Knucklebus

I've had my 2013 GS 350 AWD for barely a month and I'm investigating and learning about the various aspects of it. While replacing a broken wheel stud I discovered my Continental DWS tires looked good but are wearing excessively on the inside edge. I don't know the rotation and/or mileage on them but I was hoping to find the specs on them and if anyone else had this issue. I'm about to take a 1,000 mile trip and would prefer things be optimal.

I've aligned cars on a rack back in the 80s when I had access and recently roughed in my old cars with string, tape measure and level to get them close so I could drive them.

This will be my first time under the GS suspension. I can measure but I don't know the values I need to shoot for nor how adjustable it will be once I start finding my values. I can probably tell once I move some covers and expose things but looking for some shortcuts and I'm not finding much on youtube.

I'll probably wind up taking it to a shop I trust but I'd like to have an idea before I take it so I can talk intelligently. I like lots of positive caster and touch of negative camber but if I'm wearing the insides of the tires, I suspect too much negative camber and/or too much toe in. Temp wise I want to verify the inside is hotter (wearing more) than the center and outside.

Thoughts, ideas or snide remarks for the guy that busts his knuckles while checking the oil?

peasodos

iTrader: (1)

You can't adjust the caster in the front, it's sealed off(I asked about it at the dealership). Only reason that would be off is from a previous accident. Can't really adjust camber unless you use a camber kit. Only thing they can adjust is toe. Your toe is probably out of spec or previous owner never rotated the tires or a combination of the both. You want the toe as close to 0 as possible.

Knucklebus

Not sure about rotation, all tires are about equally worn on the inside edge. May post a pic this evening when I go home. I'll check the toe tonight if I get a chance.

Thanks

Knucklebus

Here's a pic of the tires. Rear and front, notice the lateral groove on the outside is still visible and the groove on the inside is down to the body in the rear and nearing it in the front.

Knucklebus

Update: The shop says the rear is non-adjustable for camber, which I knew, and it is -2.1° and -2.0° camber in the rear. I'd much rather have about 0.0° to -0.5° rear camber so I bought the SPC arms to install this coming week and then get it aligned.

They said the front could be adjusted but they didn't do anything yet and didn't charge me. They would have done the rear camber arms for $487 installed but I like doing these things myself and for $200 cheaper, I'm fully capable and willing. It's a lot simpler to change these than most things I've done. It will probably take longer to get the car up on jack stands and the wheels off than to swap them.

peasodos

iTrader: (1)

The manufacture put the -2° of camber in the rear for a reason, why change the manufactures design? This camber is probably optimal for the suspension setup and grip when cornering. Changing it may affect the handling characteristics of the car.

I bet the previous owner didn't rotate their tires, hence the uneven tire wear. If you never rotate the tires in the rear you'll end up with this type of tire wear because of the rear camber. Looks like all you need to do is rotate the tires and everything else is unnecessary.

Here was my printout after I had her aligned a year ago.

Knucklebus

My tires are already worn so bad in the rear that I don't think they will ever be be right from just rotating. The fronts already have significant wear there but not as bad. That's why I'm going to camber them back to a more reasonable 0. The guys with the asymmetrical F Sports can't rotate and I couldn't stand having tires wear unevenly.

Looking at your numbers, I think your car is backwards though. I'd want more camber up front and less in the back. I plan on getting -0.5° camber in back and front with toe at nearly 0, which is what you have.

I haven't studied the Lexus GS geometry as much but most cars want an ideal camber negative gain in curves so a near 0 camber while going straight ahead is not an issue. Lots of positive caster on the front really helps.

Now, I love going around corners as much as the next guy, maybe more. I had 245/60s all the way around on my old cars back in the late 70s when radials were still pretty new. I had a 5.7L V8 and still wore my front tires outside edge off before my rears were bald.

Knucklebus

WOW! There is no room to work in the inner arm mount bolt area. I've got the nut off but the bolt is jammed in there with no room to tap it out. Socket on the bolt won't even budge it. Paying 2 hours of labor is starting to look pretty good after I've spent two hours on one side and can't get the first one off.

There are NO youtube videos for this except the SPC one and it glosses over the removal as if there's nothing to it.

Anyone got any tips on getting that inner bolt out? I'd have expected it to be loose like the outer one once the nut was off.

Knucklebus

Well, I'm whipped. The arms arrived quickly from Amazon and after watching the SPC video, I thought it would be pretty smooth. I couldn't get the inner bolt out on first one after 3 hours so I'm putting it back together and taking it to the shop. I'm bummed about not being able to do this myself but my large American hands just can't get in there.

I suspect this is done before the rear cradle is attached to the body.

rog1206

iTrader: (4)

After removing the outer bolt, did you disconnect the arm from the knuckle? I remember wiggling the arm a bit and the inner bolt slid right out. There should be enough room back there.

Knucklebus

That puppy was lodged in their tighter than anything I had seen in a long time.

I had the arm free on the outside, able to wiggle up and down and a bit fore and aft but it didn't budge inside the mount. It acted like it was still torqued down and moving the arm only produced movement in the rubber part of the assembly.

The bolt was unable to be moved with a ratchet after the nut was removed. It was seized inside the bushing is all I can imagine. I sprayed it with WD-40 on both sides, bolt head and between the mount points, several times in the few hours I worked on it before putting it back together and remounting the wheel. The pros have it now. Hopefully, they have better luck after I soaked it in WD-40 and it has had 24 hours to seep in. It didn't even look that rusty but it felt like it was torqued to 200ft/lbs.

Knucklebus

I don't feel so bad now. They said it took 8 hours to cut them out because the bolt was seized onto the inner bushing sleeve. They honored their quote of two hours. It was way off alignment wise as well, toed in and negative camber are a recipe for quick, short tire life on the inside edge.

peasodos

iTrader: (1)

Messing with the factory camber doesn't seem like it was worth the trouble, not to mention voiding your warranty if it's still applicable. I haven't heard of anyone else cutting out factory camber arms over tire wear. Seems like you just needed new tires and the toes corrected. Just saying Lexus set the camber in the rear to -2 for a reason. 88k on my GS and no problems with tire wear. I just get an alignment done when I get new tires and rotate them when I do the oil change every 10k miles.

Knucklebus

Look at your alignment specs. You have way more camber in the rear than the front. That's backwards to what a performance alignment would be.

Besides, I've voided way more warranties that I can count. It's kind of my thing.

My tires showed uneven wear and I don't like it so I had it fixed. Lexus built these cars to make money and regardless of what anyone might think, the bean-counters cut a few corners. Having non-adjustable rear camber was a cost saving measure. They built a cradle, slapped it together and called it good enough. SPC and others would not sell these arms unless there was a market for them and there wouldn't be a market for them unless there was a need.

The "before" was after they had cut out the bolt for the old upper arms and installed the new arms in a guestimated position. The old arms were -2° and -2.1° camber and too much toe. I like the rears on my vehicles to be nearly vertical and straight ahead. I'd rather have tires last longer. This isn't an autocross car and without rear steer, there's very little if anything to gain beyond excessive tire wear for that much rear camber and toe.

The next time I'm on the twisties, if I experience over steer, I might consider another -1/2° camber but most cars under steer so I doubt it will be a problem.

peasodos

iTrader: (1)

From other 4GS owners. As you can see this is how the camber is factory.

https://www.clublexus.com/forums/sus...for-gs350.html