AutoX Tires

[satyajitmenon]

Well ladies n germs, it's time for yet another tire thread. AutoX season is going to start soon and I need tires for my car ('02 BMW 330i). The Falken all-seasons on the car are ok for daily driver duty. But no friggin way I'd use them on the track. Even in spirited daily driving on less than perfect surfaces, I find they're a bit slippery.

I ran Dunlop ZIIs on my Miata last year. They were awesome for the autox. Great grip even when cold, which is particularly useful for the 1st lap/run. Took very little time to heat up. I did find that the tire pressure differential between cold & hot/warm tires on the ZIIs was quite significant. Most tires, I find a difference of about 2-3 psi. On the ZIIs, I found that it went up 4-5 psi once warmed up. Which is why I usually had to drop tire pressure before my last run.

So while the ZIIs are an obvious choice for me, I am open to alternatives. Especially since there appear to be several good ones out there, in the same price ballpark.

Here are my current options in 235/45R17 (for a 7.5" rim)

Dunlop Direzza ZII
BF Goodrich Rivals (in 225s, no 235s)
Hankook RS3s
Bridgestone RE11As

I've also found some other options at TireRack like the Kumho Ecsta XS and Yokohama Advan Neova AD08. But their UTQG rating puts them out of contention for me (need minimum of 200 UTQG).

Anyone here try the tires I've mentioned above? Any other non obvious choices I should be looking at? I saw that DiscountTire has BF Goodrich T/A KDWs. I thought those were discontinued.

 

[phucheneh]

7.5" seems awfully narrow for a Bimmer. You sure that's the stock wheel and tire size?

You don't seem to clarify whether you're talking about dedicated track tires or not. Do you have two sets of wheels and swap for track days?

If not, I think acquiring a spare set may yield the most fun-per-dollar.

Really strong, really lightweight wheels, made specifically for your car (hubcentric without the need for rings, proper offset)...not cheap. Generic, decent-looking wheels (often knockoffs of the popular designs) that will require the rings- not expensive. Probably still lighter than factory wheels, and more likely to fail on the road (giant pot holes and such) than on the track.

The point is that for a minimal expenditure (somewhere in the 100-200 a wheel area), you can have a spare set of decent-enough wheels that will allow you to use VERY sticky tires and have them last quite a while, while keeping competent all-seasons for the rest of the time. Which will last longer, ride better, give you better wet traction...lotta positives. I would look at some cheapie track wheels as an investment that you will at laest come close to breaking even on. Consider the consequences of damaging your factory wheels or blowing a $200+ tire, and you might even be able to call it 'profit' in a sense.

The stickiest tires I know of that are true DOT-approved (not just 'look we cut a groove in this slick LOL') are the Direzza ZII's. The next notch up, which Tirerack seems to claim as 'track only' are the Toyo Proxes R888. Not sure if the 'track' label is a technical thing or if Tirerack is just saying 'don't drive these on the road and them come back complaining to us.' I mean, considering that the aforementioned drag slicks with some tiny grooves are legal for street use, I don't see the issue.

I was reading about the R888's a lot on one of the Mustang forums, I think. Guys with 600-700hp Cobras were stuffing 295's or larger underneath their cars and claiming they were not breaking loose. I think they managed maybe 5k miles a set. That sounds horrible, but if used you autocross only, they'd last a long time. And your Bimmer would be absolutely glued to the pavement.

edit: KDW's are not in the same league. Nor are the Bridgestones. Unsure about the Hankooks and know nothing about the other BFG's.

 

[phucheneh]

Tirerack is not the best place for wheels, but they're worth a look...
http://www.tirerack.com/wheels/resu...lse&filterNew=All&filterWeight=All&sort=Price

Out of boredom, I was browsing the selection that claims compatibility with your car...oh dear lord, I beg of you...do it old-school. :awe:

http://www.tirerack.com/wheels/Whee...lse&filterNew=All&filterWeight=All&sort=Price

Your car is just a bit too new for that style...think they used similar wheels on some of the 90's cars. But it gives me a boner to think of those as track wheels.

 

[satyajitmenon]

7.5" seems awfully narrow for a Bimmer. You sure that's the stock wheel and tire size?

Yeah. That's the stock wheel size for a square set of Style 68 wheels (OEM).

You don't seem to clarify whether you're talking about dedicated track tires or not. Do you have two sets of wheels and swap for track days?

I've thought about getting a 2nd set of rims so I can run a dedicated track set. But with my Miata, I found I didn't really need a dedicated track set. The ZIIs did pretty good for daily driver duty in Florida. Since I also have a truck and a motorcycle, 12k miles a year across all 3 means my ZIIs would have lasted ages. And I'd rather put the money for a 2nd set of rims towards sway bars.

Plus, nothing beats being able to drive to the track and not have to bother with swapping wheels.

I was reading about the R888's a lot on one of the Mustang forums, I think. Guys with 600-700hp Cobras were stuffing 295's or larger underneath their cars and claiming they were not breaking loose. I think they managed maybe 5k miles a set. That sounds horrible, but if used you autocross only, they'd last a long time. And your Bimmer would be absolutely glued to the pavement.

Hmm. I'd like a set of R888s. Only problem is they're UTQG 100. So not within SCCA street tire spec. And at that point, I could even go for Hoosier A6s.

