Memoryfab

From any case when a customer wants to fit more agressive offset with wide tire without fender modifications and without rubbing it is much easier to fit them with a neg camber than without.

Pardon my assumptions, I assumed when people lower the SC430 it is more than 2 inches which usually neg to 1 degree or more camber. Your arm-play related issue is correct in respect that the adjustment of an upper arm will fix the camber. Other arms are used to keep tow and height play such as the ss kits available out there.

There is actually a big article on this in http://www.club-lexus.net one of the largest toyota sedan based community clubs in Japan.

DoubleWhoosh

Well, like I said, it minimally affects things, but your main center pivot point for upper tire clearance will be the lower ball joint, so not a huge difference is made to fit wheels. That point does not change, nor does its relative position to the fender lip. Yes, by moving the upper pivot point outward it changes things, as the arc radius increases, but still not a whole bunch as the upper arm is still shorter than the lower arm. For true help for fender clearance with more offset wheels, you would need to move the upper ball joint point UPWARD. This cannot be accomplished without some type of longer ball joint, modified spindle, etc. This would increase what is called camber gain. "Easier to fit" wheels as used in your context is somewhat of a misnomer in this case.

I don't think you understand what "arm-play" is referring to. It has absolutely nothing to do with fixing camber, caster, toe (or "tow" as you call it), but it refers to the play in the arms' mounting point themselves. Your arms will not fix this issue, and like I said before all this, I honestly don't see any camber more than 1 degree to be a horribly detrimental issue as far as tire wear. You do need negative camber for proper handling as well. Anything from -0.8 to -1 is good.

As far as lowering more than 2", with the proper diameter tires, this would not work, unless the tires were sitting pretty far inside the fender, it would be impossible to do this with agressive or flush-ish wheels. You would need tires that are smaller sized as far as diameter goes, and most SC430 owners would ultimately end up with taller tires (which is the case with the best looking or most popular tire/wheel combinations).

Memoryfab

Oh I am not disagreeing with you in anyway. I think there could be some miscommunication between us. I believe we come from different style of tuning. I am providing the solution used by most vipstyle cars in Japan. I must say that tire width size is not as important as dish or maximum wheel width. I tend to focus on cars with no visable gap between the tire and the fender.

Here is the original upper arm 60mm height joint.


The ss arm 30mm.


This lowers what the nihongjins call "height pitch" but not shock travel.
Before Install

After Install


When I talk about arm play was to refer to the upper bone arm which does affect camber on these toyota designs. This is why some companies like ikeya, c-one have ｷｬﾝﾊﾞｰｱｼﾞｬｽﾀｰ・ｱｯﾊﾟｰｱｰﾑ, camber adjust upper arms for these toyota designs.

I do not know what knowledge confusions I may have or even if I am thinking about the same type of the tire wear the original poster is worried about, but I know that canceling abnormal tire wear due to lowering is accomplished easily with well designed products. If it did not work none of these suspension footwork companies would be in business and there is no way we would be able to sell these items in Japan.

DoubleWhoosh

Ok, I'm not sure if you understand fully what you are posting here, but you just showed something that relates to camber gain which is exactly what I was talking about above. Your shorter ball joint height there gives less camber gain, which means that the wheels will camber LESS as the suspension travels, which will give you LESS clearance to the fenders when the suspension starts to compress more. What you want is more camber gain so that the tire will tilt in more, and give more fender clearance.

The tire pictures of before and after are not related whatsoever to ball joint height, those are from different length upper arms, which change the camber at a static height or at any given suspension position.

The original question was if there were tire wear issues from excessive lowering, and some of the additional information I gave answered the question of why.