Foam tires in long main runs
 

I have a question regarding tire strategy. Tire ware in a car can be very different. For example right front tire is getting smaller quicker then the left one!

Drivers around the World tackle this challenge in three different ways:
1. use different tire dimensions at start;
2. use different shore rates (harder/softer);
3. Combination of 1. and 2.

Which methods prefer the pro-drivers?

I personally don’t like the first one because if you take two different diameters (let’s say at the front) and set the ride height equal on both sides in the end you finish with very different heights looking front left/right! So on start you have to compensate the ride height as well when the tires get worn unequally the ride height changes unequally…

Have the experienced drivers some tips on this topic?

Thanks!

I always run a harder shore in back and tune the car based on a softer front tire. I set the car up with the OD of the tire I expect at mid race, and then start with a set of tires a couple of MM's taller. By mid race I have the car in it's sweet spot and it is still running good at the end.


Also, I practice enough (and I can't stress this enough) so that I can drive the car under ANY conditions. I don't care if I'm driving on plastic wheels, I know exactly how fast I can run the car under those conditions....

And some make the tire smaller to create more tirewear....

and the reason for that is?

i think he means a bigger split. so front tires smaller than normally what you would start with. then the fronts wear more than the rears, and the split maintains longer, so the car is consistant from start to finish.

Basically you have the answer already, each round you must measure your tires and keep track of the amount they wear and how much time it took. Occasionally a harder tire will wear more on some tracks because it provides less grip. I tend to go more toward staggered sizes for example if the left side is wearing harder and I get 1mm of wear in 15 minutes then I would cut 2mm taller for 1 hour and deal with my car being less ideal during various portions of the race.

My local track eats tires at a rate of around 4mm per 8 minutes and I believe every pro driver at the last race switched tires once and some even twice (just one tire for some, just lefts for some) to last for 45 minutes.

Ideally you don't want to switch tires with a sedan, it cost Ralph Burch the 2007 nationals when his motor died.

It won the nationals for Mike Swauger in 2009 though, he was the only 8th scale driver to switch tires in the main and it helped him a lot.

Not the split but actually the width of the tire is made smaller just by cutting off some mm of the inner sidewall. In this way the tire will wear faster and when placed on the less wearing side it will follow the wear of the other side.

A few things to consider here - and just keep in mind that my knowledge on this subject comes from studying the major races to understand why people won/lost and communicating with drivers and/or mechanics after the race. I also read a lot of race reports as well.

A tire strategy for a one hour race is a big deal. Some drivers decide not to change tires while others do. Those that don't change their tires often finish with very little material left on the wheel. It's a very calculated risk on their part. Many drivers have won or lost by not changing tires. Is there a risk of running down to the plastic? Yes. As has been stated, there is a risk to changing tires as well, including flameouts (as Brian mentioned), the mechanic putting the wrong wheel on a corner, stripping threads, the car being dropped and damaged, and so forth. So no matter what a driver decides, there is risk.

Because the car drives and performs differently with different tire sizes, it's important to consider the implications at the beginning, middle and end of the race. When are you faster and when are you slower? When does handling get sloppy? When do you have no choice but to change the tires, even if your strategy was not to change tires? How much performance degradation can you handle without wrecking the car? If you do plan on changing tires, how much of a lead can you establish so that you can still be on the lead lap (or ahead of it) when you get back out on the track? If everyone is on the lead lap and you need to change tires – and you lose position, how many laps is it going to take for you to get back on the lead lap – and is that even possible given the competition? When you change your tires is also important. So as you can see, as mentioned earlier - this is a big deal.

As the driver, you need to consult with your pit man and plan ahead for various contingencies. You're essentially calling the shots and the risk is all yours. Your pit man will have an opinion of course, but ultimately, he should support your decision – regardless of if he agrees with you or not. The pit man's experience counts for something, but you're the one driving - so don't blame your pit man for accepting his advice if things go wrong.

As a side note, some drivers do have different shore and different size tires left-to-right, depending on how the tires wear. Figuring that out comes with experience.

Also keep in mind that pitting for fuel eats time. You can be the fastest guy on the track, but if your pit stops are slow or inconsistent, you can lose lots of time to guys that are just a bit slower out on the track.

Hope this helps. :)

Durring the final at the nats i used a harder shore tire on the power side of the car and my tire wear was fine for the whole hour. at the end of the main i had tire left

Hey guys thanks for so many answers and questions! It gives me many points of view, things to consider and think about ... since I'm more used to drive on rubber tires.

We have three months till the season 2010 starts and my V10 is already prepared. I won't have many time to test the machine and tire wear ... so I will remember your comments and try my best.

Thanks

tire wear
 

I've pitted for Tosolini for a couple years, and almost every long main he has run four different tires shores at each corner of the car in both eight scale and tenth scale and won't change tires.