Will this be worth the effort? 4 Space Saver Tires
 

One experiment I want to try this spring when the ice is off the roads is to mount four space saver spares on my car and find out how this will affect MPG. Has anyone tried this? What have been the results? I have an 89 LeBaron Coupe with the 2.5L. I can buy 3 space saver wheels/tires for $15.00 from a salvage yard and then use the car's spare for the fourth. This should significantly lower the car, plus I'd be putting a lot less tread on the road. I know this is no pemanent solution, but thought it would be fun to try for a couple of tanks of gas and check the mileage. I've wasted $15.00 in a lot worse of ways.
Eric Pederson
Nome, ND

Previous experiments by others (there's a video on Youtube) have indicated that donuts on the rear of a FWD car will increase gas mileage, albeit at the expense of fast-wearing tires and possible legal problems (ticketing and/or inspection failure).

I would expect using them on the front would make gas mileage worse, because the final drive ratio will be lower -- the engine will need to turn more revolutions per mile.

I'm with him^ sure you'll have lower rolling resistance but you'll need new ones every 800 miles because they'll be bald. you probably want to think about the braking ramifications before little susie runs into the street after her ball. donuts on the rear: maybe. donuts on front: not so much.

yea i think i suggested this long ago, usually the doughnut tires are ALOT smaller thus likely lower mpg by what bruce said than the regular tires and say no faster than 50mph... it would probably handle really weird (but excelent rain and snow traction, super skinny, just acts like a sawblade if they spin on snow)

Haha, my donut is actually taller than my normal wheels (14vs13). But like said, they arent supposed to be run for long distances. What is it? 50mph for 50miles is all your supposed to use them for...

Ahh yea, well rim size might be bigger but a lower profile, stiffer tire prolyl make it about the same height as the others. Yea it wouldnt last too long tho. i know its no faster than 50mph but didnt know they had a life limit.

It is a substandard tire intended for temporary use only and you risk a lot of safety by using four of them. They probably will not stand up to any hard braking or cornering for very long and may provide reduced traction on dry clean pavement than a conventional tire.

Use the $15.00 for gas

Eric,
Keep your chin up. Sorry your idea met with disapproval.
Give yourself credit for an active mind and for thinking outside the box.

Do have a look at the sticky at the top of the list under "General Fuel Economy Discussion" forum header, it's called "list of gas saving tips from best to worst".

Not that there will never be anything added - you'll see new ideas floated and tried out here often. But that list can give you plenty of good things to do - and they can be a springboard for new developments too.

Four donuts, even at 60 psi each, had MORE rolling resistance than four full sized, 32 PSI Michelins when I considered four donut spare use for a mileage competition I entered in 2005.
Simple low speed coast tests (release the brakes from a stand still on a gradual slope, how far do I coast before stopping) showed the lower pressure, wider 'normal' tires offered about 5~10% more distance than 60 PSI donuts.
Donuts are good for thousands of miles of use. The mileage distance is limited only by tread wear, and with not a lot of tread to begin, that isn't all that far, only a few thousands of miles, perhaps. The speed limitations are due to heat dissipation and carcass failure from overloading and over speed. Oh, and the fact the tire has so little contact area that loss of lateral control is more dangerous at higher speeds.