Wheels/tires for autocross/track session

[i c e b l u e]

I'm currently looking into wheel/tire combos for a autocross and track day events. What I thought was going to be a simple task, started getting complicated with weight/strength/looks/$ trade-offs. So I wanted to see what people were running. Especially those with who take their cobra to the track and or auto-x events. I currently auto-x and once the car is ready (brakes/suspension/cooling) I will be taking it to track days


Current setup
Front 18/9 +26mm offset chrome AFS (26 lbs?) 275/35/18 BFG G-force T/A
Rear 18/10.5 +29mm offset chrome AFS (30 lbs?) 305/35/18 MT Drag radials
(This setup is heavy and the wider and softer rear tires aren't helping the pushing/under-steer)

First piece of the puzzle (17 or 18)
I am currently looking for 18" wheels to allow for a brake upgrade in the near future (14" baer 6P) unless there is a known 17" combo that will clear them. That would actually be a bonus as it would save $on wheels/tires and weight


to stagger or not to stagger?
I originally was looking at toyo R888's all the way around with a staggered setup 275 up front and 305 in the rear. But the more I read and from my limited auto-x experience a square 275 setup may be beneficial. Or is there anyone running larger that a 275 on the front without rubbing issues? (if so what is your setup)

Price vs weight
I was originally looking with a 300/wheel budget. In that price range I found

Front 18/9 +32mm offset TSW Nurburgring (19.4 lbs) 275/35/18 toyo R888's
Rear 18/10.5 +27mm offset TSW Nurburgring (21.25 lbs) 305/35/18 toyo R888's
http://www.discounttiredirect.com/d...uct/byName.do?tmn=Nurburgring&typ=Car/Minivan

Or if I wanted to save some money 150/wheel AMR has a very similar wheel that is slightly heavier
Front 18/9 +30mm offset AMR (24.7 lbs) 275/35/18 toyo R888's
Rear 18/10 +24mm offset AMR (28 lbs?) 305/35/18 toyo R888's
http://www.americanmuscle.com/dark-stainless-amr-wheels-9904.html

So what are you guys running? Is there a more cost effective wheel I missed? Or a combo that results in cheaper tires? etc

Marcus

 

[Svtmustang01]

Im running 285 square toyo r888. I rolled my fenders in the front and they fit well at my ride height. On the tire options the bridgestone re 11s and the re 71 are great tires. Only reason Im running the toyos is because they came on the used ccws I bought. TSW are midgrade wheels and definitely not a bad option.
Heres a decent picture of my ride height also. If i wanted to lower my car more I would definitely have to add more camber. Im at 2.5 degrees in this picture.

 

[i c e b l u e]

Hey svtmustang01

Thanks for your input I will look into the bridgestones. What size/offset/weight are your ccw's for reference?

 

[Svtmustang01]

18x10 square
20mm offset in front
15mm offset in back
Never threw them on the scale.

 

[tomsgarage]

I have two sets of stock wheels 17x9, when I run open track events I use 275/40-17 Nitto NT-01-great track tire. I have the Cobra R 4 piston Brembo's up front, enough brakes for me.

 

[bubblehead93]

I auto-x pretty heavily... run 17" rims (FR-500s, nothing special 17x9 and 17x11), staggered with NT-01s (275s and 315s)... a lot of great technical discussion out there on pros and cons of staggered versus square... my car holds its own against Skylines and such out here... from an auto-x perspective and running a upper/lower ported eaton is that the stagger helps me get backinto it earlier out of the corners... you can help the understeer a bit with air pressures... some of it depends on your driving technique and style... stagger works for me relative to no stagger... have done both... I have bounced back and forth on upgrading the brakes... personally for auto-x, the 4 piston brembo kit with good pads all the way around is the way to go... braking is not an issue during auto-x events... for open track, something I want to do, but no tracks near me (at least not within 6000 miles)... so my perspective is biased towards auto-x... for the money NT-01s are a great tire...

another great thing to take a look at for the 17 versus 18 question has to do with the technical aspects of how the tire works with more/less sidewall for the same overall diameter... a lot of discussion out there... jmho, cram the best brake you can into a 17" rim package and go from there...

 

[i c e b l u e]

Thanks for the input guys

tomsgarage
did you track your car before the cobra r brakes and run into any issues (boiling, fade, warping) and it seems like you like the R setup but have you had any concerns on long events or tracks that really push them? Its good to know the cobra R's will fit under 17" wheels. I guess when I originaly looked into it the cobra R's they were ~1.4kand still a 13" rotor vs ~2k for a baer setup for 6pots and a 14" rotor. At the time it seemed like a decent return for $700 but it looks like it comes with the penalty of 18" wheels. (still trying to find if any 17"s will clear but its not looking good)

bubblehead93
I agree on brakes not really being a need for auto x. In previous auto-x events I had no trouble locking them up with the stock setup. I have since changed the fluid to hi-temp, switched to hawk pads (mine were nearly out and couldn't swing a brake upgrade yet), I also added cooling ducts. I guess I was just thinking ahead in terms of brakes for track days since KE = 1/2MV^2 and that velocity term will be much higher at the end of the straight on any road course and therefore generate much more heat. So even with the above mentioned upgrades I would be a little worried of temps.

