Hi,

I am looking to put RE11s for auto-x on my stock rims, so, would it be better to keep at 265mm for auto-x or go wider? And if wider - how much wider?

Have anyone tried to mount 285mm tires on stock 10" wide 18" rims?
Or is it wiser not to exceed 275mm? Tirerack guide says 285 can go on 9.5-11" wide rims. But stock Porsche size on 10" wide rims is 265. What gives?

PS. Also welcome to hear about other brand alternatives considering it is exclusively for auto-x events which is 15 miles away from my house.

 

I run with nitto nt01 275 in the rears and they work great.

 

275/40 or 275/35?

So you think 285 will not fit properly?

 

Also speaking about NT01 tires - I assume they are not usable on street at all?

 

Yes NT01's are useable on the street...Toyo RA1 and R888 are DOT street tires too.

I use 18" wheels for the track...9x18 and 12x18 with either of these size tires:

Front
245-40-18
255-35-18

Rear
305-35-18
315-30-18

If you are useing stock width 18" C2 rims these sizes will not work but keep in mind it is usually better to stretch the sidewall than use a wider tire than recomended.

There are charts to recomended rim widths on the Nitto and Toyo tires website.

 

I run 315/30/18 in the rear on the track, and if you really want to get a ton of grip use a Hoosier A6 for Autox, and a Hoosier R6 for the track. A lot more grip then R Comps in the dry, I wouldn't use them in the wet!

Enjoy it, these cars are a lot of fun when doing autox or track days.

 

The 911's biggest problem in autocrossing is understeer...major bad understeer at 2nd gear speeds. I would rather make a "square" set-up if possible (it isn't). By that I mean get the largest front tires that you can and leave the rear alone. You'll be glad the first time you fly into a chicago box or decreasing turn and you think that your steering wheel is not connected to the front tires! Also, not all SCCA classes will allow you to mess around with tire widths beyond the stock values. Re-11s are great BTW!

 

Yep, I do plan to use stock rims as I have `em already. so, I have 8" and 10" and from what I see for fronts - I can go with NT01 as front 245/40ZR18 and rear 275/40ZR18, right?
Also if I understand right 285/40 and 295/40 options for 10" rims do not exist, there is only 295/35ZR18 which has minimal rim width 10", would it be recommended to use together with 245/40ZR18 on front or should both front and rear be at /40?

 

So then based on this I would assume ideal combo would be 245/40 front and 275/40 rear?

 

Be careful with what tires you select, as it was pointed out to me that they may only help you by a half second but move you to a class where the average is a lot more then a half second faster.

 

No, it is not the issue here. Issue is that single day at auto-x reduced my PS2s by 4mm at least and I would rather burn $220 tires than $500 ones. It is for next year...

As of performance - just as expected I sucked pretty bad - just cannot get it together in this 911 at all. All reflexes are off. Just looked at results on NCR site - my instructor drove my car in 69.5sec - just to compare he had best time across Porsches in his race modded car - 65sec, so my best time was 79sec with average in 81sec. So it does not matter now what tires are there, it is not a factor yet nor as anything else.

I just want to wear something cheaper for next year season and will keep PS2 for street use only on their 19" rims. Or may be will simply put back 18" rims with those winter PA2 tires and will burn them down at auto-x as I think it is stupid to keep those tires forever - I will highly unlikely even drive on them much in winter anyway, they are practically new, 2K miles on them at most. Not sure what to do with them, why seller got them is a mystery for me. His reasoning was to prevent rims from damage as roads where quite bad in Providence and he was told that Pilot Alpines have almost same traction as Pilot Sports.

 

I would try to keep the rear a little loose if possible. If you look at the way the national solo winning GT3 was driven, the car always had a slip angle on the rear. (not a powerslide or tank slapper!) You want to be able to trail brake as much as you can. The 911 does not like to do this at low speeds. It goes into a death plow pretty easily. The last thing you want to do is put fatty tires on the back. If you are doing some PCA stuff, they will try to make a course that works for the 911 and it would be a bit faster than SCCA. The 911 can be frustrating at low speeds and requires lots and lots of patience on turn in. This is the reason why the boxster/cayman beats up on the 997 at most autoXs...they simply have a lower polar moment of intertia and more weight on the front tires.
As an aside, may I recommend the SoloPro autocross school and also Evolution School is great too! The folks who teach there are the "who's who" of SCCA solo. Look up the some of the instructors (Tim Aro is great) and students and they have some awesome results. A guy in one of the classes I took, won his national title two years after taking Evo extreme and 1&2 classes!

 

utkinpol, have you had your car aligned yet? With stock suspension the best negitive camber you can get upfront is aroind -1. If you have stock suspension I would recomend:

FRONT
-1 camber
.02 degress toe

Rear
-1.5 no more than this
.14 degress of toe

The R-Comp tires you are looking at actually require -2 degrees or more for the best wear but I have tracked many years with stock suspension and it all worked out. With the toe spec I gave you your street tires will wear much much longer.

 

Yes that will work. For AutoX having the biggest rear like I am running for the track is not necessary.

 

That is a great question, unfortunately I cannot say anything in that regard. When I got new rims I asked if it requires re-alignment and was told - no. I will keep this information, thanks!