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I have a pair of Mich Pilot Super Sports in the garage waiting to put on the rear. I will try them with the AD07s on the front. Here's what caught my attention:
- Max performance, Y speed rated with exceptional reviews and test results for handling and grip.
- Being used as OEM tires on a lot of very high performing cars like Ferrari 599 and others.
- Very low rolling resistence compared to other Max Performance rated tires. = good range
- 30,000 mile tread life guarantee. Sadly it's cut in half if your front tires are a different size.
- Lighter than the AD07s = better performance and range.
- About half the price of the AD07s and guaranteed to last 4x longer (300 UTOG).
I'm planning to report back here when I get them on which should be in about 10 days.
My 2008 Tesla Roadster is in for its three-year service, and the quote for two new rear AD07s was $855. Instead — with the help and cooperation of the good folk at Tesla — I ordered two AD08s from TireRack.com, delivered directly to Tesla in Menlo Park for them to install for me. Cost $400 for two tires, $25 two-day delivery, $25 each tire to install, making $475 total. Elapsed time to place order at TireRack.com: about ten minutes. So (unless I'm confused) the AD08s have better traction than the AD07s, last longer, and cost less. I'm puzzled that Tesla are perfectly happy to install AD08s on the rear (and indeed suggest that, if you ask what the tire choices are) but don't carry those tires in stock themselves.
Thanks. Can you report back on how you like them? Does traction seem the same... Etc. I'm not looking for autocross tires just a good replacement for the AD07s.
It may have something to do with the ADO7s and AD048s are the only officially supported tires for front and back. They technically haven't tested different tires for front and back so probably aren't supposed to recommend that.
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My understanding is that the AD07's (and A048's) are the only tires that are "officially approved", which is why they are the only types stocked.
When my current set of rears wear out I'm planning on putting AD08's on, so I'd be very interested to hear your opinion after driving on them.
Edit: What dsm363 said...
When my current set of rears wear out I'm planning on putting AD08's on, so I'd be very interested to hear your opinion after driving on them.
Edit: What dsm363 said...
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The techs at the Tesla NY service center said they don't recommend AD08's. I asked why and was told they aren't as safe as the AD07's. Went on to say "It's not just that we don't want to sell you cheaper tires. It's because other tires like the AD08s really aren't as safe with AD07s on the front."
I just replaced my AD07's with AD08's -- with a winter tire in between (so a direct comparison is very difficult). I'm pretty happy with them though. Plenty grippy and not noisy. Same load/speed/UTQG rating as AD07's. Quick Googling seems to indicate AD08's do better, especially in wet weather.
I've been running a set of AD08 tires in the back for the last couple thousand miles. I haven't noticed any difference from the original AD07 tires. Traction control under full acceleration does not come on in dry reasonably flat pavement/situations, which is very much the same as I observed with the original tires. If the AD08s have less grip than the AD07s I have not been able to detect it, but I must admit I do not try to push my car to the limit on cornering and such, nor do I go to the track. I won't know whether they wear any better until they have many more miles on them, but I'm happy to have saved a couple of hundred dollars on the set.
Well, that leaves me wondering. Doesn't sound like they said why. Are there solid engineering reasons for this statement, or is it simply that they haven't tested it?
Last year my Ranger advised keeping the same rubber on all four wheels. He said the traction control system expects the wheels to expand at similar rates, and different tires might have different characteristics. At least there was an explanation. But we're not talking about mixing Yokohamas and Toyos, we're talking about putting on the "next version" of the AD07.
So is this statement coming from engineering or legal?
Yokohama claims they have more. If anything increasing grip on the back would increase understeer. A stock Roadster is dialed in with a lot of understeer, because it's safer for street use and for inexperienced drivers (by this I mean everyone who hasn't at least taken a race school). They'd be worried about things snap oversteer and power oversteer. The TC system was designed to control both of those things.
Is it possible that the TC system is so finely tuned it only works with stock tires? I rather doubt it. The car isn't going to have different modes for AD07 and A048. And I've been running on Toyo T1Rs with no ill effects.
W.Petefish
Active Member
Most likely legal, as to avoid liability.