 

[shabby]

And at that point, I could even go for Hoosier A6s.

Might as well...

 

[satyajitmenon]

Well, ended up getting the ZIIs.

Still early days, but even with less than 100 miles on them, feels like night and day compared to the Falken all seasons.

 

[xSkyDrAx]

How long does the ZIIs last for you? I've been reading that they're great but only last about 10k miles.

 

[satyajitmenon]

How long does the ZIIs last for you? I've been reading that they're great but only last about 10k miles.

Had them on my Miata for a year. Ran the ZIIs on it for daily driver duty as well as AutoX for a season. Put on about 6k miles, and while they did grain a bit, they had plenty of tread left. Personally think they could have hit 15k easy.

With 200 treadwear, I wouldn't be surprised if they only lasted 10k under heavy use. Sounds pretty poor, but it's hard to expect more from a tire that is little more than competition spec with some tread.


Check back with me at the end of the season and I'll let you know how they look after 10k+ miles.

 

[satyajitmenon]

Well, 3 AutoX events and 3000 miles later, the tires are still in great shape.

Obligatory AutoX vid from my last event

https://youtu.be/861SbSOrnmA

I did hear that the current design of ZIIs are being stopped, and that a new one will be out around Nov/Dec this year. Bit surprised considering that this version only came out last year.

 

[satyajitmenon]

Rotated the tires a few weeks ago.

6 AutoX events and 5k miles. Still going strong.

http://youtu.be/3lJtQgGK8hg

 

[ballmode]

Star specs

 

[thomsbrain]

Star specs

They haven't made those for a year or two now. And actually, the replacement ZII is already being phased out.

However, the ZII Star Spec is coming at some point.

The fastest auto-x tire at this point is going to be a toss-up between the RS3 Version 2 and the ZII (if you can find them still). The original RS3 was by far the fastest auto-x and track tire, being very comparable to the Nitto NT-01 R comp when fresh, but there are early indications that the version 2 is more like the ZII: a one-run wonder before it overheats and goes off. That's unfortunate, because it means there really aren't ANY street/track tires that can handle a 20 min track session.

 

[jlee]

I <3 my Star Specs. Hopefully the next generation comes out by the time I need tires again (or maybe I'll just go to R888's in the back, since my fronts will likely last a while yet).

 

[satyajitmenon]

They haven't made those for a year or two now. And actually, the replacement ZII is already being phased out.

However, the ZII Star Spec is coming at some point.

The fastest auto-x tire at this point is going to be a toss-up between the RS3 Version 2 and the ZII (if you can find them still). The original RS3 was by far the fastest auto-x and track tire, being very comparable to the Nitto NT-01 R comp when fresh, but there are early indications that the version 2 is more like the ZII: a one-run wonder before it overheats and goes off. That's unfortunate, because it means there really aren't ANY street/track tires that can handle a 20 min track session.

Hmm. The only time I've come across ZIIs showing signs of overheating is when running 2 drivers at an event, without enough cool down time between runs. Otherwise, I've seen enough anecdotal evidence in my local club that the ZIIs manage heat just fine.

The RS3s are still the go-to tires for the AutoX, based on popularity. And if the new version warms up as fast as the ZIIs, then I think they'll be a great buy. Especially since they appear to be cheaper than ZIIs right now.

 

[JCH13]

Hmm. The only time I've come across ZIIs showing signs of overheating is when running 2 drivers at an event, without enough cool down time between runs. Otherwise, I've seen enough anecdotal evidence in my local club that the ZIIs manage heat just fine.

The RS3s are still the go-to tires for the AutoX, based on popularity. And if the new version warms up as fast as the ZIIs, then I think they'll be a great buy. Especially since they appear to be cheaper than ZIIs right now.

A single autox run is a very small amount of heat input compared to the track driving that thomsbrain is talking about. The original StarSpecs are/were great on the track, personally having used them for ~2hr stints, so it can be done with a street tire.

I autox on RS3s, and I'm reasonably competitive with awd cars with way more horse-ponies and more expensive tires than mine. They like a wider wheel than what I have them mounted on though. I would suggest getting a slight stretch on whatever tire is used for autox.

 

[thomsbrain]

A single autox run is a very small amount of heat input compared to the track driving that thomsbrain is talking about. The original StarSpecs are/were great on the track, personally having used them for ~2hr stints, so it can be done with a street tire.

I autox on RS3s, and I'm reasonably competitive with awd cars with way more horse-ponies and more expensive tires than mine. They like a wider wheel than what I have them mounted on though. I would suggest getting a slight stretch on whatever tire is used for autox.

Yeah, autox is pretty easy on tires from a heat perspective. Although my understanding is the S2000 crowd need to spray down the Dunlops between runs on hot days.

I've found the Star Specs to go greasy pretty quickly with the S2000 on track, but it's a heavier and more powerful car than the Miata. They don't become undriveable or anything, but they do fall off the pace after a lap or two.

No denying Dunlop's major advantage in feel and responsiveness, though.

 

[JCH13]

My experience with them on a track was in a MK2 MR2. So, a bit porkier than a Miata, but less so than an S2K. About 140hp and 2400-2500lbs.

I do see people spraying ZI/ZII at autox events... but the faster people aren't doing that. I think that some people can over-drive the tires out of their happy place and overheat them, through no fault of the tire.