itr206

Ok, I have been researching this like crazy and am finding that tire feathering in the front is a common thing on these cars.

I got my tires at like 86K and started noticing after about 5-8k they were wearing on the fronts weird and feathering and getting alot louder
I swapped the rears to the fronts and vice versa and got an alignment checked.

First time they set
FR: Camber -1.0 Toe .31
FL: camber -.4, Toe -.09
total toe .23

The car immediately did not feel right and I took it back and had the manager redo it because he is a little more knowledgeable.

So in discussion he said Lexus runs these a little agressive and always have tire problems. I researched and saw Toe seems to be the common problem on these.

We then reset to
FR: Camber -.9, Toe .08
FL: Camber -.6, Toe .09
total toe .17

Now I have seen some toe suggestions for the front to do -.03 and then another site saw to do .03
Any suggestions on which is correct?
Also I see to check the #2 LCA bushing doing this. From what I see they look fine. Could my views from the wheel well while in the air be skewing things?

itr206

Also any suggestion on the bushings. I see hard race is popular, but saw some videos of them being really loose like stock.
Worth it to go with full OE replacement arms? Or just get some bushings to press in?

mitsuguy

iTrader: (2)

-.03 and .03 will not even be noticeable and are well within tolerances on an alignment machine... Here is the problem (and I don't have recommended specs in front of me), but, there is designed in slack in the suspension - for this reason, many RWD cars have toe in settings in the front and many FWD cars have toe out settings in the front, vice versa for the rears, and not always accurate, but generally... Suspension geometry changes as you drive and in relation to speed as well... If you screw with too much from factory settings, you may actually increase tire wear... Feathering is generally not only caused by alignment, but lack of rotation, and if you are at 8k without rotating tires that have a somewhat aggressive tread design, I could almost fully attribute your tire wear to not rotating... Here's the deal though, if they are directional, might not be much you can do... Tire selection is key here...

Having uber stiff bushings isn't necessarily a good thing, I've seen too many people screw up the way their car handles by installing solid urethane bushings - not only does it make the ride harsh, but also decreases traction and handling... there is stiction induced by the solid bushings which means the suspension is not able to do its job...

itr206

Well, the tires are not agressive at all. They are falken 912's.
Not overly fond of them, but I got them new for free when I bought the car.
I can notice a ton more noise out of them as they started to wear funny. I swap my tires on any off enough, so yes they get rotated alot more in that 15k miles then they would normally. Longest stretches are summer months and honestly I am lucky to put 5k-8k on them before i remove and put my Blizzaks on

Even last time I put my blizaks on new, within a few weeks I saw them starting to wear the same way, just not as much as I do not run them as much.

Do those toe numbers look adviseable that I currently have? Or should I adjust some more tow in so it flattens out when weight is in the car?
If I understand correctly since the bushings have soo much play, they toe out when weight is in the car or once it gets up to speeds?

at 99k , would you think it is very viable it could be the control arm bushings breaking down? I can almost bet they are the originals.

mitsuguy

iTrader: (2)

I'll post specs later, but from what I see, .05" positive total toe is where you should be, you are a bit over that, out of even the wide tolerances of +/- .1" your range should be -.05" to +.15"

Beachtyme

iTrader: (1)

Toe is definitely the culprit here, this was discussed and researched in great lengths at the "other" Lexus site.

The way it works is that from the factory the toe on the IS300 is not set correctly, as it will lead to feather and abnormal tire wear.

The front end needs to be toed in slightly as when the force of driving changes the dynamics of the front end the suspension it allows the front end to toe out slightly.

If the toe settings are aligned using factory settings the road force and/or inertia of driving toes out the front end just slightly and the abnormal tire wear occurs in the form of feathering the inside of the front tires at the point closest to the back (of the front tire) tire inside point. I hope that makes sense and you can envision what I am referencing.

The ideal setting is slightly toed in, but not so much that it makes the front end respond in a "darty" fashion.

The balance here is enough toe to minimize tire wear without overly affecting the handling of the car. Again, to much toe in and the handling suffers + the steering wheel feedback becomes somewhat undesirable. No toe or not enough toe in and the feathering of the front tires becomes an issue.

