Great mpg WITH aftermarket wheels???

[PSD_Guy]

Just got a n-used '05 Corolla S. Has the 15" alloy rims with the 195's on them.

Needs tires anyhow - and the alloy rims have some curb rash - was thinking of replacing all with 16" rims and 205/55R16 tires.

How much will my mpg be effected?

Also - can a larger tire be put on the 15" rim. With my old VW Golf TDI it came with the 195 65R15 and I ended up putting 205 60R15 just fine. Can I do the same here?

[PhatRoyale]

Yes, but you should play around with the miata.net tire calculator to find a size that will maximize speedometer accuracy.

Larger wheels and tires usually weigh more and the increased unsprung mass will also increase rotational inertia which will in theory, reduce your MPGs. Unless you're wheels and tires are lighter than the stock ones of course.

[bennor]

While tires types and sizes can impact MPG's and speedometer readings the biggest factor is your driving habits. There is no sure way to tell how tires on another person's car will affect MPG's on your car as each driver has their own driving styles.

For me my MPG's pretty much stayed the same when I got rid of the god awful stock OEM Bridgestones Insignia tires and put on Michelin X Radial DT tires on my 05 Corolla over two years ago. I routinely get 34 to 36 MPG on the highway with 10% ethanol gas sold in my area and once got as high as 40 MPG with non ethanol gas once with the Michelin tires.

[PSD_Guy]

I was on Tirerack.com last night looking at tires and wheels - specifically weight and overall diameter.

I understand a bit about oversized tires - I run 35's on my PSD - 4" larger overall diameter then stock.

But getting back to the Corolla - the stock tire I have is the 195/65R15. Tirerack pretty much confirms across the board the 195 is 25" OD +/- a hair.

I came across the Michelin HydroEdge with Green X technology - supposed to be a mileage enhancer - reviews of other drivers confirmed the mileage increases of the tire on their vehicles. But when I looked at the size they have for 195 - its listed as a 24.5" tire (or something like that - definetly smaller then the "typical" 195). Got me wondering. Did they gain mileage by making the tire smaller?

Then I started looking at what in that tire type would "be" a 25" tire. The size was 215/60R15. Would that tire fit on a stock '05 15" Alloy rim? I think the rim is 15x6.5 Aluminium (not steel with hubcap)

[PSD_Guy]

Let me update myself. The Michelin HyrdoEdge with Green X 195's are 24.7" OD. I had previously stated 24.5"

The 215/60R15's are 25" OD. The rim width is listed as a 6-7.5.

Weight of the 215 is 23lbs - the 195 is 21lbs. Stock rims - the difference in weight to be 8lbs - doesnt seem like that much of a difference - heck my camera bag is 15lbs when I carry that.

[PhatRoyale]

Maximum I width of tire I would mount on a 6.5" wheel would be 205.

Any more than that and you risk causing the sidewalls to split due to the excessive overhang and stress from flexxing when heat builds up.

Ideally:

6.5" = 195 tire
7" = 205 tire
7.5"= 215 tire
and so on.