By far one of the most confusing things you can buy for your car is tires. This is an area that performance car drivers probably don’t spend enough time and money on, strangely enough, and there are many misconceptions about them that need busting.
First and foremost, when it comes to tires and brakes…spend money! Under no circumstances should you penny pinch here, because as Michelin put it “Everything is riding on your tires”. They literally govern how fast your car accelerates, corners, BRAKES, rides and handles. Because of this, it is critical that you get the right tire for your driving style, be it passive or aggressive. You must also take into consideration your driving environment…if you are driving in all weather conditions you probably want two or even three sets of tires for the various seasons you’ll encounter. If you live in a soaking area, you’ll probably want a tire that’s good in the rain. You get the idea. As it is right now, my ae86 has four sets of wheels with tires and my Platz has two.
There are lots of places online to learn about tires. Research online forums to see what other people with your car like for tires, and find out what sizes they’re using. Most tire retail sites have polling station results online where people who buy tires from them can rate the tires they bought for all to see. It’s important that you read the reviews with a grain of salt and an idea as to what you’re looking for, because what you want and what they want are two different things…but at least this will get you close. It’s key that you are honest with yourself during this process and don’t just buy the biggest, baddest tire you can find. Getting R compounds when you’re driving a couple hundred kilometers on the highway in the rain every week just isn’t a good idea. By the same token, if you’re a canyon racer buying super-hard economy tires will get you killed.
There are several factors you’re going to have to consider in the process of buying tires. The first is price. While I do council that good tires have no price too high, your wallet will probably disagree with me. There’s only so much money you can afford to spend, so having a realistic budget is important. Depending on size, dropping five hundred to a thousand dollars for quality rubber wouldn’t make me flinch. By the same token, my father would never spend that much in ten years. I would suggest that this is a reasonable budget for a quality high performance tire for 15” and smaller wheels. 17” tires could fall anywhere between five hundred and fifteen hundred dollars depending on brand and style.
Sizing is the next critical thing. Every manufacturer makes a great performance tire, but they may not make it in your size. Don’t worry about this too much…but try to stick to the original rotating diameter unless you know what you’re getting into by changing it. Don’t get me wrong, now is a great time to take a leap and change your rotating diameter for a gearing advantage! Seriously, if you’re in the market and you have a car you don’t drive much at high speed (or much at low speed), now is the time to seize the need for rubber and get a bigger or smaller tire to suit your needs. Drop to a 13” wheel for ultimate acceleration on some 185/60/13R’s or go up to a 205/60R15 for a gain in top speed on the lonely highways. It’s certainly something to think about, and it will have a dramatic affect on your car’s performance. Just make sure that you know what you’re doing, or your car can come out of the transformation a complete dog.
The other thing about sizing is width. Because you’re adjusting the size of your tire, you can also change its width. You’d think that wider would be better, but this isn’t always the case. A wide tire, while having more contact patch for grip, has less pressure on the road per area than a narrow one. This is why you want narrow winter tires in snow and ice. By the same logic, a wide summer tire can actually be less grippy because the tread has less pressure per square inch of area. Less pressure equals less friction, which is less grip or “stick” on the road. Also, the tire will stay cold longer, thus having less grip or “stick”. Cold tires can get you killed, it’s that simple, and I can think of several examples I’ve seen in my life where heating up tires could have saved a car or a life. The grippier the tire, the worse it tends to be cold because it requires heat from road contact to activate. I once heard it said that a corolla only needed between a 185mm and 195mm wide tire depending on road conditions, and I do believe it. My Yokohamas were proof off this. Being 195mm wide, they basically never heated up in my driving environment and lasted nearly forever as a result. The Bridgestone s03’s I currently run are much the same way, showing virtually no treadwear after several summers of use. For what I’m using them for, this is ideal, but if I was a canyon runner I’d probably want to reconsider.
It should be noted that sidewall height has a huge effect on tire performance as well. This is the ratio number 205*60*R15 of the tire…and what this represents (insert confusion here) is the height of the tire’s sidewall represented as a percentage of its width. So, the sidewall of this tire is 0.60 X 205mm = 123mm of sidewall height. As you go up in diameter, the sidewall size decreases to keep the overall rolling diameter. 185/60R14 195/50R15 and 205/40R17 are all essentially the same overall diameter tires. The difference is that the sidewall of each is progressively smaller as the inner wheel gets bigger. This sidewall shrinking increases the stiffness of the sidewall, making it harder and less prone to rolling. It also decreases breakaway warning for the same reason. Strangely enough, increasing width while maintaining sidewall percentage (going from a 195/50R15 to a 205/50R15) will actually make the sidewall weaker because it is taller while not changing percentage. As usual, the numbers only tell half the story and you have to learn to interpret them to understand the system.
