Geometry Question..

[bostondrunk]

Maybe this is one for the jerky boy.

How would you compare the geometry of say a stock Colnago vs a stock Trek?
The colnago seems to give a shorter top tube, by over a centimeter, for roughly the same standover height. I assume this would result in someone using a longer stem and/or a seat position a little further back.
How would the two geometries compare in handling, feel, etc.
Oh, and will one make me go faster so that I won't have to worry about losing that extra body fat?

[Marron]

Check this link; http://www.bikesportmichigan.com/reviews/colnago.shtml, for the best discussion of fitting Colnagos or Merckx I've seen. They are designed differently than Treks and the most insightful point in the article is that there is a huge difference between design and fitting; you can't design a bike by fit. I've tried a couple of times and it usually doesn't work.

[bostondrunk]

Interesting article. Especially how he says that when you fit a bike right, there is no need for spacers under the stem.

[Len J]

is crazy.

A size 56, has a 56 cm TT with (I think) a 52 cm Center to center seat tube. (I know they say it is a 56 but they measure it from the BB to the top of the seat collar). Standover on a 56 is slightly under 79 cm. Comparing this to any bike with a square geometry (56 X 56 C to C) you need 4 additional cm of spacers/stem rise to get the same position. In addition, Treks have a 73.5 degree seat tobe. this makes it worse compared to a normal 73 degree seattube by adding .6 cm to the effective tt to get the same position.

I don't know what they were thinking when they designed this, racing I guess, but for a non-limber non-racer, this geometry is a joke.

Len

[bostondrunk]

I would have to agree with you Len. I've twice looked at Treks, once about 4 years ago, and just recently for ****s and giggles, and I can't figure out how I would be able to use one unless I wanted to use a 100mm stem......

[jeffg]

Well, one might actually work for me. A 58cm has plenty of standover for me, a 57.2 TT versus the 57cm I have now (same ST angle), etc. I would likely have to use 15-25mm of spacers due to a shorter HT (that height is not listed), but it would otherwise fit. I just don't like the feel of those OCLV bikes. For the coin they charge now, a Concours would be a great alternative (or a Hampsten Tds if carbon is your bag). Just one fit perspective ...

[MadRocketSci]

is crazy.

A size 56, has a 56 cm TT with (I think) a 52 cm Center to center seat tube. (I know they say it is a 56 but they measure it from the BB to the top of the seat collar). Standover on a 56 is slightly under 79 cm. Comparing this to any bike with a square geometry (56 X 56 C to C) you need 4 additional cm of spacers/stem rise to get the same position. In addition, Treks have a 73.5 degree seat tobe. this makes it worse compared to a normal 73 degree seattube by adding .6 cm to the effective tt to get the same position.

I don't know what they were thinking when they designed this, racing I guess, but for a non-limber non-racer, this geometry is a joke.

Len

umm...it is a racing bike for limber racers in the biggest race in the world...not a french tourer...it does quite well in that capacity, don't you think? About the TT, i think they want you to sit a bit closer to the bb than other bikes, for spinning in those long stage races with climbs...seems to work for the best spinning climber out there now...

anyway, for shorter faster rides i reach for my 56 cm 5200, for long centuries, my 56x56 atlanta. if i spent all my time riding, working on my flexibility and core strength, then maybe i'd be able to ride a mountain stage on my trek....

[Len J]

umm...it is a racing bike for limber racers in the biggest race in the world...not a french tourer...it does quite well in that capacity, don't you think? About the TT, i think they want you to sit a bit closer to the bb than other bikes, for spinning in those long stage races with climbs...seems to work for the best spinning climber out there now...

anyway, for shorter faster rides i reach for my 56 cm 5200, for long centuries, my 56x56 atlanta. if i spent all my time riding, working on my flexibility and core strength, then maybe i'd be able to ride a mountain stage on my trek....


Don't know what you mean by "i think they want you to sit a bit closer to the bb than other bikes,", My position relative to the BB is the same no matter what bike I'm on. Optimal pedal action is a function of optimal seat height and setback........neither of which changes because of the length of the seat tube.

Clearly it was designed as a racing bike, however, even Lance has over 2 cm of spacers. In addition, I would guess that a very small percentage of these bikes go to other than super fit stage racers. I know they had to make a decision as to what they would mold, but I think they missed the boat somewhat. I had a 5500 and would never buy another. I loved the ride, loved the handling, couldn't live with a 15 cm seat to bar drop.......and I ride over 5,000 miles a year and am vey limber. With as many as they sell, I think they would sell many more if the geometry wasn't so extremely raceing biased.

IMO, it's one of the screwier geometry decisions in the bike world.