Beachtyme

iTrader: (1)

Also, keep in mind when you look at a vehicle on a lift, it's unladen and the suspension will look completely different from what it does when the car is on the ground and the suspension is doing it's job supporing the weight of the car.

mitsuguy

iTrader: (2)

Too much positive toe (toe in) will cause this eventual feathering as well, and the proof is right in this post - the op is running just slightly more positive toe than the Lexus spec calls for and is experiencing feathering... The Lexus spec calls for .05" toe in total, which is very reasonable. At the "other" Lexus site, did they give numbers or just speculate??? Very rarely are cars truly aligned well from the factory, you can't go by how a car is when new for specs, as they are almost always off somewhere...

Beachtyme

iTrader: (1)

I'll have to see if I can find the spec's I used. It's been quite a while, although I do still have my IS300.

What I meant by "from the factory" (and I should have been more specific) is even the factory/manufacturer's spec's are not correct for the alignment as far as toe is concerned and feathering on the front tires.

itr206

Thanks for the info guys. I have read what is said above about the slight toe in and then when weight is on the susp and at speed it will even out.
So my specs are too toed in currently?
Should I go to .05 as said above or try other specs?

mitsuguy

iTrader: (2)

If you are having feathering, I definitely wouldn't try MORE positive toe - I would go back closer to zero, which means following Lexus' recommendation...

itr206

i guess the feathering isnt as bad now as just the inner tire wear.
Seems that inner set 1 inch or so (most inner tread block) is wearing down. Nothing past there, just that first set of tread blocks.
They were feathering before the alignment.I swapped the feathered ones to the back and the better ones up front and still see wear.

Could they just be totally screwed with wear now and just run them for another couple thousand until they need to be replaced? Just kills me to replace them in less than 20k just due to one tread block and then put on better tires and have issues. I want to find a fix now on the cheaper tires

I have my blizzaks on now that are pretty new. I gotta check to see if they are wearing yet, but so far they seem much quieter than my normal tires other then like a whiring type noise when slowing down. Again not sure of that noise is due to the alignment or due to the tire characteristics themselves

mitsuguy

iTrader: (2)

Some tires will just wear worse than others regardless...

They aren't going to grow rubber in that portion, so, once they are worn like that, there is nothing you can do to reverse it, aside from buy new tires...

Inner edge wear is a combination of toe and camber, our cars are built to run some negative camber on purpose so that they handle well... Not a lot you can do with it, just be glad you don't have a Ford Focus, they do this terribly on the rear with -1.5 or more camber...

Hardrvin

Toe in creates stability, toe out generates a "darty" feel. Hence why just about every car comes from the factory with some toe in. Autocrossers will intentially toe out a car a smidge to improve turn in. But that's another discussion.

Mitsuguy is correct as well, some tires are just plain bad about feathering while others can take horrible alignment and not feather. Granted it seems you're seeing the issue on two different brands.

One thing you did not note were the units. Toe can be provided in inches or degrees. For inches, the spec for total is 0.05, for degrees, 0.1.

The spec for camber is 0.5 degrees. So you're a little high on the front right, though technically in specification. However you have some cross camber. This will cause a little bit of vehicle pull and also generate some excess wear. Get the alignment shop to pull that close to even with the FL.

Also, provide the values for the rear. On paper, it shouldn't matter. In reality, it can affect the front. Especially on a car where you can adjust the rear and generate a thrust angle. This will push the front around. Again, they may tell you it won't matter, but in reality, it can create some issues, especially if it is way out.

Last, as some others have mentioned, how the car is loaded can affect the alignment as the alignment changes through suspension range of motion. My point, do you typically drive with other people in the car, or a load in the trunk? Do you weight 300 lbs? If yes, you may have the shop align it with some weight in the vehicle to simulate your driving conditions.

To the comment about unweighted on the rack, I'm assuming you're not implying full droop on the suspension, as every alignment rack is a four post and therefore the suspension is subjected to the vehicle weight.

Beachtyme

iTrader: (1)

Check the post on this thread, sound familiar?

https://www.clublexus.com/forums/5171498-post57.html