utkinpol

I am kinda puzzled... It was about 85 degrees last weekend so it took its toll too but as today I swapped out tires on a car I see that my rear A6 got pretty well eaten almost to the point where band of vertical lines starts.

you can see on attachments - first picture shows front outside and front tires wear is OK. It was forth auto-x day for these tires and before wear mark was above that thin line above words 'for competition only' and yesterday as you can see it is all gone altogether with letters.

Rear inside wear is OK as it should but rear outside IMHO is eaten up way too low. Tires were at 38psi front, 40psi rear, camber is 2.2 front, 1.9 rear. Rear sway bar is from GT3 at medium setting. I tried it at firmest setting event before and did not like it much - rear was quite unstable. But wear was not as low.

Does this wear signifies that bar is still too stiff or otherwise? What would be the problem here? Car is 997 C2 with stock shocks so far, I will put JIC Cross soon with 8/11kg springs, front sway bar is also stock. How to remedy this problem?

MechanicalEng

If your outher edges are wearing more than normal you might need to add negative camber at the back.

utkinpol

-2 degrees are already there, similar cars with less camber do not show such excessive wear... something else must be wrong.

PedalFaster

Agreed that 2.0 degrees should be enough. Assuming you're sure you've got that much (alignment shop is competent, alignment bolts haven't slipped) -- are you sure your tire pressure gauge is reading correctly? Try comparing it to someone else's gauge to make sure you're not inadvertently running 20 psi or something.

00r101

How much oversteer are you getting? Did you spin the car? If your rear bar is too stiff and you get enough oversteer sliding the outside rear tire could cause what you are seeing. Are both rear tires wearing the same? What's your rear toe like? Personally, if those were front tires I wouldn't think much about it in a camber-challenged car but you have enough rear neg camber to fight that kind of wear.

utkinpol

Both rears are worn in same way. I also suspect rear bar may be stiffer than it should be but it is kinda odd.
I would not say it`s too much oversteer, but I did spin my car couple of times but it did not seem to be because of a bar I was just pushing it above the limit...
Several people I know track their cars with stock bar in front and GT3 bar in rear without any damage to tires and this was a some sort of common knowledge thing to get stiffer rear swaybar... Go figure.

I will try to put it to softest setting and will adjust rear camber to -2.4, may be that will help a bit. I am quite pissed, only 30% of thread is gone on top of those hoosiers and this damage to the walls really sucks. Will need to remount them now, who could expect all that additional hassle... It is really odd to get it on a forth day as car was pretty much on same settings before. Only difference was the temperature - 85 degrees outside and tires were pretty hot. front toe is 0, rear toe is 0.10. Pressure gauge is confirmed correct, I have several of them in the garage to make sure of that.

Mussl Kar

You need to have another shop check your alignment. I'm not sure what the limit for neg camber on the stock car is, but it is not very much. You may need to add camber plates, and that may bump you out of your class. A6s really like -3 camber, and I have never had to re mount them. Even wear right across the tire. Your pressure may need to get a bit higher as well. A bit more pressure will feel different, but will keep the tires cooler.
Re mount them. A PITA for sure as you only have 3 more events left on them. The damage could also be caused by over driving the tires.

utkinpol

I am mostly pissed because I cannot explain to myself why what happened happened. I have this camber setup since mid last year and on 19" tires I never had tire wall eaten up. This season is first ever as I tried A6s and to get such damage on 4th event considering I drive my car more or less similar way at each event just bothers me. Plus if it is because of a stiffer sway bar - why it did not get damaged at previous event - it wasn`t raining back then and bar was set even stiffer. It`s some total BS...

I will speak to my mechanic today as well, I really want to get to the bottom of this. I will put Tarett toe arms on car too, it should allow me to get much more of camber in rear - -2 degrees is a max one can get keeping toe at 0.10, adjustable arms are not camber plates, strictly speaking, but I do not care about classification no more, I just want to get suspension done right. What it did to those tires is definitely not right...

racer

You mention tire pressure was 38F, 40R.. was that cold or hot? Do you start with 38F/40R and bleed down during the day or start low and plan that the heat from 1 or 2 runs will bring them up to pressure?

