So what will Matt Kenseth think about Goodyear's new 17-inch racing tire?

   (Developing)

   By Mike Mulhern
   mikemulhern.net

   KANSAS CITY, Kansas
   So just as Goodyear and NASCAR have finally gotten enough good, new tire designs for this car-of-tomorrow, after extensive testing, now there is a new tire design in the works, a larger 17-inch tire, which would be to make these awkward new stock cars handle better.
   Matt Kenseth and Travis Kvapil will test the new design – maybe designs – at Richmond International Raceway for two days after Sunday's Kansas 400, in Jack Roush Fords.
   The trick: how to come up with a new tire, without forcing teams to make expensive changes to the car bodies and chassis.
   Despite all the computer simulations that have been run by Goodyear on this project, a specific tire-and-wheel combination – in any of its various permutations – has still not been run on a race track with a NASCAR driver at the wheel of a NASCAR Cup car.
   Some background – when NASCAR was developing the car-of-tomorrow, Goodyear and NASCAR discussed the option of switching to a larger tire, to make it handle better. Certainly during the first two years of the COT, handling has been a major issue for teams to deal with.
   However, the larger tire never made it off the computer screen…until now.
   "There was discussion (two years ago or so) about the chances of going to a different size tire, but there was no preference one way or the other, just discussion," Goodyear's Greg Stucker says.
   But obviously now it's more than just more discussion, because there will be a new tire on the track in a few days.
   Curiously Goodyear and NASCAR both are downplaying the upcoming test. Both insist there is no timetable for any changeover. And the next step in testing the proposed new tire – which would logically be at an intermediate speedway, like Charlotte, Atlanta, Michigan, California – is still up in the air.
   "We're just seeing what the options may be, and exploring that as an option," Stucker said.
   It would seem unlikely that any significantly different size wheel-and-tire would be okayed for NASCAR competition in 2010.
   First, it's not just a tire issue but also a wheel issue, and NASCAR wheels for 2010 are probably already produced. And it is late in the year to design and produce the number of wheels it would take.
   Second, NASCAR teams are facing tough economic times, and changing anything would be expensive.
   However Goodyear's Stucker says Roush's Richmond tire test cars have been fairly easily changed over to accommodate the bigger tire.
   And the Roush drivers will also have two current cars at the test, to do a standard tire test, which would give drivers and engineers a baseline – both technically and in 'feel.'

   It appears that Goodyear and NASCAR have three basic options:
   1) To stick with the current 15-inch wheel rims, and simply make the tread wider (currently it's 12 inches, inside to outside). Fender clearance obviously would be an issue.
   2) To go with a larger 17-inch wheel, but use a lower-profile tire (with a different, probably stiffer sidewall), to keep the overall height of the tire unchanged (so teams wouldn't have to go through expensive chassis redesign); the downside of that is the 'balloon' sidewall would be much shorter, so heat build-up would be increased considerably.
    3) To go with a larger 17-inch wheel and a comparably larger tire, to keep the sidewalls similar in design to the current one; the downside would be to have to change frame rails and shock mounts.
   However Goodyear's Stucker says the upcoming test is only to consider option 3, the larger wheel-and-tire. The prospect of a 'low-profile' NASCAR tire, Stucker says, isn't that appealing, because part of the issue is the volume of air inside a NASCAR tire – the more, the better, essentially, for heat reasons.
   
   Points to consider:
   -- Each Cup team buys about 250 new wheels for each season, at $150 apiece. Those used wheels are then sold to either Truck teams, Nationwide teams or ARCA teams, the only other racing divisions that used these particular wheels.
   -- The current wheels are 9-1/2 inches wide (the tires have a 12-inch treadwidth, which means the 'balloon' sidewall hangs a little outside the rim).
   -- Goodyear would have to come up with all new safety inner liners (about $125 each, but reusable).
   -- A current Goodyear Cup tire costs a team about $430 each; a full set, $1,720.
   -- A Formula One car uses 13-inch wheels, but at 200 mph those F1 tires feel like the car itself weighs 5,000 pounds.
   -- An Indy-car, at full speed at Indianapolis, because of downforce actually 'weighs' 1,000 pounds more than a Cup car.