Can I reduce the wheel size to improve the comfort/ride on rough road surfaces and maintain safety and performance? I want to replace the 225/65R17’s that are factory specified with 225/75R15’s. thanks, gp
Going to a higher aspect ratio - the 75 part of the tire size - will compromise handling performance. At least you chose the right diameter tire. You will be compromising whatever safety Toyota built into the handling of this car by changing tire size but as long as the load and speed ratings match or exceed the factory tire, you should be OK. This is an SUV, not a corner-carving sports car.
The bigger question is; Will 15 inch wheels clear the brakes? Tire Rack offers a 16 inch winter tire package so that wheel size will fit but no 15 inch. You might have a tire and wheel store try and fit a 15 incher but the selection of good 15 inch tires are getting slim.
Switching to a 225/70/16 wheel and tire as an alternative would be very little improvement (if any) for quite a bit of money. I looked up your factory tire size and found little selection in that size so I can’t even recommend a better riding tire. Sorry.
The rough road ride is more the suspension setting , the tire and wheel size don’t have much effect on the comfort level . You will spend a lot of money for very little or zero results.
Of course you did not really say what you meant by rough road surfaces .
A gel cushion to sit on would me much more cost effective.
tirerack.com will suggest what wheels/tires will fit on your car once you enter all the data on it. If you can find them, steel wheels are a lot less expensive than alloys and probably weigh less, too. If so, the wheels become more compliant over uneven road surfaces. That plus the added cush of higher sidewalls will increase comfort, but with less cornering traction and precision.
As Mustingman said, the size of your brakes will determine the smallest diameter wheel that will fit.
You might see improvement if you had, say, 40 series tires. But 65 series is about as tall as most come now, and going to 75 won’t make much difference. Are they worn? Are they at the correct pressure?
The quick answer to the question is “Yes, in a vehicle that has only one set of brakes across all trims you can substitute the base trim’s wheel and tire combo for the higher trim’s taller wheels with lower profile tires.” Drive a base trim to see if it offers you the ride you want. Tire Rack and other providers often suggest this “minus-sizing” for winter wheel/tire combos. Having tested multiple trims of the same vehicle at media launch events, I have found that the base trims almost always offer the smoothest and most comfortable ride.
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rav4 has different springs/shocks for base vs luxo model? tire aspect ratio and steel vs alloy construction are a minor portion of ride quality issue. would more side wall help on a non-base car? i think you would see even more difference between brands of tires that are known for soft feel vs stiff sidewall
Really? then why would anyone use alloy (aluminum and Mg alloys I assume) wheels? I thought they were used to reduce weight over steel alloy wheels.
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Style. Conspicuous consumption.
I had the same question, too, until I read “Understanding Wheel Weight” in the book Honda/Acura Performance.
Short answer: the total weight of the wheel/tire package, and the fact that the wheel/tire package on alloy rims puts the center of mass farther from the axle, reduce the HP to the wheels, thus acceleration. That’s one reason, besides cost, that alloy wheels are often standard on the 6 cylinder version of a car, and steels on the 4.
That’s comparing smaller steel wheels + tires to larger alloy wheels + tires. For equal size wheel/tire combos quality alloys will be lighter.
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Did you read the article? It compares wheel/tire combos that were within 0.01" rolling diameter of stock.
But 3" different in wheel size.
Yes. That’s the style these days: low profile, wide tires on big thick alloy rims. Overall heavier than the steel wheel/higher profile tire that the base models carry, or used to. Overall reduction in acceleration. Also less suppleness over road irregularities.
Does anyone have a car with alloy wheels that are the same size as stock steel wheels, with tires that are the same profile as the base tires? [Answer: hardly anyone.] If so, what is the weight difference?
Looking at Tire rack for Corolla wheels, for 15"x6" wheels the steels are about 2 lbs heavier than 15".6.5" alloys, for the 16" they’re 2-5 pounds heavier, each.
You’re right, the low profile tire fashion results in heavier tire/wheel combos. But for a given wheel size, alloys are lighter.
Gotta love tirerack! A bright spot in e-commerce. They are great on the phone, too.
Does anyone else wonder how many people actually buy alloy wheels the same size as the base model’s steel wheels?
i recall reading about hondas PAX wheels when they came out and the writer saying the extra weight of wheel inner reinforcement made honda use specialized shock valving and springs for those vans. and folks would replace the wheels after the tires wore out in 15k miles since you had to use specialized tires with a very odd rim diameter. like old ford TRX rims? was it 390mm?
PAX? TRX? More info, please!
Yes, I think the TRX wheels were 390 mm, at least one size. Michelin tried to introduce an entirely new standard for low profile wheel/tire sizing with TRX:
Different than PAX.