At first glance they simply look "overdriven".. so either the pressures were off, or your driving has changed (more aggressive perhaps?). Remember, 60% (or more) of your car's weight is sitting on those back wheels. They are under a tremendous amount of forces (braking, cornering, accelerating, sometimes all of those at once )

Are you keeping a log of your settings? It seems as though you are doing (or will be doing) lots of little and big things to adjust the car, but if you aren't keeping track of what is going on, you won't be learning as much as you could.

utkinpol

that pressure was 'hot' of course. cold was about 34f 35r then I adjusted it.
I spoke to my mechanic, he says it was still too much for such a hot day plus he says issue is most likely with springs which are just way too soft for hard cornering. at the end of this month I am installing front GT3 bar to compliment rear one and JIC Cross coils, hope those JICs will not fail on me right away, it was a mistake to buy them of course but I am stuck with them now...

if they will work OK then it should improve my ride tremendously - 15 way adjustment with 8/11kg springs should be way better compared to stock C2 shocks and springs. will see. Looks like if they do not brake during a first week of use then everything should be OK for 2-3 seasons.

As of driving - yes, it was aggressive as I was quite annoyed with fact I could not get below 60sec while most of people were doing 58sec consistently but every time I tried to push car a tiny bit more I was spinning out so best morning time was 60.2, best noon time 60.1 and every time I was pushing a bit more my *** was loosing grip badly and spinning in turns. I just will need to work on this car a bit more most likely as something still does not feel right.

racer

15 way adjustment sounds great.. but you are now going to have 15 ways to screw things up, imho. you were already struggling with your car.. you new it wasn't doing what you wanted (you said it was oversteering/spinning out on you).. what changes did you make during the day? Did you change the rear bar? change tire pressures? change driving style? Did you watch others to see where they looked faster/slower than you? Were they in cars comparable to you or different cars in different classes?

if you weren't already making small adjustments on a car that didn't offer many to make in the first place, how will you now understand what to do with 15 more adjustments.. and thats per corner, do 60 more adjustments? plus now a front bar with 3-4 adj? Sounds like more time adjusting than driving.

I can't speak to your current AX experience, but to me, the KISS (keep it simple, stupid) approach works best. Find a baseline and tweak it. Everytime you drive an AX course, you bring more experience, comfort and ideally speed to the event. You know every event is different, so what worked last time, may not be right the next time.

As a much better AX'er than I has said " to be fast, sometimes it must look slow" and the old "smooth is fast" and a bunch of other junk...

utkinpol

Nah, I know pretty well what I`m doing. I`m just getting surprising results from time to time but it fits into general model.

Car as it is now is already much better than it was stock. As of 15 ways to screw up - I had adjustable koni challenge shocks on a previous car I raced so I do know to some degree what is it I`m doing, with exception of some 997.1 platform specifics which I am still learning. Of course it would be great to run those shocks on dyno prior to install but, well, it is not worth it at this moment.

It is all for fun of the process itself, if I would be following KISS concept I would have to shell out for GT3 RS from the beginning and not even bother myself with any mods.

It is all relative. I am not after ultimate best, I am curious how much goodness I can squeeze out of this specific car. When I`ll be done with it I`ll loose any interest and it will go on sale. But so far it is all fun and games. I just like process of building cars, even more than driving them. It is all quite individual.

sjfehr

Do you have m030 springs?

utkinpol

nope, as I understand car shocks are usa default bone stock. soft. m030 are ROW shocks, stiffer and springs are stiffer. I saw some folks put GT3 springs on m30 shocks which are even stiffier.

I was actualy thinking to get m30 setup but vividracing had last sets of JIC cross coils on a final sale for 19 hundred ad I got them instead. not sure why. now as no one wants to buy them from me I will be forced to put them on my car apparently no big deal, i`ll survive that...

racer

I don't think the 997's have an MO30 option. They either have PASM or not, PASM effectivley replacing M030.