Tires mounted wrong way
 

I bought a used car in 2019 from a dealer in Salem, NH. It had 68,000 miles and now has 85,000. My mechanic informed me yesterday that the rear tires were mounted incorrectly with respect to "inside" and "outside." I never even heard of this before.

(1) Does this mean that these are directional tires?

(2) The tires were rotated back to front yesterday. I now have noise up front that wasn't there before--- a bup bup bup bup. What could be causing this?

(3) Why did this noise start with the rotation?

(4) At the same time, the traction control warning light is coming on randomly (that started a couple of weeks ago). What does this mean?

My theories: tires have worn unevenly because they were installed wrong, and/or the wheel bearings are worn.

Directional tires
 

Been around for decades. They either have 'Outside' written on the sidewall or arrows indicating the direction of rotation. Quality tire installers pay attention to the mounting of tires, like directional, and also the yellow dot should line up with the valve stem on the wheel.

You don't know how many times installers just do not get it! I have seen countless tires mounted wrong including TW, NTB, and VIP.

It's up to the buyer to be aware of this. The budget tires do not have these features.

Any insight into my questions? Thanks.

Directional tires are labelled with an arrow for direction of spin--just take a close look at the sidewalls. IDK on the other 2. Good luck!

Actually, you have 2 bullets. Not 3. But I assume your 2 questions are in 2.

1. As stated if there is an arrow or 'outside' on the sidewall, yes they are directional. Installing the tires wrong will reduce the tread performance while driving but I don't think it will trigger the TCS 'traction control system.

2. What does this mean? Could be a whole lot of things. Every manufacturer has different TCS and some need to be reset after changing/rotating tires. Some may need to be reset after changing tire pressure!
As far as the bup,bup,bup. It could mean lose lug nuts, alignment, or balance. If the TCS light goes off and on, it could mean a brake malfunction if there is noise.
3. Why does this start after tire rotation? Again a whole lot of issues may have popped up. Your mechanic should be able to diagnose the problem fairly quickly.

Looks like you didn't do a PPCI by a qualified independent mechanic. He would have spotted this problem and have you talk to the dealer. Most indies do this service for free.

BroadHopper, thanks very much for your helpful comments. I actually did have a thorough PPCI including test drive done by a "qualified independent mechanic" who I trust. He looked at the tire tread depth but I guess he missed the directional problem.

For what it's worth, which is NOT much, I have a Troy-Bilt 24" two-stage snowblower that's has one of its large black rubber tires mounted backwards on the rim with an inner tube inside it. It is very directional tread and has been backwards like this for three winters now, and it does not seem to make too much difference for moving it uphill while throwing the snow.

So, imagine a John Deere or a Kubota tractor with directional big-grip tires, one tire mounted backwards, and is similar for my 24' snowblower, but it don't somehow make any difference? ...... :eek2:

This tire would not hold air and would always be going flat. so I got an inner tube at Lowe's and took just the wheel to a bicycle repair business. It still works, holds the air, and is backwards but it seems to work just fine.

For your snowblower, though traction performance would be lowered, it may not be noticeable to you.

For a tractor, it could wear parts that become noticeable more quickly.

For a road tire, not only the performance, but also the wear would be unusual.
Tires with unusual wear when rotate can at the higher rotation speeds and levels of torque could make it noticeable much sooner.

I think of it more like when I run my snow's. The traction performance on dry roads is much different than my summer's.

Many tires are designed to plow water to the outside edges. I have had tires where the pattern is like a "V." You can mount them on either side of the car but they have they are only effective if the are mounted on the rims so the V pushes water aside. If your tires get rotated side-to-side, they will move water to the center and cause hydroplaning, unless re-mounted on the rims.

A diagonal pattern may not be as dangerous but you have more water hitting the underside of your vehicle.

And that's all I think I know about that.

I agree with you that mounting the tires the wrong way is a hazard and I'm getting them remounted this week. I also wonder if it reduces gas mileage, since the car is rolling against the tread.

I don't think you will have them long enough to find out!

Seriously though, I'd expect it wouldn't make much difference on fuel consumption. Tread edges round out a little bit and they are being laid-down like a track due to compression by the vehicle weight. Just a guess.

It is a hazard to have directional treaded tires mounted backwards. Especially in wet or snow conditions. These tires have a tread pattern that is specifically designed for traction, but also evacuating water and shedding snow as they rotate. Consider the opposite affect and you will see why this is dangerous. I can't say for sure but would guess also that premature wear is also something that could occur as well.

I don't think you will necessarily see any significant change in gas mileage, you will find the vehicle handles better in adverse conditions (wet and snow). It may be possible that there would be a slight reduction in road noise, but to be fair, the tread pattern not direction has a greater bearing on road noise.

If you ask the mechanic to rotate the rear tires (right to left, not front to back) that will reverse the direction they spin without going through the expense of re-mounting/re-balancing the tires.

I suspect they were incorrectly rotated at some point which is why you have this problem in the first place.

I had the tires remounted today. They're cupped and making noise so I'll replace them in the spring. (I don't have to drive much in snow.) Scary to think that I drove with them like that for two years and had no idea.

Depends. Some tires are asymmetric and require left or right directional rotation. Some tires have 'outside' stamped on the sidewall. they are symmetric tires with a different tread pattern across the tire. They have to be mounted with 'outside' facing toward you when mounted. Most all-weather and some snow tires are symmetric with 'outside' designation. Most high-performance tires are asymmetric.

The difference between all-weather and all-season tires is interesting. Google it.