My rims have to be repainted. So i waas wondering if i put on another set of rims( not sure if they will fit over brakes yet) Would it be safe to run 215/45 up front and 235/45 in rear both on 17" wheels. this would only be for a few days?? The difference is less then an 1" in height. thanks for any info.

 

For short distance (-50 miles) for few days, I would say you'll be ok. Seeing how spare on our car is smaller diameter than stock tire.
But I won't suggest to drive too much.

 

The smaller wheel is going to make 20 more revs per mile. It'll tear up your diffs, don't do it.

 

i have no real factual info, but when my rim was bent i drove on a donut for a week, around 200 miles.... no problems here, yet

i would just try to drive as little as possible

Cheers!

 

stay off the hard driving or high speeds and you should be ok

 

bad idea your going to mess thinks up Ive seen it before

 

that is true but he said they are both 17s so there rele is no smaller wheel here the difference is a more narrow tire and the tread wear difference between the 2 i wouldnt recommend it but if its for a couple days and not driving often its rele up to u

 

You're right, it's the tire. Not only is it more narrow, it's also smaller in diameter and circumference.

http://www.miata.net/garage/tirecalcold.html

Plug in the two sizes in that and you'll see how much different the tires are. 215/45/17 and 235/45/17.

Difference in diameter is almost 3/4", and the rev's per mile are off by 23.

Now imagine how a center diff is going to like having to rotate the front tires 23 times more per mile than the rear ones.

 

ok decided against thanks. anyone selling one stock tire??? i just need 1

 

The ability of four-wheel drive and all-wheel drive vehicles to divide the engine's horsepower between its four tires is especially useful on loose or slippery surfaces such as sand and dirt, as well as on wet, icy or snow-covered roads. However it's important to remember that in order to transfer this extra power, the four-wheel drive and all-wheel drive vehicle's driveline mechanically connects the tires so they work in unison.

Four-wheel drive and all-wheel drive vehicles are equipped with additional differentials and/or viscous couplings that are designed to allow momentary differences in wheel speeds when the vehicle turns a corner or temporarily spins a tire. However, if the differentials or viscous couplings are forced to operate 100% of the time because of mismatched tires, they will experience excessive heat and unwarranted wear until they fail.

This necessitates that four-wheel drive and all-wheel drive vehicles use tires that are very closely matched. This is because different diameter tires roll a different number of times each mile as a result of the variations in their circumferences. Tire diameter variations can be caused by accidentally using different sized tires, tires with different tread designs, tires made by different manufacturers, different inflation pressures or even tires worn to different tread depths.

As an example of different tire diameters resulting from tires worn to different tread depths, we'll compare two 225/45R17-sized tires, a new tire with its original tread depth of 10/32-inch and a second tire worn to 8/32-inch of remaining tread depth. The new 225/45R17-sized tire has a calculated diameter of 24.97", a circumference of 78.44" and will roll 835 times each mile. The same tire worn to 8/32-inch of remaining tread depth is calculated to be 1/8" shorter with a diameter of 24.84", have a circumference of 78.04" and will roll 839 times per mile. While the difference of 1/8" in overall diameter doesn't seem excessive, the resulting 4 revolutions per mile difference can place a continuous strain on the tires and vehicle's driveline. Obviously, the greater the difference in the tires' circumferences, the greater the resulting strain.

This makes maintaining the vehicle manufacturer's recommended tire inflation pressures and using "matched" tires on all wheel positions necessary procedures to reduce strain on the vehicle's driveline. Using "matched" tires means all four tires are the same brand, design and tread depth. Mixing tire brands, tread designs and tread depths may cause components in the vehicle's driveline to fail.

Mismatched tires or using improper inflation pressures for all-wheel drive and four-wheel drive vehicles can also result in immediate drivability problems. Some Control Trac equipped vehicles in 4Auto mode may exhibit a shutter on acceleration and/or a noise from the front driveline and transfer case while driving. Some all-wheel drive and four-wheel drive vehicles may exhibit axle windup or binding while driving. Some four-wheel drive vehicles (manual or electronic shift) with a two-wheel drive mode may refuse to shift "on the fly" into 4x4 Auto or 4x4 High at highway speeds.

 

I drove on my donut for nearly a month because Discount Tire wanted to order the wrong tires, then give me a longer delay. The donut is the same height as the stock tire, the width is much different. My car is fine, but then I drove 65 for a month (longest month ever).