Landracing Forum
Misc Forums => LSR General Chat => Topic started by: CTX-SLPR on December 29, 2012, 08:44:21 PM
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Howdy,
I'm trying to figure out things like tires for my under 200mph car and I was wondering if there was any advantage that anyone has seen to the new "eco friendly" low rolling resistance tires? I.e. Michellins Green X tires. You can find them in V+ speed ratings now that people are making high performance hybrids.
Another question probably more aimed at the dirt/salt guys. I remember reading somewhere that someone running at USFRA thought snow tires would be a good idea. I can find 17in snow tires in V ratings in 205 tread width (not looked narrower since I was looking off of Porsche listings). Is a studless snow tire a good idea or even really been tried?
Thanks,
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99 views and no replys?
My opinion is that you don't want to put energy into disturbing the salt surface. You want to gently roll over it. And at the same time have the smallest contact patch to compress the salt under the tire.
One of the reasons for the high tire pressure that most run on the salt is to get the contact square inches down. This gives a higher pounds per square inch loading on the salt. The harder you can compress the salt, the better the traction seems to be.
Years ago when there was no new tires manufactured for the fastest cars weren't solid metal tires used? Succesfully. The ultimate in contact patch reduction and ground pressure increase.
Frank
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As far as the low rolling resistance goes, this has become a major topic in the trucking industry. I know Michelin has rolling resistance numbers for truck tires on its website. As far as passenger car tires go I don't know where to find those numbers. Either way, lower rolling resistance takes less energy to turn. Energy that could be put to use going faster or getting better fuel economy. Air pressure is also a major factor.
Kevin G
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Most racers I know are running front runners from MT, Goodyear or M&H or LSR tires. I think JD has used front runners into the 230s without issue. Tire requirements are based on existing record in class or if no record exists the committee chair will decide requirement. Can't run low speed rated tires just because you think you won't go that fast, unless the tech guy will let you run with a speed limit.
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As far as the low rolling resistance goes, this has become a major topic in the trucking industry. I know Michelin has rolling resistance numbers for truck tires on its website. As far as passenger car tires go I don't know where to find those numbers. Either way, lower rolling resistance takes less energy to turn. Energy that could be put to use going faster or getting better fuel economy. Air pressure is also a major factor.
Kevin G
There are LRR tires for cars. That's what comes on a 2000 Honda Insight.
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Rolling resistance has to increase as the speed goes up due to the rising pressure difference in front and behind the contact patches . Bikes with their point contact tires must have an advantage .
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Most racers I know are running front runners from MT, Goodyear or M&H or LSR tires. I think JD has used front runners into the 230s without issue. Tire requirements are based on existing record in class or if no record exists the committee chair will decide requirement. Can't run low speed rated tires just because you think you won't go that fast, unless the tech guy will let you run with a speed limit.
All the records in classes I'm looking at are under 175mph even so I'm good there since the rulebook says I can run V rated tires up to 200mph and I doubt I'm going to be getting there on 300ish HP. I also would not try to argue if I did go that fast, just sit back and find a new set of tires if I can afford them or turn into spectator/vollenteer wrench if I couldn't.
Sounds like this hasn't really been tried. Depending on when I get a car to the Salt I might try it myself if someone doesn't beat me to it.
Anyone ever run snow tires on the Salt?
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Most racers I know are running front runners from MT, Goodyear or M&H or LSR tires. I think JD has used front runners into the 230s without issue. Tire requirements are based on existing record in class or if no record exists the committee chair will decide requirement. Can't run low speed rated tires just because you think you won't go that fast, unless the tech guy will let you run with a speed limit.
All the records in classes I'm looking at are under 175mph even so I'm good there since the rulebook says I can run V rated tires up to 200mph and I doubt I'm going to be getting there on 300ish HP. I also would not try to argue if I did go that fast, just sit back and find a new set of tires if I can afford them or turn into spectator/vollenteer wrench if I couldn't.
Sounds like this hasn't really been tried. Depending on when I get a car to the Salt I might try it myself if someone doesn't beat me to it.
Anyone ever run snow tires on the Salt?
Don't use snow tires. The surface is like hardpack clay fireroad, not like sand or snow.
These are 25" OD for a 16" rim, and $400 a set new. They are W rated (ZR+ for old schoolers), which is like 168mph, good for 200mph for SCTA.
http://www.tirerack.com/tires/tires.jsp?tireMake=Firestone&tireModel=Firehawk+Wide+Oval+Indy+500&partnum=155WR6FHWI5&vehicleSearch=true&fromCompare1=yes&autoMake=Buick&autoYear=1988&autoModel=Regal&autoModClar=
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Our local firestone dealer has those low rolling resistance tires. They are called eco tires or something similar. The sidewall seems to be thinner and more flexible than on a normal radial. It is an interesting concept.
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A Goodyear frontrunner style with 70-100 psi has a lot less rolling resistance than ANY of the newer LRR tires at the pressure they are to run.....Just look at the foot print and you make the decision.
Also pick up a 28" front runner and a 28" anything else and check the weight and you've just factored in something else that will ease your mind. Many wheel ccompanys will make you 15" X 5" wheels that are light weight and strong. Don't go cheep on tires or rims..................JD
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Been awhile but coming back to this now that I've committed to building a car.
Are you saying run front runners on the front and back on a sub 200mph car?