Probably one of the most misunderstood numbers on a tire these days is treadwear. This is a three digit number that indicates how fast a tire wears down in relation to other tires. Higher numbers are harder compounds. The lowest number I’ve ever seen is eighty, the highest four hundred eighty. Needless to say, I could sink my fingernails into the first, and broke my fingernails off trying to sink them into the second…and that should give you an idea as to how sticky the tires are. A sticky tire wears fast (low treadwear number). R compound tires don’t tend to have treadwear numbers at all because they’re only predicted to last a few hundred kilometers, or as long as a race. Also, tire life is affected greatly by how you drive. I used to own a set of Yokohama a520s, which were one of the best tires I’ve ever driven on for my location and driving style. I was told by the retailer that they would only last me four months of use…but six YEARS later I sold them to someone who then got another two years out of them. Not bad for a treadwear of one hundred sixty. I know some people with driving styles that have eaten those tires in two months. Also, don’t buy a hard tire expecting it to last forever under performance situations. These tires tend to slip, slide and spin, all of which wears out the surface even faster than regular grip driving. I had a set of Pirelli P6000 tires once…the hardest tire I’ve ever owned. Literally no treadwear after about 5 years of driving...they lost something like 1/16th of an inch of tread in that time. Lent them to a friend for his ae86…tires were gone in a summer, right down to the threads. In another example, a friend of mine had a Chevy Beretta that he liked to launch off the line because the tires spun and it went like hell. He wound up replacing his front tires every three months because of this. After taking my advice and going up to a stickier tire, he never had to replace the tires again. No spin = less wear. Obviously there’s a fine line we’re dancing across here, but its certainly something for you to think about before you buy. On a side note, I recently heard an automotive journalist claim treadwear numbers, when multiplied by 200, would give you the approximate life of the tire in kilometres.
Construction is the next thing to know about buying tires, and it is by far the most elusive. Every tire lists on its side how many plies of material it has, and what the plies are made of. You’ll see materials like nylon, polyeste r and steel listed in the following fashion “polyester 2 ply, nylon 2 ply, steel 1 ply”. While I am no tire guru, I know what I like in a performance tire…and to me there is no such thing as a performance tire without a steel ply or two. I’d humbly suggest that if you want a good tire that’s going to have a stiff sidewall. This will give you some run-flat capability and whole host of turn-in. Get as much steel as you can. Yes it makes for a heavier tire, but I have far more faith in steel plies than nylon. In my opinion, a high-performance tire should have steel in it because it stops the tire from rolling over far more effectively than other media, and that’s what it’s all about. I hate slop in tires. I have a set of Yokohama a460’s on a set of wheels right now…I bought them because I was told by the retailer that they were super-sticky compounds that would be better for my driving than a set of new es100’s. Well, it turns out these tires have no steel plies in them at all, and they’re like driving on marshmallows. It’s a nice tire to cruise on because it has so much flex in the sidewall that it acts like a second set of shock absorbers, so the ride is quite smooth…but that’s not what I bought them for. Needless to say, I’ve been quite disappointed by them. Its no good driving on tires you’re afraid of, or that you have no faith in.
A confusing part of buying a tire is the speed rating. This is a single letter designation given to a tire that indicates its ability to remain stable at high speeds. One misconception is that the letter system progresses from A to Z, with A being the slowest speed and Z the highest. In actuality, a tire’s “rating” means it has to meet both speed stability and load indexing requirements. Starting at the letter B, the chart proceeds in order through to U, where it then goes back to H, then jumps to V, Z, W and Y. Basically, every change in letter is given as a 10kmph change in speed starting at 50kph. D is an increase of 5, as is E and then the chart goes back to 10kph. B(50kph), C(60kph), D(65kph), E(70kph), F(80kph), G(90kph), J(100kph), K(110kph), L(120kph), M(130kph), N(140kph), P(150kph), Q(160kph), R(170kph), S(180kph), T(190kph), U(200kph), H(210kph), V(240kph), Z(“over 240”kph), W(270kph) and Y(300kph). Having written that, I guess a Z rated tire could be the highest rating, but “over 240kph” just isn’t working for me as well as “up to 300kph” given by a Y tire. I should point out that you usually don’t even see ratings on tires for speed until you hit the S rating. Depending on brand, you may not even see a rating until H or V.
