Advice on buying tires

General Questions
#1

We have an Infiniti G35 AWD sedan. The two rear tires have had slow leaks for a long time; one just totally blew out and is beyond repair.

I’ve never had to replace tires on an AWD vehicle before. Do I have to do anything different? Does the ‘new tires on the rear’ rule still hold?

Both rears were kind of new when we got the car (less than a year old), and we’ve only put a couple thousand miles on them. Assuming a tire shop finds and solves the problem with the existing one (e.g. a bad bead or something), what goes into deciding if I replace just the one tire or both rears? Mrs. Devil will be the primary driver (and with the Devling in the back to boot), so traction, safety, etc. are paramount.

If it is a responsible choice to replace just the one, do I need to put on a matching brand/make, or will any good tire do? If I should replace both, do they need to match the front tires brand/make-wise?

I think that’s about it—unless I’m overlooking something. Again, I’ve never had an AWD before so don’t know if there are any peculiarities involved.

Tractionally yours,

Rhythm

#2

With AWD best to replace all four. Keep the best of what you now have for a spare.

#3

You don’t generally replace single tires unless something odd occurs like a single blowout or failure on brand new tires (I had that happen about a year ago so I replaced just the defective brand new one but that isn’t typical). I can’t tell from your post how much wear the pair that failed has exactly but it sounds like they are not new anymore: one failed and one is failing.

I think you need to replace both and get the tire shop to make sure there is no issue with the rims. Let them advise you on how to rotate the tires with the remaining good pair to get the best results.

AWD drive has very little to do with this in the long-term. You need to have your tires rotated from front to back every 8,000 miles or so anyway so that they wear evenly. All your tires should see duty in on the front or back axles if you manage them correctly.

The best thing to do, if you have the money, is just replace all four tires with decent ones. That should get you through the next 50 - 60K miles with few worries.

#4

My father in law has an awd g35 and has had loads of problems with tires wearing prematurely due to the camber set up which is not adjustable. There are adjustable tie rod ends made that are supposed to help but I haven’t investigated enough.

#5

Check your owner’s manual to see whether you can get away with not replacing all four tires at the same time. Some AWD systems are more sensitive to small differences in circumference than others.

#6

That is why it is important to rotate tires at regular intervals. Most people don’t because it is a hassle and costs some money but it actually saves money in the long-run. My Toyota RAV-4 sport had some cambering issues as well after the first 35K miles. It was shocking how fast it ate the two front tires. I went from riding fine to two completely destroyed (run-flat) tires in just a few hundred miles. It was barely drivable at highway speeds when I had them replaced. The inner edge just wore to a point where the damage curve became exponential.

I don’t know much about Infiniti AWG sedans but it is likely you have some alignment issues as well as current tire problems. Any good tire shop should be able to correct that for you for a price. Decent tires aren’t cheap on their own these days ($200 a piece is common) but don’t skimp out on the diagnostics to have the alignment fixed when you replace them. It is well worth it in the long run economically speaking plus it makes the car drive much better. It is up to you and the shop whether you want to replace two tires or four but you need to have the whole wheel system evaluated and aligned.

Note: Many small shops do not have the equipment to do true alignments because it is expensive and requires experience. However, even a dedicated discount tire shop will have them. I recommend a dedicated tire center for the problems you describe. Total bill for a four tire replacement plus all alignments should be less than $1000. If you do choose to do two, you might be able to get it fixed for $600 or maybe a little less.

#7

Is there a possibility there is a warranty on the existing tires? You might contact the previous owner.

What is the situation with the spare tire? Do you actually have a standard sized spare tire or is it a donut tire?

#8

It is always best to replace all four at the same time. If you cannot afford to do so, replace both a left and right tire, either both for the front wheels or both for the back wheels.

Never replace two tires diagonally, and try to avoid replacing a single tire unless both tires are quite new so there would be very little difference in tire wear between left and right.

#9

Crap.

So take it to a tire shop, not my mechanic. Was wondering if it would be worth the extra fifty or so bucks to have a small shop do it rather than a placed with no relationship and a lot of up-selling built into the business model. Plus, having an actual mechanic under the car could (in theory, I guess) be a good thing in noticing leaks or odd wear patterns. But he’s a small shop without too much specialized equipment, so I guess that’s out.

Car well is too small for a full-sized spare (are any anymore?). I’ll look into the paperwork for the tire–it’s my father-in-law so there’s an ease to some things in that regard.

Likelihood of replacing all four. Crap.

#10

Sorry Rhythmdvl, but keep in mind that tires and brakes are the most important parts of your car for safety and that you are doing the right thing to keep you and yours safe.

#11

Check the date on the existing tires as well. See the Tire Rack website or others for pictures. I personally won’t go past 6 years unless there is absolutely no sign of cracking or aging (and of course - the tread is good:))

“Since 2000, the week and year the tire was produced has been provided by the last four digits of the Tire Identification Number with the 2 digits being used to identify the week immediately preceding the 2 digits used to identify the year.”

At least it’s the G35 sedan; the coupe had staggered tire sizes, no rotation.

#12

This isn’t going to cost you your house. I would recommend that you only try for two new tires plus a full alignment (the full alignment should only cost about $50). You obviously need that at the very least. However, we are dealing with car repair professionals here and they are the masters at the up sell and the scam. Do not fall prey to any of their bullshit because that is what they do best. A small shop typically cannot do alignments because the equipment to do it right costs too much.

It sounds like you aren’t too sophisticated about cars and their maintenance. That is OK because most people are not either but it does make you a ripe target for a ripoff. Don’t let them sell you anything. The chances are excellent that your car will need to be in the shop for a half-day to a full day to have those repairs done correctly. Ask for a quote and then question them about why that needs to be done. Write back to see if it is a reasonable idea.

#13

Thanks. I used to be shade-mechanic sophisticated to a degree. Biggest job I ever did was replacing the engine on my 1980 Ford Fairmont, but I had lots of help and things are pretty much unrecognizable to me these days. And it’s been years since I even changed my own oil. I like my mechanic, but my nominal optimism fades quickly into cynicism when at a tire shop, oil chance place or the like.
Crapulent thing is that summer music festival tickets are all going on sale now and we just decided to bump up to four this year…and here’s about a thousand dollar hit, unless it turns out that the fronts are new enough. Need to find the paperwork!