When a person purchases new tires and/or modified a vehicle, it is best to adjust the deflection rate of the tires to match the psi surface foot print of the tire.
Example on how to do this: First weigh the vehicle and the weight on the front tires and rear tires. Record the highest weight on one tire. Choose a tire that has the maximum weight listed on the side of the tire, plus 25% more than the actual weight that is on that tire. Lets say the actual weight on that tire is 1000 lbs, than you want to choose a tire that is rated for at least 1250 lbs. The reason for this increase rating is the thrust of the vehicle while accelerating will increase the tire load. You should also match the load rating of the wheel to the tire and also the wheel bearings ratings. Now lets say that you have the correct tire, wheel and bearing rating, while allowing the full rate of the vehicle on these tires wheel setting on a level grade, air up the tire to the maximum load rating that is on the side of the tire. Measure the vertical diameter of the tire and lets say its 28 inches. Now raise the tire off grade where the tire is just barely touching the grade surface. You will notice the psi air pressure has decrease. Record the vertical diameter of the tire and lets say it is 28.5 inches. Now raise the tire off grade so it is about 1 inch off grade and air the tires to the maximum load rating that is on the side of the tires. Lower the tire, where it is just barely touch the grade surface and measure the vertical diameter of the tire again. You will notice that the tire may increase in diameter with the increase air pressure. Lets say the diameter of the tire is now 28.75 inches. Lower tire on to the grade surface and measure the diameter again. Now lets say the vertical diameter now reads 28.50 inches. The deflection rate of this tire at the maximum load rating that is on the side of the tire is at 28.75 - 28.50 = 0.25 inch. On the road truckers like to have enough tires on there rig to have at least 0.375 inch on smooth dry pavement for a higher mpg. Standard passenger vehicles may be at 0.50 inch on dry pavement for increase range. On wet surfaces, you may have to go to 0.75 inches deflection rate and on ice, it may be about 1 inch deflection rate. Also the foot print area of the contact patch of the tire to the grade surface is very important. On wet or icy surfaces, you may want the tire to have at least 50 to 100 lbs per square inches of pressure to the road surfaces. Example of my Michelin LLR tires that have a max load rating of 50 psi at 2200 lbs which are air up to 50 psi with 2000 lbs on weight on the tire which I allow for the increase of thrust that may be close to 2200 lbs. At 50 psi, the foot print square area is 8 inches wide by 4 inches long which is 32 square inches. 2200 lbs of weight on that tire divided by 32 sg.in. = 68.75 lbs per square inches. This rate of 68 psi is ideal on snow and icy surface. I can walk right up a very steep hill passing some ice vehicles that are slipping all over the place, some are in the ditch. At one time, I pull up to the top of the hill one of those VW bugs my neighbor just bought!! Roland ----- Original Message ----- From: brucedp5 via EV<mailto:[email protected]> To: [email protected]<mailto:[email protected]> Sent: Tuesday, October 14, 2014 7:58 AM Subject: [EVDL] Soapy skinny lrr tire traction: EVs beware of gas-station car-washes! [ref http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EVLN-Leaf-owners-beware-the-gas-station-car-wash-tp4672092.html<http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EVLN-Leaf-owners-beware-the-gas-station-car-wash-tp4672092.html> ] In reference to Cor's valid comment (below), as our EV-cause dream is realized, more and more EV-noob drivers are coming online, and they are going to word their experiences badly/unfairly/inaccurately (equating everything to the EV rather than the real issues). Such is life amongst the un-EV-educated/un-EV-enlightened. We (the plugin community) will have to be tolerant of it, and gently let them take ownership as their idea, that the issues aren't the EV (careful now, an ego is a fragile-bomb that can back-bite if defused roughly). I posted this news piece because I am seeing more of these (released to the public with some on a seestanblog.com petulant level) ... and I had had a couple of similar experiences. After having my S-10 Blazer conversion EV a while, I chucked (recycled) the heavy steel wheels for new lighter mag-style ones (attracting more attention to my EV) and a set of Goodyear Invicta (no longer in production) lrr tires. At the time, Bill Egan of Goodyear was an excellent tire resource for the EV community (he did his company proud), advising the EV racing community on what type of GY lrr tire to use and at what pressures front and rear depending on the vehicle and weight distribution. These lrr tries did tend to slip on wet pavement/on rainy days when pushed beyond their design (driving a 2ton EV up and down twisty-turny mountain roads). From all the good-EV-deeds I have done, I had earned press credentials that gave me an in to drive some of the production EVs of those times. When I had an Honda EVplus for a day (my Blazer happily charging at my hp work site), before a mid-day show, I took the EV+ to a new station that was built to cater to the silicon affluent clientele, The Car Spa (an easy convenient way _back-then_ to drop some dough on your sweet ride). I was hoping the EV+ was going to be so much more