Thread: Oregon commuter
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Old 02-07-2012, 10:00 AM   #15 (permalink)
Ken Fry
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I used to do several types of motorcycle competition, but especially liked the very fast and the very slow: road racing and observed trials. For fun, I'd pick up my feet several (5-10) seconds before I would get underway at stop lights with my cafe racer. (A really good observed trials rider [which I was not] can balance a motionless bike forever.)

In an ordinary motorcycle, even at crawling speeds, you countersteer, to keep the contact patches under the CG. A certain amount of body english etc also helps. (At very low speeds, superimposed on the countersteering for balance is car steering for directional control. In trials riding, the bike is often leaning way over to the left while turning to the right -- all sorts of complicated stuff is possible.) But when I learned to ride a bicycle, someone told me, "if you are falling to the right, steer to the right" (which is the same notion as countersteering to pull a bike up out of a turn... In racing -- for some bikes -- this is the time when countersteering really becomes noticable, especially in switchbacks: the bike has gravity helping it to fall into a turn, but you have to work against gravity to get it back up.).

A lot of this stuff is incredibly subtle. A bike I rode in the 24 Hours of Nelson (for two years) was a 350 four cylinder Honda. I used to tell people that all I had to do was think about where I wanted to be and the bike would just go there. Because it was so easy to ride, we were not beaten to hell and back after an hour, so could still walk without falling over at rider changes. The people getting off the big bikes looked like zombies. In the second year with this little bike, (after a few mods to make it go a little faster than in the first year) we beat all the 500s 750s and open class bikes. The only bikes that could not pass us on the straights were "tricked out" Harley sportsters. But the Honda was so good in the corners that we were not working so hard, and could stay sharp... and as a result not fall off: while the big bikes were in the pits fixing crash damage we were out there ticking off the laps. I think you could ride that bike fast and never really perceive the need to countersteer: ounces of force on the bars was all that was required: a tiny shift of the shoulders would easily do the trick.

In my experience, almost all this (no-effort-required handling) goes out the window (wait no, it can't) in an enclosed bike. To bank the bike, you have to consciously countersteer. I rigged mine with a joysick, thinking that this would feel more natural. It did, sort of. At speed, it flew like an airplane: nudge the stick to the right to bank to the right, center the stick once the bank angle is established. (The stick was rigged so that pushing it to the right caused the wheel to turn to the left.)

But with the outriggers down, I'd have to use the stick in reverse. This felt really weird. If all roads and intersections were flat, then this would be a non-issue: you could have the outriggers up within the first foot of motion, provided it is clear ahead. But in very slow stop-and-go traffic, and when having to start out with the bike tilted, it was a significant issue.

My driveway slopes down at just under 20% to meet a road that slopes at 15% to the right. There is a dip between the drive and road surface, for drainage. At 5 mph with outriggers lifted on the drive, 15 feet before the road, this was pretty much OK. But at low speeds, I could easily be leaning a lot as a result of the dip combined with the effect of road slope. In my manual system, it took a lot of force on the pedal to keep from falling.

A couple things to notice in the Ecomobile video. One is Wagner thinks there is something wrong with a short wheel base. I think that is just plain wrong. Our 350 Honda was the best handling vehicle (land, air, sea) I have ever driven, and I've driven Ferraris, Loti, Porches, planes, sailboats, windsurfers, powerboats, etc. A well-sorted race bike is hard to beat for anyone with reflexes.

Another thing to notice in the videos is the jerky motion in turns and the amount of road used. You can see the countersteering happen in a way that you don't see in roadracing videos. It's notchy. I suspect that's because conscious effort is required, or maybe there is a tiny bit of friction (sticktion) in the steering. (In the shot where you see the wheel closeup, the motions are pretty large and abrupt as compared to typical motorcycle front wheel motions, which you can barely see at speed).

(All this is not intended to dis the Monotracer. It is a very good effort at a tough engineering problem.)

Last edited by Ken Fry; 02-07-2012 at 10:11 AM..
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