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Tire Talk: All-seasons best for summer driving

Over the years, the "summer only" average tire has disappeared.

Published July 20, 2012

Q: I have a 1998 Toyota Celica convertible with P205/55R15 size tires. I was wondering if using P225/50R15 size tires would affect the driving. They’re on new chrome rims.

A:The tires will fit the car. They are the same overall diameter as the original tires, but will be almost an inch wider. The extra width may make the car follow the irregularities in the road a bit more than you are used to. This is called tram lining. You say the tires are on extra rims, be sure that the rims are meant for your particular Celica.

The wheels should be 5-100, that means five bolt holes on a 100 mm circle. Also, most aftermarket wheels for your car will have an offset of 35 to 40 mm. That is the spacing of the centreline of the wheel relative to the mounting surface.

Q: I live in Toronto and have all-season tires and winter tires that I rotate each season on my Matrix. The all-seasons are nearing the end of their lifespan and I am wondering if it is better to replace them with a set of all-seasons or perhaps use a set of summer tires instead given that I run winters in the colder months?

A: I would stick to good all-season tires for the summer. Over the years, the “summer only” average tire has disappeared. I can’t think of an average performance summer tire, by that I mean one meant for average sedans. Summer tires have all moved up scale to become H speed-rated and higher. Unless your car needs those, stick to A/S tires.

In fact, there are all-season tires right up to the W speed rating, so an all-season tire can provide lots of grip in the summer, I just don’t like them for winter. By using modern A/S tires you are not losing any summer grip. Moreover, in the fall if you are caught driving on a cold day, they will have more grip than a summer tire.

Q: I want to replace my current tires both all-season and winter tires on my 2010 Honda Civic Sports. It has P205/55R16 tires. However, I find the above size tires are too low for my car as the bottom front & rear end body are easily scratched. Can you suggest another appropriate sized tire?

A:That tire size is correct for your car. The issue of your car scraping is not a tire problem. Cars cannot be raised or lowered by changing the tire size. The auto manufacturer has a set diameter in mind for your car’s tires. The whole car’s suspension is designed around that information. The car’s CPU needs to know how many revolutions the wheel makes per kilometre at any given speed. From that, the car company determines what gear ratios go into the transmission. Those gear ratios in turn affect the car’s acceleration and its fuel economy.

If you changed the tire diameter to make the car higher off the ground, all of the manufacturer’s calculations would be tossed out. In addition, the car would accelerate slower, use more fuel and the transmission’s shift points would be changed. Sorry that there is no easy fix for your problem. It may be worth having the car’s suspension checked at a Honda dealer. Perhaps the car’s springs are sagging and thus lowering the car.

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