Goodyear’s Tire Solution

There’s a wonderful gadget called wordle that analyzes text and picks out the words that are used with greatest frequency. So I had it analyze the blog and this is what it came up with.

Maybe it’s because they counted tire and tires as two separate words, but I sure feel like we’ve been talking about nothing but tires lately. I guess wordle could be used as a kind of blogger Rorschach test. According to it, I clearly have an engine fixation.

We’re talking about tires anyway. It took them a week, but Goodyear”>outlined their plan for making sure that what happened at Indy won’t happen again. They expressed the plan in corpo-speak, that unique permutation of the English language spoken only by PR types, upper-level managers and university administrators. Personally, when I hear “stakeholder”, I think vampire. I’ve included a bit of translation and exposition beneath each point. Goodyear says their plan includes:

• Completing the extensive post-race analysis in process that includes all internal aspects of tire design and manufacturing and discussions with key external stakeholders, including representatives from NASCAR, team owners, crew chiefs and drivers to gain insight to information that will provide clarity to the final analysis.

Translation: We didn’t create this problem and we can’t fix it by ourselves.

• Engaging research scientists and engineers, including available assets and modeling capabilities from the Sandia National Laboratories, to develop a range of potential short-term solutions.

Translation: We need to do something really quick and we’re calling in outside experts to make sure we’ve got something by next July.

Comment: Metals are usually pretty well behaved. Rubber is made of intertangled polymer chains with a lot of other stuff added in. The polymer chains stretch and squish and the other stuff in the mix affects how they stretch and squish. That’s what happens on an atomic level. Then you make the rubber part of a macroscopic item like a tire, into which you have to build belts, cords and other structures. This is not a simple problem.

The folks at Sandia National Laboratory have great expertise in computer modeling. ‘Modeling’ is producing something in the computer and then testing it in the computer. Modeling is to tire testing sort of like computational fluid dynamics is to taking a car to the wind tunnel. You can test a lot of ideas on the computer at fairly low cost and then take the most promising of those to try in the real world. The danger is that the output of computer models is only as good as what goes into the models. Sometimes you get surprised when you find that your model doesn’t agree with reality and you have to go back and tweak the model. Sandia scientists use computers to model things like surface water in Iraq, biobatteries that can be implated to power things like artifical retinas, and combustion. Sandia has expertise in non-linear responses, which is when a small change in an input can produce large changes in the output. Think of a really touchy volume knob that blares if you touch it just the wrong way. Tires exhibit bigtime nonlinearity, so if you’re going to pick minds, Sandia is a good group of minds to pick.

• Scheduling a fall track test at Indianapolis with multiple participants to test solutions to full fuel stop capabilities and test again in the spring of 2009 to fine-tune the specific race setup.

Translation: If we have problems again next year, no one is going to be able to complain that they didn’t get to have some input. We’re leaving the Spring test with everyone there saying that we’ve got a good tire, so if something does go wrong, we’re going to remind everyone that we brought what they were happy with.

“Full fuel stop capabilities” is a fancy way of saying that we need tires that will last as long as a tank of gas. Goodyear counted on the track rubbering up the same way it had in the past. They had how many years of coming to the track, having tire problems in the first practice, and then having the track rubber in. They need additional track time to see exactly what is happening. You can do all the computer modeling you want, but the ultimate test is on the track.

• Accelerating discussions with appropriate NASCAR representatives, team owners, drivers, crew chiefs and track management on any future tire. Among elements already being considered are larger overall diameters, wider section widths, and larger bead diameters.

Translation: We didn’t create this problem and we can’t solve it by ourselves. We’re tired of everyone blaming us. If we have another disaster, we’re not going down by ourselves. More about the possible changes below.

• Developing future tires as a long term solution, looking proactively at the vehicle, tire, setup and track combinations for a complete package to assure only the highest level of performance for NASCAR’s racing fans.

Translation: We know fans were unhappy. Don’t look for anything radical in the near term. Our first goal is to fix the problem for next year, but the long-term solution is probably not going to be making a minor change to the existing tire. NASCAR is going to have to give us the flexibility to do something very different in the long term because we’ve learned that adapting the old tire may not work everywhere. Teams are going to have to help us out by giving us set-ups so that if they’re going aggressive with the suspension, we’re testing aggressive.

