How to Buy Tires for your Car in Panama
When people talk about tires I often hear, to my dismay, how they picked them solely based on price, or price and brand, or how long they last. Now if you don’t know much about tires this may seem reasonable, but unfortunately that buying strategy can be detrimental to your safety, especially in Panama where driving is probably the single most dangerous activity you will undertake. That is what has prompted me to write this little essay.First let’s make one thing clear: tires are the single most important factor affecting the safety of your car. Period. Nothing else on your car is more important to your safety. Those 4 little patches of rubber are all there is between your car and the road, and they are what determines whether or not your car stays on the road. There is no point in having fancy safety systems if your tires are not good. Therefore it is really important to buy good tires, maintain and inflate them properly, and change them before they are completely worn. In a country like Panama where we often get tropical downpours, that last point is doubly important as tires that have less than 1/8” of thread left will be very prone to hydroplaning. 3/16” is recommended as the minimum for proper wet performance.
Of course, most of us have to buy tires that fit within our budget, but I would recommend you buy the best tires you can afford, rather than the best deal you can find. But how do you know which tires are good and which ones are not? Now that is not a very easy thing to do, but I’ll try to provide you some guidelines and tools to help you with your decision.
I buy from a good brand so I’m fine, right?
Actually, no. Every brand out there produces some good tires and some not so good tires. The top three brands, Bridgestone, Goodyear and Michelin, while they certainly make some of the best tires in the world, they also make some of the worst. Same goes with smaller brands like Kumho or Hankook, while they may not have the R&D budget of a Bridgestone, they still produce some tires that provide good value for your money. Each company produces different tires which emphasize different characteristics at the expense of others. Tire design involves dealing with a set of compromises. For example, a rubber compound that lasts very long will tend to be hard, decreasing comfort and adherence on dry pavement. Or tires with lots of deep grooves and channels should evacuate water better, but will not handle as well as a tire that is mostly smooth rubber with few grooves.
So brand doesn’t tell you much, you also have to look at the particular model of tire. Take Michelin for example, considered by many to be the finest tire company in the world. They certainly have some very advanced technology and produce many of the best tires on the market, but they also produce some duds. Same goes for Bridgestone and Goodyear. In particular, OEM tires that came with your car are almost always optimized for fuel economy and low noise and often not very good at anything else (high end cars are an exception, they tend to come with better tires). That has been my experience with Good Year Integrity tires and Bridgestone RE-92 tires for example: both were downright dangerous on wet pavement. Changing them for better tires transformed the cars in question. So different models within a single brand will provide a different set of qualities. Where the big brands excel, is at providing premium tires that do well in almost all performance criteria, but they are not cheap.
Tires have a variety of ratings marked on them, can I use those to make a decision?
Unfortunately, the answer is yes and no. Some of those ratings are minimum requirements that you must respect, but others are wildly opened to interpretation. Let’s look at an example. The tires on my Toyota Prado are Bridgestone Dueler A/T D694 (Revo 2) 265/65R17 110T 500AB. Let’s break this down:
-Dueler A/T D694 (Revo 2 in the USA) is the model name. You have to be careful with that because this is a VERY different and much better tire than the similarly named Dueler A/T D695.
-265/65R17, of course that is the size. It roughly means a thread width of 265mm, a ratio of wall height to thread width of 65%, and a rim radius of 17”. I say roughly because if you look at the actual dimensions of different tires with the same size specifications, you may find some surprising variations. -110T, the 110 is the load rating and you need to look at a chart to determine exactly what it means. 110 means this tire can take a load of up to 2337 lbs whereas a tire with a load rating of 80 can only take a load of 992 lbs. It is very important that you buy a tire that meets the minimum load rating specified by your car manufacturer. The “T” is the maximum speed rating, and in this case it means up to 190 Kph. You should generally stay with the same tire sizes as what came with the car, but it is possible to change size as long as you stay within 3-4% of the original diameter. You can use this handy calculator to see what other sizes might work for your car.
Those are the ratings that must be respected but they don’t tell us anything about how well a tire performs in various scenarios. The US-DOT has attempted to come up with some performance ratings to alleviate this problem, this is called the Unified Tire Quality Grade (UTQG), that ’s what the 500AB is, but unfortunately the tests are done by the manufacturers themselves and they are opened to extrapolation errors and interpretation. They can however be useful to compare different tires from the same manufacturer as presumably they would use the same method for all their tires. Here’s what those ratings try to tell us:
-500, that is the thread-wear rating. The tires are run on a standard course and compared to a monitoring tire. If the tire being tested wears twice as slow as the monitoring tire, it gets a rating of 200 (200%). So this 500 rating means the tire is estimated to last 500% longer than the monitoring tire. I say estimated because the test is run for only 7,200 miles and the results are interpolated from there, and this interpolation is left to the manufacturer to do!
-A, the first letter following the number is for grading wet traction when braking in a straight line. It goes from A to C (except that they recently introduced an AA rating as well). You should look for a tire that has at least an A rating to cope with our tropical downpours. Unfortunately the UTQG traction test does not evaluate dry braking, dry cornering, wet cornering, or high speed hydroplaning resistance.
-B, the second letter is for the temperature resistance grade. It is related to the speed rating (T) as speed and friction are what determines how hot a tire will get. They go from A to C, A being best again. Generally speaking a B rating or better is fine for most purposes as long as you respect the minimum speed rating recommended by your car manufacturer.
So these ratings really don’t tell me much, how can I find the best tires?
The best thing I can recommend is that you use the excellent website of Tire Rack, one of the largest tire retailers in the USA. TireRack.com is a wonderful resource because there you can find all the comparative tests done by the staff of Tire Rack and you can find the results of their yearly tire surveys, which directly compare tires to others in the same category. The surveys are not bullet proof since they come from consumers, but there is strength in numbers, and the more miles of usage has been reported on a tire, the more accurate the survey results should be. Look at this chart for example. You can see the Dueler A/T Revo 2 at the top, and you can see the various criteria being reported across the top header. For me living in Altos del Maria with steep and curvy roads and lots of tropical downpours, I think the “Hydroplaning Resistance” and “Wet Traction” are the most critical factors to my safety. You can see this tire gets outstanding ratings in those areas. I also pay close attention to the “Dry” performance factors as well as “Ride Comfort” and “Noise Comfort”, but unless the tire does really well in the wet, I’m not interested. You may also want to look at “Threadwear” although this really just becomes a factor in the overall cost-per-mile of the tire.
One other thing, it is generally not a good idea to have different models of tires on the front and rear wheels of your car. While you might not notice the difference during normal driving, in an emergency situation one set of tires might let go of its grip well before the other, causing you to completely lose control of the car.
So there you have it. It’s not foolproof but that is how I’ve been selecting tires for the last 6 years and I’ve had very good results. I bought these Bridgestones last year and after 35,000 Kms I can report that I am VERY happy with them. They are comfortable, quiet, handle well and most importantly, they are fantastic in the rain. They are a giant leap over the OEM Bridgestone Dueler H/T that were on the car when I first bought it.
Hopefully this will help you chose your next set of tires, and keep in mind that 5% better performance from your tires can make the difference between life and death in some situations.
Artilce by Sylvain Duford of Living in Altos del Maria