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Old 12-08-2011, 09:42 PM   #1
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Boxster Spec Allows 245/40/17 Square

I just read that the Boxster Spec class is going to allow 245 or 255/40/17 tires on all four corners (square) in additional to the existing staggered (225 or 235/45/17F and 255/40/17R) setup for 2012. The "or" sizes depend on the particular rules of differening sanctioning body's.

Anyone understand the advantages/disadvanages of the square vs staggered setups? 255? That seems like a lot of tire up front and it seems so different from stock that I wonder what the handling characteristics are like?
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Old 12-09-2011, 07:43 AM   #2
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for starters you would be able to 'rotate' tires front to back.
I know from experience going from a 205 to a 225 up front reduced some of the inherent under steer on our boxsters, so that could be a factor...
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Old 12-09-2011, 08:36 AM   #3
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Hi Thomas,
I have run both 255 square and 225/255 staggered since 2009. I hesitate to make any car setup decisions until I see the BSX rules in print though. Here is my take:

All 3 setups will be pretty close in terms of lap times on most tracks.

225/255 is very fast for an experienced driver and I have logged my best TT laps with this.

255 square fits without rubbing on my car. It is fun, you can go deeper into braking zones but it really works the front brakes, is easy to rotate the car, allows 4 wheel rotation to get the most out of a set of tires, allows you to depend on the steering wheel maybe too much instead of your keen right foot. ( the steering wheel is a brake). This setup might be faster on a tight AX course but I have never set my best track laps running square. They average 1-2/10ths off but very close. It might just be the loose spacer behind the wheel.

245/40/17 square looks interesting. This might be a good compromise tire setup. 4 wheel rotation and a bit more contact patch than staggered without the extra weight and wind resistance of 255s. I may run a set next year and test them. It does still allow a novice driver to overuse the steering wheel. This will work the front brakes.
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Old 12-12-2011, 07:52 PM   #4
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We were DQ'd at Thunderhill for running 245 square.. LOL (we didn't care, we were testing for next year)

and would have probably been DQ'd at WSIR a week or so back if we hadn't popped an engine on Sat.

The 245 square is MUCH faster at WSIR. Within a few laps on Sat. we would have qualified 2nd only 2/10ths off no.1 qualifier.

The square setup on 255's or 245's requires a completely different bar setup and completely different camber settings.

We have been running 255 square with PCA club racing for several years now. ALL the track records across the USA have been set on 255 square 888's.. then reset when they went to 255 square RA1's.
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Old 12-14-2011, 05:30 PM   #5
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What wheel specs are using in these square setups?
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Old 12-14-2011, 06:02 PM   #6
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We just buy another few sets of stock 17inch rear wheels~!!
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Old 01-11-2012, 10:46 AM   #7
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Would there be any problem or advantage for running stock 17" rear wheels on the front with 245s on the front and normal 255s on the rear?

I feel like the car pushes too much right now and that a little more tire up front might help. I would not want less tire on the rear as I can overepower the rears now.

This would be for DE events on a Boxster S.
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Old 01-11-2012, 12:13 PM   #8
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Is there any square experience for 18" wheels. There is a little more contact patch there so there maybe less favourable results. I already have 15mm spacers up front. I find this takes the twitchiness out of the steering wheel with the wider track.
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Old 01-11-2012, 12:34 PM   #9
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Quote:
Originally Posted by maj75 View Post
Would there be any problem or advantage for running stock 17" rear wheels on the front with 245s on the front and normal 255s on the rear?

I feel like the car pushes too much right now and that a little more tire up front might help. I would not want less tire on the rear as I can overepower the rears now.

This would be for DE events on a Boxster S.
You could run either 245 or 255s on the front. Running square allows 4 wheel rotation so you can make the most out of your tire budget though. Some fast Boxsters in SoCal run 245/275 on 8.5 & 9.5 wheels to good effect.
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Old 01-11-2012, 12:37 PM   #10
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Originally Posted by jaykay View Post
Is there any square experience for 18" wheels. There is a little more contact patch there so there maybe less favourable results. I already have 15mm spacers up front. I find this takes the twitchiness out of the steering wheel with the wider track.
Yep, forum member SBD rolled his fenders and ran 285/30/18 square. Tons of grip for AX but top speed suffered a bit.
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Old 01-11-2012, 02:45 PM   #11
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I'm running a BoxsterS with stock fenders (no rolling) on 275/18's 888's



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Old 01-12-2012, 05:26 AM   #12
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How in the world do you fit 275's on the front, lot's of negative camber?
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Old 01-12-2012, 06:56 AM   #13
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Quote:
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I'm running a BoxsterS with stock fenders (no rolling) on 275/18's 888's



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Wow what is your steering effort like on slow corners? What wheels and ride height allowed you to fit in the fenders???? Jeeeez.... how many shims do you have in your LCAs
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Old 01-27-2012, 12:26 AM   #14
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boxster motor are a amazing power and engine efficiency great.!
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Old 01-27-2012, 10:40 AM   #15
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who are the moderators of this forum?

The above post is pure spam. Its a spammer checking to see if anyone is watching.

Ban him, ban his IP address, ban his *@bullS_H_I_Tdomain.com

If you need help with banning/filterring.. ask me..



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