Current thoughts and experience on Track day/Autox Tires

[BlackBMWs]

Here is a dialogue between Ed and I in Facebook we had for tires and suspension for folks reference.
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Ed: What are your alignment specs?

Rich: Funny you should ask, as they just finished my alignment. So when I swapped the rack I was off on Toe only about 1 1/4".

I'll set the camber to -.5 for the travel between home and track. Reset to -2 once I am there.



All better now. Fluids and brakes tomorrow.


Ed: Next time try zero toe. Easy on the tires and crisp turn in. The rear naturally toes in when you lower it so the car will still track straight.

If you adjust the camber you will alter the toe and might not achieve the tire saving wear you're after.

Rich: Ed, thanks! Am I running too much camber for general circuit track events? I realize it differs from car to car.

Ed: Rich - so that's hard to say. I would not say you're running too much camber but there are some things to consider.

The more negative camber you have the more straight line braking you give up. Running only 225s up front this would be a consideration for me. Are you trail braking or doing all your braking before you start your turn in?

Adding caster gives you more negative camber when turning. It also makes the steering more heavy but I honestly don't notice, even with 245s on the front. Caster allows you to back off on the negative camber a little bit.

You're driving your car to the track and on the street. I think there is real value (in terms of time, money and being used to your car) in driving the same set up all the time. Set it to something aggressive that won't kill tires and learn to drive on that till you can out drive the car.

All that said, Ricky Marrero is probably the better one to speak on this subject.



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[BimmerBum]

Thanks Rich! Hope that helps. Input from Dave would be good here too.

[joe1602]

Carl, sorry about the delay, I was going to send you a picture of our tire wear last night but I was unavoidably detained by going to look at an E24. Hopefully I will send some out tonight. That being said, Depending on the distance to events, I just keep the RE-71r's on the car. If I am driving anything over 10-15 miles, I put the old 16 inch Ventus RS-3's back on. The only problem with that is they are basically bald and I am not too comfortable driving in the rain with those tires. I am currently having to drive it back and forth to work (only about 5 miles) so I am keeping the Bridgestone's on for now. The wear from road use seems to be minimal but they are taking a beating from autocrossing. My son & I share the car so we are basically putting twice the wear on them as normal. Add to that we had a test and tune to start the year, we actually have 3 seasons worth of runs on them already this year! I am hoping to get next year out of them as well but I am not sure if it will happen. Will try to post pictures of the wear tonight.

[BlackBMWs]

Thanks! I will for the 200 mile round trip, swap wheels. My minimum round trip travel to an event is 100 miles or so. So how many sessions(Runs) do you think you all have done so far? I know on the Toyos, they are treadwear 200. I have prolly driven 5000 miles on them as DD tires, six trackday sessions (360 minutes) and 30 AutoX runs (>40 seconds) over 3 sessions.

I am at about 40-45% wear with 50-55% tread left. Some effect of camber on the front tires. As the Toyos are square, I will rotate them before flipping them on the rim after this next trip.

I thought Boating was a costly sport. This is a different sort of fun and just as costly.

Totally worth it!

[joe1602]

OK, we have done a total of 154 autocross runs since the beginning of may this year. The lap times are on average 40+ seconds. If you figure an average of 8 runs per event, that would give us about 19 events for the year so far. I would say there is at least 2/3 of the tread left on the tire, but as I said before, the wear is funny on the fronts and I am going to have rotate the tires by dismounting them and switching them to the opposite side of the car to even out the wear. I have driven the car a total of 1200 miles since mid April, probably about 900 of those on the Bridgestones. The wear is opposite of what you would expect on a car with -4 degrees camber and 1 degree toe out on each front wheel. The outsides are wearing faster than the insides due to the extreme amount of cornering we are doing on these autoX courses. One thing I have nor really thought about is the effect of the weight of the wheels on the tire wear. The wheels we are using are HEAVY (About 25 pounds each w/out tire). Not sure if that has any bearing on the wear or not but you are correct, this is VERY expensive. I need stiffer springs, a stiffer rear sway bar and lighter wheels, all very expensive and not going to happen any time soon!