>15" wheels + lower aspect ratio tires?

[BerniniCaCO3]

This November, partly because they were cool, partly because winter was coming, and in large part because they were new and cheap off craigslist (guy bought them for a jeep he totalled before getting installed, new with stickers still on 'em) and much less money than any hankooks at sears
I've got 4 225/75/R15 pirelli scorpion atr tires on my stock 15 wheels, for a 1990 grand marq wagon. Stock size was 215/70/R15; these tires are a little bigger but fit just fine.

However...
last summer I was getting 18mpg for sure, often 20, and once even 24mpg (allll highway on that trip).
This winter? 16mpg consistently.
Yuck.

I'm wondering if it was just winter gas, if that could really shave 3+mpg off average fuel economy?
But I'm worried that these light truck/suv/"all terrain" tires might have killed my fuel economy from the higher rolling resistance.

The high aspect ratio and softer quasi-mudslinging design, at least compared to a dedicated highway tire, certainly can't help.

So I'm wondering if I might want these for winter tires then, and consider --when I have some money in 4months, I'm wiped out for now-- larger wheels, like 16 or 17", and shorter aspect ratio tires for the highway?

The lug pattern must be the same,
and the final diameter should be the same too...
I was just playing with some numbers. If it exists, and is a common size, a 215/55/R17 tire will be the same total diameter as 215/70/R15 just for example.

What are some common sizes of wheel with the same lug pattern, or popular donor car?

Finally, can't be too pretentious. I *hate* 20" chrome wheels + a lift kit on a grand marquis, and if I go for a larger tire I can't begin to approach that aesthetic. Something toned down.



thanks for the advice!

[BerniniCaCO3]

OK: I've answered some of my own questions. It's a 5x4.5 lug pattern.
Most of the jeeps and explorers have 5x4.5 lugs but seem to also be 15" wheels.
Unfortunately, mustangs DO have the right bolt pattern, but they all seem to be very wide tires, like 245-285?
Hmm... seems a lexus actually has a 5x4.5 lug pattern, and have narrower and less flashy wheels than the mustangs....

Any other thoughts for compatible wheels?

And, is the entire premise --that replacing a high aspect ratio truck tire with a low aspect ratio street tire + wider wheel, will improve fuel economy while admittedly looking somewhat cool-- correct, or in fact unfounded?
and my fuel economy issues are either winter gas, subtly changed driving styles, or some other undiagnosed issue!

[Lincolnmania]

it's the tires....those are prob good in snow tho and not cheap.........get some 16" wheels and a set of 225/60/16 tires........keep the 15" tires on the wheels for winter driving

[1987cp]

What's this about fuel economy and 20" wheels? I get lousy fuel economy in the winter mostly because it takes 4-5 gallons of gas just to get the car started. And traction and safety always take precedence over rolling resistance.


I have one set of 235/60/16, and they're almost exactly stock height (27"). I really like my two sets of '98-'02 wheels. I also like avoiding those endless irritable e-mails back and forth with sellers trying to explain that you really do need more info than just the bead seat diameter!

[gadget73]

Also consider the speedometer is not accurate with different size tires. Taller tires log less mileage which shows as lower fuel economy.

[mrltd]

Uh, did you do the correction factor for the oversized tires? The tires are taller so the odometer will read LOW. The travelled distance will be farther than the odometer thinks it is. which will f up your MPG calculations.

also, winter gas and cold weather in general kill fuel economy. I normally lose 3-4 mpg in the winter- with all of my cars

As for 17" wheels tires....mustang wheels have been discussed a lot.. The stock 17" crown vic tire (late model panthers) are 235/55/17- which are also used onthe newer mustangs. They are widely available, inexpensive and 27 overall diameter.

[Glen]

But, will the later CV 17" wheels fit on the older cars?

[mrltd]

But, will the later CV 17" wheels fit on the older cars?

READ THE FAQ!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Glen]

Are we back to that silly answer again?

[sly]

since the answer to your question is already there in the FAQ... I would guess so.

but the LMGTFY answer is yes... all later wheels will fit older cars (within panther models that is). The lug spacing is the same. The reverse is not true since the later models have larger brakes (don't remember which years off the top of my head) and need at least 16" wheels. So the 15" turbines on my 82 Mark VI will not fir a current CV, but will fir fine on my 93 CV or 88 MGM.

[1990LTD]

since the answer to your question is already there in the FAQ... I would guess so.

but the LMGTFY answer is yes... all later wheels will fit older cars (within panther models that is). The lug spacing is the same. The reverse is not true since the later models have larger brakes (don't remember which years off the top of my head) and need at least 16" wheels. So the 15" turbines on my 82 Mark VI will not fir a current CV, but will fir fine on my 93 CV or 88 MGM.

IIRC 98+ can't use smaller than 16" wheels.

[Glen]

And, do you have to use spacers to get the right offset?

[1987cp]

'03+ Panthers went to a high-offset wheel (more backspacing) with the suspension redesign. What wheel are you using on what?

[Glen]

I just want to go to a 16" wheel. 15" tires in the size I want are getting rare.

[1987cp]

If you're currently in a 15", it must be a pre-'98.

In that case, a stock 16x7 from '98-'02 works good. No spacers. See my sig pic, I've got two sets. Again, 235/60/16 is 27" tall, and 225/60/16 is a bit shorter and has a pretty big selection.