01-22-2018, 10:47 AM | #2 | |
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If you use other tires other than oem and as long as you fit the car with Bmw star rated tires the car is still neutral. Understeer occurs only when (1) tires are really cold (2) in the wet on sharp turn Oversteer occurs on power when (1) in the wet on exit of a corner (2) on cold tires Otherwise you would have to be absolutely flying to produce other handling characteristics. |
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01-22-2018, 07:52 PM | #3 | ||
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I'm currently on relatively brand new Yokohama Advan AD08. I have no intention of changing, but would like to know what BMW thinks regardless.
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01-22-2018, 08:41 PM | #4 | |||
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If you are on Yoko's you have already changed the set up of the car and are leaning more than you want and the car is under steering when it is not suppose to and oversteering stupidly... Yoko do not come star rated. Also note the tire sidewall will have a Large star marked on the sidewall (see owner's manual) I recommend: Michelin ps2. - who cares if they are the old design Michelin pss - only the star rated size Continental has a tire as well but I forget (tire rack will help you). Revert back to BMW star rated to restore the handling characteristics of your car. You can tell the shop you bought them from that they have provided you equipment contrary to you owner's manual (look there and you will find star-rated only) Star-rated = stiffer sidewalk, manufacture overall diameter and compound formula specific to Bmw. I have been in your position... which is how I know all the above. |
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01-22-2018, 09:22 PM | #5 |
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Do you have any supporting documentation for all of that?
I’ve never heard any of that before, legitimately curios. The ad08 is a very aggressive tire with a much firmer sidewall and more grip than any Bmw oem tire. Also, the diameter of any 245/35/19 is the same, no matter who makes the tire. |
01-23-2018, 09:57 AM | #7 | |
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Now with that said, I don't think the the star rating will make that big a difference if you use the same tire. My 1M came with star rated tires. The tire shop had the same size Michelin supersports with porsche rating and they are identical. I read about the ratings and they are minuscule changes. For example the Porsche version has to stop a Cayman in the rain in x distance. So they tweak the compound slightly for that. Then bmw says it has to do this. And they do a slight tweak to get the contract. But it is very minute. If you use the same model tire whether star, Mercedes or Porsche they are all close enough. Finally your 1M was tuned with PS2s which had quick turn in but are hard to even find nowadays so you will most likely have to go to other model. In turn in I think the AD08 is closer to PS2 than super sports that have more grip than PS2s but softer turn in. ADO8 is sticker in dry than al of them. Also the 1M corners very flat already and changing from bar to stiffer makes no sense to me. If anything I would soften rear end slightly as it wants to step out. |
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01-23-2018, 10:00 AM | #8 |
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You are correct that star rating is almost insignificant but not completely. Oil ratings are not insignificant if you understand them. If you don't understand them then they seem so. Ignorance is bliss until the foreman tells you you have engine sludge, a bad bearing or some other issue exacerbated by using k mart 30 w because you think those engineers are all idiots and you know more than they do.
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01-23-2018, 10:53 AM | #9 | |
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Ad08 has little in common with a ps2 or pss. It’s a track tire that can be driven on the street. The sidewall is stiffer and the compound is grippier. It’s much better on track. I’ve got several years of track time on all these types of tires as do a lot of members on here I’m sure. |
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01-23-2018, 11:32 AM | #10 | ||
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01-23-2018, 08:07 PM | #11 |
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Black Gold & nachob thanks for the informative dialog. OP, before you think the thread has been completely hijacked note that nachob did suggest a possible tweak to the rear stiffness.
Black Gold interesting that you think of the AD08 as a track tire that can be used on the street. My perception, just perception, is that the Yokohama marketing in Japan is more along the lines of a street tire that can be used on the track. Based on your experience with the tire do you have any concerns with my use which is 99% street? |
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01-23-2018, 09:00 PM | #12 | |
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If you don’t mind the reduced tread wear and road noise, the better steering feel from a stiffer sidewall and more grip to me feels great on the street. I would say the tire is best suited for someone who does a lot of hpde and auto x events and or likes a performance tire on the street. True racing tires like an r comp are a little harder to drive on as the limits are higher and they don’t break away quite as progressively. At least in my experience. An ad08r is a perfect weekend track warrior tire imo. |
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01-24-2018, 10:13 AM | #14 | |
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the stock strut bar is pretty good as is. On the sway bars, the car corners very flat and when pushed will understeer. In an autocross environment with tight turns, an adjustable or thinner bar that can be "softened" for more turn in would help. A hollow bar can help with weight savings, so for me an adjustable hollow bar seems like a real upgrade. I believe Dinan makes a hollow bar but can't recall if it's adjustable. On the track, at high speed, the current bar gives you a margin of safety with some understeer but the car polywags even in a straight line and the rear wants to step out. I would consider a slight softening of the rear, to keep both tires down. Traction is an issue on the 1M. Again, an adjustable bar is your best bet in my humble opinion. Especially if hollow because no matter what, at least you will get savings. Now what I just said applies to stock shocks. If you start to change shocks and springs, that is all interconnected. Recently one of the BMW engineers was quoted as saying that perhaps they went to stiff on the 1M. If you watch Chris Harris' video of M2 and 1M drifting side by side, you will see that the M2 dips slightly more in a corner than the 1M and when drifting the 1m is very flat. The firmness works well on on perfect surfaces but get out of sorts on bumpy ones. Your driving style also matters. A clinical technical driver can do better with a slightly softer setup that has more turn in because they can balance the weight transfer better whereas a Banzai Dive-into-the-corner driver would do better with a firmer setup. After market bolt-on strut bars are mostly for looks, save your money and spend it on a good adjustable sway bar. If you get one, let us know what you find out too. Thank you. |
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01-28-2018, 06:05 PM | #15 | |
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Car started to understeer when fitted with the pss tires. I went to the local BMW dealer and pressed on the sidewalks of the "star" rated pss tires installed on their M2 (same tire size +\-) and the pss were rock solid where my non-star rated pss tires were soft. Swapped out the pss for the original ps2 and back to normal. There is no documents that illustrate what the "star" rated tires are and how they are different. Like it is some huge secrete... losers... In any event, I spoke with a Michelin engineer who explained that the star rated are a different diameter, sidewall stiffness and compound. Stick to star rated... otherwise ...💸💸💸 |
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01-28-2018, 07:11 PM | #16 |
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I’m sorry man but that’s just in accurate
Pressing on the sides of tires means nothing. How do you even know they were inflated to the same psi? And I seriously doubt the car understeer when moving to a newer version of the same tire. Pass from ps2. Star rated means very little and for true performance or track driving there are many better choices including Michelin’s own cup 2 And finally, they are not a different diameter. The diameter is determined from the listed size as in 2xx/xx/xx All brands are the same diameter if they are the same size. |
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