I am carrying a used tire as a spare. That’s mostly because I bought a used car with no spare so I found a wheel at a salvage yard and didn’t want to spend a lot on a tire that might never see the road, and if it does will see it only temporarily. I doubt that I would ever buy used to run as my regular tires for reasons mentioned. I will also dump the current used spare when I get new tires on this car. I will take the current wheel with the best tire on it and throw that one in the trunk as the spare, and one of the new ones will go onto the wheel in place of the used spare. It still leaves me a “used” tire as a spare, but one that I know the history of and hasn’t been mounted and dismounted who-knows-how-many times.
@bertrand
The mechanic is correct as far as the alignment is concerned but not as far as different traction front to rear is concerned. You may turn with your front wheels but just like your body needs your left foot braced to step right, you need a bracing of the rear wheels to properly turn a car. Most people don’t seem to understand hold important good traction on the rear is to turning. Any movement to the right for example by the front wheels, will move the rear to the left if the traction isn’t good enough on the rear. Sorry, you actually avoid spin outs by having better traction on rear.
But, if you feel lucky, and the tread is within 3/32 of an inch of the front, it “might” be OK…but the treads are different which is another issue. Just avoid driving fast or in bad weather. ;=(
Let me put into perspective what several posters here have said. Your life and the lives of everyone who rides with you depends on 4 little rubber spots on the pavement. Those rubber spots support your car, allow you to accelerate, turn and brake. They are the only things between you and that telephone pole you don’t want to hit. I understand cash flow or the lack of it. Don’t gamble with used tires unless you REALLY know what you are doing. Spend decent money to get decent tires.
We have a local tire store chain that has been in business for years and has a good reputation. They ship all their used tires to one store. The tires are thoroughly inspected before they are put in stock.
With all the 4 and all wheel drive vehicles on the road they wind up with a lot of 3 tire sets when someone gets an unrepairable tire.
I have bought used tires for years for my work car and for any car I plan on getting rid of soon.
The last one I bought was a 217-70-15, a good brand with 8/32 tread for $35 mounted and balanced. That was a year and a half ago.