accepted by the non-EV-knowledgeable public than my Blazer EV conversion, that I took a chance and turned the keys over to the attendant at the counter for their riders to use. But yea, sure enough, they had problems. I was keeping an eye out encase they did and spotted the driver confused as to how to get the EV+ moving. I went over and instructed him, with him saying, 'Oh, its just like a regular car', and he was off toward the ramp to let their conveyor system push vehicles through the wash-rinse-wax-n-dry tunnel. Upon its return, a different driver expressed that the EV+ did not line up with the wheel tracks like other cars. After happily not seeing any body damage to the EV+ I was responsible for, when I drove out of their lot to head to the show with a fresh zip-wax coating on it, I did notice, the EV+ tires did slip a bit on turns. But after the soap and or wax wore off the traction surfaces, the EV+ drove fine. In a different experience back in my Blazer years later, I chose to use an automated quick wash that was part of a stations' services. It was pretty straight forward, so I did not have to interface with a gas person to explain I did not want any chemical-fuel. You just drove up to the beginning of the machine built into the side of the station, ran your credit card though it, chose your wash-n-wax options, and rolled up your windows. The conveyor work engage and pull you through their machine. My S-10 Blazer fit their tracks with no problem. After the robotic arm power rinsed and then soaped, with different roller arms coming down and going around to 'non-touch' wash the surfaces, the 1st arms then rinsed and waxed, with powerful blowers to push the water off the car more than actually dry it. When I was finally released from the automated machine, I had trouble leaving after the cycle had ended. I too had a brief back thought that I might get stuck. But as an experience EV driver, I knew thus did not blame the EV, but knew it was the lack of traction on the soapy/waxy lrr tires that was the culprit. Perseverance allowed me to eventually get-out of the clutches of their machine and drive away. It pretty clear that the experiences of the writer of the news piece had could have happened to any vehicle that had tires that lost traction, and not just because it was a Leaf or an EV. For EVLN posts use: http://www.evdl.org/archive/index.html#nabble+template%2FNamlServlet.jtp%3Fmacro%3Dsearch_page%26node%3D413529%26query%3Devln%26sort%3Ddate<http://www.evdl.org/archive/index.html#nabble+template%2FNamlServlet.jtp%3Fmacro%3Dsearch_page%26node%3D413529%26query%3Devln%26sort%3Ddate> {brucedp.150m.com} ... http://en.wikipedia.org/wiki/Dog_with_a_Blog#Premise<http://en.wikipedia.org/wiki/Dog_with_a_Blog#Premise> ref seestanblog.com ... http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv343.shtml<http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv343.shtml> Had had is the past perfect form of have ... [video http://www.youtube.com/watch?v=PNQk0VPX3nY<http://www.youtube.com/watch?v=PNQk0VPX3nY> Blackadder - You Twist And Turn Like A Twisty Turny Thing 123koekje321 Mar 16, 2012 Blackadder Season 2 Episode 5 "Beer". ] ... https://www.facebook.com/pages/Sunnyvale-Car-Spa-INC/259820914107409<https://www.facebook.com/pages/Sunnyvale-Car-Spa-INC/259820914107409> The Car Spa http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EVLN-Leaf-owners-beware-the-gas-station-car-wash-tp4672098.html<http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EVLN-Leaf-owners-beware-the-gas-station-car-wash-tp4672098.html> On Mon, Oct 13, 2014, at 06:01 PM, Cor van de Water via EV wrote: > What a hogwash article! > This has litterally nothing to do with EV, but everything with the > ability of the driver to deal with slippery surfaces and the design > of the car wash to allow a car getting "trapped" on low friction > surfaces. The electric drivetrain has no part in this car wash's > trapping scheme or the ability of the driver to negotiate this > treacherous terrain, so I am puzzled why the heading was chosen to > warn specifically the Leaf owners, as if they are the only drivers > that would be affected by slippery car wash surfaces. > To me, this sounds like fear-mongering of a person who rather sits > in a 4WD truck, but I may be biased. > I have never had an issue negotiating any terrain that I wanted to > cross in my FWD Prius or in my RWD electric truck. I can't remember > which year I last visited an automated car wash. I wash my vehicles > at most once a year (not because I am lazy but out of conviction to save > precious water resources for drinking, not unnecessarily shining up > paint that eventually gets dull anyway). Occasionally I will clean > windows to be able to drive safely and for the rest I just let the wind > and rain take care of the dust on my truck. - -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EVLN-Leaf-owners-beware-the-gas-station-car-wash-tp4672092p4672106.html<http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EVLN-Leaf-owners-beware-the-gas-station-car-wash-tp4672092p4672106.html> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub<http://www.evdl.org/help/index.html#usub> http://lists.evdl.org/listinfo.cgi/ev-evdl.org<http://lists.evdl.org/listinfo.cgi/ev-evdl.org> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA<http://groups.yahoo.com/group/NEDRA>) -------------- next part -------------- An HTML attachment was scrubbed... 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