How to PROPERLY select and size TIRES for PERFORMANCE

How to PROPERLY select and size TIRES for PERFORMANCE

by Billy Johnson

The most important part of your car is not the engine, suspension, or brakes. It’s the TIRES!!!  This is because your car can only perform as well as the capability of its tires. I’m often asked which tire is best and what size to buy.  In this article I discuss my methods for choosing and properly sizing the right tires.  I’m not into the “hella-flush” or “stance” scenes so this article is focused towards those who care about the PERFORMANCE of their car, whether on the street or on the track.

Pirelli had the best slogan for a tire company: “Power is nothing without control.” This is true for all forms of driving since it does not matter how much power you have if you can’t put it to the ground, it doesn’t matter how much you spend on a big brake kit if they easily lock up the tires, and your $7,000 coilovers can only deliver the performance that your tires are capable of.  It really does not matter how great and expensive your car is or how much money you’ve put into modifying it if you cheap out on tires; which is the only component on your car that actually touches the road.

Bad Tire Size
I often see really nice cars with a ton of money thrown at it in power upgrades and ‘blingy’ wheels wearing an improperly sized tire or something that is obviously not up to the capabilities of the car.  Most people really do not understand the importance of their tires, not only from a performance standpoint but from a safety standpoint as well.  This includes the age of the tire.
GTLM series Tires
In order to have a better ‘show’, keep costs down, and regulate competition, most racing series use a “spec” tire.  For those series that allow for more than one tire manufacturer, tire wars ensue and millions of dollars are spent in developing tires which often determine the success of a team or car.

Tires are consumable and expensive, but this should not be a justification for crippling the handling of your sports car, sports sedan, or minivan.  Whether you’re trying to break records and win races on the track or simply avoiding an accident on the street, choosing the right tire will often dictate the success of either.

There are 3 main steps that I follow when looking for tires: CHOOSE A TIRE CATEGORY, SIZE THE TIRE, and SELECT A TIRE.  SIZE & SELECT A WHEEL is my fourth and last step when also looking for new wheels.


“What is the car being used for?”

Buying the right tires for your grocery-getting, baby-hauling daily driver in the northeast or Florida (where it rains most days of the week) is going to be a lot different than buying tires for your weekend toy in Southern California that never sees rain.  Determining the importance of dry, wet, snow performance, tire longevity, ride quality, and comfort should be the first step when looking for a tire.

Just like everything in life, choosing the best tire is often a compromise since it’s rare to find a tire that is really good in the rain, quiet and lasts a long time that can perform well in the dry and hold up to extensive track use.  Usually as you increase the dry capability of a tire, you start to suffer wet performance and comfort in terms of noise and ride quality.  However, in recent years a few manufacturers are starting to make tires that are very good in all categories. is a great source of information for everything tire related.  They have numerous customer reviews, independent tests, and are a pleasure to do business with.  They break down tires into 5 main categories, while I added a 6th.  These 5 main categories are further broken down into sub-sections like “Ultra High Performance”, “High Performance”, “Performance”, “Touring”, etc…  I won’t go into detail since I usually pick tires from the top sub-section of every category.  I have arbitrarily listed some examples for each category below:

Bridgestone Blizzak, Michelin Alpin, Continental ContiWinterContact, Pirelli Winter Snowcontol

Michelin Pilot Sport A/S 3, Continental ExtremeContact DWS, P Zero All-Season

Michelin Pilot Super Sport & PS4S, Yokohama AD08R, Hankook R-S3, Dunlop ZII StarSpec, BFG Rival, Bridgestone RE-11, Pirelli P Zero Corsa System, Continental 5 & DW & DW SPORT

4.Streetable Track & Competition:
Michelin Pilot Sport Cup 2, Pirelli Trofeo R, Hankook Ventus TD, Continental ContiForceContact, Nitto NT01, Toyo R888, Yokohama A048

5. D.O.T. –Approved Slick:
Hoosier R7 & A7, BF Goodrich R1, Hankook Ventus Z214

6.Racing Slick:
Yokohama A005, Michelin, Hoosier, Pirelli

*Notice there is no “R-Compound” (“R” = Race Compound) tire definition in the above categories.  “R-comp” is not really well defined other than the vague description of “race-derived rubber” and as a middle ground between street tires and racing slicks.  This nomenclature is used for everything from the treaded NT01 and R888 to the slick A7, R7, and Ventus Z214.  I prefer Tire Rack’s separation of the treaded “R-comps” into the Streetable Track & Competition category while placing tires with only circumferential grooves (like the Hoosier R7 & BFG R1) into the “D.O.T.-approved Slick” category.

