WWCD? Wheels/Tires

[RandomTask]

So were finally going to handle our wheel/tire issue. We had been running the ’84 salad shooters w/ some C5 wagon wheels. Were really limited on tire selection. . .

 

Our only design constraint is running a square setup. Looking to buy 2 sets. How budget minded should I be when it comes to this? Here’s the options:

 

1.)    Run ZR1 replica front’s at all 4 corners (17x9.5” 36+); this lets us run 275’s which there are a plethora to choose from, wheels would be ~$110 a piece and tires ~$160 a piece. (Probably get the 615 Azeni’s or Ecsta XS’s (180 treadwear!) )

2.)    Run ZR1 replica REAR’s at all 4 corners (17x11” 50+); this would mandate we run ½” wheel spacers (thoughts on those?), and tire selection would be limited. Probably run the Nitto NT05 315/35/17. Wheels are ~$130 a piece and tires ~$230 a piece (200 treadwear).

3.)    Run actual ZR1 offset rears at all 4 corners (17x11” 36+); doesn’t require a spacer, but run into the same tire issue as option two. Wheels are $230 a piece.

 

 

Thoughts?

[Hi_Im_Will]

Free yourself from ZR1 wheels.  Let's start with the basics:

 

1. What is the car?
   1. Weight?
   2. Downforce/aero?
   3. Power
   4. OE bolt pattern/offset
2. What is the OE tire diameter - are you happy with this?
   1. Are you gearing limited anywhere such that you need to increase top speed by increasing tire size
   2. How much ground clearance do you have?  Is there room to reduce your CG height by running a smaller diameter tire?
3. Are you restricted to a 17" wheel?
4. Is increasing track width an option?
   1. Are you willing to modify fenders
   2. how's your wheel bearing life?
   3. At the tracks you generally race, is it worthwhile to trade off straight line speed for grip?  (daytona: no.  AMP: yes)

Once you're got that all sorted out, start looking at tires.  For racing you generally want a slightly stretched tire for handling predictability, but this will be a bit limited by what's available.  In general:

• 10" wheel
  • 245
  • 255
• 10.5" wheel
  • wider 255s
  • 265
• 11" wheel
  • 275
  • 285
• 12" wheel
  • 285+

Your actual ideal wheel width is dependent on the specs of the particular tire you choose.  The nominal size is a rough guide, the actual OD and actual tread width (not section width) are what matter.  

 

I wouldn't run a pinched tire (actual tread width wider than wheel) unless it has a very short sidewall.  Pinch is generally used for improving ride quality and NVH, and tends to make the car vague at the limit.

 

You'll have to do some iteration loops of figuring out what wheels and tires are actually available to narrow your options down to a few setups.  Spacers are fine, as long as you stay under the 1" points limit and spend the money on some high quality pieces.  

 

It's likely that you'll end up back at the 17x11et36 ZR1 reps with a 255/40R17 Dunlop Direzza ZII*, and maybe a spacer on top of that, but go through the exercise above to see what else is out there (and look at actual specs!!!  The falken 275s are only 9.7" wide, but the dunlop 255 is 10"!!!). I haven't spent a lot of time looking at american car wheels, but there seem to be a lot of really good options in very wide sizes.  And budget is only limited by what you're comfortable spending, but $250/wheel and $200/tire is probably a where people start wondering.

[RandomTask]

!!! Thank you so much! 

 

1.     ’84 Corvette

1.1   2880lbs w/ driver

1.2   No.

1.3   Stock Camaro LT1 - ~285hp.

        1.4 5 x 4.75”

 

2.) Stock salad shooter was a 255/50/16; it sucks for tire selection. Wagon wheels were 245/45/17 and 275/40/18. No.  

2.1)Not gear limited; plenty of gear left.

2.2.) Plenty, probably 5-6”

 

3.) Yes; 17+. Running the C5 brakes limits us.

4.) Yup. Already a pretty wide car, but we can always go wider.

4.1) What fenders? . . .(yes)

4.2) Good.

4.3) VIR so . . .may be?

[ross2004]

We run 4th gen Camaro SS wheels on our 3rd gen, 17x9.5", with 255/40/17 BFG Rival's with great results. You're quite a bit lighter than us, I would expect it would work ok. 

 

C4 sawblades are also pretty easy to find- I believe some years were a 17x9.5" square setup and others had a 8.5" front, so you'll need to check.

Edited May 23, 2017 by ross2004

[Hi_Im_Will]

25 minutes ago, RandomTask said:

!!! Thank you so much! 

 

1.     ’84 Corvette

1.1   2880lbs w/ driver

1.2   No.

1.3   Stock Camaro LT1 - ~285hp.

        1.4 5 x 4.75”

 

2.) Stock salad shooter was a 255/50/16; it sucks for tire selection. Wagon wheels were 245/45/17 and 275/40/18. No.  

2.1)Not gear limited; plenty of gear left.

2.2.) Plenty, probably 5-6”

 

3.) Yes; 17+. Running the C5 brakes limits us.

4.) Yup. Already a pretty wide car, but we can always go wider.

4.1) What fenders? . . .(yes)

4.2) Good.

4.3) VIR so . . .may be?

 

That's a lot of power.  I'm jealous.  At 2880 w/driver and no aero, you may be able to get away with something as small as a 245, but I think 255/40R17 is probably your best bet because the tire selection is so good.  You'll get a bit lower since it's smaller diameter than your old wheels, and should get you a little higher in the revs for the long straights. If you want selection at that size, get a 17x10, and it will work with all the available options.  If you want wide, go 17x11 and run the Direzza ZII* in 255/40R17.  It's bigger than most 275s, and grips just as well as anything not labeled "RE71R" or "Rival S".  The Dunlop on an 11" wheel and will be lower and gripper than the same wheel with the 275 Azenis.  Since you don't care about fenders or wheel bearings, get as low of an offset as possible, run the max spacer, and push those suckers way outboard.  You can even run a 1" adapter instead of spacer to really open up your wheel choices - there's a lot of good stuff in European and Japanese patterns with low offsets available in 17x10.  