I don’t mean to sound anti-Goodyear, (except for my general dislike of people who make up words when there are perfectly fine words that say the same thing.)

The big long-term changes are wholesale modifications to the tire size, construction, bead size, etc. What does a bigger tire do?

A wider tire will do a better job dissipating the heat induced in the tire by friction between the tire and the track. If the volume of the tire increases, there are more gas molecules inside the tire. The heat generated by friction is spread out over a larger number of molecules. The pressure won’t increase as much when the temperature increases (and you thought you’d never use the ideal gas law!) The larger number of rubber molecules will also help dissipate the heat better, which will also keep the tires cooler. But if there is a larger area of tire rubbing on the track won’t that create more heat? Remember back to high school physics: The size of the frictional force (which is what creates heat) is independent of the area of the two objects that are rubbing together.

If you have a wider time, there is more rubber, so more rubber should be available to rub off on the track (provided, of course, that the rubber sticks to the track.)

There are some stress issues as well. The wider the tire, the better force is distributed across the tire. If you have 1800 lbs of force on a tire, it makes a big difference if the force is being supported by 36 square inches or 42 square inches. Each square inch of the tire will support less force becuase there is more total area. If you don’t believe me, go put on a pair of stilletto heels and walk around for a half hour, then do the same thing in your flip flops.

A wider tire WILL provide more grip, but not because it creates more friction. (You can look in the book for the ‘why’ of that one.)

There are a lot of benefits to a wider tire; however, the teams are going to have to develop new suspension setups. Look for engineers scratching their heads during practice the first couple of races with the new tire when the setups that were working wonderfully last year are failing miserably with the wider tire.

The other tire issue this week was at the Montreal Nationwide race, where they raced (for the first time ever as ESPN reminded us again and again) in the rain. Rain tires have grooves instead of the entirely flat surface of the slicks they normally race. Why? Treads aren’t for grip: the recesses allow water to get out from under the tires, giving the tire a better shot at gripping the track. Slicks allow hydroplaning: Water gets between the tires and the track. The problem with water (as with any liquid) is that the molecules aren’t connected very well to each other, so when you push on water, it doesn’t push back. That makes it really hard to get any traction between the tires and the track.

One of the teams almost put the rain slicks on the wrong wheels. This is significant because the treads are directional: They are angled to channel the water away from the car. If you put them on backward, the water gets directed under the car, which is not so good.

The most important thing they learned from Saturday’s experiment is that you can race when the track is wet, but maybe not when it’s actually raining. The windshield wipers are not exactly state of the art, and I wonder if some teams didn’t believe NASCAR would make them go out in the rain since a couple cars opted not to use wipers, One of them was Carl Edwards (loved him trying to squeegee the outside of the window under caution). You know that money isn’t the reason they didn’t have windshield wipers. There were two major crashes under caution because it rained so hard the drivers couldn’t see. So maybe rain tires are a solution to very long track-drying times, but it remains a fact of motorsports that the driver has to be able to see where he’s going.


  1. The fogging of the inside of the windshields were also (maybe a bigger) factor in driver’s visibility, that the teams will have to deal with in the future if NASCAR decides to run under wet and humid conditions.

  2. A couple of things that are rarely, if ever, brought up:

    1. The weight placement on these cars is “adjustable”–would it not be reasonable and/or possible to restore some degree of left-side weight bias for specific CCW oval events with low banking as part of the rules and car setup?

    2. Overall, horsepower is probably now at least 25-30% greater than when the wheel/tire size currently in use became a part of the Cup package–a 15 x 9.5″ rim, if I’m not mistaken, along with a relatively similar overall vehicle weight (3400#)–for at least 20 years. Driving a Cup car today has to be like riding a bucking bronco for the entire length of the race, with THAT much HP. NASCAR has allowed this HP escalation, and it seems to me that the boys in Daytona Beach ought to be able to mandate a de-escalation as part of the solution to tires that shred in just 25 miles and 40 turns on a “smooth” flat asphalt track. Simple translation–they’re blowing the tires off of the car–the characteristics of the total package require one of two adjustments, either more tire or less engine, or maybe some of both. In today’s
    “green” environment, the most appropriate solution perhaps should be one that reduces racing’s environmental impact, in it’s own small way, and engines that produce less power probably would have a smaller impact, overall. Engine building today is such a game of one-upsmanship, because they can (or are allowed to)…where does it stop? And regardless of what anyone reading this thinks, I’m not a “greenie”….

