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Old 12-23-2013, 12:17 PM   #1
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2008 Boxster S Track Tires

I am trying to buy track tires for a 2008 Boxster S to put on the original rims. Original tires are 265/40/18 and 235/40/18

I am doing track days and I am still leraning but I am having a hard time finding track tires that are the correct size.

I wanted to use Toyo RA-1's but couldn't find the right size,

I found some BF Godrich g-force R1 either 225/40 or 245/40 for the front and 265/35 for the back but wasn't sure if these sizes would work.

Any advice would be appreciated.

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Old 12-23-2013, 12:32 PM   #2
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I have minimal 987 track experience, but it is a slow day on the forum, so I will say I don't foresee any problems with either size other than best front size for the specific type racing you plan.
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Old 12-23-2013, 12:40 PM   #3
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Do you trailer the car to the event or drive back and forth?

If you drive to the event, look into tires like Michelin Sport Cups, or Yoko AD08. You need a road worthy (and legal) tire with some track worthyness.
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Old 12-23-2013, 01:32 PM   #4
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225/265 will fit but make sure you have done the necessary suspension prep first. Soft R-Compound tires need 2-3 degrees minimum negative camber or they will destroy themselves in about 3 hrs of track time on stock suspension. $1200 Poof! Ask me how I know this.
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Old 12-23-2013, 04:00 PM   #5
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As Topless said, unless you have the suspension setup (my Boxster Spec car has -3.5 deg) and the driving skills to make use of an R-compound tire, I'd suggest using a sticky street tire; you'll get more laps out of it and it will be more progressive and give some warning at the limit. Most R-compound tires grip fine right up until they don't, and this tends to happen without much warning.

Furthermore, the Toyo RA-1 is really a rain race tire and as such, it needs to be shaved to 4/32" if you're going to run it in the dry. Yes, this is shaving off HALF of the tread, which means half the life (welcome to the reality of track costs, my friend). If you run them unshaved (full tread depth), they will wiggle, squirm, and slide all over the place until they wear down.

If you're hard over about using a Toyo R-compound tire, then get the R888. It doesn't need to be shaved, has excellent handling characteristics, and you can run it down to the chord without too much drop-off in grip/speed. The most bang for the buck in R-compound tires is the Nitto NT-01; great grip, long lasting, and little drop-off until they are worn to the chord.

To find a great street tire that will work well on the track, do a search for your tire sizes on Tire Rack and then sort by UTQG (upper left box). Look for a tire that has a UTQG less than 240 or so.

I just took a quick look and there are several great tires listed in your stock size: Bridgestone Potenza RE-11, Yokohama Neova AD08, and Michelin Pilot Sport PS2.

Here is a link to that search: http://www.tirerack.com/tires/TireSearchResults.jsp?filtering=true&frontWidth=225/&frontRatio=45&frontDiameter=18&rearWidth=265/&rearRatio=40&rearDiameter=18&wtpackage=false
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Last edited by thstone; 12-23-2013 at 04:06 PM.
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Old 12-23-2013, 04:58 PM   #6
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another thread with multiple opinions

Here's a link to a past thread with multiple opinions concerning track tires:

Heat Cycling for DE Track Tires

I've been extremely pleased with the performance increase of combining Nitto NT-01 tires on 17" stock rims and M030 sway bars. I had the tires heat-cycled and they lasted a DE season on a largely stock '01 986 S. You need to increase the tire pressure in the front to equal that of the back, and you need to pay very close attention to tire pressures at the track. I tend to drive to the track and 36 psi, drop to 30, and try to keep them under 38 all day. Any higher and they get slippery, which invokes the ABS more, which heats up the brakes, etc etc.
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Old 12-23-2013, 05:15 PM   #7
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If you haven't done any camber modifications, then you can run close to a "square" set-up front to rear to reduce the understeer tendency.

On Cayman rims, which are 18" x 8" front / 18" x 9" rear, I would run something like a 245 front / 265 rear combo. Dunlop ZII, Goodrich Rival, Bridgestone RE-11a, Hankook RS-3 are all good choices that can be driven on the street if the temperature is above 40F or so. NT-01's are good and very friendly track tire, but probably not much if any better than these 140- 200 treadwear "Extreme Summer" tires.

If you have optimized the front camber with camber plates or GT3 control arms then it is a different story: you need front to rear stagger to take care of the major difference in front to rear loading. Something like a 245 front / 285 rear is appropriate with the proper size wheels.

As 'Stone suggested, you need to do some research on tirerack.com. Pay attention to the following:

1- Each tire has a recommended wheel width range. You should try to stay in this range, though sometimes it can be exceeded slightly (1/2" or so).

2- In general, the tread width should not exceed the wheel width by more than 1/2" to maybe 1" depending on the application.

3- For PASM equipped cars (your 2008 could be one), the front to rear diameter should be similar to stock, which puts the rear at about 1/2" larger diameter than the front from what I recall. Otherwise, it can fool the computer. look around over at Planet-9 for advice on this. Otherwse, I like running the same OD front and rear.

4- Pay attention to gearing changes with tire diameter. A smaller tire OD will improve acceleration off turns, but may max out revs at other places on course.

5- For optimum performance, in selecting tires, you need to predict what temperature range you will be running in. Even for "street" tires, there is a huge operating range difference between an RS-3 (loves 90+ F ambient), and a Rival (rather have 70 F ambient). Study Tire Rack data, cruise the SCCA forums, and choose your weapon wisely.

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Last edited by LAP1DOUG; 12-23-2013 at 05:21 PM.
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