Because I have a spike the size of a pen sticking out of a tire, I am forced to make a decision. It can't be patched because it is too close to the sidewall. I wanted new tires before the end of summer anyway, because as well all know re92's stink! I am considering switching to 225/45/17's for the performance and selection. what do you guys think of Bridgestone Potenza RE730's??? Here is the link

http://www.victoriatire.com/tires.ht...otenza%20RE730

Any others I should look at??? I picked these because of price and all season traction.

 

I don't have any personal experience with those tires but from posts that I've seen about it (TireRack.com) it seems like a pretty good tire.

If you're worried about ride harshness or anything, I'm running 235/45-17s and it's not any worse than stock. Actually, my friends tell me that it rides nice and smooth.

 

The minimum acceptable rim width for 235/45R17 tires from ANY manufacturer is 7.5". The stock rims are only 7" wide. They are therefore unsuitable for 235/45R17 tires, period!

For a discussion of just how foolish it is to exceed manufacturer guidelines, see the section under RIM WIDTH in the following article:

http://www.dunloptire.com/tiretech/?...tire_width.txt

Pay close attention to the words, ". . . could result in failure", and don't say you haven't been warned.

 

Thanks for the link.

If you read a little into the page, however, you will see this:

This states that if you get a narrow or wide rim (or by inference a tire) that is within the acceptable range of rim widths then you're fine. It is only when you take this to the extremes is when you'll have a problem.

You may be correct - 7" may be incompatible with 235/45 but TireRack.com recommends 235/45-17 for Maximas.

Do you have links to information about why 235/45 on 7" is not good? I couldn't find anything on this forum about it when I was going to buy my tires.

Thanks.

 

So are you saying that if I order the 18x8 and get 235/40/18 would not be the right tire size for that rim?

 

Thanks for your inquiry, TCm.

First, your point regarding the acceptable range of rim widths is dead on the money. The acceptable range of rim widths for 235/45R17 tires is 7.5" to 9". Thus, the stock 7"-wide SE rims are not acceptable by definition.

This is not open to conjecture. NO TIRE MANUFACTURER WILL WARRANT THEIR TIRES AGAINST FAILURE IF YOU MOUNT THE TIRES ON RIMS THAT FALL OUTSIDE THE ACCEPTABLE RANGE OF RIM WIDTHS. AND NO RESPONSIBLE TIRE DEALER WILL MOUNT TIRES ON RIMS THAT FALL OUTSIDE THE ACCEPTABLE RANGE OF RIM WIDTHS. Most important, NO SANE INDIVIDUAL WILL PERMIT TIRES TO BE MOUNTED ON THEIR RIMS IF THE RIMS EXCEED THE ACCEPTABLE RANGE OF RIM WIDTHS.

And why is that the case? To quote the Dunlop article:

"If the rim is too narrow, the flex point moves toward the shoulder area, creating heat buildup in the shoulder which reduces tire life and could result in failure."

"If the rim is too wide, the flex point moves towards the rim area, causing heat buildup in the lower sidewall which reduces tire life and could result in failure."

I'm willing to assume certain risks when it comes to modifying a motor vehicle, but I draw the line at tires and brakes. My life is worth more to me than that.

I hope I've covered everything.

 

I understand what you're saying, don't get me wrong. I know that you shouldn't mount tires that are out of spec for a given rim.

What I don't get is how does someone make a determination that 7" wide rims are not a good fit for 235/45-17. Do you have links to reasons why this is true?

It sucks that I JUST bought these tires and it would suck even more if they fail. I'd like to get as much info about it as possible so I can judge for myself if it is safe to run these or not.

I'm planning on AutoXing with these tires in the spring/summer. I don't plan on the tires lasting longer than 25k-35k so my next tires will probably be 225/45-17... If I realized that they (tirerack.com) had that size I would have bought those. The sales guy was adamant that it was a perfect fit, though.

Thanks.

 

No I don't, TCm. The only thing I know is that acceptable rim widths are established by national and international standards bodies. Every tire manufacturer WITHOUT EXCEPTION complies with the standards established by those bodies. The national standards body is the Tire and Rim Association. You can access their information at the following web site: http://www.tirestyres.com/assn/tara.html.

NEVER TRUST A TIRE DEALER! ALWAYS CONTACT THE MANUFACTURER IF YOU HAVE ANY QUESTIONS REGARDING THE SUITABILITY OF THEIR PRODUCTS FOR YOUR APPLICATION.

If your sales guy knew that you were planning to mount 235/45R17 Kumho tires on 7"-wide rims, then he materially misrepresented the facts. The minimum acceptable rim width for Kumho Ecsta 712s in 235/45R17 as published on the Tirerack web site is 7.5". Go to their web site and see for yourself.

I would advise you against autocrossing on 235/45R17 tires mounted on 7"-wide rims. Don't forget . . . the life you save may be your own.

 

It looks like you're OK, CIRCO. The minimum acceptable rim width for 235/40R18 tires appears to be 8".

 

If this was the case, then I would complain to tirerack.com. Probably won't get you anywhere, but as you know sometimes if you bark up a tree long enough you might get what you want. Its worth a try.....

 

I agree, maxman00. TCm should complain to Tirerack.com, but only if he informed his salesperson that he was planning to mount 235/45R17 Kumhos on 7"-wide rims. If he didn't, then the salesperson isn't under an obligation to inquire as to rim width nor is it reasonable to assume that the salesperson knows the OEM rim widths of every vehicle manufactured for sale in the United States.

As I indicated earlier, it's not safe to trust tire dealers. There's a lot to consider in purchasing a set of tires and tire dealers aren't in the business of educating you regarding everything you need to know. You have to do your own homework in advance, especially when the dealer you purchase from publishes specs for every tire they sell . . . as is the case with Tirerack.com.

PS: Tirerack.com does a better job than most dealers in providing the information required to educate their customers regarding tire and rim parameters. Unfortunately, Tirerack.com does not provide an adequate explanation as to why their customers should not exceed the acceptable rim width range for a given tire geometry. Perhaps that's why so many members of this forum have decided to make unsafe purchase decisions.