So, Tire Warmers?

[HO RacePro]

Somehow it seems my car doesn't achieve its best performance until I've turned a few laps.

I was just running my Thunderslot -- which has its stock tires -- and dang if after ten or a dozen laps my lap time gets consistently better by a couple tenths of a second.

I've noticed this before, quite often, with different cars and tires, and I've wondered just what is going on. I've a few theories:

1) It's not the car, its me. I just need a few laps before my driving dials in.

2) It's the car, but not the tires. Something needs to warm up -- maybe the motor -- before the car reaches peak performance.

3) It's the tires. The surface of the tires gets warmer and more grippy, due to friction, after a minute or two of running.

4) It's the tires, but not their temperature. A bit of abrasion 'activates' the rubber, producing more grip.

I've actually tried measuring the temperature of the tires after some running, using a contact-less infrared thermometer. I've never seen good evidence that the tires have heated up. But physics tells us they must do. Maybe not enough to make a difference. Or maybe they cool off too fast for me to measure a difference.

That business about 'activating' the rubber may be more likely than it sounds. There is such a thing as the 'surface energy' of a material, which can be measured, and is important when it comes to adhesives and printing. To get ink to stick to some plastics, like polyethylene or polypropylene, you need to increase their surface energy. That can be done by briefly exposing the surface of the plastic to a flame, or an electrical corona discharge. Raising the surface energy of plastics only works for a while. A day or two later that added surface energy will be lost. But if you do it right on the printing machine it works really well.

Does something like that happen to rubber when you scuff it around a track? Magic 8-Ball says, "Reply hazy. Ask again later."

I have tried scuffing tires on an emery board to improve grip by exposing fresh rubber. Seems to maybe work, but don't quote me on that.

So what actually is happening during those first few laps? Enquiring minds want to know.

Ed Bianchi

[millconroy]

Dear Ed,
This is why I make, as well as others, a tire cleaner/traction compound that will make Rubber, Silicone and Urethane perform up to their potential. In Retro Racing, and Top Level Wing Racing, to have optimum grip available in qualifying is key. You need on foam tires to get the pores working to their maximum capabilities, and with Silicone and Urethane, you need to have them cleaned and have a compound that helps them to achieve maximum tackiness

[Kevan]

Ed, fresh clean rubber is good, fresh treated clean rubber is best

[Maddman]

Don't know about tire warmers. RC cars are using them. Can I see HO tire warmers in the future. No I can't. I think its all the molecules in the car, track and driver coming together to become what you remember from practice. For some that process takes a few laps. Some go fast right off the line. In my latter days racing Fray and some other cars I had a bad habit of leading off the line and never looking back. Did the car get better after a few laps? It might have. Through lots of practice I learned how to drive a cold car. What I remember was that typically I would turn my fastest lap of a heat well inside the first minute.

What I also know that a cold motor is a more powerful motor. In the old Tyco superstock days you could watch the motors fade just a bit over the first minute. The fastest laps were set with a cold motor. After the first minute those who set up the car to keep the motor cooler had more motor to play with. The motor needs a few laps to come up to temperature and become what you remember from practice. Likewise the track may have changed since you were last on it and that too takes a lap or two to relearn. It takes lots of practice and some talent to get the max out of a cold car. However, the advantages of being able to walk away from the field in the first few laps are priceless.

With tires you need to make sure they are dry and squeaky clean at the start. As soon as power comes on the tires will start to degrade due to dust buildup. New tires take some time to break in. I never started a race with new tires. The race tires were well scrubbed before race day. Not saying that treated tires aren't fast. They are. You just don't want to treat them immediately before putting the car on the line.

[Aptosc6]

#3 plus track temperature.

[slothead]

I've seen this a lot, most pronounced on my oval track cars. I attributed that to the tires warming up too, but now think it could be the tires sweeping the track clean during the early laps. In many forms of full scale racing the tires have to come up to temperature to offer full grip, and in F1 the tires have warmers on them till just before going on the track. Drivers also weave back and forth before a start to scuff the tires clean. So, perhaps a bit of both but for slot cars I credit a clean surface and tires more.

[War Eagle River]

Yes, in our experience, warmer tires do make a difference.

[Fathead59]

How many laps do you think you would need to warm up the tires before the race ?

[4424ever]

I have scaly sport road course and a wood oval both in the same room
Seems to me the better quality tires on the car the more they seem to respond to warming them up usually 2 or 3 laps on the sport and 5 to 10 on the wood ( shorter track
NSRs come in quick and are noticeably better as compared to Carrera stock rubber comes in slower with a little better grip
Urethanes respond on the wood immediately with a light scuffing love them

[slothead]

A way to test the role of tire temperature would be to use a hair dryer or something similar to heat the tires on a car before doing some timed laps. If this actually has a benefit I can see guys having a heating pad or microwaved gel pack (like is used to keep your backside warm at sporting events) in their box to use before starting a race.

But, tires would cool down to track temperature quickly so it would likely be only a short term advantage.

[Fathead59]

Ok , no advantage with the hand warmer packets , just track time to warm up the tires

[Fathead59]

And the reason I ask the question to also see if anyone else has tried it, and if others think if it is a good question to ask

[HO RacePro]

Well I don't think it is clearing dust on the track. When I switch cars in a practice session I still seem to need a few laps to get the most performance.

I was sort of joking when I titled this thread, "So, Tire Warmers?" But maybe not so much of a joke...

I do know Gerry Cullan and Richard Dumas take note of track temperature when they are conducting -- their highly professional! -- testing programs. I've sort of considered that maybe not quite necessary. But then, geeze, maybe actually needed.

Ed Bianchi

[Tuner28]

Here’s a novel idea, heated tracks!

[4424ever]

I’ve run on a heated drag strip and yes it was FAST

[RichD]

When I was doing research I learned that you need to keep all of the variables under control if your results are going to be valid. If I was going to develop a new process I had to be sure that it had reproducible results.
I have been testing tires for a long time, rubber tires can be frustrating because there are often batch to batch differences in how they are made. You can buy a particular make and part number and they are great, a year later you might buy more of them and find that they are not as good. I expect that is not as much of an issue with silicone or urethane tires.
If possible I do all of my tire testing at the same temperature. Any sort of tire will have the best grip if the tread is perfectly smooth. If I have trued a set of tires I always polish them. Tires will polish on the track, but you would be at a disadvantage until they do. Some silicone tires will polish quickly on the track, others take a long time.
It can be difficult to determine if a particular set of tires needs to warm up before it has the best grip. Other factors can cloud the issue, the track may be a little dirty, the rails or braid may not be in top shape, the car's motor or running gear may need to warm up and finally I expect that the driver will usually need a few laps to get into the zone. That being said I have run on some tires that do need a few laps before they really hook up well.