Wheel and Tire optimization for lowered vehicles

[PfadtRacing]

Recently we've been taking a lot of calls from customers asking us what we suggest for wheel and tire combinations. This is far from an end all be all thread on the subject of wheel fit, but we feel like we've got something positive to contribute to the community.

As a function of our involvement with 3 professional Camaro race teams we have done quite a bit of research lately into what will and wont fit the Camaro chassis. Development with Autohaus Motorsports in Grand Am, Total Performance Racing in World Challenge, and the Carriage House Customs NASA American Iron Camaro has led us to a few observations about wheel and tire choice for both full race teams, and performance street drivers. Keep in mind that the following CAD drawings were modeled after race cars at a race ride height, in this case 88mm. Your mileage may vary with street car use. Cars riding a little higher may be able to fit taller tires without rubbing in some instances.

To begin we've found that for a performance street driver, weekend autocrosser and track day user the best tire size combination tends to be a 275 Front and 295 Rear. We've been mocking up different wheel and tire sizes in our CAD program, and we feel these widths give a good balance of packaging, width and compound selection from major tire manufacturers. More rubber is typically a great idea, when used appropriately in the right application. If it is being used to solely change balance, and not overall grip levels with the right amount of roll resistance, than you really are not gaining anything. The use of 305's seems to be possible even in the fronts with the correct offsets and camber settings, but we feel they are unnecessary with proper suspension and sway bar modifications.



ABOVE: Here is the CAD drawing of the front. This particular drawing illustrates a car with our Pfadt Coilovers installed, setup at a ride height allowing 88mm of total travel. The 10.5 inch rim does have a 285 tire installed, and as you can clearly see there is going to be interference between fender and tire with a rim offset of 22. You can see there isn't a whole lot of space available between the spring perch and the tire, so you cant just run say a 25 offset rim and hope for clearance... there is only so much room to work with under those stock front fenders. With camber plates it may be possible to dial in camber at the top of the strut, and dial out some camber at the bottom to gain some clearance between the tire and strut. Other options without camber plates are to roll the fenders, or run a slightly slimmer front tire. There are plenty of sticky tire options at 275 and with proper suspension tuning it's possible to build a car with incredible grip and balance, without the use of massive fronts.



ABOVE: So here is our situation in the rear. It's looking more promising for the use of wide tires. This drawing is using the exact same wheel and tire size that would not fit in the front, but in the rear only requires a minor fender roll. With a less aggressive 30mm offset you could easily get a 295 in the rear without too much trouble.

As with every other vehicle out there, be sure to select your offsets carefully when choosing your wheels. Hope this helps those who are picking out new wheels and tires for the summer driving months!

[PTS]

Excellent Information!

[Buffnshine]

good read, but looks like a lot of camber for a street car

[JOHNSONROD]

i got the PFADT kit with rear sway and springs. i think you guys call it a stage one kit. of the three suggested setups that came with the kit, i went with the middle caster/camber setup and the car turns great. i have BMR connectors and tunnel brace. i want to get wheels eventually for this car. would you say that 20x9's all around would be a good track setup or 10s in the back 8.5s in the front? im headed to putnam park to wear out the pzeros the first of april. i was planning on getting some all temp tires for my stock wheels and then getting a track wheel/tire setup by fall when we go to VIR with the vette museum. sorry to ramble i was excited to see something form PFADT. love the product.

[PfadtRacing]

Originally Posted by JOHNSONROD

i got the PFADT kit with rear sway and springs. i think you guys call it a stage one kit. of the three suggested setups that came with the kit, i went with the middle caster/camber setup and the car turns great. i have BMR connectors and tunnel brace. i want to get wheels eventually for this car. would you say that 20x9's all around would be a good track setup or 10s in the back 8.5s in the front? im headed to putnam park to wear out the pzeros the first of april. i was planning on getting some all temp tires for my stock wheels and then getting a track wheel/tire setup by fall when we go to VIR with the vette museum. sorry to ramble i was excited to see something form PFADT. love the product.

Hey there! Very sorry this post slipped through the cracks. How was Putnam park? What kind of track day was it that you were running?

We just got back from the Camaro5Fest II so we have the track on our mind! I'll have to double check but I think we are running 10.5s up front and 11's in the rear. We found this combination to work the best for a good race set up on street wheels. This is what we ran all day on the Pfadt Camaro during the Official Track Assault at the Fest. Quick Pic below!