 

So, in summary, 17x11et36 ZR1 wheels with the 255/40R17 Dunlop Direzza ZII*  and maybe a spacer sounds like a winner. Just make sure the fenders can be adjusted to still cover the tires.  American Racing Torque Thrust 17x10.5et44 may also be an option with the same tire, but preserves the option to run a cheater tire when you want to burn money quickly. 

[RandomTask]

Umm,  255 on an 11" rim? Even tire rack puts the max rim width at 10". That seems streeeetched. 

[Hi_Im_Will]

6 minutes ago, RandomTask said:

Umm,  255 on an 11" rim? Even tire rack puts the max rim width at 10". That seems streeeetched. 

 

Only the Dunlop.  If you scroll down to the specs on TireRack, you'll notice the Dunlop has a 10" wide tread, while most of the rest of the 255s are around 9".  I wouldn't put a 255 rival on an 11, but the ZII* has dimensions closer to a 275/35R17 than a 255/40R17.

[Bandit]

On 5/23/2017 at 11:45 AM, Hi_Im_Will said:

 

Only the Dunlop.  If you scroll down to the specs on TireRack, you'll notice the Dunlop has a 10" wide tread, while most of the rest of the 255s are around 9".  I wouldn't put a 255 rival on an 11, but the ZII* has dimensions closer to a 275/35R17 than a 255/40R17.

Are the designed like the way old school TA tires? They had a 8 inch max rim width so Goodyear and a Firestone just designed 11 or 12 inch wide tires with sidewalls to fit the wheels.

 

Saying that, if a 255 has more tread on the ground than a 275, it sounds like the manufacturers are getting as loose there as they are with tw ratings.

[Bandit]

On 5/23/2017 at 10:11 AM, ross2004 said:

We run 4th gen Camaro SS wheels on our 3rd gen, 17x9.5", with 255/40/17 BFG Rival's with great results. You're quite a bit lighter than us, I would expect it would work ok. 

 

C4 sawblades are also pretty easy to find- I believe some years were a 17x9.5" square setup and others had a 8.5" front, so you'll need to check.

Sawblades, in 9.5",  are my current wheel of choice for cost and size unless I come across something better.

[JBgotM]

The newer owner of the old firebird we built went to 17x9 snowflakes with 275/40 falkens. With a couple spring rubbers, it has really come alive. The hp and weight is pretty close to yours. He reported that they need some heat and are tough to get up to temperature in cold weather.

 

 

[RandomTask]

^^ Like to hear that. Talked to someone yesterday who recommended the 275/40/17 BFGoodrich Sport Comp 2's on 17 x 11'.s . Just wish they had less positive offset. 

 

[Bandit]

13 hours ago, JBgotM said:

The newer owner of the old firebird we built went to 17x9 snowflakes with 275/40 falkens. With a couple spring rubbers, it has really come alive. The hp and weight is pretty close to yours. He reported that they need some heat and are tough to get up to temperature in cold weather.

 

 

17 inch Snowflakes? 

 

Those Year One or something? I know they came out with N90's, the late Monte SS alum wheel, in a 17.

 

Snowflakes are just right on a 'Bird.

[DRVOLKS]

We went with at WGI with on the Beetle 275/40/17 all 4 wheels and a 9.75 rim  with a rollcenter of 3.5 and bump steering of .010  for 2 inch down and up from ride height.

We had a bad week end on the engine  blowing boost hoses and then a head gasket . but did get a few hot laps on it With TomM and TomT  both drivers said it was the best handling car they ever drove!! TomT did get to 2.32 was running in 4th  the whole track he was just getting ready to push it when it let go. At one point i saw TomT pass 5 cars going in to turn 1 so I feel good on the setup. I felt bad for my team having so many things go wrong its not like I did not spend 2 week checking ever thing over.

Bob Mann

www.DRVOLKS.com

bobtec@comcast.net

 

[Ron_e]

38 minutes ago, DRVOLKS said:

We went with at WGI with on the Beetle 275/40/17 all 4 wheels and a 9.75 rim  with a rollcenter of 3.5 and bump steering of .010  for 2 inch down and up from ride height.

We had a bad week end on the engine  blowing boost hoses and then a head gasket . but did get a few hot laps on it With TomM and TomT  both drivers said it was the best handling car they ever drove!! TomT did get to 2.32 was running in 4th  the whole track he was just getting ready to push it when it let go. At one point i saw TomT pass 5 cars going in to turn 1 so I feel good on the setup. I felt bad for my team having so many things go wrong its not like I did not spend 2 week checking ever thing over.

Bob Mann

www.DRVOLKS.com

bobtec@comcast.net

 

 

Is that a split front bumper?  Those Camaro's sure command a premium doll... Oops, nice design to cover those big front wheels.  Good job.

[JBgotM]

On 5/26/2017 at 11:32 PM, Bandit said:

17 inch Snowflakes? 

 

Those Year One or something? I know they came out with N90's, the late Monte SS alum wheel, in a 17.

 

Snowflakes are just right on a 'Bird.

I think they are the Year One. Would have preferred the lighter weight CTW, but not the higher cost.

https://www.ctw-motorsports.com/

 

You are right though, the snowflakes look really good on that car.