[python] Re: Ice python and ice races

  • From: Jürgen Mages <jmages@xxxxxx>
  • To: <python@xxxxxxxxxxxxx>
  • Date: Thu, 23 Feb 2006 21:58:14 +0100

Hi Tim,

just read the impressive ice-race report on your site:

http://bikes.jkcc.com/python%20clone.htm

Too bad that the tire of Marcel went flat. I understood that he
would have won the race otherwise.

Here is the text for those who are interested:

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So, how well did it work? Well, as you can see in the picture, he appears to be zipping along fairly well as he's setting himself up to go into the corner. In fact he went extremely well, and generally faster than most of the three wheelers there. Traction on the front wheel was great and the only problem he had was not being able to get enough bite with his rear blade, even though it had a pretty wicked edge ground on it, and polished with a whet stone. In the 2 man pursuit races, he got so much speed in his first heat, that the rear end slid out on a corner unfortunately, and he went down. In the slaloms, his masterful riding control enabled him to whip the python around the cones by sliding out the rear end slightly, and he beat all but the fastest two or three trikes. In the 10 minute criterium race, he was cruising around, and lapping other riders, and well on his way to a podium finish when one of his tire screws somehow managed to cause a flat and he momentarily lost control and hit the boards pretty hard. He got right up and back on, and finished out the race on a flat for the last few minutes and still managed a 4th overall (I think). Overall, it was an amazing effort for such an extreme bent and the biggest part of the success was due to Marcel's riding ability.

As for the traction issues on the rear end, I think that was due to two reasons. I think the largest part of the problem is how the python turns. On a normal bike, the rear wheel gets pulled through the corner and follows a line inside the front wheel's track, and has a fair bit of weight on it - likely close to 50%. The python rear end doesn't follow, but rather it "turns" through the corner on its own path and as a result, I don't think it puts down nearly the same force as a normally steered bike does. I know that Marcel and I could easily slide the rear wheel out on dry pavement by turning hard and at speed. Now take that same force, and try to turn hard with a blade on ice that can chip away under heavy loading, and I think that is part of why the python rear end was weak at fast cornering. Add to that, the fact that as the ice got chewed up from the racing, the blade was tracking across rough ice on the corners and further minimizing its traction every time it encounterd crossing multiple ice grooves, and it lost even more traction. Even though the rear end would start sliding, Marcel quickly mastered the art of letting the rear end do a power slide, while he kept the power on and deftly used his left hand as an outrigger on the hard turns. It was amazing to watch him rip up the corners right on the edge of disaster, lap after lap, after lap :)

Anyway, the ice python did an excellent job at the ice races, and I think it would definitely be tough to beat on larger tracks with larger radius corners. In the mean time, it'll get converted back to a "normal" python, and he was talking about possibly selling it.

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