New tire must keep load rating of original rubber

John Mahler

SPECIAL TO THE STAR

Q: I have a 2007 Hyundai Sonata with P225/50 R17 tires with a 93 V on the side wall. One of the tires has developed a bulge on the side of the Michelin Pilot tire. I have been told that this is a road hazard and not under warranty. The new Michelins cost 259.00 each. I was shown new Goodyear Arriva mileage tires that are supposed to give better mileage and are supposed to be similar to the originals in speed rating and performance. When I looked at the tires they had a 85 H on the side not a 93 V. There was also a Uniroyal Tiger Paw that had a 94 H. Please advise what the difference in the H and V are and if there is much difference between the 83 and the 93.

A: You are getting some bad advice when someone recommends a “similar tire.” Similar “better” is fine but similar “worse” is bad and can lead to tire failure and/or a crash.

The V and H are speed ratings. That means the tire can run at the rated sustained speed without problems. A V-rated tire can run 240 km/h and an H-rated tire can run at 210 km/h. Even if you never run these speeds, it is why the tires can run this speed that is important to the driver. As speed ratings go up, the tire has strong better internal reinforcing belts and is stiffer. And stiffer handles better.

Moving from a V rated tire to an H is usually not a big deal and is done often, but it is not recommended.

The 93 number on the sidewall is hugely important and you can never go lower that what was OE on the car. The 93 is the load rating it means the tire can carry a maximum load of 1433 lbs. A load rating of 85 means 1135 lbs, and a rating of 83 can carry just 1074 lbs. Look at what a vastly weaker tire an 83 is than a 93, 359 lbs difference.

If you do the math you will find that the load ratings are greater than the car weight. That is a safety margin. Every car manufacturer would like to use a lower load rating to save money, but they calculate how low they can go and still be safe. So for your car 93 is the number.

Remember under heavy panic braking as much as 70% of the cars weight can transfer onto the front tires. Those two tires’ sidewalls have to take that load, or bang and you’re in a ditch.

Downgrading speed ratings, maybe; load ratings never.

Email tire questions to John Mahler at thetireguy_1@hotmail.com. Please include vehicle’s make, model and year, tire brand and size, as well as your name, address and phone number. Due to volume, personal replies cannot be provided.

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