One more thing that I did not mention.
Is the square area of the solid rubber sections of the tire face against the driving surface. You calculated the square area of the actual contact surfaces of the tire and divided that into the vehicle weight that is on that tire. The best way we did this when we were road rally racing, is to ink the tire and than lower it on a white plastic cover board. You will find that a wide tire will have a narrow foot print about 2 inches long for the width of the tire. If there is no thread on the tire and the tire is 12 inches wide, then you have about 24 square inches of contact rubber. Lets say the weight on that tire is 720 lbs, therefore 720/24 = 3 lbs per square inch which is not good for traction. A narrow tire foot print will be longer than 2 inches which a standard vehicle tire may be up to 6 inches long and about 6 inches wide. Again with only solid rubber area, the contact patch would be about 6 x 6 = 36 square inches. Therefore the smaller width tire will have more contact area. We found out that on dry smooth pavement, 10 lbs per square inch will work, while on ice, it takes about 50 lbs per square inch to maintain the traction. Roland ----- Original Message ----- From: Ben Goren<mailto:b...@trumpetpower.com> To: Roland<mailto:e...@msn.com> ; Electric Vehicle Discussion List<mailto:ev@lists.evdl.org> Sent: Monday, May 18, 2015 11:23 AM Subject: Re: [EVDL] Wheels for efficient vehicle. On May 18, 2015, at 9:24 AM, Roland via EV <ev@lists.evdl.org<mailto:ev@lists.evdl.org>> wrote: > If you use a open spoke wheel that allows air to go thru the wheel, it is > recommended to install a aluminum deflection plate about 0.125 inch thick > that goes between the wheel and the axil flange, to prevent the air to go > thru the wheel. To save on (unsprung!) weight and expense, a fabric covering might be preferable. At least at one point, they were commonly available for bicycles, though I haven't seen as many recently. Superficially resembles a solid carbon disc wheel. The basic idea would be a wire hoop the same size as the wheel and a round sheet of fabric stretched around it like a drum. Clips on the extremes of the spokes can hold the hoop in place. Depending on how the wheel is mounted to the axle and the like, you might also need an hole with a grommet in the center. b& -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150518/0389ff0d/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
