We recently had a lot of talk about tire tests, and lots of opinions were voiced regarding other possible tests. Good conversation.
So, my assignment for you: Design your ideal tire test.
The big limiting factor: You can't test more than four different tires (or tire configurations).
Go!
My ideal tire test has me behind the wheel of a great car doing hot laps all day on an autocross-style course. I don't really care about the results, I just want want to have the fun and the seat time.
Not what you were looking for? 
my totally biased opinion is to test DD performance tires. something good enough to autox in but not so soft(or expensive) that I am going to dreading that I have to replace them all the time. lets say somewhere in the 300 to 400 treadwear rating.
if i can't get what I want for myself then I would like to see a test of larger tire sizes for cars like the newer camaros and challengers.
I would set up some quantitative tests. Not overly scientific, but a way to measure speeds, times, etc.
Skidpad would be one. I also often like to know sticktion/friction. One of the first things I do on a new set of tires is to mash the pedal to see how quickly I actually go forward versus how much just goes up in smoke and rubber chunks. I don't go crazy with it, just test it once or twice.
Maybe a timed distance? Mash the pedal for 1/8 mile? 100 feet? See how long it takes for different tires. This test wouldn't do much on under- or over-powered cars. An 800-hp muscle car would just roast tires forever, and an 84 LeBaron couldn't break traction with any tire. In those cases, you could maybe rig up a pulling thing with something to measure weight inline. Start pulling a parked car slowly (someone in it with the brake on) until you see a peak weight before it starts moving and then record the moving weight for a couple feet.
I'd build a tire test rig (trailer) that would consistently vary the variables (vertical load, slip angle, camber) and measure the measurables (lateral force, temperature, diameter). The objective data could then be analyzed and compared against subjective drivers notes, to get a more complete picture of what the numbers themselves mean and how they can be applied across a variety of situations.
Skid pad.
If you tell me that a certain tire picked up 30 seconds at VIR, or Leguna Seca, I have no idea what that means.
But if you tell me a certain tire can pull .95g on the pad, I can quantify that, the same way quarter mile times are, no matter where you are.
In reply to David S. Wallens :
Ya gotta test rain tires. Rain is the great equalizer that turns racing into a skills event rather than who’s got the most power, brakes, best aero package, or sorted handling.
Test the 4 tires on a simple figure 8 autocross course. Flooded by a friendly fire truck a minute before each run.
One or two drivers, one car. You might want to test the best tire in a size smaller to see if that helps or hurts.
Proper road race. Buy four sets of tires for the Chumpy Lemons Miata. Run each for six hours with each driver having an equal stint. Variable track temps and conditions through the race would berkeley with the results, but the difference in wear, speed and feel between an RS4, Rival, Dunlop etc... would give at least some data points worth learning. Plus, not really a whole lotta extra work. You are running the race anyway.
It is shocking to me how different a Rival feels from an RS4, yet how the lap times stay reasonably consistent. I'm also not talented enough to really get a good idea of what a tire does in sixty seconds on an autocross course. Two hours in a road race track is a different story.
I like the quantitative tests that do not rely on the driver so much. Always call me first to see what tires I'm debating on running for the challenge and test those.
Events:
Skidpad, braking (that's all you need to get all directional forces of a tire).
Test 1 known tire against a different size of the same tire, and then two competing tires in the same size as the known one. Always test the known one first and last. Be prepared to change quickly so conditions are as similar as possible. Wheels should be the same if possible.
Braking - use a telemetry system to measure stopping time and distance from 60 mph. Full slam abs. Measure before and after tire temps to see how much each heats up, and also to see if heat changes the tire's abilities. Repeat 5 times per tire.
Skidpad - same telemetry to measure cornering gs and lap time. Avg g and max g. Run a few laps, measure temps, repeat 5 times. Again, see not only the capabilities, but how they change with heat. You can "setup" each tire by playing with air pressure etc to achieve the best grip, but that should be done before the testing starts to minimize time between tire tests. Also make sure to present all the setup data you found as best.
Finally maybe throw in a slalom to get some qualitative data from the test drivers, feel, transitions, slip angles, etc.
I'd say run a test of the popular large sizes for heavier cars (such as CAM). Use... say..... a 78 C10. lol
Eh. I've always thought the tests you do are pretty good.
I'd do 4 tires with a dry and wet comparison, on a common rim width/car prepped for ST.
In reply to frenchyd :
This!
Nice follow up on the replies to the tire test announcement. GRM is the best!
