Tires

I found some really good used tires but the ones on my car read 215 45 r17 and the ones I found are 215 55 r17, is this gonna matter?

The only difference between the two tire sizes is, the side wall height will be a little taller on the replacement tire. But not enough to worry about.

Tester

They will be a little taller. It will matter if they don’t fit or rub on the inner fenders. Otherwise, it should not be a problem as far as ABS is concerned as the difference is slight. A problem might arise if thou have a flat on the front and the car has to wear a tire of a different size on one side for very long.

The main thing is not the tire size so much as whether or not the tires have any dry rot, or weather checking as it may be referred to.
Inspect the sidewalls and down in the tread grooves for any tiny cracks.

If my calculations are right, the replacement tires will be close to 2 inches taller.

You’re calculations are wrong.

The overall diameter of the tire will increase by .81 inch.

Or on the radius .40 inch.

Tester

IMHO that, combined with the tires’ unknown history (yes, tires can e internally damaged by potholes and/or develop irregular wear patterns from improper balance and/or alignment), combined with the fact that the OP doesn’t seem to know the age of the tires, is WAY more than enough to make me suggest not using them.

Joshua, you only have four patches of rubber the size of your palms keeping your thousands of pounds of vehicle safely in control on the pavement, even at 70 mph on the highway. Are you really willing to risk your life by taking risks with this thin margin of control to save a few bucks?

Tester
You’re calculations are wrong.

The overall diameter of the tire will increase by .81 inch.
Or on the radius .40 inch.

Not according to this, Ace:
http://www.tacomaworld.com/forum/tirecalc.php?tires=215-45r17-215-55r17

I only see the difference between the two tire sizes as being a little over 3/4 of an inch and nowhere near 2 inches.

Tester

Now now, boys. Let’s play nice.

Tester
I only see the difference between the two tire sizes as being a little over 3/4 of an inch and nowhere near 2 inches.

I think you’ve overlooked that you need to include both the top and bottom of the tire, which comes to about 1.7", as the chart indicates.

The tire chart I used online showed a difference of 1.7 inches, the 55 being taller. But as Mountain Bike states is your well being worth saving a few bucks when new tires have warranty and most places include rotation and balancing.

45% of 215 mm is 96.75mm. Times 2, it equals 193.5mm total sidewall in the overall diameter.
55% of 215 mm is 118.25mm. Times 2, that’s 236.5mm total sidewall in the overall diameter.

That means the 215/55 will be 43mm (1.69291 inches) larger in diameter that the 215/45.

That’s enough to change the car’s handling and cause possible interference problems.

But, to my mind, no less important is the unknown history of the tires and their unknown age. IMHO tires are one of the most critical safety items on a car, one of the few items that you absolutely should not compromise by taking risks with to save money.

J.J. You can use the tires serial number to determine their age…They should fit okay but your speedometer might be a little off …Your true speed will be a little faster than what the instrument indicates…Maybe 3% off. Same with the odometer…Inspect them carefully…During the balancing process, most hidden defects will show up as a need for excessive weight. I start to worry when a tire that size needs more than 3 ounces of lead to balance it…

http://www.carbibles.com/tyre_bible.html

The above link will tell you how to read the date code.
But I still recommend against the use of used tires.

Just some food for thought, but a 215 from one tire maker will not necessarily be the same size as a 215 from another and that also leads to sidewall ratio differences.

Those figures are also for brand new tires and the OP is considering used tires which have an unknown amount of wear on them. I could see a 3/4 or 1" difference being feasible; all depending.

I’m also in agreement with Caddyman about the amount of weight needed to balance a tire. When a tire needs 3 ounces or more there’s a problem and personally I don’t care to see one that takes more than 2.

The difference in radius is about .9 inches which is the measurement other then the width that affects fitment problems; the diameter which is twice the radius does not. You will hardly notice handling differences which will be more dependent on the tire design and construction. If they are a better tire and fit, go for it especially if they are free.