Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Geometry

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Old 04-22-03, 09:16 PM
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shokhead
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Geometry

So the new term is compact geometry.So what is it and what is regular.Less then 1000cm for the wheelbase would be reg.410 for chainstays.Is there a bike with reg. geometry and one with compact as an example.Is it the slope of the top tube.Someone please inform me.Oh and what does one do over the other.Better ride or handling or corning.
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Old 04-23-03, 03:02 AM
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MichaelW
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Compact frames are ones with a sloping top tube, and are fitted to ride with more exposed seatpost than regular frames with a horizontal top tube. That is the only defining feature of compact frames. They do not have shorter chainstays or shorter wheelbase than regular frames, just a sloping top tube.
You can get compact framed touring bikes which have long chainstays, and light-touring versions with medium sized ones.

They were invented by Mike Burrows, bike designer for Giant, as a system to allow fewer basic frame patterns top fit a wider range of ridrs, using replacement seatposts and stems.
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Old 04-23-03, 03:33 AM
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ParamountScapin
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The commentaries I have read in the bike mags are not too flattering. They say that the only advantage is a very small weight loss and perhaps some more stiffness in the frame. The disadvantage is that this stiffness goes away with the much longer seat-post.

The two commentaries I read both felt that main advantage was to the bicycle companies in that they could offer fewer frames sizes, giving a lower cost to the fabricator, but not necessarily to the end user. They also felt that the rider would have less opportunity to get a good fit on a compact frame as there are fewer sizes offered. Thus, you must fit what they offer through seat height and stem length adjustments, etc., and not proper frame size choice.

Call me old fashioned. I also think they look strange. My new bike is a 'traditional' frame in my proper size.
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Old 04-23-03, 04:34 AM
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TimB
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I agree with PM on the bike fit scenario.
Another aspect you never read about is that bike geometry is worked out so that the riders weight is placed more or less over the front axle. Excessive long stems then aactually make the biikes handling less managable.

Having tried out a Giant Compact and a Litespeed Sienna before buying the Tuscany, I found the Sienna was not lighter than the Tuscany, 14 grs heavier in fact and it was not stiff when climbing in the saddle.
Out of the saddle sprints and acceleration on a climb is great, almost instantaneous but I am not that explosive in these modes as it wastes energy. So the compact geometry did not suit my style.

There will be people who will fit onto a compact without having to go to extremes and who will like the stiff feeling in out of saddle acceleration. As an overall riding machine is was not what I was looking for and decided on conventional geometry instead.
For me I made the right choice
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Old 04-23-03, 07:56 AM
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shokhead
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Then what kind of geometry is putting the rider in a more upright riding position,sloping top tube,or a shorter top tube or seat angle and head tube angle.
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Old 04-23-03, 08:16 AM
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To get a more upright position, ie so your back is nearer to 45 degrees, you need the bars to be higher and closer. You need a shorter top tube/stem, and a higher bar position. This is independant of compact/standard geometry frame.

These days, seat-angles are pretty standard, and saddle fore-aft location is done using seatpost choice. UCI racing bikes are restricted in the angle, but trathaon bikes can use a steeper angle for the specific triathelon aero positiion.

Head-tube angles are mostly standard, and set for steering stability, except in small-sized bikes, where headtube angles are bodged to fit extra-long cranks into small frames.
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Old 04-23-03, 09:28 AM
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Hey ParamountScapin, Santayana also said “Enjoying life and living it well is more important than understanding it.”
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