Len

[MadRocketSci]

Don't know what you mean by "i think they want you to sit a bit closer to the bb than other bikes,", My position relative to the BB is the same no matter what bike I'm on. Optimal pedal action is a function of optimal seat height and setback........neither of which changes because of the length of the seat tube.
What I mean is that because the bb is located 1.5 cm behind the intersection of the seat tube and down tube on a OCLV trek, I tend to think that they didn't mean for you to then move your seat back 1.5 cm to compensate. Set back to me is not locked in stone and I've played with it a bit to experiment with pedaling mechanics and weight distribution. I've discovered that I don't like to push and grind from behind the bb and that I prefer to sit a little forward of where my serotta fitter put me. If I kept the set back constant between my two bikes, my 56 cm trek would effectively have at least a 57.5 cm TT (and anyone will think that's long). On the trek I have a little more weight on my hands, but I think it still handles great down hills and feels a bit faster too (but still more fatiguing on really really long rides).


Clearly it was designed as a racing bike, however, even Lance has over 2 cm of spacers. In addition, I would guess that a very small percentage of these bikes go to other than super fit stage racers. I know they had to make a decision as to what they would mold, but I think they missed the boat somewhat. I had a 5500 and would never buy another. I loved the ride, loved the handling, couldn't live with a 15 cm seat to bar drop.......and I ride over 5,000 miles a year and am vey limber. With as many as they sell, I think they would sell many more if the geometry wasn't so extremely raceing biased.

IMO, it's one of the screwier geometry decisions in the bike world.

I'm just saying it can make sense for a weekend warrior type who's not into distance events. I do see them on centuries, and if it were my only bike i'd put some spacers in or maybe get a stem with more rise. With both i could get the bars even with the seat. 90% of riders i know could not care less if their stem is low and/or parallel to the ground. I also think that riding a lot and stretching won't do much for your core strength, and I only got rid of some fatigue issues I'd been having through some swiss ball and foam roller exercises. If I worked on it a lot more then maybe I'd be able to ride 130 miles in a mountain stage on the trek.

Regards,
madrocketsci

[vaxn8r]

Maybe I'm a freak, well.....

Anyway, i still think the OCLV was, and still is, perhaps the easiest, most natural fit I have ever had on a bike. I've done 2 double centuries and tons of centuries. I feel great on it.

It's hard to get actual measurements off this frame because the center of the BB lines up with the rear of the top of the seat tube. As close as I can tell, a 58 cm to top of collar is really about a 56 to top of top tube and has a 57 top tube. I still use a set back post, never have been able to use one without setback.

Anyway, I know nothing of front center or science of bike fit. All I know is it works really well for me. I have to believe there's a lot of others who love them because the design has been around so long. If it was a flakey design would they still be going so strong? Lance or not, I don't think so.

[Matt Barkley]

The Colnago vs. Trek stock geometrys?

I was going to comment earlier - in the "Champions Geo" thread. Really, the Colnago's top tubes are not short. Remember: You can subtract 2cm off the seat tube height and get a to ctr measurement, when corisponded to the mated top tube, it ain't "short" - Example: a 57 colnago is 55 to ctr with a 55.6 top tube. Colnago is looking for something different in fit... (See Preying Mantis Comment Below)

And larger sizes in the Freuler extension geometry give compareably equal or longer top tubes in equivelant sizes of other brands.

As for the comparison to Trek - Treks are mass market American bikes made for American builds of more weught in the upper body, especially in the arm and shoulders (We Americans love hitting the gym and McDonald's)


Colnagos are set up more for preying-mantis build Euro-Racers to run long stems on (not much weight being stuck out front)

Not to mention the Treks only come in 2 cm increments and you have to size up (in number size) a lot get get an equivilent top tube - really you can make anything fit but how is that going to handle. I would love for someone to give me a 58!! trek to test ride. Man, I never new I'd ride such a large frame. (I know the top tube/standover is low but.....)

[zap]

I just love it when it's mentioned how big Americans are. Not just on this board, but others as well. Especially from European's.

Gees, these people must live in midget colonies or something.

I'm from Europe. I'm bigger than the average NA. Where I come from, everyone is large. Not just height, but girth (not me :) ) as well. Last time I checked :rolleyes:, German women have, on average the largest bust size.

When I visit the old country, I gain quite a bit of weight while enjoying local cuisine. Europeans state the same when visiting NA. Europeans mention that portions are large in NA. Funny, but I find the portions are just as big in Europe.

Has anyone seen Eddy or Indurain lately?

Apologies for the rant. I've been simmering (well, not really) on this for a few weeks now ever since I read a post on another board from some midget frenchperson exclaiming how everyone in NA is big and fat and pigging out on super size portions.

Anyhooooow, back to bikes. I had a 58 Trek some years back. Used a 14cm stem to get the correct extension. Handling was OK. Since then, I've gone to other brands with longer tt so I could use 12 or 13 cm stems. I looked at Colnago's a year or two ago but just didn't want a frame that required the butt to hang way back there and hands way honder. Not to mention that chopper style HA.

I felt there were better bikes being built in the US.

[Peter]

Colnago's are CRAP in the geometry department.

All frame sizes, while using different head angles, use the SAME fork rake. That's just lazy construction and a lack of attention to detail.