Compact Frames... - Page 2

Gearing is a whole different story. Damn, I hate running out of gears on a climb! Back to geometry; if you compare a compact geometry bike with a traditional geometry bike and assume all angles (seattube, headtube) are equal than in theory the only difference will be the length of the top tube. Now in a miniscule way the top tube is shorter and thus lighter, but everything else being the same you are still in the same position over the cranks regardless of frame geometry. Speaking of the Siena, I have an 2004 size 53, but I also have a traditional geometry 54. The Litespeed does climb very well indeed, but I would attribute that to being a slightly smaller frame.

Frames cannot be fairly compared by "switching bikes" unless they have the same wheels and tires since these affect ride alot. Also geometry can't be compared unless you also have the same bars, crank length, pedals, and other things that subtly affect bike fit.

I don't necessarily dispute that the Siena bicycle as tested climbs "better" than the Tuscany but rather suggest that there are multiple factors that contribute that are independent of the top tube slope.

I've got a custom frame with a semi-sloping top tube. My builder told me the bike would climb like a full-compact design, yet have all the comfort of a traditional bike on century rides. Sounded perfect for the mountain century events, so that's what I ordered

Certainly some truth to the "fewer frame sizes" argument, but compact frames also fit a lot of people better than traditional designs ever did. Folks with long torsos and short legs for example, or short arms, or people with hip and back flexibility issues.

There's a zillion horizontal frames out there, and a zillion compact frames, choice is good.

There is no reason why compact frames can't fit as well as traditional frames. As long as the bars, saddle, cranks, and angles match up, the path the tubes take has no effect on sizing.

The fact that there are less sizes is because production has gone away from the made to order systems where your bike was made in the size you selected then shipped to the dealer, to making half a million frames at a time, having stock waiting, and you picking one up off the floor. Mass production and inventory levels demand lower complexity, hence the drop in frame sizes. Most of this efficiency is passed onto the customer in the way of reduced prices (Giants cost less than made to order bikes).

There are still brands out there that offer 10 sizes, and some of those are compact style frames. If you don’t suit one of the huge array of mass produced compact frames, then you have to look at the more expensive options.



Compact frames probably do weight less size for size because the shorter absolute top tube, seat tube, and seat stay lengths are shorter. This would make the bikes a little bit stiffer. However I would expect the overall torsional stiffness may go down due to less division of forces in different directions. Tubing shape can make up for this and we are now seeing more Al and carbon frames with very wide elliptical top tubes for better torsional stiffness while maintaining vertical compliance.



Better climbing is probably due to different chainstay lengths. Compact frames have a tendency to go for short everything. No reason a traditional frame can’t have short chain stays and the same seating layout.



All up I believe the same ride characteristics can be had out of either frame style if you design the tube lengths, shapes and basic handling dimensions the same. I think a compact frame will weigh a little less due to the shorter tubes (which are only then replaced with a comfortable carbon seat post 30-50mm longer.

Well, my amplifiers all go up to 11, which is one more than 10, so it must be louder.

I will admit that it could all be smoke and mirrors and BS, or the 11 amplifier in "Spinal Tap" But in addition to my impromptu roadtest because my Tuscany buddy thought I was nuts when I suggested that my Sienna climbed better, I also tested both bikes brand new at my LBS and the compact geometry of the Siena just felt quicker and more responsive. It's also good to know that I shoud not be giving up any comfort when I ride a 150 mile charity ride (MS150) this weekend.