The other is the perception that a high speed rating means a softer or grippier tire. All the rating means is that the tire is safe and stable at the rated speed, not that it grips like an angry gorilla while going so. Yokohama Pirada tires are highly rated for speed, but feature a treadwear rating of about 380. I wouldn’t call that a soft tire in any sense of the word. Also, you won’t see any SR, HR, YR, TR or otherwise…it’s either R or ZR that is stamped on the tire. The other rating *will* be present on the tire, but its usually just a big letter off to the side, saying something like “H 82” in the middle of the sidewall. Lastly, ultra high performance R compound tires don’t tend to have high speed ratings because the actual top speed of a car on a track isn’t really that fast. You’re not going to wind up to 300kph down the straight of your local track, much less even reach 100kph on an autocross course. Buying R compounds isn’t buying a ticket to nirvana, so make sure that you know what you’re buying.
Make sure the tire you’re looking at suits your climate. If you drive in a lot of adverse weather conditions, buy a tire that fits your needs and don’t be afraid to sacrifice a bit of “on paper performance”. Getting an R compound for rainy places is like asking for the kiss of death, and won’t make you faster once it starts to come down. For example, Bridgestone used to produce a tire called the RE71. Compared to its contemporaries in regular hot and dry weather, it certainly placed in the lower third of its category. This was rather intriguing because it was an expensive high performance tire! It turns out that, while the RE71 had mediocre dry performance, it had identical performance in the rain. Wet or dry, same grip. None of its competition could say that, with most tires in its category completely falling apart under even the slightest drizzle. These tires would be perfect for Vancouver weather, but would completely suck if you lived in Death Valley. But they certainly make my point about tailoring tires to their environment. Also, make sure you’re not shopping for an all-season tire (sometimes called a Mud and Snow, or M+S tire). All seasons aren’t good at anything, summer, winter or rain and I do council staying as far away from them as possible. In fact, my friends and I refer to them as “no season tires”. Get a real snow tire for winter, like a Blizzak, and a real summer tire for summer like a Toyo T1-S. You and your car will thank me later. A good snow tire and a good performance tire are far superior to a tire that isn’t really good at anything. There simply is no compromise, and anyone who tells you there is needs to go back to school.
Lastly, there is some mystery concerning “D.O.T. compliance”, and it is an issue that has been rearing its head a lot lately. Basically, not all tires are created equally. The Department of Transportation (or whatever they’re called in your area) spends a lot of time and money legislating tires for legal road use in North America, and they do this for a reason. So, every tire sold for road use in your area has to meet their regulations or it can’t be sold. Thus, running uncertified R compounds on the street may just get you busted for unsafe tires. Some states/provinces won’t care either way. Others will tow your car and impound it. I know in Canada, tires are legislated country wide, and tires not having visible certification from the government stamped into their original sidewall will be destroyed upon entry to the country. They will do this regardless of where the tire is from or how good it is. They won’t care if it is the same tire under a different name from another country, or even if it’s a tire that is light years ahead of ours (like most Japanese market tires). The issue isn’t whether or not the tire is any good, it’s whether or not the tire has passed government testing. That’s all their looking for. Now, you’re not going to be able to buy a non-D.O.T. tire unless its for racing use only, but there are a lot of people importing used wheels from other countries right now…lots of them have tires…and some of them do get by government inspectors. I’d hate to see you get pulled over and towed because you got a good deal on some sticky rubber from another country, so please be careful. Again, its not that D.O.T. is the god of tires or knows it all, it’s that they test them to meet a minimum certification. An untested tire is an illegal tire, the same way a un-crash-tested car is an illegal car just because they haven’t tested it, not because it isn’t safe. Basically, if it hasn’t been proven to the government, its not legal.
As I said at the beginning, you’d ideally have a set of wheels and tires for every possible scenario you could ever run into, and you’d just change wheels and tires accordingly. That having been said, I’ve literally met people with a garage full of wheels and tires, a set for every purpose. This is somewhat excessive, and expensive. Hell, when I was at Techno Pro Spirit, there were about a dozen sets of wheels and tires for racing just sitting on the staircase going from the main floor to the second! They were all for one car! I think ideally you’d have three sets of wheels and tires for any given all-year car. One high performance, maximum wheel diameter set with an ultra sticky tire. A winter set of steelies, ultra narrow and possibly studded with a super-aggressive winter tire. The last set? An ultra hard, flabby sidewall regular everyday tire for long trips on the highway, maximum fuel economy and ride comfort. Then you could have it all.