Can I convert my AWD car to front-wheel drive during the 6 months of the year with good weather?

Dear Car Talk

Dear Car Talk | Jan 01, 1999

Dear Tom and Ray:

I have a 1996 Subaru Outback. As you know, this is an "All-Wheel Drive" vehicle
in which the four-wheel drive mode is always on. I got a flat tire soon after I
bought the car. While checking the owners manual for the specific speed limits
while driving on the mini-spare, I found that it was suggested that if I use the
mini-spare, I should insert a fuse that disables the rear-wheel part of the all-
wheel drive. My question is this: Would it make sense to keep this fuse in there
during the six or so months out of the year when there is no need for all-wheel
drive, thus increasing my gas mileage? -- Ivan

TOM: I wouldn't.

RAY: The reason you put the car in "front-wheel drive only" mode when you use a
mini-spare is to prevent damage to the center differential. Because the mini-
spare is a different size than your other wheels, you would be using the
differential in a way it wasn't designed to be used. It would be as if one wheel
were slipping on snow for 50 straight miles, which never happens in real life
and could cause unnecessary wear to the center differential.

TOM: But I wouldn't disable the all-wheel drive the rest of the year. First of
all, it's a pretty compact system, and it has a very small negative effect on
your fuel economy. But more importantly, a good all-wheel drive system improves
the car's handling all year-round, not to mention on wet, sandy or gravelly
roads, which you can encounter in any season.

RAY: Besides, what if you forget to pull the fuse in the fall, and you're
driving home from work one day and it starts to snow. It might not be until you
bounce off that telephone pole that you say to yourself, "Oh yeah, the fuse!"


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Ways You May Be Ruining Your Car Without Even Knowing It!" Send $3 and a stamped
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