If you want to talk tires with someone at General Motors Corp., then Jim Gutting's probably the guy you want to look up.
As director of GM's Tire & Wheel Systems unit, he oversees a team of more than 80 that validates about 30 new tires and 70 new wheels annually. Formed in 1968, GM estimates the group has evaluated between 15,000 and 20,000 tire constructions.
In this edited version of a recent interview at GM's Proving Ground in Milford, Mr. Gutting talked about such topics as tire safety testing, run-flats and the new federal rules covering tires.
Talk about GM's Tire & Wheel Systems group.
We've been in this business since 1968. We work with the tire companies; the folks who are responsible for engineering and designing tires to meet the requirements we place on the tires for our vehicle level needs.
So when a program comes down, we'll get definitions of what the imperatives are, what the targets are for fuel economy, for mass, for handling. And all of that gets dialed into what we call the Tire Performance Criteria.
The TPC is that list of characteristics from air permeation to electrical resistance to treadwear to long-term durability performance, to dry and wet traction and handling. All of those criteria are part of our TPC spec.
People probably don't realize that tires are an important part of the development of the vehicle.
It's integrated in the overall wheel performance. Picture the number of knobs you can turn to tune a vehicle.
Well, tires are one of those, and a big one. It makes a big difference on how the vehicle performs and handles, and starts and stops. And it's got to be integrated into the vehicle from the get-go.
When you're designing the vehicle, you better understand and know exactly what tires and wheels you're going to have on that vehicle so you can understand how the vehicle performs.
So you work fairly closely with the tire manufacturers?
We're working right now with Bridgestone/Firestone, Goodyear, Michelin, Continental, Pirelli and Hankook. They have tire development engineers who spend time in Milford in our building working with our tire development engineers to make sure the overall tire performance ends up where it needs to be.
How do you think your tire program ranks against the other major auto manufacturers?
We clearly have a longer history. I guess I don't have current knowledge how they're staffed. But I do know that we've had a team working on tire development for a long time. We have TPC specs that are on our tires that other folks don't have.
Obviously, the other OEMs are making sure tires are working on their vehicles, but we've got a dedicated team who have been doing it for a long time.
Over the years the group has tested more than 15,000 different tires?
Not all of those tires found their way on a vehicle. But each time one of the tire companies develops a tire, we'll do an evaluation of that tire on the vehicle. And it may be that it needs adjustments.
It seems like tires don't make the news unless something bad happens. To what degree does the public take tires for granted?
I don't know but I would speculate that they take it a lot for granted. One of the things that we continue to encourage is that tires are a component that needs to be maintained, too.
And that includes keeping the proper air pressure in your tires. My sense is not a lot of people do that on a regular basis.
With tires, there is a certain permeation. Air will go out of a tire on a long-term basis. And that's one of the TPC specs: what percent of air loss over time is set up. Even if there's no puncture in them, they're going to lose air, so you have to maintain them.
How much impact has what happened with the Firestone tires and the Ford Explorer situation had on your testing here?
It really hasn't changed our testing and our criteria. We've had TPC specs and our tire endurance testing and our treadwear testing. None of that changed with the incident that occurred recently.
Having said that, though, we have folks in Washington who have promulgated new rule-making that has changed some of the performance requirements of the tire, and has changed some other characteristics as far as reporting.
We now have to report on a regular basis-as does every tire manufacturer and OE manufacturer-as far as warranty issues and what's going on in the field.
So while it's changed the reporting requirements, it has not changed our test requirements, except that there are some new re-quirements that FMVSS 139 places on the tire manufacturers. Part of that is tire pressure monitoring.
That's one area where there's been a little bit of controversy. It seems like the tire makers want direct systems and some of the auto companies favor indirect. What's the feeling here?
I think the feeling here is that it ought to be performance-based. Regardless of what technology is used, it ought to inform the operator as to when he or she has a condition in which they need to seek service.
Whether that can be done with direct measurement or indirect measurements or combinations thereof, the position's always been, ``Specify what the requirements are, not the technology that you use to meet it.''
Have you done much work with run-flats?
We have run-flat tires now. For example, our Cadillac XLR has a run-flat extended mobility tire. Corvettes have run-flat tires. That is the standard tire on those vehicles.
So far it's only been mostly the upper end vehicles that have run-flats?
There's some technology development that still has to occur. Long story short, for an extended mobility tire to function with no air in it, it has a stiff sidewall. That by nature gives you a stiff ride.
On performance vehicles, that's not as much of an issue. But put it on a family sedan and it is an issue. And if the tire size gets too big, the section height gets too big, then what happens is the tire physically can't support the weight.
Is this one of the main things keeping run-flats from becoming more widespread in use?
You'd have to speak to the tire companies, but it's my belief that they're all moving as quickly as they can to develop run-flat technology that's more forgiving as far as loads and ride quality.
And those tires are heavier, and the mass goes up, and they're more costly, so you'd also have to dial in the technology so the price of these tires are reasonable.