BayAreaLex

Hi folks,

I'll start off with a little background:

I bought my 2001 GS430 from a member here a couple month ago. The car was shipped from Missouri and exceeded my expectations as it was exceptionally clean. My only issue with it was that it had a bit of steering wheel shimmy at highway speed (about 55-65mph). I lived with it for a couple of months and finally decided to let the Lexus dealer here in the East Bay take a look.

They rebalanced the wheels and returned the car to me. Upon taking the car back, I noticed that the steering wheel shimmy was still very present on the highway. I got back on the phone with them and told them that the problem is still very present. They agreed to take my car in for a 2nd time.

They reported that the full inspection of the suspension/steering shows that nothing is wrong and all components are tight and within spec. They then road force balanced all the wheels again and said that they balanced out perfectly.

Now here is where things get interesting. The previous owner swapped the OEM 17x8 wheels for a set of larger 18" wheels from a 2007-2008 RX350. They are good looking wheels, but require a small spacer to clear the big brakes.



Well, the spacer that was used was one of those cheap, "one-size-fits-all" spacers that is not hubcentric. More importantly, the spacer covered the hub which did not allow the 60.1mm hub bore in the wheel to sit on the 60.1mm hub. Since Lexus lugnuts are flat instead of conical tapered, that mate between the hub and the wheel bore is critical to ensure that the wheel axis is in line with the hub axis. My front spacers did not allow that to happen. And so the front wheels were being tightened down off axis leading to the steering wheel shimmy that I was experiencing.

I temporarily swapped to the OEM wheels (no spacers) and the steering wheel shimmy problem is completely solved! In order to run these 18" RX350 wheels, I would have to replace the cheap spacers with real hubcentric spacers.

I'm bringing this up because there are a lot of guys on this forum with steering wheel shimmy issues and also a lot of guys running spacers. Maybe this could help someone.

I want to stress that there is nothing intrinsicly wrong with wheel spacers, but if you are gonna use them, it's critical that they are HUBCENTRIC for your application.

Before I got into Lexus cars, I spent years in the Mustang world. The nice thing there is that lug nuts usually have a conical taper which means that the wheel is forced to align to the hub as you tighten the lugs. Because the Lexus world uses flat lug nuts, having your wheels hubcentric is absolutely critical.

I hope this may be helpful for some of you with this problem that don't realize that it's the lack of hubcentricity that is leading to your steering wheel shake in some select cases (if this is your problem, you may be losing a lot of time chasing wheel balance, tie rods, suspension bushings, etc).

Cheers!

perry05g35

iTrader: (4)

The steering wheel shimmy was caused by ichiba "hubcentric 10mm spacers they come with a hubcentric hubring to make them hubcentric to our cars so I tossed those.

repugnante

Good info...

Feelin those wheels!!

GS300LUV

Thats a lot of hub....................bub....lol

Chin

iTrader: (34)

The lexus lug nuts do center the wheel just fine, but in a different fashion as compared to your Mustangs. Instead or centering via a conical shape, there is a portion of the lug nut that actually enters the opening of wheel and forces the wheel to be perfectly centered on the hub and perfectly centered between each wheel stud...

BayAreaLex

Hmmm, I will have to look at it again but that's not how it seemed to me when I was studying this yesterday in the garage. If what you are saying is true, then the problem would be caused by nothing other than the spacer.

I'm not buying this 100% because the hub is there for a reason. And with the 5mm spacer, its like the hub wasn't there and it created a severe problem. If what you are saying is true, there would be no need for hubcentric rings, and we know that's not the case.

Chin

iTrader: (34)

The hubcentric wheel is there to help carry the load of the car. The wheel bolts are there to center the wheel properly and attach the wheel. If the oem lexus wheel was not hubcentric, it would still be perfectly centered due to the design of the lug nuts and how the shaft of the lug nuts enter the wheel opening.. Im no expert but that is my .02

All this is assuming you are using the correct lug nuts on the correct wheels. Just because the lug nuts screws onto your wheel stud does not mean that they are correct for your wheel...

Lazy

iTrader: (2)

The spacer was in front and rear?

BayAreaLex

Just front... rear spacer not needed due to smaller rear calipers.

BayAreaLex

Chin, I got my hands on one of my wheels along with an oem lugnut.

When I looked into the wheel's bolt hole bore, I noticed that the end is completely flat just like the flat lugnut. If you notice the Lexus lugnuts have a washer. The bolt hole bore diameter is larger than the diameter of the lugnut washer. When I mount the wheel onto the hub, there is absolutely no play. I can't move the wheel up, down, left, or right. It's perfectly centered on that hub. Now if I put on 5mm spacer (which effectively covers that hub) I can actually move the wheel up, down, left, right just a little. And I can tighten the lugs favoring any of those directions and it's that misalignment between the hub and the wheel that can cause shimmy.

I agree that the flat lugs help to center the wheel, but they can't do it perfectly like a conical taper lug can.

Yes that hub bares the load of the car but thats not all its there for, especially when flat lugs are used.