    A new engine package is in order–limit it to 500 HP and 7500 RPM, and let the manufacturers supply whatever they want to achieve that “spec”–regardless of size, and allow both NA and turbo or supercharged engines–give the NA engines a weight advantage, since the engine package for a turbo or SC engine producing 500 HP is liable to be a 4-cylinder of much lower weight/mass, and a possible fuel economy advantage. Mandate fuel injection, with ECM (engine controls) standardized and supplied by one source, whether NASCAR or an independent entity.

    (I digress) Yes, the cars will be slower, but racing doesn’t require “blinding speed” to be exciting or entertaining. It may mean fewer cautions, which NASCAR won’t like, since it means fewer opportunities for revenue enhancement while keeping the sponsors and TV folks happy–which should be a much lower consideration than it has become in today’s NASCAR.

    Off my soapbox!!!

  3. Hi Bill: Most of the engineers will claim that the weight placement really isn’t adjustable because the cars are so heavy already. Some of the teams are running very little ballast. The problem with doing something track specific is that NASCAR really wants to go the opposite direction: They’d like one car that runs every track. They could, of course, just make the car heavier (it did go up 50 lbs with the new car), but that’s going to increase the stress on the tires.
    You’re right about the tire size and that the horsepower has risen quite a bit without the wheels increasing to keep up with the horsepower. I would think it might be easier in terms of changes to decrease horsepower than increase wheel size. We don’t know what wheel size change is likely to do to the suspension set ups, and we have a pretty good idea of what could be changed to limit HP. (Maybe we shouldn’t be discussing this. The easiest way to decrease hp is the restrictor plate and I don’t think many of the drivers want more plate races!)
    The problem with limiting the engines to a specific rpm and hp is that is it very difficult to enforce. The current limitations are mostly geometry and materials, plus the gear rule. NASCAR is already taking a lot of heat about the cars being so similar, so I doubt they’re going to go with what is essentially a spec engine. You do want to leave the engineers some room for creativity. The other problem is that coming up with an entirely new engine spec is going to be expensive for the manufacturers because they are the ones that have to provide the blocks, manifolds and cylinder heads. With the economy the way it is and rumors that manufacturers are cutting back, NASCAR probably doesn’t want to hit them up with something like that just now.
    I’d like to see them go in the direction of F1, which is mandating kinetic energy recovery systems (KERS), technology that may be feasible to use in passenger vehicles. I’ll write a column about that in the near future. There are a lot of really clever minds in NASCAR and, in my opinion, it’s a shame that we’re not putting them to work for the good of the auto industry, not to mention the country.

  4. Joe: Some of the people I’ve spoken with tell me that the inexperienced drivers sometimes give better feedback because they aren’t trying to make the new car drive just like the old car. Plus, a number of veteran drivers (neither of the ones you mentioned) don’t like tire testing and don’t provide very good feedback, so I think you really have to go driver by driver. I’d argue for numbers over specific drivers. There’s probably no need to have more than one driver from a company, but the setups that different companies have can be very different. Thanks for the comment.

  5. I don’t think limiting HP is something viable. As mentioned, how would it be enforced? I think the bigger, wider tire is an excellent idea. This new car has a different mass, less down force, and a considerably different center of gravity than the old car. I was actually pleased that Nascar wanted to go back to more mechanical grip and less down force. However, using the old tires, and suspension limitations that were imposed on the previous car (Nascar handing out springs and such) is not the way to get this car to perform to it’s potential. two or three inch wider tires on 17 inch wheels will make a huge difference. It would also mean bigger brakes and better brake cooling for short tracks, so there’s added safety as well as everything the tire itself would do for the quality of the racing.

  6. “One of the teams almost put the rain slicks on the wrong wheels. This is significant because the treads are directional: They are angled to channel the water away from the car. If you put them on backward, the water gets directed under the car, which is not so good.”

    Are you sure about putting the tyres on backwards ?

    Looking at the tread pattern, I would suggest that it normally channels water out of both sides of the tyre, and putting it on backwards would channel the water towards the middle of the tyre, causing increased aquaplaning.

  7. “intertrangled polymer chains?

    Are you sure that not what Robert J. Keegan’s brain is made of?

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