OK, I’ll try to keep this short and to the point. We’re driving a long way for Thanksgiving next week, and before we go, I needed to get two tires replaced on the Honda Pilot we’re going to be taking, because they were nearly bald. For reasons, I didn’t have time to take it to our usual mechanic, so I took it to a tire place instead.
What the tire place guy told me is that Hondas have some sort of rule where all the tires on the car have to have matching tread depths - within 3/32" of each other. The way he phrased it made it sound like this had something to do with the fact that it’s all wheel drive, but I’m not sure of that. So he measured the tread depth on the two good tires so he could find new tires with tread depth within the acceptable range.
After some time on the computer, he announced that apparently there has only ever been one single solitary model of tire ever made in the right size with the right tread depth, and further, that said model has been discontinued, and the nearest remaining tires of that model were located halfway across the country. So I had a choice of having the required tires shipped in, or replacing all four tires, including the two perfectly good rear tires. Since shipping would have been too slow for the Thanksgiving trip, and since the price difference was only about $150 (shipping costs, natch), I coughed up for four new tires.
So. Is this “tread depth” thing legit, and should I be thankful to this guy for being so conscientious? Is it one of those things where the manufacturer recommends it, but everyone knows it can be ignored, except for tire places that want to squeeze a few more bucks out of you? Or was it just complete bullshit?
Sounds weird to me. I’ve never had a Honda, but the only thing that I’e ever seen as far as tire specs are concerned are the diameter, tread width and aspect ratio.
I always replace complete axles at the same time (left and right tire). But I keep newest (best tread) on the front and rotate the ‘current front’ to the back when I buy new tires.
I believe the side to side issue because of steering on the front end. You want similar traction/pull against the control stuff.
But, how a different size between front and back matters? Maybe if your rear tires are so bad that they spin out all the time so put extra strain on the rear end? But if you have reasonable tread and are not going to have a significant difference in traction… ???
Was this some young kid? I’ve noticed that these tech educated kids come out of school with some really screwed up beliefs. I talked to one CERTIFIED mechanic who thought that gasoline was swappable with kerosine and would not believe me when I said NO, diesel and kerosine are swappable. NEVER, NEVER, NEVER put kerosine in a gas engine. This kid was a certified mechanic and the exact sort that a Walmart type place would hire in their garage.
(His belief is probably coming from the fact that gasoline and kerosine are both clear, while off road diesel in this area is dyed red.)
Hopefully, if you still had good tread on that set of tires you at least kept them to either rotate back in over the summer or sell on Craigslist to someone who would use them. Either would be better than paying them a disposal fee.
But… my advice is worth what you paid for it. I’m not a mechanic and my tires are always huge mud lugs.
I have to say, I don’t know anyone in my area who drives a 4x4 truck that changes all tires at once. And I’ve never heard of them having problems like described in the linked article.
But, I guess I could certainly see auto manufacturers making cars quite a bit less sturdy and less durable. At least, now I know to never buy AWD on a car.
I’m on my phone so I can’t do research right now, but yes some AWD systems require tires that are matched. I do not know if you Honda is one of them.
It actually can cause major damage. I know of a case where a customer with an almost new car blew out a tire his AWD car and replaced it with the same size of a different brand. At speed the effective diameter was different and caused the angle gear assembly to burn out.
Replaced under warranty (nobody noticed the odd tire)
Drives car, burns out angle gear AGAIN
Replaced under warranty
(You know what’s coming)
Drives car burns out angle gear.
Factory sends engineers out
Heads are scratched.
Finally somebody notices, hey this tire is a different brand.
You don’t even want to know how much all those repairs cost.
It is common for Subaru to need all matching tires, so much so that there is a special mode you can get your car into if you need to use the donut spare or mismatched tire size that puts the car into FWD only mode.
As I understand it the difference is ‘full time’ AWD vs off road 4WD. A car/truck with a selector to allow 4WD for off road conditions, which includes snow/ice, the limited traction of the driving surface allows a degree of slippage. These systems, which are really ‘hard core’ 4WD systems, are not meant for pavement. OTOH the Subaru system and other full time AWD systems is meant to be AWD on all surfaces, including surfaces with great traction, this does not allow for the road to be where the slipping occurs. Having a difference in tire size over a certain amount stressed the drivetrain instead as the smaller tire will turn faster the the larger one, but when the system goes in to a locking AWD mode they all must turn the same.
Not really. It depends on the hardware used in the AWD system. Some types of hardware allow for slippage due to different tire size, other AWD systems don’t.
No comment on the OP issue, but wanted to comment on this. The general advice on front vs. back is to put the best tread on the back.
If your tires lose grip at speed, having the rears lose grip is considered more dangerous because it is harder to regain control. If the rears keep their grip, you can brake and the car will true up, if only the fronts have grip, braking will cause the rear end to swing around uncontrollably.
As mentioned, I know Subaru is pretty clear that all four tires should be very similar in circumference, and all four tires should be replaced at the same time. I don’t know what kind of AWD system the Honda Pilot has, but I would read the manual.
Relying on a tire store, or your auto mechanic, might not be the best idea. Even if honest and knowledgeable, there are too many models to know everything about. If flaky, or prone to generalizations, the problem becomes worse.