red apples and sweet oranges
I think it causes confusion to keep using the term "compact geometry".
Although there are angles involved in each, so "geometry" is involved in each, compact vs. traditional style frames is one thing and relaxed vs. aggressive geometry is a completely different thing.

I agree with Artkansas. It has nothing to do with the top tube. It has everytihng to do with the angles of the seat tube and the head tube with the horizontal. Smaller values = more relaxed in general. However, we can discuss the effects of those angle changes for ever, especially the head tube.

Road Fan

Isn't compact geometry just defined by a dropped top tube, and perhaps an extra-short chainstay? Everything else is dictated by the needs to fit the rider and to provide good handlling and steering response.

show me one frame that has a right triangle! If what you say is true, then all frames are relaxed.

Right, relaxed = slack

Compact frames has pretty much become the standard for all types of bikes, relaxed and aggressive. I prefer the traditional type, but I don't think it really makes much difference unless you have short legs for your height.

Both bikes are compact frames. The Pilot has relatively relaxed geometry (72.6 degree head angle) while the Buenos Aires is more neutral to slightly aggressive road geometry (73.5 degree head angle).

OK, that makes sense. I had ridden the Pilot on different days from the Lemonds. I couldn't tell a difference and when I saw the frames side by side I thought they looked the same. I wish I would have ridden them on the same day for a better comparison. Since I'm a dirt-head and like the "slack" angles, perhaps I would have been a bit more comfortable on a Pilot than a Buenos Aires. Part of it was that I wasn't willing to buy a full carbon Pilot, even with my wife's money.

Still, I'm going to keep the Buenos Aires.

I am very mathmatically challenged and just want to see if I have the concept- is this a true statement:
A bike with a 70 head tube angle and a 74 seat tube angle is more relaxed than a bike with a 72 head tube angle and a 75 seat tube angle?

Maybe I should have used a smiley?

Good question, farrellcollie. I'd like to know if that's true. But what about the Pythagorean Theorem? :)

Now that I take a longer look at the geometries of the Trek Pilot 2.1 vs the Lemond Buenos Aries, I think my sales guy steered me wrong. The Treks come in even numbered frame sizes (52, 54, 56, etc) vs the Lemond's odd number sizes (51, 53, 55, etc). The sales guy had me try a 52cm Trek vs a 53cm LeMond. He should have had me try the 51, as the smaller Lemonds are very close in measurements to the larger Treks.

Just picking a few measurements

Trek 2.1 52cm
Eff Top Tube: 531mm
Seat Angle: 74.8
Standover: 734

Lemond 53cm
Eff top tube: 545mm
Seat Angle: 73.0
Standover. 757

If he had put me on a 51cm LeMond instead:
Eff top tube 531
Seat Angle: 73.8
Standover: 744
plus the stem is 10mm shorter on the 51.

I'm sure my fit would have been much better on the 51 than the 53.

Yes, and I would guess they would both be time trial bikes?

My wife and I each have the Cadent 2.0 carbon forks and seat post with 105 and Taigra from 2006 and we really love to ride these bikes, very comfortable but you can still get into the drops and get after it. If this is the sort of bike you might be looking for check them out.

When I first read this post, I was profoundly insulted. Then I remembered, that I hadn't posted any of the responses! :)

Does this mean I'm not a knucklehead anymore? :)

Or does it mean that I'm still a knucklehead, but just didn't express it during the course of this thread? :(

this thread is making my head hurt...

I believe that "compact geometry" may have been a marketing phrase to describe the compactness of the front triangle of a frame when using a sloping top tube. Often used by designers to get a better standover height for a given frame size and sometimes touted as providing a stiffer frame (notice how marketing uses the same word to appeal to Freds and OCP'ers)

Relaxed geometry usually is used to mean more rearward lean in the steering tube (think chopper bike) which will make the bike more stable in a straight line but less responsive to steering input.

Marketing people however can change the definition of a phrase with but the firing of a single neuron thus leading to all sorts of theories about what they really mean. The best side effect of this is to provide hours of entertainment on 50+

And for Big Paulie...............yes.

Isn't it strange how many problems in the modern world can be traced back to someone with an MBA? ;)

In the world of lasers we get a new flock of MBA's with new 5 year plans every 4 years......:p

I've never dug into the differences between compact, relaxed, standard, etc. I just know they called the 1800C relaxed when I bought it:)

Don't forget the set-back on the seat pin can make a difference comparable to a couple of degrees of frame angle. Different pins can have different set-backs.

On this side of the pond we call them seat posts and the set-back is referred to as offset.

Ah, countries divided by a common language (so somebody said once!). We say 'Campag' you say 'Campy' etc. etc.

Sorry, I had to go back to work. Besides, Tom did a good job sorting out this stuff. As others have said, marketing plays a big role in all of it. The "compact" style road bike's main advantage is fewer sizes supposedly fit more people, instead of making a 49,50,51,53, etc., they just have a small, medium, large, and a not so extra large. If you're built like me, most makers don't provide a frame big enough.

Yes, our friend Stapfam always confuses me when he talks about food.

Yes.

Yes, sorry!

Road "humorously challenged" Fan