Tire size

[fourthmeal]

Am I crazy or did I just catch that you are only installing new tires on the front?!?!

New, wider, WRONG size tires, at that?

Never change the tire size unless you are doing them all (or unless the car uses staggered sizes to begin with, like a Porsche 911 for example.) Further, if you are going to go with wider tires, they need to fit properly on the wheel. The stock 18x7 wheel is not wide enough for the tire you put on. I'm surprised as hell they even did the job. Here's another part that caught me off-guard...you mention that you were looking for an All-Season replacement tire for the stock one, while keeping the summer tires on the rear...not a good idea at all.

Lastly, why did you not rotate your tires? This would allow them to all wear much more evenly, allowing you a longer run on the set, so they could be replaced as they should be...a set.

I'm really curious as to what the tire installer shop was thinking when they OK'd this.

 

[SharkDiver]

Thats right,I only put 2 new tires on the front untill I get enough money to buy 2 more for the rear.The only problem with the stock tires on ther rear is that the rear end may slide around in the snow a bit.Its not going to hurt anything to do that for awhile.As far as the 235 on our stock wheels that is not a problem either from all the reading Ive done and from what the tire shop said.Im assuming that the tire shop isnt going to do something that will but them in a position to get sued so when they say the tire size is fine on my wheel I baleave them.Its not a father and son shop,Its a well known tire and auto place in this area so Im not worried at all about my setup but I will be getting 2 new tires for the rear in a month or 2.

 

[fourthmeal]

I'm not crying, "For SHAME!" on you or anything, so please don't take it that way....However:

This reputable tire shop broke many of the "rules" of tire installation...the very ones that I had to learn, uphold, and occasionally break in the name of customer satisfaction at the possible expense of their safety (though they certainly signed a document understanding their decision would not lead to a suit.)

Violations -

--Different sized tires on the same car, different axles (without a staggered setup in mind.) This causes the front of the car to have a totally different handling characteristic then the front. Think about it, the tire has a different shape, height, width, everything. The turn-in, cornering limit, wet-handling characteristics, and many other factors are different because of this.

--Installation of a tire that does NOT fit the wheel. An 7" wheel will comfortably fit a 215mm tire when fit with a 45% sidewall. Each manufacturer has their limits as written on the spec sheet available for each tire.

Here's the Goodyear F1 All-season as an example:
235/40ZR18
Load Index 95 = 1521lbs (690kg) per tire
Speed Rating Y = 186mph (300kph) 95Y XL
Treadwear: 420 Traction: AA Temperature: A
Rim width Range 8-9.5"

So this means that there is a huge disparity between the tire's design range (which is already very flexible) and what you've had someone do. I wouldn't do it. I wouldn't b**** too much if it were to say, for example, 7.5". That difference is negligible. But an inch is really pushing it.

--Installation of an All Season tire combined with a Summer-only tire. This is a huge no-no because an All Season tire behaves completely differently then a max-performance summer tire, especially at the handling limit. The difference can easily send you in a spin if you are making an emergency maneuver. I've seen it, and I've seen the wreckage from it.

Bottom line...its a dangerous thing you're doing, and on several counts. Again, I'm not trying to point and wag a finger at you, I'm actually trying to save you and potentially others who may (wrongly) follow your example. It worries me, because this is exactly how accidents happen.


Our car has electronic safety nannies, but they aren't designed to compensate for a drastic change in handling caused by ignoring all the precautions a tire installer should take.

You have to think of it this way...a tire installer can kill you and your family if they screw up. They can kill or seriously injure themselves if they screw up, too. Its not a job that is for people who don't care about others! Its also not a job for people who don't care about rules or about the details. Its those details or lack thereof that can kill. Just ask anyone who's had their lugnuts skip a torque-down or ask anyone who's had a blowout because nobody told them the inside of the tire had a bubble from a previous impact.

