace]

This thread is so right, I don't know where to start. If 531 was good enough for Eddy, it's good enough for me. And back in the day, showing more than an inch of seatpost was considered downright obscene--and it still should be. What's with the kids today, with their new geometry, and their disgusting seat tubes right out there in the open... Hey you--yeah you with the carbon wheels--get off my lawn!

Man, you people are GROUCHY. What happened--were they all out of prune Gatoraide at the Kwik-Stop?

 

[karlboss]

This must be the grumpy old man thread. Agree compact was nearly 100% about fewer frame sizes to fit more people, cheaper production. To most, they wouldn't notice the change in fit and/or would adapt to it fast.
Performance is close to traditional frames and depends on many factors.
To sell more bikes there was also a benefit in having something new and different, and claimed weights were lower. Good for marketing.
Frames can't have been too much cheaper built in this manner out of aluminium but they sure were out of carbon. Monocoque carbon frames need moulds and moulds are expensive. If you aren't sure people will buy your frames, your costs had best be low. So this aided the transition to carbon frames. Which we all know are better...the best carbon frames are demonstratably lighter, stiffer and more vertically compliant than any other metal counterpart. Having said Carbon aint carbon and steel aint steel, I could make a centremetre thick rod of both you could break over a bench without much of a swing. There are more variables in a carbon bike with fibre orientation and layup, these are opportunities and risks, the good companies make the most of it the bad...well they copy and hope for the best.
As for aesthetics...ideas about beauty constantly change, look at art architecture, and fashion over the years. You find what you find attractive I find what I find attractive, who cares. Some new bikes that I hate...de rosa tango and carrera phibra, but I like the lines of a specialized tarmac (also some little engineering details). I find many classic frames beautiful also.
As for the feel of a bike...you feel a combination of things stiffness in different areas sometimes wanted sometimes not, vibration, and restitution when you ride...their is no perfect combination, maybe you like swedish massage and I like shiatsu. Hell have a look at the number of different saddles in your local bunch.

Buy something that fits, looks good to you, feels good to you and ride it.

 

[Black Dog]

This is not about wishing that the golden age would return. There is no such age...every one thinks that when they started to ride was the exact same time that bike tech reached its zenith.

The issue here is that these changes are being sold as something that they are not; as are many new technologies in cycling. There is always hyperbola with marketing but it is now just pure BS. Claims are no longer just unsubstantiated they are simply false.

I love to see technology improve. I do not want to ever ride toe clips again, I love me comfy bibs, my STI etc... I just hate blatant BS from marketers. Where the hell are the engineers? They used to design bikes...those were the days...

The rich boomers will not be supporting cycling for ever. Can the escalating costs of some tech be sustainable?

 

[Inner Peace]

I'm very glad my thoughts are echoed!!

Compact = ugly
Traditional = beautiful

Enough said really.

My original thought was the weight saving thing, but the point about having to include a longer seat post practically cancels that out.

Must be a cost thing. Most pro bikes are amongst the largest manufacturers (you know, don't see many Soma Fab bikes in Roubaix - although that would be totally cool as per my single speed thread) who are clearly looking to make cost savings, especially if all their competitors are doing it...

I also had heard Giant came up with the idea, which makes economic sense, with them being a mass market producer, but could of been Spec too.

I'm glad to know that there is absolutely ZERO performance/comfort benefit from these frames, other than the massive personal cost of looking like you ride a girls bike to swing your leg over...

Goes to show, if you've got the cash, may as well fork out for a custom made frame so you can design a geometry that suits you, rather than the mass market consumers... well at least that's what I plan to do when I upgrade to a new roadie.. (still looking for a new single speed if anyone is wondering from THAT thread, so gotta sort that out first)

 

[mercycle]

Sloping top tube doesn't always mean "compact" geometry. It can be used to raise the head tube in relation to the seat. Why do this? Say you have limited flexibility in your back and you need the handlebars up instead of slammed wicked low. With the good old style quill stems you could get one with a longer tailpiece and just raise it up to the "minimum insertion" line. With the new fangled "threadless headsets", you wind up needing either a stack of spacers or a stem with a huge amount of rise. But if you tweak the top tube so the head tube sits higher, you can use a "normal" stem (+/- 6 degree) and a few spacers. Mechanically it's probably a wash, but it looks a heck of a lot better.

Riding a 53 cm frame, there's a good argument to be made that I'm already riding a compact, but for looks, I just don't like them. In a huge size (say a 60 cm) it could be a weight savings, but how much depends on the material.
Horizontal top tube on a TT bike: keeps it behind the head tube and out of the wind. At the Pro level, every little bit helps. For a USCF Cat 5, if you think it makes you faster it does.

More important than compact geometry: why the heck did they move away from the classic -17 degree stem that mated so perfectly with a 73 degree head tube? You want ugly, modern stems and Ergo handlebars.
Shallow drop, round bend Cinelli.

 

[Bustedknuckle]

i think Specialized was the manufacture, not Giant.

Giant was the first to do compact then paint the s/m/l/xl frame sizing as some sort of 'wonder and amazing innovation' when, like threadless and MTB fork steerers, all they were trying to do is same $ in a flat market.

 

[usedtobefast]

wiki frame article
http://en.wikipedia.org/wiki/Bicycle_frame