Joined: Feb 2006
Posts: 12,286
Likes: 317
From: Lake Geneva, WI
Bikes: Ridley Helium SLX, Canyon Endurance SL, De Rosa Professional, Eddy Merckx Corsa Extra, Schwinn Paramount (1 painted, 1 chrome), Peugeot PX10, Serotta Nova X, Simoncini Cyclocross Special, Raleigh Roker, Pedal Force CG2 and CX2
The most dependable indication of aggressive bike frame geometry is head-tube angle. Any angle 73.5 degrees or more is considered to be aggressive on a midsized frame. Good framebuilders will increase the headtube angle on larger sizes to mitigate the longer wheelbase on the larger sizes.
A steeper headtube angle makes the steering more responsive. This is important in pelotons where many small adjustments are quickly made to avoid other racers.
Don't confuse aggressive geometry with bike fit. It's possible to have a bike with aggressive geometry and still have the handlebars above the saddle.
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When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.