CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Larger Tire Problems?

I own a 2000 Toyota 4 Runner, 2WD, 4 cylinder, automatic. I do no off road driving. The original tires are 225/75/R15. An optional tire is 265/70/R16. I’m thinking about going to the larger tires. I’m not concerned with any possible speedometer errors but I wonder if the bigger tires will be a sruggle for the 4 cylinder engine. Any thoughts?

Your engine will not notice any difference in the change in tires. I do not foresee any other problems with the larger size.

The “larger” tires are mounted on 16" wheels and you have 15" wheels now. That means you will have to buy a set of 4 wheels as well as the larger tires. The overall weight of the tires is the same and therefore there is no change in the workload on the motor.

The originals will have a smoother ride and better traction in the snow. Still want to switch?

I’m completely puzzled why you want to change tire size and buy an extra set of rims. As stated, you do no off road driving and the 15" tires will give you a better ride.

If you use summer and winter tires, you will need TWO sets of rims.

I would just stick with the original size.

The additional 40mm in width might increase rolling resistance and adversely affect gas mileage.

The aspect ratio can be deceiving, as it’s a percentage of the section width. In this case, even though the ratio is smaller, the sidewall will be larger.

Your circumference will be 7.28 inchess larger, which will not only affect your speedo accuracy but also, when combined with the wider width, the greater sidewall, and the larger wheel, will add weight. This will adversely affect gas mileage, especially since it’s rotating mass.

The added mass and the added rolling resistance will place added load on the powertrain, however since the manufacturer offers it as an option I doubt if it would be significant.

IMHO the added unsprung weight will also cause a poorer ride. But “poor” is a highly subjective term.

See the attached link for the actual tire size diferences.
http://www.discounttire.com/dtcs/infoTireMath.dos

I think the circumference will be a little more than 10", the diameter will be about 3.2" greater. Diameter 27.4" vs 30.6. That is almost 12%. It will work the engine a little harder because it will be like changing your final gear ratio by 12% higher. It will be most noticeable on hills.

Your measured gas mileage will be lower because your recorded miles per tank will be 12% lower, but if you compensate for the change in the odometer, your gas mileage may actually improve slightly.

Since the sidewall ratio hasn’t changed and the diameter is greater, bumps and dips in the road will be smaller to the larger tires, so theoretically the ride should be smoother, but there will be other factors to consider.

Are you sure the optional tires are not a lower profile tire, like a 60 or 55 series tire? If not, was this optional tire only on the 4WD version?

The aspect ratio changed from 75 to 70. But even then, the section width is wideer enough that the sidewall hight will be greater.

While I see your point about the larger diameter, I’m betting that the increased unsprung weight will more than offset that and the ride will be worse. The new setup will have a much wider carcass, more sidewall, and larger wheels. Unfortunately, there’s no way to know for certain what the fefect will be without tryng it.

I too wondered if this option was for the 4X4. But I took the OP at his word.

That “optional tire” was not offered on the 4 cylinder 2 wheel drive version. it was however offered on the 4 cylinder 4 wheel drive version. This is due to gear ratios. The two wheel drive having a 3.73 ratio and the 4 wheel drive having a ratio of 4.10. I would offer that a two wheel drive 4 cylinder 4 Runner with an automatic doesn’t have the cajon’es.

Changing to a significantly larger diameter tire has resulted in a loss in performance and fuel mileage on several vehicles that I have owned and many that I have worked on. It wouldn’t surprise me if almak is troubled with the 4 Runner constantly shifting in and out of overdrive when cruising at 60+mph if he installs the larger tires. More often than not the oversize tires are removed and left to dry rot after a few thousand miles of unhappy motoring.

Two reasons I was considering the larger tires. 1. Looks better in the wheel wells. 2. The manufacturer of my preferred tire brand doesn’t make the 225 tires anymore. I’ve decided to keep the 15 wheels, they’re alloys and cost of new alloys is hard to swallow. I plan to go with 235/75/R15 which are available in the preferred brand.

Thanks to everyone for their input and giving me additional information to make my decision.

235/75-R15’s should work fine.

The larger tires have an 8 % bigger diameter and will make a difference in gearing and odometer error. The larger tire is standard for the 4 gen 4runner. Yours is a 3 gen. The biggest problem, assuming you DONOT have traction control, abs and stability control, is fitment. YES , a significant diffrence in work load.

Rims, if you have a 6 bolt pattern, they are pretty standard on 4wd Toyota, some GMs, Isuzu etc. So, you should have no problem finding some. 4wd Tacoma, 4 Runner, Tundra and all truck based 6 hole wheels from Toyota for years till now, wear the same wheels. Brake clearance would be an issue, only going from newer truck to older rims, not the other way. If yours are 5 hole, change with 5 hole 2 wd drive Tacoma but you will have problems finding 5 hole with sufficient rim width…good luck there.

As far as the larger tire/ rim is concerned, the larger size offers no overall benefit in 2 wd as you will go few places you need flotation. But, they look a lot cooler. So, borrow a rim from a friends newer Tacoma, test fit the 265/70/16 which IS optional for them in 4 wd. If it fits…go for it. Nothing like COOL !

I think “meat” on cars looks much better then the cookie cutters which you now have…relatively speaking. Yes, your 4cyl auto on a heavier SUV with too large tires will struggle more, but if you don’t tow, carry much weight, it just means three cylinder Geo Metros will leave you in the dust…but you WILL look better in the rear view mirror.

Overall, @same has the safest’s bet as you stay with your own rim with just a little change in gear ratio. Btw, preferred tire brands are overrated as tire makers are more inbred then ever…as long as they work, made of rubber and are cheap is all drivers of 13 year old trucks need care about. Be safe !