Autocross: Stock tires vs. *real* street tires

[lynx17]

Even though our factory tires feel relatively sticky for a factory-stock tire, I'm curious how they compare to a "real" street tire for autocross (e.g. Azenis RT-615, Ventus R-S2, etc.). Anyone have experience with both on the MS3 they'd like to share?

I ran an event over the weekend on the stockers and ended up 5th of 6 in DS and about 2.5 seconds behind first in the class -- a new Audi TT Quattro rolling on 245-width R-S2. Second and third were a Neon SRT-4 and WRX wagon, both on slicks. Still managed 19th of 91 in pax-adjusted times, which isn't too bad, but I'm itching for a bit more grip (and more experience finding the right line...).

I've run my Jetta with a 225 Ecsta MX, which felt somewhat stickier but a little less responsive on turn-in. It's hard to compare to the MS3, though, since there's such a difference in power and suspension.

 

[udontknowjack]

depend how much u want to spend....Potenza RE-01R are the best street tires for autox steet tires...but they are $236 a pop for the size u need with stocker wheels.....u cant go wrong with RT615 for the price....i dont get kumho mx cuz the are coming out with a new tires in a month or two...hope that help

 

[Yoo Shin]

I hear Kumho has something really nice coming out called "ES" or something like that. Supposed to be the perfect compromise between wet/daily and dry/autox, but of course they all say that (ie Falken RT).

I think the RE050s are a really good tire though not as sticky as the RTs which I ran on my WRX in a 225 size. The RE50s definetly are more responsive and have a better feel when breaking away. Though the RTs feel like they have a much stiffer sidewall, this didn't neccesary translate to better response. In fact, once heat cycled 3-4x, the RTs get a bit unpredictable and go from grip to break farely quickly with little communication. I understand that the WRX is quite a bit different from the MS3 and might not be the best comparison.

Another popular new tire is the Derizza (sp) Star Spec.

 

[LER42]

I switched to the Direzza Star Spec's a few months ago from the OEM Bridgestones. The Dunlops are noticeably grippier, but not by a huge amount. And they're still not r-compounds.

I wouldn't junk the OEMs for new "street" tires until you've worn 'em out, which won't take long, anyway.

 

[gtlaw]

I wouldn't get azenis unless the size your getting is reinforced. trust me the difference is night, and day the non reinforced ones don't feel any better than most other performance tires
http://www.falkentire.com/rt615_sizes.html

 

[mordant80]

I'm about to find out how the stockers compare to the kuhmo ecsta mx. They may about to be replaced by kuhmo for something better, but dang are they cheap on tirerack right now ($112). Just ordered them today so I'll know the difference soon. Last autocross tore up the stockers I had on the front to the point some of the tread has actually ripped up on one of them.

Hey LER42, you ever get a chance to run your stockers in the rain at the autox? Mine felt MUCH grippier in that rainy event than the dry ones... weird.

 

[udontknowjack]

I'm about to find out how the stockers compare to the kuhmo ecsta mx. They may about to be replaced by kuhmo for something better, but dang are they cheap on tirerack right now ($112). Just ordered them today so I'll know the difference soon. Last autocross tore up the stockers I had on the front to the point some of the tread has actually ripped up on one of them.

Hey LER42, you ever get a chance to run your stockers in the rain at the autox? Mine felt MUCH grippier in that rainy event than the dry ones... weird.

most will choose rt615 over the mx....oh well...enjoy

 

[mordant80]

most will choose rt615 over the mx....oh well...enjoy

Well, those were my 1st choice since they're listed for $121 on edgeracing, BUT they're sold out and tire rack doesn't carry them. I really didn't want to go any higher than that price wise because tires weren't in my budget, otherwise I would have got the Ventus R-S2's. This was kind of a surprise have to have a couple new tires thing, ya know? But regaurdless, the Ecsta MX might not quite be up there with the other two mentioned, but they're not slouches either.

 

[ericrapp]

Even though our factory tires feel relatively sticky for a factory-stock tire, I'm curious how they compare to a "real" street tire for autocross (e.g. Azenis RT-615, Ventus R-S2, etc.). Anyone have experience with both on the MS3 they'd like to share?

I ran an event over the weekend on the stockers and ended up 5th of 6 in DS and about 2.5 seconds behind first in the class -- a new Audi TT Quattro rolling on 245-width R-S2. Second and third were a Neon SRT-4 and WRX wagon, both on slicks. Still managed 19th of 91 in pax-adjusted times, which isn't too bad, but I'm itching for a bit more grip (and more experience finding the right line...).

I've run my Jetta with a 225 Ecsta MX, which felt somewhat stickier but a little less responsive on turn-in. It's hard to compare to the MS3, though, since there's such a difference in power and suspension.

Do you have the sway bar upgrade? This is still about tires. honest

 

[///M Compact]

I spent 3 days at Putnam Park last week and the RE050s worked fine in the rain and overcast conditions we had on the first day. However, once the sun came out and ambient temperatures neared 90F the tires were only good for about 15 minutes of track time- after that point they started to overheat. Most of the other instructors were running R compound tires and I think I'll be forced to do the same.