Here’s a Top Tip: “Tires are the most important.  A narrower, but better (compound, construction, tread design, etc…) tire will, to a point, generally outperform a wider, inferior tire”.


  1. Nice, but what’s the optimal weight to mm for tire width? I want a good compromise for street/weekend warrior use and looks on my 09 daily driven Scion tC. Don’t wanna take too much of a hit to mpg, but I want more room to soak up hard cornering and, as I said a more aggressive look.

    Stock sizes are 215/45r17 and 225/40r18. I know a 235 will fit, and I’ve seen a couple of 245 and 255 fitments online, but it’s mostly 245 or below. Currently running BFG sport comp 2 a/s tires and like them. Live in Florida and was recommended those for my application. The car is FWD with a manual and 160hp, I intend to run a square setup.

  2. Thanks for pointing out that choosing the right tires will be able to dictate the success of the race and also keep you safe from accidents. I will share this information with a friend of mine since he will be joining races once he gets his car customized. It has really been his goal to do so after being obsessed with a series of movies that focuses on this.

  3. This is probably the best ‘layman’ article on tires I’ve read! Here’s why I’m here. 2018 Mustang GT, stock except exhaust, air box and multiple tunes including E85. Daily driver with track weekends. Stock rims are 18 x 7.5 rolling on Pirelli P Zero Nero P235/50ZR18. I want more grip in the rear. Don’t care to change wheel diameter bc Ford Engineers are smarter than I. Contemplating going to 10″ in rear with MT ET Street SS 285/40R18. Not married to them and am open to any suggestions you may offer. I’m interested in grip and of course a better ET.

    1. Thank you for the kind words, it’s great to hear that feedback (which was the goal). To be honest, I’m not the best source for tire sizing when it comes to drag tires since I do not have firsthand experience testing how wheel widths affect longitudinal grip and launches of drag-specific tires.

  4. Thanks for listing all the details which are of importance for proper tyre selection.
    Yet, I did miss the part explaining the influence of “aspect-ratio”.
    I actually trashed a set of all-weather tyres and damaged my rim, due to driving a bit to fast on a very poor rural road. Consequently, I searched for information regarding rally tyres on the web. Interestingly, the majority of rally tires of Michelin have aspect ratios of 60-65. Yet, these tyres have very stiff side-walls. What is your opinion regarding the influence of aspect ratio?

    In addition, you mentioned that you consider load-index not to be be very useful. Yet, does load index influence the strength and stiffness of the side walls? Consequently, the higher the aspect ratio, the more important load index, especially using poor roads? Appreciate your view/

  5. Mr. Johnson, your article is the most clearly explained writing I’ve found on the matter. Still it is not very clear for me what would happen to my 2019 Toyota Camry, with original 17″ x7.5 original wheels if I change original tire size of 215/55/17 to 235/55/17. My intention is to gain half an inch in underbody clearance, and of course any gain in performance would be wellcome. I appreciate any light you can give me on this matter.

    1. Going from a 215/55 to a 235/55 would give you a tiny bit of ground clearance but would also change the circumference of the tyre, which may throw off your odometer and other systems. I suspect it’s not a good idea, if you want more ground clearance the proper way to do it is to install adjustable coil-over suspension.

  6. Than you for writing this article! It is very informative! What I did miss was information on what would be a balanced mm/Lb for track use. You present a table with multiple vehicles, but do not comment on whether you find those values too high or too low, with the exception of the Elise, that isn’t even on the table. What would be a good range for mm/Lb?

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