245's all around for AX?

[Sammy]

It's almost that time of year when I start prepping for the autocross season. In looking at last years tires it is definitely time for new ones. I am going back and forth about using 245's all the way around (I have 8.5" wide front wheels) versus 245's up front and 275's in the rear. I have been using Victoracers and the fronts have worn out significantly on the outside edges (the rest of the tire is definitely worse than the rear tire wear). I am not willing to adjust the alignment for a competition setup as I would like my daily driver tires to last. Does anyone have any thoughts about the two different setups? I've heard the 245's all the way around should help balance out the understeer which I believe is causing the fronts to wear out a little faster; however, I sure would like to try the increased grip of the wider tires (this could be me being goofy about wider is better).

I had been using 225's in the front and 255's in the rear and felt I had a pretty good balance; however, the wear on the front has me thinking that maybe I am pushing the front a little too hard? I also noticed that in carousel style turns that I have a very hard time getting the car to rotate, instead I push like crazy until I induce oversteer with the throttle and this correction only lasts for a second or two.

Help???

[renzop]

I think you are on the right track with non-staggered widths for AX. But I would pump up the volume a bit. If you are on 18" in a 987 then think about 285/30/18 Hoosier A6s. The Kumho 18s are just too wide and heavy. On 17" then 275/40/17 Hoosier A6 or a 275/40/17 Kumho v710. Either way 245s are pretty puny IMHO.

Regards,
Alan

[Benny986]

245s all around has been talked about a lot. there are a lot of guys that like it. there is a guy named kenny jones that knows his stuff, you can find him on babblers and on the golden gate pca site.

for me, i am running 255/265 on 9.5s all around. i bet i could have gone with a widder wheel, but thats ok.

the first event for me isn't for another couple of months. i will miss the first event of the season cause I will be at the national tour with the SCCA in SD in our VW.

as far as alignment, what are your rear toe settings? an ever so slight change in that will help, and will not hurt st. tire wear that much either. I have found that a little change makes a big difference in the rear.

[Topless]

It depends on the courses you run and your driving style. The symptoms you describe may clean up with 245's. Graeme (Highlander) holds multiple SCCA National championships and runs 245's all around to good effect. You may want to give your alignment another look. I think Hoosiers run /wear best with lots of neg. camber. I am running 225/255 17 with no wear issues street or track. I find myself running faster times in cars and Karts with just a touch of threshold understeer on full throttle track out. It reminds me to drive the smoothest line.

[racer_d]

I ran a 225/275 18 combo and wished I had gone to 245s all around. For me, I like a car to rotate and with the 225/275 combo, it just didn't happen. I won't say if 245s are faster, but they do feel more fun. 245s all around will help reduce understeer, but realize that the Boxster left the factory desgined to understeer - especially with the 205 stock fronts (plus, understeer is safer and limits lawsuits)...

If you are committed to a "stock suspension" then you will always chew up the outside edges of the fronts. R comps need at least 2-5 degrees of negative camber and the stock set up only allows about -1.8 at most (unless your car was in a collision )

So, an advantage to 245s all around would be to spread that wear evenly around the car by rotating wheel positions.. and then flip tires on the rims as well.

[silver arrow]

Does anyone have the offset of the 18x7.5", 18x9?

[Sammy]

Originally Posted by Topless

It depends on the courses you run and your driving style. The symptoms you describe may clean up with 245's. Graeme (Highlander) holds multiple SCCA National championships and runs 245's all around to good effect. You may want to give your alignment another look. I think Hoosiers run /wear best with lots of neg. camber. I am running 225/255 17 with no wear issues street or track. I find myself running faster times in cars and Karts with just a touch of threshold understeer on full throttle track out. It reminds me to drive the smoothest line.

I think I may stick with the 245/275 setup since the only problem I really have is the carousels (skid pad). I have spun my car numerous times and appreciate the grip and speed that I get going through slaloms and other higher speed corners that understeer is virtually non-existant. I am installing the lower stress bars on the rear and hope this will take a little of the understeer out.

[John V]

I run 245/35/18 fronts and 285/30/18 rears (V710s) on stock-sized wheels. With the right alignment you won't be complaining about understeer, that much is certain. I ended up adding a GT3 front bar to the car to manage the oversteer.

We don't have issues with our stock suspension and chewing up front tires. The car is actually pretty easy on tires. We have gotten around a hundred runs out of a set of front V710s. Hoosiers are less tolerant, but they are a couple pounds lighter per corner. It's a tradeoff.

[silver arrow]

What were the optional wheel sizes from the factory on a 2000 Boxster? I'm looking to get R comps for my Boxster soon and want to stay with 17" inch wheels, but they aren't very wide. Was hoping to get some big rubber. Being classed in AS for the base 2.7 Boxster is bull. I was 2 sec. off the pace on well worn Bridgestone RE750's (treadwear rating 340 :dance: ) against S2000's and STi's on R-comps.

Not convinced of the larger bar in the front, but does anyone know the part numbers for the Koni DA inserts for a Boxster and if the 030 springs are considered a factory option or dealer installed option?

If autocross in the Boxster today. Very long gearing compared to my 05 STi. Down shifted to 1st quite a bit, though that may have been due to lower cornering speeds because of the Fred Flinstone RE750's?

Where is the best place for Boxster autocross information on the web?

[insite]

available tire options were:

205 / 255 on 17x7", 17x8.5"
225 / 265 on 18x7.5", 18x9"
225 / 265 on 18x8", 18x10"

M030 is a factory installed option. larger bars front / rear help a LOT; too large in rear will get you wheel spin on tight exits. don't personally know anyone who's done koni inserts, so no clue on the part numbers there. get an aggressive alignment pronto.

great info on the boxster racing board here:

http://boxcar-racing.com/forum/index.php?board=1.0

[John V]

Originally Posted by insite

available tire options were:

205 / 255 on 17x7", 17x8.5"
225 / 265 on 18x7.5", 18x9"
225 / 265 on 18x8", 18x10"

M030 is a factory installed option. larger bars front / rear help a LOT; too large in rear will get you wheel spin on tight exits. don't personally know anyone who's done koni inserts, so no clue on the part numbers there. get an aggressive alignment pronto.

great info on the boxster racing board here:

http://boxcar-racing.com/forum/index.php?board=1.0

18x8 / 18x10 were not available stock on Boxsters. Some dealers may have installed them, but they were not factory available. Your only wheel choices in terms of STOCK wheels are the first two insite listed above.

Koni does not make inserts for the 986 Boxster.

John

[insite]

Originally Posted by John V

18x8 / 18x10 were not available stock on Boxsters.

ah; thx. they were listed in the '00 manual & i figured they were an available option.

[John V]

Originally Posted by insite

ah; thx. they were listed in the '00 manual & i figured they were an available option.

They're listed in the manual for the purpose of identifying the hollow spoke 18 x 8 / 18 x 10 versus the 'turbo look' 18 x 7.5 / 18 x 9. But interestingly the size they list won't even fit on a boxster (18 x 10 et 65) without spacers. They make no mention of it being an option.