1 larger tire 3 smaller ones on car?

205/60/R15 tire is 24.68 inches tall and 8.07 inches wide.

195/65/R15 tire is 24.98 inches tall and 7.68 inches wide.

That's just under 5% difference. 2% is the max allowable difference. 2% because tires don't always wear evenly. That's why you're supposed to rotate them.

IF you put matching tire sizes on the driven axle then the differential would have no problems. But if you put an odd size on then the differential will have to work hard to keep the tire speed constant. You can burn up the spider gears and spider shaft.

I wouldn't recommend doing that. Better off putting the odd size tire on the un-driven axle. (front wheel drive - put matching tires on the front. rear wheel drive - put the matching tires on the rear. 4WD? Just don't do it.

The 205 tire is a quarter inch wider than the 195 and shouldn't be a problem. Especially if it's on the rear end. Front end steering means there's a chance the tire could rub when you go around a corner. That could kill the tire.

If you're doing it just to get you by for a day or two - shouldn't be a problem. But if you're going to ignore the mis-match for months on end - then you deserve what happens next.

That difference is so small (less than 2% if you do the math) that you likely would never notice even if it was on a driven axle.

You obviously DON'T know what a DIFFERENTIAL is.

Having different sized tires is not wise.

It's fine to drive it that way to the tire shop, and maybe for a week or so. My suggestion for you is to buy two tires for the rear axle and put the other tire on the spare so it's the right size.

If it is not mounted on a driven diff, you can get away with it, but depending on where you live, it may not be legal. Ideally tires on the same axle should be the same size

Driven differential? All differentials put power to the wheels. It's ok to use the spare tire for short periods of time. Why the hell do you think it's in the trunk? Just to take up room?

It would be illegal to drive like that here.

You don't mount tires on the differential and unless it's a 4 wheel drive vehicle it won't have a differential on an undriven axle. That said, yes, you can easily use those tires together if you're just going to do it temporarily. There is hardly any difference between the two and it will be far better than driving around on one of those stupid compact spares which really do cause dangerous handling characteristics.

No, not okay. The tread and sidewall measurement difference is sufficient enough to disrupt proper handling, control and stability of your automobile.