I did some looking into tires and the street NT05 is also a reasonably priced tire with a little more tread life (may help me save money until I figure out what I am doing :rollseyes). Just for a comparison that tire for a staggered setup on 18" wheel is ~$960 a set vs ~$760 on a 17" wheel. If you went to a square setup (all 275's) it would be even cheaper ~$700 and you could rotate them to get some more life out of them. So I am trying to figure out where I lie on cheap vs ultimate performance/cool looking stagger scale:bored:

 

[tomsgarage]

iceblue. your welcome
I ran the original 2 piston PBR front brakes at Carolina Motorsports Park (very technical track, hard on brakes/tires) when the car was completely stock back in 2002. They held up well but rotors and pads were completely wore out at the end of the event. The next event at the same track I had installed the Kenny Brown Brake Duct Kit and they lasted a lot longer, even had front brakes for the drive home. After that I purchased the Cobra R 4 Piston Brembo kit and they have been great since. However I do have pads and rotors for street use and for track use. I use the stock Brembo Rotor and Hawk HP+ pads (front and rear) and they have held up well on tracks such as CMP, VIR, Road Atlanta, Roebling Road and Daytona. You can buy more expensive/better pads and rotors, but the bang for the buck that I get from using the Hawks and plain Brembo rotors keeps my budget in line.

Regarding my square setup for rims and tires. By going this way I can rotate tires front to rear and side to side. Our Cobra's are nose heavy cars and I believe that going to a staggered setup will cause the front tires to push more because of the extra grip from the wider rear tires. This square setup also provides a lower overall cost and longer life for the tire.

The changes I have done to the car since 2002 have always been to get the setup I like (she's almost perfect now) and keep the costs low in order to have funds for more track events.

 

[i c e b l u e]

tomsgarage

On a side note. What can I expect for life on consumables.

Brakes
I guess in my head I was expecting pad changes every 1-2 track events, does this sound about right? I hadn't really thought of the rotors. I guess I was hoping a 14" setup with conservative pads would help prolong them. What about fluid changes?



Tires
With you square setup and being able to rotate them. How many session do you get out of them? or do you have it by heat cycle?

 

[tomsgarage]

iceblue

Hmmmm, it all depends on what type of events you run, but from my experience..

Brakes,
At tracks like CMP or Roebling Road the brakes never really get a chance to cool off so brake cooling is very important for pad and rotor life. Tracks like VIR, Road Atlanta, and Daytona with long straights but higher entry speeds into the corners the brakes have a chance to cool off, but again brake cooling helps with pad and rotor life.
Saying that I usually use up a set of front brake pads a year, rears last about 2 years. Rotors-I have them turned by friends of mine that own a auto repair facility and they take the minimum off to clean/true up the rotor. When I get close to the minimum thickness they become my street rotors and I start fresh with new rotors. Usually the rotors will last 2 years by doing this.

Tires,
Again, it all depends on the tracks that you run-at CMP and Roebling Road you spend more time in the corners generating heat in the tires. At VIR, Road Atlanta and Daytona you spend a lot of time on the straights which minimizes heat build up in the tires. I don't rotate tires at the track but when I get back home I will look at the tires and then swap the left front to the right rear, right front to the left rear, etc... The left front takes a lot of abuse (depending on the track) and by doing this I have been able to maximize tire life and replace them all at the same time. Now as the tires get older, and the more heat cycles they have, they do get hard and slippery...but then I get to practice car control. I just replaced the NT-01 that I bought 2 years ago with another set, great tire for the $

I usually run 3-4 track events a year with NASA-SE. These are 2 day events and I keep track of the miles I run at each event-usually about 150 miles per weekend. I use this as a gauge to replace brakes and tires but I always put the car on jackstands and check pad wear and tires after every event. I also change engine, transmission, differential and brake fluids at the end of every season. I also change her back to street pads/rotors and tires to enjoy on some back roads.

Now another thought, I run in DE-2 or DE-3 groups and go out there to have fun. Am I the fastest car out there....not by a long shot.... I learned a long time ago that while this sport is the 2nd most fun thing I can do in my car (and the older I get it is rapidly becoming the 1st) that to go really fast costs money!! So I decided when I got back into it when i bought this car 13 years ago that I would concentrate on improving the driver first, and improving the car as the driver improved. Now I have a car that is pretty much bullet proof and I have a lot of fun with minimal impact on the budget.

 

[Bigggy]

I've started to open track the cobra this summer and had a really hard time with the brakes (old fluid, cheap pads etc). I'm going to replace all that the next spring and also put back my brake ducts (that I had removed cause I ran the car only in the street). I read all your comments, this is a great help to understand the needs etc, I'm happy to see that brake cooling will help that much.

Post like this are very interesting, keep it up guys ans thanks for sharing the info!

 

[SlowSVT]

For me rim weight is #1 priority. All my sport bikes have magnesium wheels. I know the wheel physics on a motorcycle not quite the same as a car but the difference from the OEM wheels is astounding where you can really feel the impact it has on the dynamics of the suspension and chassis. I have Volk TE37's @ 19 lbs. but they are expensive, The CCW Classics are suppose to be around 22-23 lbs. The GT350R CF wheels weigh 18 lbs. The thing that sucks is most of the mfg's conceal the wheel weight so you have to dig & scrape to get it.

Every time I pick the boat anchor OEM wheels the weight makes me cringe!

Those TSW Nurbergring rims are pretty nice and a steel at $300 if they are as light as you stated.