Thread: Top Speed
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Old 08-15-2011, 09:41 AM
douglasseattle douglasseattle is offline
Motorized Bicycle Member
Join Date: Oct 2010
Location: United States
Posts: 24
Default Re: Top Speed

I have a stock HT with a 32 rear sprocket and have been able to get 40+ miles per hour. My speedo is correct. How do I do it? It is by reducing drag, primarily aerodynamic. I am using a shimano front wheel with 16 spokes and a 700 x 23 tire. I also use a bmx chain and my frame is well aligned. The wheels roll perfectly, especially the front.

When I was doing my undergrad degree at Western Washington University, I took a vehicle design class given by Dr. Seal who was known for designing fuel economy cars that successfully competed worldwide with other cars, including those from MIT. Some things I learned:
weight is not a significant issue for top speed or fuel economy on level ground once the speed is established
lowering rolling resistance is especially important at lower speeds
frontal area is critical for reducing drag

I also have been a bicycle racer and coach, so I know how much those tight fitting clothes mean to speed. I once was riding down Mt. Rainier with sweats and a t shirt. Normally, I could go significantly faster than the cars and would pass them. This particular time I had to pull over so they could pass me.

One I ride the motorbicycle for speed, I make sure that I am not wearing a floppy jacket or baggy pants. I am considering putting on an old skinsuit just to test the difference; the same as used in Tour de France time trials.

I would like to see some of you experiment with reducing frontal area (less upright perhaps) and wearing less baggy clothing (OK, I do not expect spandex).
I love this forum and wish I had a great shop to do what some of you do (time would be nice too!)
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