I have a 2006 SC 430 with 20,000 miles on it. The "run flat" tires are wearing on the inside and the dealer says that they need replacing (for almost $2000). The local tire shop agrees, and will sell the tires to me for less, and also throw in an alignment. He says that alignment is the reason for the uneven wear. Makes sense to me. But the dealer says that the wheel on my 2006 SC 430 cannot be aligned, and that the new ones will probably wear the same way. So,anybody know about whether the wheel on my car can be aligned? Who is jerking me around?

 

Kind of funny, we have almost identical cars, SC430 with just over 20,000 miles on it. I recently purchased mine with 16,500 miles. I have also already run into the exact problem that you just encountered. I had my car aligned a couple of months ago and they said that I need four new tires because of the inside tread wear. I looked at the tread wear and have seen much worse. They aligned the car by making slight adjustments to the camber and toe, but did not do anything with the caster because it cannot be adjusted. My inside tread wear is visible, but I have seen much worse and since the alignment I’m now monitoring the tread wear. They also told me the same thing, my tires needed to be replaced. Thus far, after about 2,500 miles of driving, I have not seen any more or measurable tread wear on the inside of my tires. Each RFT that I have retails for about $360, hence one of the reasons, and due to a more comfortable ride, I will be replacing them with conventional tires. As far as the comment they made saying that they cannot be aligned, I’m not sure if that is true. There are several threads in this forum that have previously discussed this issue and if I recall correctly the control arm bushings may have something to do with this inside tread wear if the alignment specifications cannot be met vs. a camber kit.

 

The 2002 SC service manual references wheel alignment front and rear - at least for toe and camber. Apparently the steering axis inclination is fixed by suspension geometry. It doesn't discuss changing the caster either, only measuring it. The dealer is more or less saying they will align the car but it won't help you with tire wear. Doesn't sound like a very good explanation for a car in this class. I haven't faced this situation (yet) because tire wear and handling have been good, but I hope it is resolved to your satisfaction. For what it's worth I think you could be happier without run-flat tires.

 

Inside wear is most likely due to camber. The wheels are slightly angled if you don't know what that means. It's adjustable, but not enough to compensate completely.

That said, the last thing you want to do is put new runflats on your car. They ride like wagon wheels. You'll get a much smoother ride with non-runflat tires. You'll save a lot of money and get a better ride if you switch to a tire like michelin pilot sport ps2s.

Or if you want to customize your car a bit, now would be the perfect time to get aftermarket wheels. There are a ton of styles that will enhance the look of your car dramatically.

This thread will give you a good idea of some of the styles out there...

https://www.clublexus.com/forums/sc-...d-threads.html

 

The dealer is jerking you around, as usual.

The factory camber and toe setting is for better handling, but is very bad on inside tire wear. I recently changed my alignment setting after the inside tread showing wear, now the tire wear is a lot better now. So yes, the camber and toe is fully adjustable from the factory.

I think one of the reason the dealer say it is not adjustable is because the dealer can't change it away from factory spec. And the factory spec is designed to wear out the tire unevenly. I think it is easier for the dealer to just tell you it is not adjustable, then to tell you the factory suspension is designed to wear out tire unevenly. Then you will get all pissed off and go get a class action lawsuit against Lexus like those NSX boys did back in the days, Lexus will lose and have to go create a milder suspension setting spec, then have to do a free alignment on every single SC430 they sold.

 

Do you know what you set the toe / camber to?

 

In my experience, and I have years as a Lexus mechanic, the RX 350 can easily make 20,000 to 35,000 miles between alignments...Unless the vehicle has a Massive impact to the from end or is continually driving dirt roads that are full of pot holes. Your vehicle will be pulling to one side if it needs an alignment. The ONLY way to check for this is to get on an open and FLAT road, set a certain speed (say 55-65), let the vehicle stabilize and feel how much pressure must be applied to the steering wheel to keep from drifting. If excessive pressure has to be applied the vehicle may be out of alignment. NOTE: This test CANNOT be done on downtown or neighborhood streets - It must be carried out on long flat stretches of highway where a good rate of speed can be maintained - ANY pulling on downtown streets cannot be attributed to alignment because of the excessive camber of the road will give false results. If you take your vehicle to a car of tire dealer at anything less than 20000 miles since your last alignment and he recommends a new alignment I would definitely get a second opinion. I know of many dealers out there who will tell customers when they come in for a tire rotation that they need (in a Big Way) an alignment also (Even when the alignment on the vehicle is fine). This is 8 times out of 10 BS. I have also seen dealers tell customers that the vehicle is very badly out of alignment when absolutely nothing-and I mean NOTHING is wrong with the alignment just to get an extra dollar. If you have had an alignment in the past year and you are being told you need another - You BETTER find another dealer or at minimum GET A SECOND OPINION. Too many mechanics charging for unnecessary procedures. (Many big retailers push their employees to sell unnecessary procedures for profits) SHAME SHAME!!!

 

I got 10k out of my last set of tires. On the back two tires, the inside was bald outside was great, I would say 8/10 tread left.

So, the question is, when I go back, should I tell them as close to zero on the back to tires for camber and toe in?

 

Took my 06 to an Indy alignment shop, told the tech to take all of the negative camber out that he could, he got all four below .6. You are probably over 1.5 with factory specs. Search SC430 alignment, lots of previous threads. My tires are wearing evenly. ✔️
Mike

 

Nice little thingy about alignment and the terms used. I've been thinking of increasing the caster on my 430 if that's possible. I haven't check on the factory spec and the latitude available in that adjustment. I want better high speed tracking. http://www.tirerack.com/tires/tirete...e.jsp?techid=4

 

Same thing I did but my selling dealer did it for me in 2008. Tire wear has been nice and even the last 7 years.

 

Caster is not independently adjustable on these cars. Very few cars these days are.

 

Yeah, I figured but I was hoping. Well, I've got a list of things to try to make the car track better. Tower strut brace, lose the run flats, ball joints and bushings. Nothing radical. Thanks for saving me from wasting research time. It's appreciated.