Tire purchase quandary

I bought a pair of Yokohama tires for the front wheels of my 2005 Cadillac STS last year. Now that I need rear tires, I see that the size is different and Yokohama does not make a tire in the “correct” size. So the quandary is whether to buy the matching tire in a slightly smaller size OR go with a different manufacturer in the proper size.

The correct tire is a P255/45/17. I can get a P245/45/17 instead. The width is .39" less, height is .18 less (4%), diameter .36" less (1.4%), 809 rev per mile rather than 799. Continental makes the correct tire in their DWS 06 line. That’s also a good tire at about the same price.

What do you think? Do I flip a coin?

Go to tirerack.com and buy four of the correct size tires. There is a reason that these are “correct sized” – your car was designed for them. I used to be a Yokohama tire guy for my BMWs but switched to General Altimax – much better tires. Read reviews on tirerack and buy what you like. They will drop ship to one of their recommended installers near you. Mis-matched tires are never a good idea. If you can afford the car, you can afford the tires.

Get the right size. It isn’t imperative to have the same tires on all four wheels. Also, make sure the speed rating is correct. Don’t drop down to a lower rated tire to save money. You won’t save much, and it won’t meet the Cadillac rating.

If your STS is front wheel drive AND you don’t push it to the limits of adhesion AND you don’t drive it fully loaded (passengers in every seat and max luggage in the trunk), then you can use the smaller tire.

If it is rear wheel drive AND you don’t push it to its absolute limits of adhesion, I’d recommend that you use the correct size tires, even from another brand, as long as it is pretty similar.

As long as this car isn’t AWD, I wouldn’t be overly concerned about different brands, front vs rear. But I’d want all four tires to be the exact size recommended by the manufacturer. The engineers who designed the suspension system assumed that’s the tire size the car will be equipped with, and any other size could change critical suspension system angles, both static and dynamic, affecting steering, handling, and tire wear.

+1 to George’s post.

What George said. Correct size /rating trumps brand.

Here what isn’t obvious in the OP:

The only 2005 Cadillac that takes a P255/45R17 is one with a staggered fitment: P235/50R17 front / P255/45R17 rear. So obviously the OP wasn’t concerned about matching before.

But, I agree get the proper sized tires, but in this case, the fronts and rear should also be compatible - so I think that means the same make and model, which means purchasing 4 tires. If this doesn’t happen, then there is a possibility that the vehicle could be unstable in emergency situations, which the driver won’t know about until it is too late.

Ugh. I will never buy a car that has staggered wheels/tires. What a pain.

Thanks for the comments. My OP may have been misunderstood in some instances. The car has a staggered fitment as CapriRacer points out. The quandary results because I purchased Yokohama P235/50R17 for the front without thinking to verify that the Yokohama P255/45R17 would be available for the rears when needed. They are not.

And Keith, the car is rear wheel drive. You frame the problem nicely. It’s a touring car. I save the max adhesion and max traction driving for the sports car. But it is the drive tires were talking about here and smaller tires are probably not going to wear very well.

So I’ll go with the Continentals in the correct size. As Texases says: The correct size trumps brand.

Thanks for talking sense.

Good choice. I have mismatched brands on my staggered MR2 setup. Yokos on the back, Firestones on the front because Yoko no longer made a performance tire in the size I needed when it was time to do the fronts. Hasn’t hurt anything.

I would buy 2 tires for the rear, same size as Cadillac specs. Since the car has handled OK with the Yoko’s on the front and whatever brand is currently on the rear I’d price the same tire you are now running on the rears. If the price is too high, then shop for another tire.

My son’s Infinity had different sized tires on the back. I never understood why and makes rotating impossible. My G6 had two Yokos and two something else. They looked the same and never noticed it for a couple months but felt a little better when I just replaced all four with the same thing. After all, what has been said before is the tires are the only thing between you and the road.

Remember the Plymouth Prowler?

Back in the 60’s and 70’s it was very common to have wider tires in the back…especially on muscle cars. Some people went too far…but it was still very common.

True, but not from the factory.

The muscle cars - no…the Prowler - Yes.

My V-6 Fiero GT (but not my 4-banger) Specifies Different Sizes For Front And Rear, From The Factory.

I bet a lot of Porsche 911s also had staggered sizes beginning years ago.

I Rode In A 930 Turbo (I believe That Was It) Years Ago. That Thing Had Huge Tires On Back. That And The Whale Tail Caused People To Stare.

In the '60s and '70s almost everything was front engine/RWD and the tires were almost all bias ply. 4X4 was pretty much reserved for trucks and AWD had yet to be heard of. Limited Slip Differentials we uncommon on daily drivers. Everything’s different now.