Warning: Grumpy old man yells at cloud and tells kids to get off his lawn. TL,DR: Tires wore out, dealer said alignment is fine, so I aligned it myself. You have been warned...
For our 27th Anniversary, Misses Valve Gear and myself took a longish trip out to the Northeast and back. Of course, the Mustang was our preferred mode of transportation, and I took it to the dealer to have it serviced before we commenced our 3000+ mile trip.
Now, I don’t cut corners on car maintenance, and although I’ve twisted wrenches for many years (decades?) on my personal stuff, I’m to the point in life that I don’t relish trying to access the oil filter on a very low automobile. I’ve done my best to build a good customer/dealer relationship with the local service department, and the Mustang has been serviced at said dealer since it was brand new - full synthetic oil, “The Works”service program, including inspection of various items on the car (ie, brake pad thickness, tire wear, etc). I looked over the report closely as I usually do, and satisfied with the stated condition of the car, we set out on our adventure.
However, sometimes things creep up on a person so gradually that you don’t really notice them until one day it just hits you - that just ain’t right. Such was the case as we were driving back home, and I suddenly thought, “Wow, this car has a lot of road noise nowadays.” It wasn’t that way when it was new, but it sure did seem noisy then. And of course, once I was aware of the noise, it really got on my nerves. Nothing really alarming, just - noise. It almost sounded like tire noise, but it couldn’t be the tires... the dealer had just inspected them for tread depth and proper wear pattern, right?
The car did in fact have tires that were worn almost bald on the inside corners - all four tires as it turned out, courtesy of the tire rotation I have done at every service.
Needless to say, I wasn’t happy. I wasn’t happy that the dealer had marked everything OK when it wasn’t OK. I wasn’t happy with myself that I didn’t flop down on the ground and look things over for myself instead of just taking the dealer’s word for it. And I wasn’t happy that I had got cheated out of some tire life due to what was obviously an alignment issue, especially since I had the car aligned this past spring.
The trip to the dealer was somewhat enlightening and entertaining. I brought the report, presented it to the very same service adviser that had handled the last service visit, and then we went out and took a look at four bad tires. I had assumed that the servicing tech filled out the tire wear portion of the report, but that turned out to be the responsibility of the service adviser. He is at the same disadvantage that I am - the Mustang is a low car, and you really can’t get a good idea of the tire’s tread wear without laying down on the ground to get a close look at the tire. He admitted he just checked the tread depth on the outside of the tire (which was fine - 7/32" depth) and gave a cursory look at the tread when he did so. He was obviously embarrassed about the situation.
That embarrassment, however, did not translate into any financial incentives on, say, a new set of tires. And, although I tried to get some proverbial blood out of the turnip dealer, I really didn’t expect to get any consideration on a set of tires that lasted 34k miles on a performance car. Apparently, a lot of people get a lot less than that, and they just consider it the price that you have to pay in order to play. The service guys did do a 4-wheel alignment check - it wasn’t free, but they did it for a pittance, which was good. And, of course, the car’s alignment was “within spec”.
“Within Spec”. Hmmm. That spec has a lot of negative camber front and rear. I know that it is set up that way to make it corner as well as possible, but that same spec tends to wear out the inside edges of the tread when most of the miles are on the highway. Ford doesn’t have any TSB’s that address this sort of tire wear on S550 Mustangs, and the service guys weren’t willing to do anything to a suspension that is “within spec”. And I do understand their position - they are a Ford dealership, this is a Ford car that is under warranty, and the suspension meets the specifications that Ford has supplied to them. To do anything outside those parameters opens up a whole lot of liability for them should something go awry. Understandable.
I, however, am not bound by those conditions. The Mustang community has a lot of niches within it, and the people in those segments tend to modify their Mustangs to suit their purposes, and those modifications include suspension setup. As one might imagine, the desired suspension settings for one purpose - say, drag racing - tend to be radically different than those settings for another purpose, such as autocross. My segment (long distance highway travel) is willing to sacrifice a few tenths of a g during cornering in order to get the most mileage out of the tire tread.
So, I’ve spent the better part of this weekend tweaking the alignment on the Mustang. It actually had enough adjustment in the camber arms to set the rear wheels nearly vertical; I left just a touch of negative camber on the back wheels (-0.25 degrees), and was easily able to dial the rear toe in where it should be. The front wheels also had a lot of camber, but unlike the rear, they aren’t adjustable from the factory. A set of BMR camber bolts did the trick, and they are now sitting at around -0.8 degrees. If I notice that the tires are still wearing uneven, I can always tweak those a bit more. A slight adjustment on the front toe, and all is well.
The car is now quiet just like it was when new, and no longer darts over longitudinal lines in the road. Hopefully, this alignment will translate into more even tire wear over the next several thousand miles. Will it work? Stay tuned to find out... I’m planning on a couple more long trips this year, so we will see what happens!