What would be the downside of replacing three old tires and using the unused spare tire and wheel as the fourth, switching the best existing tire/wheel as the spare?

 

None that I can see. I would try to stick with the same brand and model of tire. The only problem might be the age of the spare, even if it's never been used. I think most tire makers recommend 5 or 6 years old as max age to be using a tire. I think.

 

You would be constrained in selecting 3 new tires to match the make and type of the spare.

If your spare wheel (rim) is different then you have to pay for un-mounting and balancing.

Also some time you get 4 tires for the price of 3.

Not too many people know but tires have a shelf life. [date of manufacture is marked].

Salim

 

^^^^1, six years is max for my spares

 

I'd add a comment on the quality of the OEM tire. My OEM was Goodyear 18" and they were about the worst tire I've ever driven on. I'd not give that tire a second thought about buying. I chose to switch to 4 new Alenzas and couldn't be happier. I'll leave Goodyear on a spare.

 

You will probably find it difficult to find 3 matching tires today to a tire made 6 years ago! The world moves pretty fast to expect the same tire design to still be in production.

But it is worth a try. I was able to find 3 matching MXV's on mine and saved the $ on the fourth.

Do keep in mind that there are often deals like buy 3 and get the 4th tire free, so shop around.

 

If it were me, I would shop around as others have stated for a good deal on a set of 4 new tires. I think you and your RX will be happier with a matched set of 4 tires, especiallt when it comes time to rotate. You don't want a mismatched set on the front of your vehicle which will eventauuly happen with regualr rotations.

 

I replaced all five tires on my 04 x2. Expensive? Yes, but I don't fool around with my shoes My dealer had the best prices and a coupon for free alignment the last time around. Check for manufacturers rebates too. And strangely enough, the Alenzas are cheaper than OEM, much better tire and will last much longer. I'd definitely recommend them.

 

Assuming that you can find a replacement set of three, the biggest issue that I would have is that tires age from ozone and UV radiation. I read a technical report on tires and they suggested a ten year cycle to replace tires, regardless of mileage, just due to chemical breakdown in the rubber compound. When I replaced my OEM Michelins, I saved the best of the five (I did five tire rotations) as a spare and bought four new Bridgestone Dueler Alenza and I couldn't be happier with these tires.

 

I would do all 4 just to be safe !! Tires are way too important to mess up, yes it may cost more to do all 4 at a time but the cost of driving safe is priceless

If you can afford it do 5 tires and do 5 wheel rotation each time

 

I put Bridgestone Dueler Alenza's on my '04 and really like the way they look, (wider than the original Goodyears). However they are about 4 lbs. per tire heavier so I noticed a 1-2 mpg. drop in fuel economy. I am going to replace them with Yokohama Avid Envigors provided they are about 8 inches wide and weigh no more than 30 lbs. each. They are due to come out in March, '10 so Yokohama hasn't released any specs yet.

 

LBCDan so are you going to sell the Bridgestone when you get new Yokohama ?

 

Yes, agree on getting 4 tires. Leave the spare as is. The best value would have been getting the 5th wheel rotated with the others. Them leaving the best for the spare and get 4 replacements.

If I were you, leave it. Get 4 new ones. And yes, they also have a time limit for road use. As a spare you can use it even if it has been years.

 

My tire guy says leave the spare where it is due to its age.
My spare is the original spare from '04, and he says it's good as a spare, and much better than the small size spares, and it should be good if called upon for a hundred or two miles, but he would not drive such an old tire at high speeds for any extended period of time.

 

should have done 5 tire rotation and you wouldn't have this issue