is it safe

[neuro_funk]

to run diferent size if wheels? 17 in front and 18 in the back

 

[jayson427]

if you can fit 18s in the back without rubbing then yeah its not unsafe but to me that would just look weird imo.

 

[My1GLaser]

No!!! Not on an AWD car. It will destroy your viscous coupling quickly. Not to mention that I'm sure it will screw up other things that I don't know about.

 

[crash89]

Assuming you are talking about the 1g awd under your avatar.. As long as you have the same size tire you would be ok. So say you have a 25 inch tire up front and a 26'' in back you will eventually start eating up drivetrain parts. But as long as the circumference is the same you will be fine.

But I agree, it probably will look goofy as shit..

 

[neuro_funk]

that was out of curiosity because i've seen it in nissans and they look cool

 

[crash89]

that was out of curiosity because i've seen it in nissans and they look cool

Thats because the majority of Nissans arent AWD.. In and AWDs case the differentials are spinning at different speeds there for working against each other and tearing up drivetrain parts. I would assume the center diff, but Im not a drivetrain expert so dont hold me to that!

 

[nuclearr]

the only way you could do this on an awd is to run tire sizes that have the same rolling diameter which also varys with rim width.

So in other words the front tire would have a taller sidewall than the rear tire.

 

[neuro_funk]

i get it guys thanx

 

[honda_burner]

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Like this gem?

 

[DSMTaggart]

Everybody's consensus of "not on an AWD car" is correct. My wife recently got a flat on her subaru, and had to replace all 4 tires because in AWD cars they have to be the same size. So the same would apply to using different sized rims, unless you used different sized tires to even things out. I've posted a little "tech talk" thing I found explaining why below:

Tom: The anecdotal evidence suggests that all-wheel-drive systems can be damaged by using different-size tires on different wheels. Even if the tires started out as exactly the same size, if one pair is worn down, that difference in circumference can cause problems.

Ray: Here's what happens. On all-wheel-drive cars -- cars that are permanently in four-wheel drive or can be left in four-wheel drive all the time -- there's a part called a center differential. This is a clutch assembly or viscous coupling that's so complicated, we couldn't possibly explain how it works without using our hands. And maybe the hands of at least two or three innocent bystanders.

Tom: When the car is going straight down the road, the center differential doesn't have to do anything. It just sits there. But when the car turns, the front and rear axles need to turn at different speeds to keep the wheels from binding up and the car from flipping over. The job of the center differential is to allow the axles to turn at different speeds.

Ray: The problem is that if the front and rear tires are different sizes, then the front and rear axles are always turning at different speeds. Even when the car is going straight ahead. That means the center differential is always working -- and that wears it out.

Tom: And the center differential costs big money.

Ray: Maybe someday they'll make center differentials more robust, so they can take the constant use that different size tires require. However, that's not how they're made at the moment.

 

[bryanwheat]

\

Tom: And the center differential costs big money.

Ray: Maybe someday they'll make center differentials more robust, so they can take the constant use that different size tires require. However, that's not how they're made at the moment.

Center differentials aren't that expensive, you can usually get them for around 100-150 bucks in good working order. The center diff isn't what is damaged by using different size tires, the viscous coupler is what will be damaged. You can use what ever size rim you want as long as the outer circumference of the tires is within 5 percent of the others. They don't have to be 100 percent the same diameter, there is around a 5 percent difference that is acceptable. Front and rear tires wear differently, so every awd car out there would have a bad viscous coupler if a slight difference in diameter was that big of a deal.

 

[DSMTaggart]

Right. They mention the viscous coupler, but I was really just posting that bit to explain why it gets worn out more than it should on different sized tires. I also agree that pricing for us would be much different, especially if you're doing the work yourself, it was just a part of the "pasting" and i didn't feel like cutting and editing. Some % of difference is acceptable, I don't know if I made that clear in my posting, even different sized rims can be used as long as it is compensated by tires that bring the overall circumference to within that 5%.