Please Tell Me I Can Go Over Rec. Tire Size by 1/2"

[Drak]

I've found the tires I want to use, and am going to run 17x9 wheels.

The recommended range for the tire is (you probably already guessed)
7" to 8.5".
Pretty common range for most 265/65 (or 70)/17's I've found.

I know you should never go out of manufacturer recommended sizing, I know that, but seriously can 1/2" make that much difference?
Am I putting my life on the line with a 70mph blowout doing this?

I'm guessing the sidewall danger zones would be towing and overloading for running a tire on an oversized wheel, but under normal DD conditions pretty much 'probably OK?'

What's the verdict?

 

[4Running Daily]

Some places won't mount tires that aren't in the recommended range, but yes you can do it. Is it the best situation, no, but will you be ok, yes.

 

[Mike W]

What dimension are you talking about going 0.5" over OEM recommended size...diameter or width?

Either way (or 0.5" larger in both width and height) should not affect your safety as long as you are not exceeding speed/weight ratings

 

[hearno]

Slightly different animal but I had a 255/40 on a 18x9 on my old G35. There was a mild stretch but I never had an issue.

 

[Drak]

What dimension are you talking about going 0.5" over OEM recommended size...diameter or width?

Width.
Recommended tire range is 7-8.5, and I'm going to be using 9" wheels.

Thanks so far for weighing in.

 

[MarkinWMich]

What you are speaking of is actually the norm in the world of high performance track racing (GT-series, Trans-Am, etc.) as well as those in SCCA events. Even BMW's M-series sport sedans come with a purposefully narrow tire-to-wheel ratio. Why? It has to deal with tire sidewall forces during cornering. Generally speaking, the narrower tire will provide less sidewall flex than a wider tire on the same rim.

Even the Baja desert racers, pro truck series, and cross country expedition vehicles are running a rather narrow tire-to-rim width. Which begs the question, "Given the choice between a slightly wider tire or a slightly narrower tire on your wheel, which would provide better vehicle handling?" If the pro's are leading by example, then the answer would be the narrower tire.

 

[BlackWorksInc]

Which way are we talking? Width or Diameter? Diameter shouldn't be an issue, width may or may not be a big deal either if you're talking tire.

 

[t-man]

This reminds me of the guy at Belle Tire telling me there was NO way I could fit 285/70/17 tires on my T4R after I put my Bilsteins on it. I was so disgusted with his attitude that I never went back. Guess what, I ran the tires that I DIDN'T buy from him, and after my body lift have plans of bigger.
Moral is, do the research as you have, don't listen to jackass know-it-all minimum wage tire jockeys, and everything these guys said is correct. That .5" don't mean squat. Some of the tuner cars nowadays are doing much much more, stretching the tire way out to fit a wider rim. Not my thing, but it works.

 

[MarkinWMich]

This reminds me of the guy at Belle Tire telling me there was NO way I could fit 285/70/17 tires on my T4R after I put my Bilsteins on it...and after my body lift have plans of bigger.
Moral is, do the research as you have,...and everything these guys said is correct. That .5" don't mean squat. Some of the tuner cars nowadays are doing much much more, stretching the tire way out to fit a wider rim. Not my thing, but it works.

I totally agree with my fellow Michigander!

I had a similar experience with mine, years ago, when I had a simple Daystar spacer lift and went to Discount Tire in Grand Rapids, Michigan to have a set of 255/75R17 BFG Mud Terrains put on. They were like, "Dude, they ain't gunna fit." I looked at them with a smile and said, "Give it a try anyhow." I had done my research, measured and remeasured before I purchased the tires. After the "drama" of having the disbelieving manager walk out there in the shop with his team of "tire jockies", shaking his head, and having them glance at me and smirk like I was a fool. Yes, I could see this "discussion" through the glass in the waiting area. Guess what? They fit beautifully and with room to spare...I could have went with a slightly larger diameter. The manager and his team had to eat crow...and I loved it.

 

[kevinpt]

I totally agree with my fellow Michigander!

I had a similar experience with mine, years ago, when I had a simple Daystar spacer lift and went to Discount Tire in Grand Rapids, Michigan to have a set of 255/75R17 BFG Mud Terrains put on. They were like, "Dude, they ain't gunna fit." I looked at them with a smile and said, "Give it a try anyhow." I had done my research, measured and remeasured before I purchased the tires. After the "drama" of having the disbelieving manager walk out there in the shop with his team of "tire jockies", shaking his head, and having them glance at me and smirk like I was a fool. Yes, I could see this "discussion" through the glass in the waiting area. Guess what? They fit beautifully and with room to spare...I could have went with a slightly larger diameter. The manager and his team had to eat crow...and I loved it.

i also had 255/70/18 installed not to long ago. told the tire shop what i had and what i wanted. after about 5 minutes of talking with the guys in the shop they said they would install them. installed on a stock 4th gen with almost no rubbing. moved the fender liner and everything is good

 

[Drak]

Not meaning to incur the wrath of any well-intentioned tire-jockeys out there, the information comes from the tire manufacturers themselves, they all list the recommended wheel range acceptable for their tires, I imagine for optimum performance and to keep their asses out of court.

I pretty much figured it was OK and I've seen many rides here dancing on the same edge of the knife, just didn't know the actual level of risk, which I take is pretty low if you use some common sense.

It wasn't so much if it would fit the car so much as would it become unseated and pop off the wheel under normal DD conditions.

I'm planning on using 265/70/17 on 17x9 wheels, and most tires in that range are giving 7"-8.5" as the acceptable wheel size range.

I feel safe now, thanks! :thumb: