Tire 1 (Original)

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Mid-size Sedan
Length:192 in
Width:72 in
Height:57 in
Weight:3,500 lbs
Ideal Tire:225/50R17

Tire 2 (New)

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Comparison Results

SpecificationTire 1 (Original)Tire 2 (New)Difference
Diameter25.86 inches26.68 inches+0.82" (+3.2%)
Width8.86 inches9.65 inches+0.79"
Sidewall4.43 inches4.34 inches-0.09"
Circumference81.24 inches83.82 inches+2.59"
Revs per Mile780756-24
Suspension Clearance--+0.39" closer to suspension
Fender Poke--+0.39" pokes out more
Scrub Radius--No Change
Visual StanceFactoryFlushFlush
Tire StretchMild StretchSquare / IdealSquare / Ideal
RPM @ 100 km/h (est.)2500 RPM2423 RPM-3% (Lower Revs)

Speedometer Error

When your speedometer reads 100 km/h, you are actually traveling at 103.18 km/h.

Warning: The diameter difference is greater than 3%. This may cause brake failure, suspension rubbing, and ABS issues.

👨‍🔧 Expert Simulation Review

Let's break down what happens when you switch from your original 225/50R17 tires to the new 245/45R18 setup. The new tire has a total diameter of 26.7 inches. This means it is 3.2% taller than your factory tire. Knowing this size difference is the first step to making sure your new tires won't rub against the car's body when you go over bumps.

A quick heads-up: car experts usually recommend keeping the size difference under 3%, and your new choice goes a bit past that limit. Because the new tires are quite different in size, your car might feel a bit slower to accelerate, and it could confuse your anti-lock brakes (ABS). You might also need to raise your car a little bit or trim the fenders so the tires fit safely.

Because the new tires are a different size, they will spin at a slightly different speed. When your dashboard says you are driving 60 mph, you will actually be going 61.9 mph. Also, when you are cruising on the highway, your engine will run about 3% lower (less RPM) than it used to. It's a good idea to keep this in mind so you don't accidentally get a speeding ticket!

Now, let's talk about how the car will look. Your new setup pushes the wheels out by 10.0 mm, bringing them right in line with the edge of the fenders. Car enthusiasts call this a "Flush" fitment, and it is known for giving cars a very sleek, sporty, and custom appearance.

Finally, looking at how the tire fits on the wheel: you have chosen a "Square" or ideal fitment. The tire width perfectly matches the wheel width. This is the best choice for everyday driving because it protects your wheels from curbs and gives you the safest, most comfortable grip on the road.

Alternate Tire Sizes

Looking to change your wheel size? Here are tire sizes that will keep your speedometer accurate (within 3% of original diameter).