Mark Dreyer

I've gone through front tires in consecutive DE weekends. Last weekend I corded the driver/front at Roebling and this weekend the passenger/front turfed out at Sebring. The tires only had a few laps on them prior to these past two weekend DE's.

My alignment was setup with by a track guru prior to this past weekend, so that's not the issue. Also I start at 29psi in the tires and get up to 35 hot.

I've been running 17 inch wheels which limit me to a 205 front. I've picked up a set of 18's from a track friend, so I'm hoping that the narrow tire is the major cause of the accelerated wear and that the wider patch of rubber on the road at future events will extend the tire life.

Is it typical to only get a couple weekends out of the tires when you are pushing things pretty good around the track? When I say pushing things good one example is that I was reticent to give passes to GT3's on the back straight since invariably I'd be riding their bumper at considerably slower speed than I could carry normally through 17. This little Boxster is absolutely amazing in the corners, and I still don't have all the suspension work done on it I plan to do!

BTW I'm running Hoosier R6's.

M758

There is a reason most don't recommend R6's for DE...

VERBOTN

understand the cording at RRR due to all the right-handers but at Sebring ??? I have not experienced that type of wear , how much front camber are you running?

Mark Dreyer

I'm running as much camber as Jim at Porsche of Orlando could dial into it. I don't have the numbers right off hand. I'm thinking that this problem will resolve when I go to the 18 inch wheels.

Mark Dreyer

Could you expand on this thought?

Dave DE

If your car suspension has not been modified, then the amount of front camber that can be achieved is fairly small, probably around -1. This is not optimal for track use. You will need camber plates or lower control arms to get up in the 2.5-3.0 range you need for better tire life.

paradisenb

Mark, this is not normal. I tracked a Boxster S for a year and it was very easy on tires. Very nuetral front to rear. Got to be something else that is wrong. I don't think 18" wheels are the final solution to your problem. Dig deeper. Shocks?

M758

I can't afford to run Hoosiers as they wear too fast.

One thing that happens on soft to moderatly sprung street cars is that due to a combination of body roll and limited camber you can dail in you get excessive outside shoulder wear. This made worse really stick tires like Hooisers which don't last that long under ideal circumstances.

2 weekend from Race rubber when used on the same track in same positions on the car is quite normal. I can get much more from RA-1's on my 944 spec, but that car has optimized camber settings and suspension settings to make the best use of the tires. Plust after each day a rotate the tires since each corner of the car uses the same wheel and tire size. This helps even up the wear so that all 4 wear at a similar rate. The other thing is the RA-1 is much tougher longer lasting tire than the hooiser. I simply cannot afford to run hoosier in my race car and that is one big reason I run in a spec class.

Running hoosiers in DE is like using $100 bills to light your cigar. In DE you have nobody to beat so you don't need that least second or two of lap times. There are other R-tires that will last much longer and still provide the same sure footed grip albiet at slight less apex speed. However in DE who needs 10/10th in the first place.

Mark Dreyer

I just checked and my alignment has -1.25 and -1.31 R & L camber in front and -2.79 and -3.05 on R&L rear.

I have the PSS9 suspension on the car. I have delegated the settings on those to the mechanics, one of whom runs Sebring himself. I need to get a bit more knowledgeable on that also. What is the consensus on the ideal settings for the PSS9 for Sebring, the track I run most of the time?

The feel of the Hoosiers is intoxicating. I'd love to keep using them. I don't mind buying them every handful of events but can't afford to only get 2 DE's.

I know there are further suspension mods that can be done to the Boxster just from hearing track talk and forum talk. However I am not knowledgeable enough to know if those further mods will allow me to get more negative camber in order to have longer tire life? I presume so.

analogmike

I would get outside edge wear prematurely with 225s on 7s but I think you are running 205s, so the tire should fit your wheels fine.

Try tightening up your rear swaybar or loosening the front and see if you can still drive the car, you may have the car set up for understeer but have gotten used to it, and it's killing the front tires.

sbelles

It could also be that you are just over driving the fronts and pushing through a lot of corners. It's pretty easy to do at both RR and Sebring.

what kind of pressures do you run? Are you running a stock sway bar?

Edit: ^ Mike beat me to it.

racer

You are at NEG 1.2 front.. and you need to be at NEG 2.5 or more to really make the tires (r comps or hoosiers) work right. You will continue to wear out the outside shoulders because of this. It is also possible that your driving style (or overdriving? or preference for understeer) are exagerating the wear as well.

I would also run more front tire pressure.. With RA1s, my boxster felt best running 33-34 front, 34-33-32 (cold) rear. 29psi front, the stock pressure, is just too soft imho and it also ensures understeer in regular street use. And if thats your cold pressure, how long is it taking to get to hot? you could be hurting the tires while you spend time warming them up.

205s are also a bit small imho. 225 would help the car turn better (I had 18s with 225 front and 275 rear) and the rear end just never got loose. Running a smaller rear might help too.. say 225F, 245 rear? or 245s all around? (of note, I prefer my cars balance to be a bit tail happy vs an understeering pig)

Mark Dreyer

So what do I need to add to my suspension such that I can increase the camber up front? It was my recollection that the alignment guy put as much negative camber as he could into my car as it is now. The sale of my house is going to happen in a couple months and then I'll have some play money some of which I want to use to get the suspension on this car as track potent as possible.

Mark Dreyer

I am using a stock sway bar.

I came across this link in my forum reading. Is this a recommended setup and will it get me to where I need to be in terms of the negative camber desired:

http://tpcracing.com/products/986987...-2-Suspension/

utkinpol

you need to decide what is it you are going to do first of all, define a budget, an organization you want to run with and then based on that define your setup.

if all you want to do is to run PCA DE events and that is it - then imho none of that even matters - as the only single person you compete with at DE is yourself. car slides off course based on same physics no matter what tires you got on it.
rebuilding car is quite a delicate topic. AX SCCA car is one thing, racing NASA car is a bit of a different thing, if you do not care at all what do you want to run and just want to get something done - best approach is to make friends with a good local racing shop and ask for an advice.

direct answer to your question - first set of 997 suspension mods is a set of front 996 GT3 LCAs (camber), front fork arms (caster) and rear toe arms (better toe angle stability and to allow more rear camber maintaining 0.10 toe - with stock one you are liited to -2 degrees). for more or less complete set of initial suspension mods - look at 996 spec cars:
http://www.tarett.com/items/996-997-...996-detail.htm

if you do not have good local shop to give you advice - call tarett.

Again, I would be quite careful with what you do and why as if yo do not know what is it you need to change and where it brings you may lead to unexpected surprises. I would only go down that path if you have run stock classes and you have a definite feel that you do not want that.

Ps. my browser apparently lost saved links to spec boxster pages - but I bet you know where they are.