Mark Stonich's lightweight LWB


I finally finished my lightweight LWB project. The long, light Monotube frame has significant vertical compliance which I found disconcerting at first. Now, after a few hundred miles, it feels just right.

The main tube is 2" x 0.035", I weigh 175lbs and the wheelbase is 60". For a longer wheelbase, or a heavier rider I think the main tube could be inadequate.

Weight as shown here is 24lbs, 5 oz. (I have since put fatter, heavier, but faster tires on it.)



Currently it has a 3.5 lb seat. The seat base is adjustable fore & aft, up & down and for tilt, in relation to the backrest. After I get it adjusted to my liking, I'll build a non-adjustable one out of lighter tubing. Hope to save a pound.

I've never had good luck with sling bottom seats before, but this one is different. Besides the adjustability, there is a breathable pad containing 2" of open cell foam. Unlike other all mesh seats I've seen, this one is open behind the glutes. I believe this allows the muscles to work more efficiently.



See http://mnhpva.org/meetings/May_02/MS.html for more about the rear of the frame, and the logic behind the bike's design.

BTW the funky rear brake described there works flawlessly. Feels like any good Canti setup. Squealed like a stuck pig the 1st time I used it, so I thought I'd screwed up. Then I remembered that Mafac's needed 2-3 times the toe-in of modern brakes.



Seats have always been a problem for me, most likely because of my 3 hip replacement surgeries. This one is amazingly comfortable. One time I had a sore butt when I started an 80 mile. By the time we finished, the soreness was gone.

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