Cheap Chinese tires VS cheap brand-name. A Chinese summer tire VS the Firehawk Indy 500 and a Chinese all-season VS the General AltiMAX RT43 on normal roads, a dry skidpan and a wet skidpan. See how vast the difference is and hopefully convince an average joe or two to reconsider cheaping out.
I second the everyday performance tire test idea. Long life summer tires that are good for 40,000+ miles.
On a related note, I'd like to see a test of an aged set of ultra high performance tires. In my experience, low treadware tires seem to lose a lot of grip as they age. I'd bet a 3yr old ultra high performance tire does worse than a 3 year old regular high performance tire.
Daeldalus said:my totally biased opinion is to test DD performance tires. something good enough to autox in but not so soft(or expensive) that I am going to dreading that I have to replace them all the time. lets say somewhere in the 300 to 400 treadwear rating.
Tirerack has literally already done this test:
https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=217
Hoosier, m/t and nitto drag radials versus an A7 for dragstrip launching on a car, say around 3000# with an 18x10 wheel and around 400hp
I'm pretty happy with how recent tire tests have run with the hotshoes on known courses in known cars. It makes the tests relavent to most of us that autocross on them. I would like to see some outliers put in the tests. Some sort of "normal" street tire and some sort of suuuuuuper cheap tire. It's nice to know that the four top tires are withing 1/2 second of each other, but how far ahead of a $60 tire are they? Lots of us say to ourselves "if I had that guys tires I'd be right with him" but is that true?
Driven5 said:I'd build a tire test rig (trailer) that would consistently vary the variables (vertical load, slip angle, camber) and measure the measurables (lateral force, temperature, diameter). The objective data could then be analyzed and compared against subjective drivers notes, to get a more complete picture of what the numbers themselves mean and how they can be applied across a variety of situations.
That's a thing - happens every day in the industry. No, you won't get the data :)
In reply to collinskl1 :
Exactly...What would be more GRM than that?
As far as test method, you can include the Braking/Skidpad/Acceleration components into a single layout, which allows for time (temperature) dependent effects.
I did this for a cooling capacity test several years back by setting up an 1/8th mile center to center figure 8. This gives you a constant radius turn in both directions, a generally 2nd gear acceleration run and a significant braking zone. Using data acquisition you can break out all the data you need to make the necessary analysis of each section. Additionally, the total 'lap' time could be used to show time/temperature trends.
The distance between centers could be adjusted to keep the test car in second gear. One of the biggest benefits of this layout is the fairly small footprint needed for the test and little required run-of area. Another variation would be to do the same layout on various surfaces AND/OR wet/dry comparison.
Andy Hollis does a great job of being consistent with the tire testing and may have a tweak or two to my test method.
In reply to collinskl1 :
There are also a few independent tire testing facilities that do the testing in a lab environment, but the cost is prohibitive to most users (but not manufacturers).
The amount of data is ridiculous and the tires do not last very long at all (more than 10 tires in a single 8 hour test session).
To add to the idea of which tires to test, how about a comparison of the current go to from the 200TW and whatever the 300-400TW range would be. That should show the trade off in performance vs daily driver life. If you were to get really silly add a set of slicks in to show the complete range from daily driver fare to track use only...
I would like to see an endurance road course test for tires.
Take the current crop of best tires and run them on your Miata at the racetrack during a race.
Which ones wear better? Which ones get greasy with heat? Which ones heat up more? Which ones recover the fastest? Which ones provide the most grip (I think this could be accomplished by looking at 2 or 3 corners of data, not the entire lap, and compare those corners across the entire group of tires).
Doing your regular race and changing tires every other pit stop or every 3 pit stops might be enough data if you run a data recording device.
For the test results, note the following pre-test:
Tire pressures (cold)
Weight on each corner of the car
Camber
Toe
When the tires come off, note the following:
Tire temps (IOM)
pressures
wear - if possible objectively
Ask for any subjective info from the driver.
After the weekend, look through the data and you can add highest sustained"G" through the chosen corners to the data as well as lap time (because people like lap time).
This is what we did about 2 years ago when the really fast tires starting coming out. We found the best combination of wear, drivability, and grip that worked for us. We tested RS3 v2, Toyo R1R, Rival, and Star Spec Z1. The rival was the best for us at the time, but we also found out that you MUST heat cycle them once or you will destroy the outside edge of the tires.
We have not had the opportunity to do this test for the newer tires due to cost and time (4 babies have joined the team since we last did this test).
That's my .02$.
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