Track Wheel Setup - Square vs Staggered

[Bigsmoothlee]

17X9 Cup1 rims on all four corners

[Brad Roberts]

Two cars from the shop.. square, so you can see how the 8.5 fits the front (it fits better than it does on the rear) lol

[Brad Roberts]

Dare I show everyone our "15inch" square car? lol

How many people will tell me "you can't do that" lol

[bela928]

please do, I'm having trouble finding an 8 or 9 X15 with the right offset.

Originally Posted by Brad Roberts

Dare I show everyone our "15inch" square car? lol

How many people will tell me "you can't do that" lol

[com3dorm3]

... meant to give feedback a lot earlier. So...
I took the Boxster out to the local track High Plains Raceway on a square setup.
The car felt well balanced. The front was planted and the rear was easy to rotate.
I'm stil using the stock sway bar, so the rear bar is disconnected. Even so, the rear is a bit too tail happy if there is any surface bump under trailbraking. ...for my skill level anyway.
I have some other springs I'll be trying (600lbs/in F and 700R to replace the ~900F and ~1000R)

I was on very old R-S3s an corded two of them by mid day. Having a staggered setup definitely helped then
A couple of guys that race Spec Boxsters were out there and their choice is square.

[stephen wilson]

Are the spec Boxster cars allowed to replace or have adjustable sway bars?

[BrantyB]

Originally Posted by Bigsmoothlee

17X9 Cup1 rims on all four corners

Could you tell me what the offsets are for those rims?

[zvovchik]

just got a 99 boxster, want to run square. everything is stock, best way to try square is disconnect rear sway yes? i want to try toyo ra1. to get ultimate grrrripp hehe.

i have stock sized staggered michelin as/3 now and like them a lot, thinking to run square ra1 for autocross and track next year. any recomendations would be very welcome.

PS
my 1st post btw, just installed EPS eternal fix, only 700miles on new bearing now.
thanks

[thstone]

Originally Posted by zvovchik

just got a 99 boxster, want to run square. everything is stock, best way to try square is disconnect rear sway yes? i want to try toyo ra1. to get ultimate grrrripp hehe.

i have stock sized staggered michelin as/3 now and like them a lot, thinking to run square ra1 for autocross and track next year. any recomendations would be very welcome.

Boxster's are designed with inherent understeer. Most owners increase the front tire width from the stock 205 to 225 to reduce understeer. 235 is even better.

However, if you go the next step and install 255's up front, the car typically goes from natural understeer to natural oversteer (because now the front has a lot more grip). This won't be an issue while driving around town at normal speeds, but crank it into a freeway on-ramp with a set of RA-1's or take it to an autocross and at the limit the rear end is going to be loose.

Thus, most owners who go square install adjustable coilovers, adj drop links, and adj sway bars so the handling can be adjusted back to neutral (or however the owner likes it best).

If you wanted to try going square on the stock suspension, then yes, disconnect the rear sway bar and set front tire pressure slightly lower than the rear tire pressure. The car should still exhibit quite a bit of oversteer so be prepared to react accordingly.

[zvovchik]

Originally Posted by thstone

Boxster's are designed with inherent understeer. Most owners increase the front tire width from the stock 205 to 225 to reduce understeer. 235 is even better.

However, if you go the next step and install 255's up front, the car typically goes from natural understeer to natural oversteer (because now the front has a lot more grip). This won't be an issue while driving around town at normal speeds, but crank it into a freeway on-ramp with a set of RA-1's or take it to an autocross and at the limit the rear end is going to be loose.

Thus, most owners who go square install adjustable coilovers, adj drop links, and adj sway bars so the handling can be adjusted back to neutral (or however the owner likes it best).

If you wanted to try going square on the stock suspension, then yes, disconnect the rear sway bar and set front tire pressure slightly lower than the rear tire pressure. The car should still exhibit quite a bit of oversteer so be prepared to react accordingly.

