California: The Good, the Bumpy and the Frustrated

I know this isn’t a picture of California.  But it’s a picture out my window, which is why this is a sort of short post.

There seems to be a clear division between the people who are upset about the tires Goodyear brought to California and the people who aren’t upset about the tires Goodyear brought to California.

The people who had problems are upset.  The people who didn’t have problems aren’t upset.

Here are the facts:

• Goodyear brought the same tire they brought in 2013 – the first year of the Gen-6 car, which featured weight reductions, higher speeds, and higher loads.  The same tires (D4522 on the left/D4408 on the right) were used in 2012.  There weren’t a lot of complaints after that race – in fact, those two races have been cited as some of the most exciting races at California ever.
• NASCAR tweaked the aero package and the suspension setup rules between 2013 and 2014.  The biggest suspension change was the removal of the minimum front ride height. These were relatively small changes compared to the changeover to the Gen-6 car.
• California continues to change as a track.  The seams between lanes are getting more pronounced.  The bumps down the backstretch are getting bigger.
• The teams continue to improve their setups as they learn more and more about the Gen-6 car. They are moving closer and closer to the edge of stability in an effort to make their cars faster.

Goodyear looked at the changes and considered how they would affect the current tire. In the end, they opted not to change the tire.  I have no way of knowing how much notice Goodyear had of the suspensions/aero changes for 2014.  They start making Daytona tires in October of the previous year, so they need a minimum of 3-4 months advance notice.

The teams knew about all these changes, and knew that Goodyear was bringing the same tire.  Most teams likely started off with something close to their fastest setup from last year.  A number of the drivers mentioned they had to back off their setups from practice because they weren’t happy with tire wear. That’s part of setting up a car – taking into account changes from the last time you were at the track.

NASCAR is still looking into the issue, but their initial impression was that the teams were too aggressive with their set ups.  They cited very low tire pressures as one reason for the failures, many of which appeared to be sidewall related.  Goodyear recommends 20-22 psi in the left-side tires and apparently some teams were starting off at 11-14 psi.  (Most of the failures were on the left side.)

Teams have always started out with low pressure in the tires because tire pressure increases as the tires heat up.  If you put the pressure you’d like to have in the tires at the start, it would quickly get higher than you want it to.  So you start with a low pressure and let it build up.

The problem with very low pressures is that instead of the air in the tire supporting the car, the tire sidewall is supporting the car.  This puts a lot of stress on the tire and, given how punishing a full fuel run is on tires, the stress can, over time, lead to early tire failure.

This is a very common pattern with race car setups.  NASCAR makes changes, Goodyear tries to anticipate how the tires will behave under the likely setups.  Teams try setups, make changes and Goodyear tries to keep up with the changes.  I suspect the reason we’re seeing the problems this year and not last is that the teams have become more bold with their setups.

It’s a never-ending iterative process, with Goodyear trying to anticipate the effects of new setups, rules changes and track changes, and teams constantly pushing the envelope.

That’s the challenge, though.  How much are you willing to risk to get just a little more speed out of your car?