Friday, May 13, 2011

Rotational Weight Matters!

I proposed a question on the Bentrideronline forums to fellow members asking whether weight matters in performance depending on where it is. Will weight in the wheels affect my ride differently than equal weights put in my bag?

For instance, if I use heavier thorn resistant tubes in my tires but carry regular spare ones in my bag, is this any different than using the regular ones on my wheels and carrying the thorn resistant ones in my bag as spares? The overall weight being carried is the same obviously the same since I'm carrying both, but will the location of each make a difference?

Apparently the answer is yes.

With so much excitement with the new front wheels, I decided to mount the rear 406mm Schwalbe folding bead Marathon Racer tire last night. Boy, what a change in appearance! Although I like the aggressive look of a monster back wheel, the new narrower 1.5" one looks pretty slick. With the tube, the new setup is 0.4lbs lighter. It makes a bigger difference than I would imagine!

I'm losing 1.6lbs total just in tire/tube (3) weight reduction. Adding the loss in weight benefited from switching to spoked wheels, puts me at a 2.2lb loss! Wonderful!

I'm no physicist but I can just imagine how heavy weights would "feel" if strapped to my legs vs my chest while walking. My legs have to move much more and would notice the weight more than if it were on a part of my body that doesn't move as much in stride. As with the trike, the overall weight is identical no matter where it's placed, but it takes more noticeable energy to move it swinging on my legs or turning of my wheels than it does on my body or frame of the trike.

Upon spinning the rear wheel by hand, it continued to spin much longer than when I had the heavier BA tires on there. I guess I shouldn't have been so surprised, but the difference was huge. When applying equal force (only gauged by feel) on the BA's, the tire would spin barely two rotations. Doing the same thing to the Racers made the wheel spin at least 6x. I never counted but the difference was extreme and very noticeable.

As I mentioned in the last post, I could totally feel the difference of lighter tires while turning my front tires back while seated to go in reverse as I sometimes do to get out of the way of pedestrians trying to cross my path.

So why does any of this matter? Well, it matters a whole lot! If I can go the same distance up the hill w/less energy, I'll have more stored up to cover longer distances. This makes a huge difference in performance across a full day's ride. This is all true in theory, but I'll find out tomorrow morning as I take a 50+ mile test ride around familiar territory.


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