[kookykrispy]

Originally Posted by The Champ

A 7" wide wheel is too narrow for a 275/60/15. I know people do it - but the MINIMUM recommended width is 7.5" and most people run at least an 8" wide rim.

I have 255/60/15's on a 7" wide rim and wish I had 8" rims as they "balloon" more than I like on a 7" rim. 255/60/15 is the largest/widest tire that is safe to run on a 7" wide rim.

I currently run a 15x8 rim.. but I have to respectfully disagree with your last sentence that it is not safe. There is no safety problem running a 275/60r15 on a 15x7 rally wheel. I've done it for years on several cars including my 67 GTO on pontiac rally II's and my old 72 chevelle SS on chevy rallys. I don't see what the issue is. It fits fine, looks cool, handles well, no uneven or premature tire wear...

I understand that BFG lists 7.5" as the min recommended width, but we're talking about the rim width difference of just half an inch... which I think is not enough to worry about.

It it were not safe, tire shops would refuse to mount a 275/60 on a 15x7... I have never experienced any such refusal.

As they say however... to each, his own! and.. Your mileage may vary...

[Overkillphil]

Another factor is the "cut" of a particular tire. Different brands/designs appear differently on a given rim despite being the same tire size. I remember my old Firestone SS Radials looking like balloon tires and another brand/same size looking completely different on the same rims.

[F ROCK]

car in my signature is wearing 275/60/15 0n 7" factory rims in rear.
215/70/15 up front.

my orange 71GTO has the same rears but 255/60/15 out front. i like that stance a lil better.

i used these tall fronts on this one because i had some LOW hangin hooker comps! i've got RA manifolds now.

[The Champ]

Originally Posted by kookykrispy

There is no safety problem running a 275/60r15 on a 15x7 rally wheel.

It it were not safe, tire shops would refuse to mount a 275/60 on a 15x7... I have never experienced any such refusal.

And there are people that say that it's perfectly safe to run a 35 year old tire, too.

A guy used to be able to take an old used tire into a shop and get it mounted. Today many shops will refuse to mount used tires at all, or if they will, not if the tires are more than 5 or 6 years old - regardless of the amount of tread remaining.

The reason they have a MINIMUM recommended width is for SAFETY reasons. It's not because of looks...

Today, there are many tire shops that will refuse to mount a tire on a rim that is outside of the manufactures specs.

As a kid, I used to stand up in the front seat between my Mom and Dad. Today they'd get arrested for allowing me to do that...

[lust4speed]

Originally Posted by The Champ

A 7" wide wheel is too narrow for a 275/60/15. I know people do it - but the MINIMUM recommended width is 7.5"...

Key word in their charts is "recommended". Too many of us have run the 275-60R15's on 7" wide rims tens of thousands of miles without incident. If you think about it, you are only bringing in the bead a quarter inch a side. Is it better to run a 7-1/2" rim, yes -- will it be catastrophic if you run a 7" rim, no.

[Grand73Am]

I've wondered about the recommended wheel width lately myself, and here's the example I was thinking of. ln the late 70's, the factory put 225-70-15's on the Trans Am WS6 8" wide snowflakes. Now, if you look at the wheel widths recommended for 225-70-15, the chart will say that the maximum width should be 7.5", when we all know that size came on 8" wheels from the factory.

[kookykrispy]

Originally Posted by lust4speed

Key word in their charts is "recommended". Too many of us have run the 275-60R15's on 7" wide rims tens of thousands of miles without incident. If you think about it, you are only bringing in the bead a quarter inch a side. Is it better to run a 7-1/2" rim, yes -- will it be catastrophic if you run a 7" rim, no.

Thank you. There is no safety issue with 275/60r15 on a 15x7 rim.

Champ, a whole lot of members here are running this combo. I have never had an issue with a 275/60r15 on a 15x7 rim. I personally have run this size on a 7 inch wide rim for thousands of miles. I believe it is perfectly safe. I would never put a wheel and tire combo on my car if I felt it was not safe.

Half an inch difference from a tire manufacturer's 'recommended' rim width to the actual width of the rim does not make the combo unsafe. If you want to repeatedly claim that a 275/60r15 on a 15x7 rim is in fact not safe for highway use, please state a credible source... like an actual DOT study or something. Otherwise lets stop arguing on the internet because everyone knows what they say about that..


