$Hoosier A6's - ouch!

Keith Quistorff · **Posted:** Fri Sep 24, 2010 9:46 am

Given the cost of 18" Rcomps on my ZHP, for past autocross seasons I bought used A6's and V710's and had pretty good luck with them. This season I decided to finally bite the bullet and buy a brand new set of A6's, thanks to a Hoosier discount certificate one of our club members graciously gave to me (thanks, M!). With the discount, the price for a set of four A6's shipped to my door was $1125. I had them mounted and ran them at our April, May, and June points events (at Danville, Sanford, and Greenville), then had the fronts flipped before running the July points event at Danville. (Due to concerns about destroying A6's quickly on the concrete at Laurinburg, I ran an old set of V710's for both the March and August events at Laurinburg.) After those 4 events (18 laps) on the new A6's, I had all four tires remounted with the best tires up front and best edge on the outside of each wheel and ran them at TSCC's TrialCross in Danville last Sunday, which included 6 long (106 sec. avg.) laps. I noticed after my 4th lap that my right front and right rear were starting to show cord. After the final/6th lap, my left rear also starting showing cord:

Given the known issues with A6's on the front of camber-challenged stock class cars, it's not surprising to see them cord along the outside edge like this, but cording THIS soon was a huge surprise - these tires had just 22 autocross laps - which was 23 minutes total run time. Including mounting costs, these tires cost me $60 per lap!

I ran a couple sets of used A6's on the same car in past seasons and got nearly twice the autocross mileage out of them, the only difference was size - the used ones were 245/35/18, new ones were 255/35/18.

I know Chuck Branscomb ran into similar issues with 245/35/18 A6s on his ZHP when he was running stock front sway bar, but until now they seemed to hold up okay on my ZHP with a very large front sway bar and high pressure (45 psi front).

I requested a call back from Jeff at Hoosier to discuss this early this week but haven't heard back.

Have any of you seen or heard of similar experiences and/or have any idea why this new set of A6's corded so quickly?

Steven Carter · **Posted:** Fri Sep 24, 2010 10:22 am

$60 per lap is :shock:

Keith,
Sorry they wore out so quickly. That would make me very disappointed to run through $$$ tires that fast. I don't know why this happened--seems like an aberration-- but there is an easy fix....welcome to Tire Class!

Keith Vail · **Posted:** Fri Sep 24, 2010 10:42 am

Keith, this is unfortunately what you run into with the Hoosiers and seeing that you bought the 255/35/18's just tells me what I had heard. That size has premature cording issues for some reason, even on RX8's and other cars that are easy on tires. I corded a pair of Hoosiers in 40 runs on the front of the S2000 back in May and I had -2 degrees of camber. In 07 I corded a pair of 245/35/18 A6's in 27 runs on the Crossfire and they had been flipped.

My suggestion is to call Hoosier and talk to Jeff Speer. Tell him what pressures you ran and that you have flipped them and rotated them and they still corded that quickly. They might offer to help you out some way or another. Their customer service is awesome!

Matt McGrain · **Posted:** Fri Sep 24, 2010 4:00 pm

Man that stinks Keith. This thread is like a touch a deja vu compared with Chuck's thread a few seasons ago. Be sure to update this if anything positive comes from the correspondence with Hoosier.

I'm afraid my Si is the same way.

With the mac struts and lack of camber (O'Maley jokingly told me at a Dixie event that it looked like positive camber on the front wheels- which I actually though prior) I'm a little out of luck for running the purple next year. The V710's are nice but I'd like to be able to get at least 40 runs out of the faster A6's, which I don't think is happening with my car either.

I chatted with the only Si owner (w/ codriver) brave enough to travel to Nationals this year and he told me that between he and his co-driver they got 19 runs out of a fresh set of 245-40-17 A6's and swapped wheels front to back after day one. Not encouraging... :cry:

I know the big event courses are super grippy and sometimes faster, but still, 19 runs?

Looks like V710's again for me next year. I never thought I'd buy an autocross car based on it's tire wear, but next time that may be the case.

Good luck!

