My car has some rather aggressive alignment specs, based on my sleuthing around BMW forums. But I have an annoying front end vibration, and when I went to Discount Tire to have my tires re-balanced, they said they couldn’t do it because the front tires’ inside edge was totally worn down. Doh!
First things first: yes I know, forums are more like guidelines than rules, and I probably should not be running -2.25 degrees of camber and a little bit of toe in on the front of a street car with a McPherson strut front suspension. But the stupid track rat BMW forum people were like, “you should run at least -1.75 degrees in front for good grip, and more is better!” This was a bad decision on my part.
I have Kumho PS91 summer tires, and while I’ve been very happy with their grip, they have a stiff ride and they make a kind of rhythmic wub-wub noise from around 35-50 mph that’s particularly irritating. They smooth out on the highway but then once speeds approach 70 mph or higher they introduce a higher-frequency vibration of the whole car. Blech. The uneven wear on the inner edge of the front tires has only made things worse.
UPDATE: Ok, ok, even though it’s damn cold outside and a mini flurry is happening at this very moment, I took a picture of my front tire to compare to what it should look like.
The grooves on the inner tiread blocks are rounded off on the inside edge of the tire. That’s my problem.
Carrying on now...
I’m going to my excellent alignment guy tomorrow who is going to zero out the toe and take the camber to a more reasonable -1.75. That should give decent handling while hopefully not chewing up the inside edge of the tires so badly.
Since the front tires need to be replaced, but the rears are basically fine, I think it’s time to choose a different tire for the front, and then match them when the rears wear out. I’m probably going to switch to the Firestone Firehawk Indy 500 (a.k.a. Bridgestone Potenza RE003), in the hope that they won’t have the same noise issues as the Kumho PS91. I bought the PS91 like a month before the Indy 500 came out, to immediate acclaim, and ever since then I’ve kinda regretted choosing the Kumhos, especially with the annoying noise.
Since I usually swap on my winter tires the weekend before Thanksgiving, there’s no good reason to spend money now on fresh front summer tires. It would be objectively stupid to spend $385 now for less than 3 weeks of hopefully-noise-free driving before my winter tires go on, and then stack those $385 worth of practically new tires up in the corner of my garage. And yet, I find myself thinking about getting fresh front summer tires. The rational part of me is like, “dude, no, just wait til spring!” but I am a thoroughly irrational person when it comes to spending money on car stuff.
I hope that by posting here, I’ll stop myself from making a bad decision. Except I’m sure all of you will encourage me to spend the money now, like the bunch of bad influencers that you are.
Patience. Breathe. The winter tires don’t have this noise issue. Let it be. Save the money until spring time. Woosah.