Thanks for the advice, everybody! Right now I'm leaning toward the Trek FX 7.3 Disc, as it looks like a lighter bike with decent components (Deore) for a good price. I'd also prefer to support my local Trek dealer (Bike Tech in Olympia WA) - it's a great, friendly no-pressure shop and I've never paid for an adjustment there.

This bike has 32s, so it it safe to say I can expect a decent ride even with a straight alloy fork?

It seems pretty clear that you will not get a consensus on that. My personal opinion is that frame and fork material is fairly irrelevant to ride quality. I believe it is based on fact, logic, and experience. But others believe otherwise.

I do think that I won't get any argument with these statements: If you run 32's, you can run at lower pressure without risk of pinch flats. Lower pressure = a significantly more comfortable ride. 32mm tires at a reasonable pressure will give acceptably low rolling resistance for noncompetive applications.


I actually run my 32mm fatties (actually marked 35mm) at around 90 psi -- nearly the same pressure as my 23mm tires on my road bike. But I'm crazy like that. I am unsure whether a 32mm tire at 90 psi is cushier than a 23mm tire at the same pressure. I suspect that it is.

Pressure is pressure, measured in pound per square inch. 90 psi has the same feel on a fat tire as a thin one because both tires have the same pounds per square inch pressure being exerted on the tire wall.

Coworker has been commuting year-round for a few years now on a novara buzz (I saw it there on your spreadsheet). 27# stock (pre-fenders, rack), but low gears, although only 18 of them (less duplication w/ double than triple anyway). I would say worth a test-ride. REI's big sale just ended, of course, unfortunately.

Okay.

Compare two tires, one a thin (1") tire, and the other a fat (2") tire. Both are at 100 psi.

Imagine the tires are mounted on wheels and placed in a fixture that will apply a steadily increasing downforce at the hub. The stiffness/compliance of the tire can be expressed as the relationship between the force (applied at the hub) to the deflection (at the hub). Both tires start out with a force of zero and a deflection of zero (tire just touching the ground, no deformation).

The volume of the tire doesn't change much as the tire is loaded, so the pressure in the tire doesn't change much.

Okay, now the tire testing machine is up to 100 pounds of down force. Each tire has deformed sufficiently that its contact patch is one square inch. Now, the big question is: is the vertical deflection at the hub equal between the two tires - meaning the compliance of the two tires is equal? I don't know, but I don't think it is. I think that the relationship between contact patch size and deflection at the hub is NOT going to be the same with the fat tire as with the skinny one. Also, I think that the relationship between contact patch size and deflection is nonlinear and pretty tricky to figure out analytically.


EDIT: Here's an article that makes a reference to an article that sez that some guys approximated the force/displacement of a road tire as linear: http://www2.bsn.de/Cycling/articles/...eflection.html So maybe I'm wrong; maybe pressure is pressure.

Ok. When I bought my Fuji Absolute,the ride was very harsh. It was all aluminum with a straight blade fork and 120psi 26mm tires. I swapped the fork for a Winwood carbon cross fork,and the result was dramatic. Not a small improvement mind you,a major one.

Sorry man,but I call BS on your above statement. Carbon forks give a better ride than alloy,and steel frames ride better than aluminum. In fact,you're the only person I've ever heard to say that frame/fork material doesn't make a big diff. I gotta say you're just wrong.

http://www.sheldonbrown.com/frame-materials.html
makes two people...

:)

(noticed that Sheldon has revised the page recently. cool.)



I actually believe that carbon fiber forks are superior to metal forks in vibration damping. But I think that aluminum gets a bum rap - it's as smooth as steel. In the early days, the aluminum frame makers touted aluminum's superior vibration damping...

Sheldon was talking about frame material and shock felt at the saddle,not shock at the handlebars or overall ride quality.

He also noted that it depended on the construction of the individual material. Perhaps aluminum is not being constructed to its full potential? For what it's worth, I've toured on an all aluminum bike. It was okay, but the steel specialized hardrock with the same tire sizes I had used before did have a better ride quality.

Ditto