 

[lynx17]

No sway bar upgrades. Both vehicles are still just as they came off the factory floor, other than wear items and the tires.

 

[ericrapp]

Add the bars it might help to reduce the understeer and get you on throttle sooner. Oh yes you still need some tires, the stockers are a compromise. With the stickier tire the steering will be a bit softer but overall grip will be improved. 2 cents worth. Will the bars affect your class rating that you run?

 

[lynx17]

I'm probably not going to do anything with the sway bars -- I'd like to stay in D Stock with the MS3. The alignment, on the other hand, could use a little work to help rotation since it still has the factory toe in out back. Still playing with with tire pressure, too (45 front, 40ish rear felt ok, but not great).

I just wanted to hear peoples' impressions of the stock tires, since everyone already brags on all the others.

 

[LER42]

Hey LER42, you ever get a chance to run your stockers in the rain at the autox? Mine felt MUCH grippier in that rainy event than the dry ones... weird.

Yup, a couple of times. I didn't think they were grippier in the wet, but they were pretty good. The Dunlops are better, tho'.

 

[Mid_Life_Crisis]

Still playing with with tire pressure, too (45 front, 40ish rear felt ok, but not great).

I just wanted to hear peoples' impressions of the stock tires, since everyone already brags on all the others.

That sounds like an awful lot of pressure for the stock tires. Wouldn't that much lift the shoulders off the road and reduce your contact area? I have reinforced tires that are supposed to run typically 6 psi higher than standard tires and they only call for 41/39 at manufacturer specs for an MS3.

 

[ericrapp]

I'm probably not going to do anything with the sway bars -- I'd like to stay in D Stock with the MS3. The alignment, on the other hand, could use a little work to help rotation since it still has the factory toe in out back. Still playing with with tire pressure, too (45 front, 40ish rear felt ok, but not great).

I just wanted to hear peoples' impressions of the stock tires, since everyone already brags on all the others.

my impression of the stock tires was not so good. At 34f/32r they felt over pressurized. after a tire upgrade and a wider wheel 8" the limit in lateral traction has bumped up several notches. I am sure you will be happy with a softer dedicated track tire.

 

[lynx17]

I tried lowering the pressure in the front tires to around 41psi at one point, but I was rolling over onto the shoulders too much for my taste. From what I've seen, 45psi up front isn't uncommon on cars where camber can't be adjusted. I've seen others run up to 50psi, just not on an MS3.

Keep in mind this is at an autocross, not normal street driving.

 

[drledford93]

Raise the pressure of the rear tires. This will essentially lessen the grip in the rear and allow the car to rotate better.

Also, get an alignment. Go for ~1/8" toe out front and 0-1/8" toe out in the rear, depending on how much you can or want to catch the car. The more toe out you have in the rear will cause the car to be twitchy and oversteering. I've used this set up on numerous FWD and AWD cars to great success in autox. This small amount of toe will not chew up tires too much, but will greatly improve handling characteristics, especially at autox's.

Another thing that will improve your times is just seat time. Practice, practice, practice. Ask the better guys in your area to watch you, give you input, and if possible, ride with you. Attend a driving school as well. They're all worth it.

FWIW, I would run up to 50 lbs (in R compound tires) up front on the car in my profile. You can do it, just watch where the scrub line is. That's the best way to tell if the tire is suffering or not.

Daniel

 

[joe149]

Pressure for stock tires in autox

I'll be headed out to my first autox in my MS3 with Bridgestone Potenza RE015As tomorrow, and I figured I'd set them to 42/38 (f/r) BEFORE I drive to the autox. Then I'll check the pressure gain from the drive, and shoot for 45/40 or so hot after a run. I've had a lot of track experience in another (RWD) car, and with stock tires we always tried to hit 40/44 hot (Michelin Pilot street tires). We could always rely on 8lbs pressure gain from 'cold' (ambient temp less than 75 degrees) after a track run, so would set it to 32/36 the night before. I figure in autox it won't gain as much - not enough time on track, so I'll start closer to optimum hot.

As for increasing pressure to REDUCE traction (for better rotation), in my experience it's tricky. Every tire has its optimum pressure, and either increasing from that OR decreasing from that will reduce traction. Trick is finding that sweet spot...
Joe

 

[slprrex]

I have now destroyed my factory 'stones' after about 4-5 solo events, 17K miles and they seemed to do fine. There are 5 MS3 that run in the Houston region with differing setups and classes. The guy I have been running with uses R comps which I will hopefully soon get into. Guys in the other classes (X, STU) are running Direzza Star Specs with good results. I am personally going to buy the Direzzas after reading the reviews and seeing the results.

Tire pressures differ on the driver and conditions. I have been running 39r/36f cold and 40r/37f when the tires heat up. Moving the temps depending on how the car reacts in certain sections of the course. More pressure in the rear will help you rotate, but you need to be aggressive enough to get the initial movement started.

I have personally had what I consider good results with limited SCCA experience. The last event I was third to two guys running slicks (on some bald ASS tires). Can't wait to try it out on some better tires (especially the R comps).

Hope that helps.