My advice to you: Cut your losses and put the 235/40-18's in the REAR (that's right, where they belong! The better tires always belong in the rear, so the rear won't come around when you least expect it to.) Then, put on your ASAP list to get a new set of WHEELS (at least 8", like RX-8 wheels for example) and two more tires. Then ROTATE those every 3,000 miles or so, and you'll not have this problem again.

 

[SharkDiver]

Thanks for all the advice.Even tho I dont have the extra cash now I said screw it and went and bought 2 more of the same tires to put on the rear,I dont like to use my credit cards but Thanks VISA!Im not going to worry about the 235s on the stockers.I guess If I autoX I would think about that being a problem but I dont.I really dont think Im going to have a problem with my tires breaking there beads.I may get a bit more side wall flex now but that is why I went with the 40s and also these tires have Carbon Fiber reinforced sidewalls.Ill post if I have any problems tho.

Shark

 

[RelliMS3]

So some people are rubbing with 225/45? I'm thinking of getting 7.5 wide wheels with a 49 mm offset. Will the combination of 7.5 in 49 offset wheel with 225/45 will rub?

 

[Hirudin]

So some people are rubbing with 225/45? I'm thinking of getting 7.5 wide wheels with a 49 mm offset. Will the combination of 7.5 in 49 offset wheel with 225/45 will rub?

I seem to be the only one saying this, but the RIM width shouldn't have much to do with the whether the tire rubs. Seems to me that the tire width is what is important, then the offset.

I'm running 235/45 17s on 8" rims with a 45mm offset. Last time I checked (admittedly kind of a long time ago) I wasn't able to determine whether my wheels were rubbing or not conclusively. One looked like it was rubbing a VERY slight amount (but again, I'm not sure).

I'll try to remember to check them again in the near future, if there's something drastic I'll update this post...

I only have my own tires to base this, but I'd say the tire/rim setup you're talking about will be just fine!

 

[drledford93]

The better tires always belong in the rear, so the rear won't come around when you least expect it to.

Man, this completely contradicts my background in Autox. But, I understand this premise for people with less or no racing experience. Good advice. (However, I won't be taking it--I know how to rotate a car properly, thank you!) (sun)

Daniel

 

[fourthmeal]

Cool, Shark.

I didn't want you to get in debt just because I say so or something, but I also hope that with matching tires the car behaves properly. The width thing is always an issue, but if you know your risks and the wear it will produce, then at least you're informed, right?

Rotate these tires every 3-4K...do it every oil change! And keep those pressures up at 32-33psi or so.


And to drledford93...LOL racing is sooo different compared with street survivability! Cones aren't people or cars, or mailboxes. Also, you've got your concentration hat on, whereas in a street environment there are so many variables and so many distractions,...it just helps to have the right set of tires on the car to reduce the risk of losing control.

To expound on what I was talking about with experiences at the tire shop...During a tire replacement from 245/47-17 to the customer's Demand of 275/4017 I was working on, a tire's bead snapped due to the stress of this on the narrow wheel combined with a bit of bad luck. I narrowly escaped with my fingers and shoulders intact. I have an uncle who owned a repair shop who wasn't so lucky with a tire...it blew and it took his shoulder and arm with it! This stuff happens every day.

 

[RelliMS3]

I seem to be the only one saying this, but the RIM width shouldn't have much to do with the whether the tire rubs. Seems to me that the tire width is what is important, then the offset.

I'm running 235/45 17s on 8" rims with a 45mm offset. Last time I checked (admittedly kind of a long time ago) I wasn't able to determine whether my wheels were rubbing or not conclusively. One looked like it was rubbing a VERY slight amount (but again, I'm not sure).

I'll try to remember to check them again in the near future, if there's something drastic I'll update this post...

I only have my own tires to base this, but I'd say the tire/rim setup you're talking about will be just fine!

Thanks for the advice. Now i'm thinking they'll be fine or will rub very little so it wont really matter. I think i'll ask where i'm getting my rims and tires installed, but if anyone else can shed more light on this specific fitment of 225/45 18 with a 49 offset that'd be great. I just dont want to end up with tires that don't work with the car.