Grand73Am makes a good point... the FACTORY went over the recommended rim width by 1/2 an inch... was this safe? I'm sure it was quite safe for highway use or the factory would never have done it.

Because of this controversy, I read up on this subject and here is what I found: The narrower rim width causes the sidewall to flex more compared to the same tire mounted on a wider rim. The increased sidewall flex makes for a softer ride, and so a 275/60r15 tire on a 7 inch rim may not last quite as miles as if it were mounted on a 8 inch rim for the duration of the tire's life due to the additional sidewall flexing over the thousands of miles that the tire will be in use... Using a rim within the recommended rim width will ensure maximum mileage out of the tire before it is worn out.

Now obviously, you don't want to go way too narrow or way too wide on the rim, because then you can run the risk of the tire bead becoming unseated during hard cornering or something. I would say a 275/60 on a 6 or 5 inch wide rim probably would be unsafe for this reason.

I found this statement on the tirerack interesting:

some vehicle manufacturers and tire companies have permitted rim widths that are not within the tire's original approved rim width range. For example: BMW has combined 235/40R17 sized tires on 17x7.5' rims (which are 0.5' less than the narrowest 8.0' wide rim listed for the size) on certain M3 models; and Chevrolet has combined P255/50R16 sized tires on optional 16x9.5' rims (which are 0.5' wider than the 9.0' wide rim now listed for the size) on certain Corvette models.

http://www.tirerack.com/tires/tirete...jsp?techid=194


So there you go, proof you cannot argue with! Two manufacturers of high performance vehicles (corvette and M3) run rims half an inch narrower or wider than the tire manufacturer's published recommended rim width for that particular tire.

Chevrolet or BMW would never put these tires on a new corvette or M3 if they thought there was any chance of it being unsafe!!

[studda]

Originally Posted by Overkillphil

Another factor is the "cut" of a particular tire. Different brands/designs appear differently on a given rim despite being the same tire size. I remember my old Firestone SS Radials looking like balloon tires and another brand/same size looking completely different on the same rims.

I also had Firestone SS Radials just before the tires I have now. They looked so much wider than the tires I have now and had very square shoulders on them instead of a more round transition from sidewall to tread.

[The Champ]

Originally Posted by kookykrispy

Thank you. There is no safety issue with 275/60r15 on a 15x7 rim.

Champ, a whole lot of members here are running this combo. I have never had an issue with a 275/60r15 on a 15x7 rim. I personally have run this size on a 7 inch wide rim for thousands of miles. I believe it is perfectly safe. I would never put a wheel and tire combo on my car if I felt it was not safe.

Just because you and some other folks have done it, doesn't mean it's safe.

I found this statement on the tirerack interesting:

"some vehicle manufacturers and tire companies have permitted rim widths that are not within the tire's original approved rim width range. For example: BMW has combined 235/40R17 sized tires on 17x7.5' rims (which are 0.5' less than the narrowest 8.0' wide rim listed for the size) on certain M3 models; and Chevrolet has combined P255/50R16 sized tires on optional 16x9.5' rims (which are 0.5' wider than the 9.0' wide rim now listed for the size) on certain Corvette models."

So there you go, proof you cannot argue with! Two manufacturers of high performance vehicles (corvette and M3) run rims half an inch narrower or wider than the tire manufacturer's published recommended rim width for that particular tire.

Funny how you didn't post the whole paragraph as printed on the tirerack site:

Let's finish the paragraph:

While these applications have received the approval of the vehicle and tire manufacturers, staying within the approved rim width range helps assure that the tire's internal stresses are within its design parameters.

So, I've just countered your proof positive, as you have not been in contact with both the vehicle and the tire manufacturer to assure that the internal stresses are within it's design parameters.

As I posted earlier, the narrower rim also makes the tires "balloon" too much. I don't really like the balloon look on my 255/60's with 7" rims. I can't imagine how bad it looks with an extra 20mm's of section width.

[kookykrispy]

[The Champ]

Keep yelling through you're bullhorn...

I don't need one.

When you left out the critical part of your posted paragraph, you lost all credibility.

I used to believe old tires were safe - until I had a "new" looking redline radial have the belts separate at 70 MPH. The tire had 80% of it's tread left, no sidewall checking and no checking on the tread area. But it was 12 years old.

That's when I started paying closer attention in regards to tires and safety.

[David Jones]

Jeez.

[1969GTO]

that's a nice looking tire-wheel set up you have David Jones

[kookykrispy]