DickRasmussen · **Posted:** Fri Sep 24, 2010 5:25 pm

I know it isn't what most of you really want or could do especially if open track is important, but for your information a Mod car (such as CM, FM) is extremely easy on tire wear. They typically never "cord" out. Time and/or heat cycles separate FAST from not so fast and then slow. Just another thing to keep in mind if/when such a car starts to get on your "potentially doable wish list".

Tires are much less expensive also compared to big car A6's, etc.

FYI my best crosstrial time was a 96 flat . . . and I am very rusty. :wink:

Aaron Buckley · **Posted:** Fri Sep 24, 2010 6:26 pm

Keith Quistorff wrote:

After those 4 events (18 laps) on the new A6's, I had all four tires remounted with the best tires up front and best edge on the outside of each wheel and ran them at TSCC's TrialCross in Danville last Sunday, which included 6 long (106 sec. avg.) laps. I noticed after my 4th lap that my right front and right rear were starting to show cord. After the final/6th lap, my left rear also starting showing cord:

Keith, do you spray your tires between runs? 6 runs of 106 seconds is a lot of heat (considering it's probably double the average autocross run), which combined with the hard edge wear from the ZHP and a loose car at the event, I can't say I'm completely surprised.

With the Corvette, we moved from a 325/30/19 rear tire to a 315/30/19 for better gearing, we corded each rear tire on the edge in less than 35 runs. This was mainly due to a really loose car.

I only ran 285/30/18 A6's on the RX-8 at Nationals 2006, but otherwise we ran 245/30/18 V710's with zero wear issues. - AB

Les Davis · **Joined:** Fri Aug 29, 2003 2:04 pm **Posts:** 2059

Lots of static camber and double wishbone camber gain ftw! Both the Miata and the vette are super easy on tires. Like Dick's formula car, V710s heat cycle to the point of being useless before they cord and A6s last 100+ runs and will cord the inside edge rather than the outside.

Chuck Branscomb · **Posted:** Sat Sep 25, 2010 8:01 am

Keith,

I can't believe it's been four years since my A6 rant (after the '06 NCAC). However, obviously nothing you experienced is considered out of the ordinary as far as I can tell. I did put the larger front bar on the car for '07 along with switching to R1s. Given we were just running club events, that switch to R1s made a lot of sense. The first set of BFG R1s lasted 140+ runs versus the 16,18 or whatever it was on the A6s. On a 40 second course, we were likely giving up 0.3-0.5 seconds to A6s from what I recall from mag comparison tests.

Jeff was very helpful four years back. At the time, it was somewhat of a shock to them (supposedly) that the tires would cord that quickly.

I told him that I suspected the design of the carcass in the edge to sidewall region needed attention given the poor response to loading on that outer section of the tire. My back of the envelope mech eng analysis would have me strongly looking at the tread face to sidewall interface of the tire as it seems clear these tires sort of roll off the tread face onto that diagonal edge that forms very quickly. I envisioned this dynamic situation where once you reach a given level of loading versus direction (wheel camber angle vs pavement), the tire sort of "pops over" onto that initially worn edge creating a huge stress concentration as the load/unit area soars. That initial rounded treadface to sidewall interface disappears after about 300 seconds of autocross usage and forms that diagonal edge where the cords end up showing so early.

If there was any serious competition between tire makers where longevity was a requirement, issues like these would have been addressed long ago. Many stock class cars destroy A6s on that outer edge, but the market hasn't required anything different. The serious competitors just fork over the $1200/set for each event (else they risk not being competitive) so each event starts anew. So as it stands, Hoosier sells that same "2006" edition tire now almost 5 years since it came out.

Back in '06 Jeff sent me two new A6s and had me ship mine back to them for analysis. I doubt they will be as accommodating today, but it's worth a shot.

Chuck Branscomb · **Posted:** Sat Sep 25, 2010 8:08 am

Looking further at your pictures, your cording didn't happen completely at the interface I was referring to above and where mine had the issue. It looks like given the large section width of the 255 A6 (i.e. it has a 275 A6 width) coupled with the small sidewall, your tires sort of bunched up on the edge and the major loading occurred along that interface and even further inward. It looks like the expected outcome of a tire that wide on an 8" wheel on a camber challenged installation. Perhaps if I had continued using mine below longer, they would have ended up looking the same.