I have to go in for a new set of rear tires today. The Coopers that I had lasted about 10K, but it was slower than most. I think that I'll try the Michelin Pilot Sport and see how they handle.
The statement your Ranger made is actually a valid engineering statement. Even tires from the same manufacturer can have very different characteristics. Perhaps surprisingly, this can include the exact same tire made a different batch.
Tesla is not able (and probably doesn't want to spend the money) to test every combination and the Roadster is one of the few cars that doesn't have the same size tire all around. These kind of tests are actually quite costly. So they pretty much have to go with the one they've tested, because if they guessed wrong...
So there's a legal reason as well.
I called Tire Rack yesterday and spoke with a guy with considerable knowledge about high performance tires. I asked what the difference might be between the AD08, AD07, and Mich Pilot Super Sport on a Tesla Roadster with AD07s on the front. First he said "it's not ideal [mixing front and back]." He said the AD08 would be at least as good or slightly better than the AD07 with better tread wear, and the PSS would be "comparable" to the AD08, "you would probably not notice any difference except better wet performance and much longer tread life" with the PSS. I asked about future availability for the fronts in either AD08 or PSS and after checking both he said "I don't see either one coming in that size this year."
FWIW I recommend taking it with a grain of salt until you try it. But I wanted to report what he said.
FWIW I recommend taking it with a grain of salt until you try it. But I wanted to report what he said.
Keep in mind I'm not doing anything outside of "daily"-type driving here. Just 80 miles of highway most days. My battery and paint will take much bigger beatings than the tires, and I'm not interested in squeezing every last .01 out of my acceleration times.
What do you think his implication was for "not ideal" for mixing front and back?
What do you think his implication was for "not ideal" for mixing front and back?
Except in extreme mis-match cases where the car becomes unstable at even very low speeds, the time you usually find out about the mis-match is at the limits of adhesion. If that happens during an emergency maneuver it's likely to ensure an accident or make an unavoidable accident worse.
frequencydip
Sig 100 - #52
I call bullocks on tire expansion issues front and rear. Tires never expand ant the same rate even if you have the same 4 on all corners. Tires dont even expand equally left to right although the are more likely to. Front tires take the majority of breaking, that heat from breaking heats the front tires faster than the rear tires. Front tires also warm up faster due to them being turned in a cornering maneuver, they do not follow a strait line and therefore have higher friction. The rear tires have considerable weight on them and they heat up if you accelerate hard especially if you disable traction control. Due to the weight they also heat up due to the side walls compression and re-expansion over the tires contact patch.
When cornering the outside tire takes the brunt of the load making it heat up more than the inside tire. The main reason you want matching tires is so the revolutions the tire makes are the same side to side at normal temperatures thats why you replace them both you dont want a 50% worn tire on the left and a new tire on the right that will lead to different circumferences in tires regardless of heat expansion. This is why you also dont mix tire brands or models side to side. Tires with the same 195/35 sizing from two different manufactures will have different circumferences in addition to different grips. Matching different tires front to back will make no difference to TC in regards to heat expansion if they work cold they will work hot.
At operating temperature all 4 tires will have a different temperature and different level of expansion. Buy tires that fit and don't put cheap tires that have high Treadwear ratings these tire will not perform well for the roadster. I would not recommend any summer tire with a higher than 200 rating.
When cornering the outside tire takes the brunt of the load making it heat up more than the inside tire. The main reason you want matching tires is so the revolutions the tire makes are the same side to side at normal temperatures thats why you replace them both you dont want a 50% worn tire on the left and a new tire on the right that will lead to different circumferences in tires regardless of heat expansion. This is why you also dont mix tire brands or models side to side. Tires with the same 195/35 sizing from two different manufactures will have different circumferences in addition to different grips. Matching different tires front to back will make no difference to TC in regards to heat expansion if they work cold they will work hot.
At operating temperature all 4 tires will have a different temperature and different level of expansion. Buy tires that fit and don't put cheap tires that have high Treadwear ratings these tire will not perform well for the roadster. I would not recommend any summer tire with a higher than 200 rating.
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