Hello Drew, Before choosing a tire and wheel, first weigh the vehicle front and rear on a scale recording weight of the the front and than the rear.
How to calculated the load rating for a wheel and tire: My vehicle after major modifications, the weight on the front suspension is 2600 lbs or about 1300 lbs per wheel. The rear suspension is 4000 lbs or about 2000 lbs per wheel. Therefore the tires and wheels must have a minimum load rating of 2000 lbs load rating for normal driving. There is also a thrust rating of the wheels, wheel bearings, and suspension. The manufacturer normal takes the weight on the wheels times 2. In my case I had to put in a heavy duty set of bearings with a thrust rating of 4000 lbs. Normal acceleration and driving on very rough roads as we have. If you have intersections that have V drains, then every time you drive over these concrete form drains, there is a increase resistance which will jolt the vehicle a bit which increases the motor ampere every time I drive over these units. Change the deflection rate of the tires will reduce this resistance by adjusting the deflection rate of the tires depending on driving surfaces and speed. To adjust the deflection rate of the tire, first raise both rear tires off the grade but have the tires just touching the grade, so you can get a accurate measurement from a reference point of the side of the wheel and the pavement. Air up the tire to the maximum PSI rating that is label on the side of the tire. Measure the distance to the rim of the wheel to the floor. Lets say it reads 5 inches. Now lower the vehicle to the pavement and measure this distance again. Lets say it now reads 4.5 inches. You tire now has a deflection rate of 5 - 4.5 = 0.5 inch which is a normal ride. If your deflection rate is more than that, than you do not have the correct load rating tire. Truckers like to run a 0.385 deflection rated for better mileage. If you live in a cold climate like I do, you do not want all nylon tire because if you let the vehicle set outside for awhile, the tire develops a flat spot, causing increase resistance for about 2 miles of running until it rounds out. My first EV came with a all polyester tire rated at 2600 lbs at 40 psi back in 76. It had fantastic roll out distance. Drove a steep hill up to work which was 5.56 miles up to speeds of 70 mph at a battery ampere of 600 amps. Coming down, I could coast all the down this hill getting up to 85 mph and coast all the way into my garage without adding any power. Ten years latter, I install a Dunlap radial ply with the same load rating and it felt like I was dragging something. The deflection rate was way over the 0.5 inch normal set at the maximum psi rating. At 30 below zero, could not do a complete roll out running down this hill. Had to add more battery power. Today, I am using the Michelin Energy LX4 245/60 R17 rated at 2000 lbs load rating at maximum 50 psi. Has a high percentage of polyester to very low percentage of nylon and steel. Weighs 28 lbs. The wheels are solid aluminum made by Center Line which also weighs about 28 lbs. These tires are a all weather tire. Can drive through a foot of snow going up a steep hill passing ICE that are slipping and sliding. The next door neighbor bought one of new VW bugs and could not make it out of the drive way. I only air up the rear tires to 45 lbs, which gives a better ride and less resistance when hitting these intersection V drains where the higher pressure would not let the tire roll over smoothly thus the overall Wh/mile is less. I now for the first time I can drive in final gear using less energy as before in 2nd gear! Roland ----- Original Message ----- From: "Ds2inc" <[email protected]> To: "Electric Vehicle Discussion List" <[email protected]> Sent: Monday, April 15, 2013 4:52 PM Subject: [EVDL] Ev wheels and tires??? > Would love to hear thoughts on wheels for EVs and Tires. Specifically > combos= > that are not specifically hi performance but lend then selves to low > rollin= > g resistance lighter weight ect! I live in so cal but would love to hear > abo= > ut northern options as well for winter and rain. > > Thanks Drew! > > Sent from my iPhone > _______________________________________________ > 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) > > _______________________________________________ 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)