Here's a pic of the 245/35 cording I experienced for comparison:

Kevin Allen · **Joined:** Thu Aug 28, 2003 6:42 pm **Posts:** 3479

Meanwhile, my STi has been using Dunlop Z1 Star Specs and stock camber adjustments, and being driven by me for several thousand miles, including many drift runs at autox events and on back roads in Johnston County. Around halfway through the tread depth, and nowhere near the cords anywhere.

I wish I had your tire budget - which is exactly what a lot of uninformed people have been saying to me. :lol:

Graham Jagger · **Joined:** Fri Aug 29, 2003 12:53 am **Posts:** 1718

I'll just post the link as this image is fairly large.

http://s242.photobucket.com/albums/ff25 ... g&newest=1

That is an A6 that corded on the right inside edge. Totally opposite of what you guys are seeing. This was track, not AX. They do not take well to running the outside edges regardless of position. That one corded right in the bevel the tires get from being used. It was down to the steel belt, below the nylon.

These tires had already been flipped across the rims. One of them the guy did not flip correctly and I think that was the tire. You most certainly need to flip them a lot. For AX I wouldn't bother balancing them and flip them regularly.

All I can figure on mine is that there are so much more right hand turns on track and the inside edge is getting dragged across the track. It's happened to me once before with Nitto R2s also.

Given how violent the turning is in AX and lack of camber. You need to be looking at the top/shoulder and keeping them as even as possible. The only Hoosiers I've seen that are not as sensitive to this are their GrandAm/VRL tires. They were completely dead long before the edges would cord. Compound is way too hard for AX though.

Good luck. I hope you can get Hoosier to give you some kind of break on replacing them. I know your pain on the 18's. I'm running fatter ones and they cost a lot. But they are like crack after street tires.

Karl Shultz · **Posted:** Sat Sep 25, 2010 2:48 pm

Keith, if you want to stick with Hoosiers, you might consider getting R6s instead. Chris and I used a new set of R6s at the Solo Pro school in August. They were new when we got there, and were just starting to show a whisper of cord on the outside shoulders of the fronts. We put what I'm guessing is the equivalent of 140 autocross runs on the car in the span of two days. Runs back to back; two laps around a 40 or so second course, five or so times per session, three sessions per day. And there were some instructor passes done in the car, too.

It took less time than I would have guessed to get enough heat into them at the beginning of a session. On a hot day (90*F or so), they were working great by about fifteen seconds into the first run, maybe less than that. They didn't fall off much at all, and we didn't spray them.

FWIW, we get approximately 80 runs out of a set of A6s on my car, assuming I flip the fronts at ~40. So, the R6s wore nearly twice as well as A6s do, and did so while being used in a much more severe use case.

Chuck Frank · **Posted:** Sat Sep 25, 2010 3:48 pm

I'm certainly not an expert, and have never watched you drive, but I'd venture a guess that you might be driving in too deep/overdriving the corners, and/or be running too little air pressure. I have never found Danville or Sanford to be very hard on tires. I typically get > 100 runs on A6s on the Solstice without showing cord. We rotate the tires front to back every event and flip them >40-45 runs. We run 40-45# all around depending on surface, increase pressure for sticky surface, bleed down to that pressure after every run until pressure stabilizes then leave it alone. Since GMS heat tests found that A6s don't lose any significant grip in the heat ranges generated in AX we don't water the tires unless running in extreme temps and/or rapid back to back runs.

Karl Shultz · **Posted:** Sat Sep 25, 2010 6:38 pm

But Chuck, don't forget, you guys have a car with adjustable camber and double wishbones. Keith's BMW has neither of those things. Think like a stock class Mini.

JamesShort · **Posted:** Sat Sep 25, 2010 7:23 pm

Karl Shultz wrote:

But Chuck, don't forget, you guys have a car with adjustable camber and double wishbones. Keith's BMW has neither of those things. Think like a stock class Mini.

Plus a lot of pounds

.

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