Adjustable coilovers(pss9 2k $),
adjustable drop links (front/rear Tarret 1k $)
, and adjustable sway bars (gt3 front/Tarret tear 1k$)
And we havent got to lower controll arms and other bits.
Plus my time installing the stuff, sounds like about 4k of dollars and that much closer SPB build. 4k can buy a lot of tires of going staggered for $4k. Oversteers that bad huh if just doing square and no mods.. I do notice that bit of understeer a bit when pushing the car, its not that bad though.
Hmmm you made me think. Seeing that photo of Boxster on three wheels got me waay exited.
Hmm it sounds like ALL IN or nothing hehe

[zvovchik]

Forgot to ask, what tire pressures are we talking about if going squared? Maybe i try put my existing 255 AS/3 up front and install new RA1 in the back for starters. Existing as/3 are fairly new and i live in portland OR, so im trying to have wet weather capability..back to pressures....What would be reccomeded?
Im thinking as/3 fronts would offset the grip with RA1 in the back. Am i tottaly wrong here?
Thanks

[Topless]

Originally Posted by zvovchik

Forgot to ask, what tire pressures are we talking about if going squared? Maybe i try put my existing 255 AS/3 up front and install new RA1 in the back for starters. Existing as/3 are fairly new and i live in portland OR, so im trying to have wet weather capability..back to pressures....What would be reccomeded?
Im thinking as/3 fronts would offset the grip with RA1 in the back. Am i tottaly wrong here?
Thanks

Completely incompatible tires. Your car would push like a pig all day.

Maybe choose some middle ground and mount RE71R on all 4 corners. This is a fast tire that works street or track. Almost as fast as RA-1 but works better on stock suspension. You will still toast the outer shoulders but a better fit than RA-1 tires.

[thstone]

Originally Posted by zvovchik

Im thinking as/3 fronts would offset the grip with RA1 in the back. Am i tottaly wrong here?

Trying to balance the handling with different front and rear tire compounds is the wrong way to go about it. Well, that is unless you have a large selection of tires to choose from and have time to do a lot of testing (which I am assuming you don't).

Here is the standard process to set up a car with one set of tires: Install the same tires on the front and the rear, THEN use the suspension to adjust the handling, THEN use tire pressures to fine tune the handling. And don't forget, the driver may need to adjust their driving technique to get the most out of any given setup.

In this case, the problem is that the stock suspension has no adjustability. The Porsche factory gets around this by doing tons of testing to find the right mix of tires (type and sizes), suspension, and tire pressures that result in the handling that they want. Without adjustable suspension and with only one type/size of tire, you don't have anything left to use for adjustment (except pressure which is not going to move the needle very far).

I've done lots of laps on RA-1's; shaved vs full-tread, heat-cycled vs non-heat cycled, in the dry and in the wet, but I've never mixed them with an all-season street tire.

Best of luck.

[thstone]

Originally Posted by zvovchik

Seeing that photo of Boxster on three wheels got me waay exited.

I think that you mean like this? The photo earlier in this thread shows a Boxster on TWO wheels (most likely after hitting the curbing and bouncing both inside wheels into the air).

It takes the full Spec suspension to get the car to handle like this. And look at the right front, the tire is nice and flat to the track while the wheel is at roughly zero camber (when fully loaded). It needed -3.7 deg camber (static) to be able to achieve that and the only way to get that kind of camber is adj lower control arms.

[Topless]

Originally Posted by zvovchik

just got a 99 boxster, want to run square. everything is stock, best way to try square is disconnect rear sway yes? i want to try toyo ra1. to get ultimate grrrripp hehe.

i have stock sized staggered michelin as/3 now and like them a lot, thinking to run square ra1 for autocross and track next year. any recomendations would be very welcome.

PS
my 1st post btw, just installed EPS eternal fix, only 700miles on new bearing now.
thanks

Welcome to the asylum

FWIW, my 986 ran faster on most tracks with 225/255 stagger. I ran this and 255 square over 8 years with a LOT of comparison data. With the 225/255 setup you don't need a sway change but either staggered or square, you will destroy the RA-1 outer shoulders quickly (1-2 days) unless you get more camber into the car. RA-1 feels best to me with -3 degrees F, -2.5 R.

R-Comp tires= suspension setup changes. GT3 arms and lowering springs are the poor man's track setup.

[steved0x]

Originally Posted by BrantyB

Could you tell me what the offsets are for those rims?

Probably ET55