We did the VIR NCM event last year with our C6Z race car. It is a GREAT event and you will have a TON of run.

Thanks for your kind comments! Let us know if there are any more questions you have.

[PfadtRacing]

Better pic of the wheels we ran.

[JOHNSONROD]

thanks for the reply. i knew you guys were busy being the title sponsor of the track day and stuff. ill post a link here to our road track driver group. camaricopa started this up and how cool would it be for us all to have you chime in there. he started it up so we would have a place for road track stuff without having to sort through all the thousand 1/4 mile threads. my track videos are posted in the track day video thread. stop by and check it out.

http://www.camaro5.com/forums/group.php?groupid=244

[Stay Marine]

If the factory offset is 40mm for the rear, is there an optimum offset for 10.5" rims in the back? I'm looking at your stage 3 to go with larger tires front and rear (275 up front on 9's; fat in the back on 10.5s....is 315 out of the park for possible rubbing when lowered. Is there an ideal tire/offset to go with for the rear? Thx (I know squat about offsets)...

[full of days]

Originally Posted by PfadtRacing

We just got back from the Camaro5Fest II so we have the track on our mind! I'll have to double check but I think we are running 10.5s up front and 11's in the rear. We found this combination to work the best for a good race set up on street wheels. This is what we ran all day on the Pfadt Camaro during the Official Track Assault at the Fest. Quick Pic below!


We did the VIR NCM event last year with our C6Z race car. It is a GREAT event and you will have a TON of run.

Thanks for your kind comments! Let us know if there are any more questions you have.

Just read this post and have a few questions about road race setup. My car is running your roadrace coilovers. I'm running 20x10's on all four corners with a custom offset. Do you have a tire reccomendation for this wheel size that will fit best with your coilovers?

Are 285 front & 315 rear tyre a good choice? I'm concerned about tire rub due to the coilover and 10 inch wide wheel size package I'm running.

Thanks!

[PfadtRacing]

Glad to see more people getting busy with track day setups!

If the factory offset is 40mm for the rear, is there an optimum offset for 10.5" rims in the back? I'm looking at your stage 3 to go with larger tires front and rear (275 up front on 9's; fat in the back on 10.5s....is 315 out of the park for possible rubbing when lowered. Is there an ideal tire/offset to go with for the rear? Thx (I know squat about offsets)...

The rear has quite a bit of clearance back there as you can see, but a 315 is a pretty big tire. I would go to a local tire shop and do some test fitting to see exactly what's going to work for your application.

Just read this post and have a few questions about road race setup. My car is running your roadrace coilovers. I'm running 20x10's on all four corners with a custom offset. Do you have a tire reccomendation for this wheel size that will fit best with your coilovers?

Are 285 front & 315 rear tyre a good choice? I'm concerned about tire rub due to the coilover and 10 inch wide wheel size package I'm running.

We are running a 285/35F and 315/30R Toyo R888's on our Camaro with no issues on our coilovers. It's tough to say exactly whether or not you'll rub with your custom offsets, but my feeling is that you're on the right track.

[Mr. Notorious]

Originally Posted by PfadtRacing

We are running a 285/35F and 315/30R Toyo R888's on our Camaro with no issues on our coilovers. It's tough to say exactly whether or not you'll rub with your custom offsets, but my feeling is that you're on the right track.

Do you guys have the notes on the offset for the wheels handy for those tires to fit? I'm looking to do the same stance

[PfadtRacing]

Originally Posted by Mr. Notorious

Do you guys have the notes on the offset for the wheels handy for those tires to fit? I'm looking to do the same stance

So we don't have the information on the offsets for these wheels. You can call up BBS and ask for the offset information on a set of BBS CH-Black wheels for a Camaro in 20". When we ordered ours you only had one offset choice in 20", so they should be able to tell you!

[full of days]

Originally Posted by PfadtRacing

We are running a 285/35F and 315/30R Toyo R888's on our Camaro with no issues on our coilovers. It's tough to say exactly whether or not you'll rub with your custom offsets, but my feeling is that you're on the right track.

A 275/40/20 tire on a 20x10 forgeline rubs on the Pfadt coilover up front FYI --

What size wheel and offset are you running up front to get a 285/35F tire to fit?

Forgeline is building custom billet spacers and lugs to fix the rub with the tire on the coilover. I'm a bit concerned about the fender clearance now that the wheel and tire will be pushed out with the spacer to clear the coilover...