Upgrading Wheels

[ViperJ]

I have a 99 Malibu stock wheels are, 15x7 (5x115) wrapped in 215/60R/15. I will be getting some 17x7's (5x114.3) wrapped in 205/40/zr17. Are there going to be any problems? Thanks

[Automatic 51]

i wouldn't think so the wheel width is the same as stock, i'd just make sure the offset is te same as stock as well. that's the only thing form what i see there that might be ab issue. other than that it should work. oh, and be sure to have them put on the hubcentric rings too, makes it fit nice and flush withthe wheel hub and prevents rattling.

[ViperJ]

Okay thanks Automatic 51

[Rufe]

Did you have a particular tire in mind?

If you can give us the model tire you have, and the model tire you will get in 17" I can give you a better answer.

Otherwise, it looks like your stock tire is about 25.1" diameter, and your new tires will be about 23.4" diameter. A 215/60 series, (regardless of rim size) GENERALLY is wider than a 205/40 series. By 10 millimeters at the tread, and proportional for the section width.

So, Speedometer will be off, tire will be narrower by ~1/2 inch, car will accellerate a bit faster, use a bit more gas.

There is also a load rating for tires, you need to be careful you do not go below the factory recommendations here. You are losing some airspace here.

To repeat: If you can give us the model tire you have, and the model tire you will get in 17" I can give you a better answer as to what to watch for.

[drdisque]

it may end up handling worse with the 17s than it did with the 15s because of the lower width, I'd go with 215/45/17s instead

[Grant@Tirerack]

You need to be looking at a 225/45-17 tire size to operate safely on a Malibu. A 205/40-17 is way too short on O.D. as well as load rating. Those would be over 200 lbs per tire under the load rating you need for the car. Unless you plan to drop 800 lbs of vehicle weight somehow, I'd be looking at a larger tire.

[ViperJ]

Okay well the rims have already been bought, 17x7 so what tire should I put on them? I’m fairly new to the tire and rim game. So what is the max width that this tire can have is it the rim size that matters? The rims I am getting are Primax 618.

[ViperJ]

Originally Posted by Grant@Tirerack

A 205/40-17 is way too short on O.D. as well as load rating.

How do those relate? Why would O.D. matter?

[ViperJ]

Also how would the spedo be affected if I am doing 60? Would I be doing 65 or 55 etc? Thanks

[drdisque]

http://www.miata.net/garage/tirecalc.html <-you can fiddle with tire sizes here

[ViperJ]

Well I did the tire calculator and it said " When it reads 60mph, you are actually traveling 55.9"

[rwood13]

listen to the guy from TireRack, they know their stuff

[Grant@Tirerack]

The load rating is the greater concern. With an air chamber that small, the tire can not support the same amount of load and will generate more heat in the sidewalls (read Ford Explorer). At the very least, the tires would wear out very fast due to more heat buildup. In the worst case, they would experience overheating in the sidewalls leading to sidewall failure at highway speeds. As far as the O.D., many newer cars/trucks are set up to run with a specific tire O.D.. That can effect the fuel mixture at a given RPM, ABS brakes, traction control, shift points on an automatic transmission, as well as the speedo and odometer. Vehicles with variable valve timing can start to run to rich or lean depending on how you change the O.D. of the tires. It all has the same effect as changing your gear ratios on the back end of everything.