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From my understanding reading through the IS forum, where lower control arm bushings mods are quite popular due to issues with inner tire wear on the IS, the LCA bushings on our cars can also be directly swapped to OEM GS F / RC F version of the part. The GS F part is made of a slightly stiffer rubber, but definitely not super stiff polyurethane or anything like some of the aftermarket options, which apparently helps tighten up the steering feel and wandering a bit with minimal/if any added NHV. I live in the north east and our roads have all kinds of banks, divots, and uneven roads where if I'm pulling up to a stop light and only going a few mph, if I lighten up on my grip on the wheel the car with veer off center. Stiffer LCA bushings apparently help with that and general stability, so even if I achieve that let alone better spirited steering feel, I'd be happy. I expect the difference to be fairly subtle, but maybe quite worth the modest cost. The best deal I could find seemed to be like ~$120 including shipping. The one part I'm not sure 100% sure about yet is even our GS 350 LCA bushings come in 3 different offset variants into order to correct minor caster differences between the left and right sides for the individual car. It seems like the vast majority have 0 offset, and the IS people just basically say to buy that, unless you know for sure you car has a different offset (which apparently you may be able to tell from paint markings on your part) or you are trying to fix you bad alignment. Has anybody tried this on our cars and care to share their impressions?
Original Non-F GS/IS/RC Parts 48075 - BRACKET SUB-ASSY, LWR ARM, NO,1 - Right 48075-30030, RIGHT; ORANGE MARK & BLACK MARK, OFFSET:0 48075-30040, RIGHT; BROWN & BLACK MARK, OFFSET:+20 48075-30050, RIGHT; PURPLE & BLACK MARK, OFFSET:-20
48076 - BRACKET SUB-ASSY, LWR ARM, NO.2 - LEFT 48076-30030, LEFT; BLUE & NO COLOR MARK, OFFSET:0 48076-30040, LEFT; BROWN & BLUE MARK, OFFSET:+20 48076-30050, LEFT; PURPLE & BLUE MARK, OFFSET:-20
GS F/ RC F Parts
48075 - BRACKET SUB-ASSY, LWR ARM, NO,1 - Right 48075-24010, RIGHT, OFFSET:0 48075-24080, RIGHT, OFFSET:+20 48075-24090, RIGHT, OFFSET:-20
*Note: I value ride quality quite highly, but if steering feel is you top priority you may want to look into the RR Racing Ultimate Steering Response System which are super stiff polyurethane LCA bushings. They supposedly take steering feel to BWM like levels, but do increase NHV. In addition, they greased regularly or can develop squeaking problems.
Generally speaking from the factory the car will come with the 0 offset, the others are service parts to adjust caster if required.
I can't recall ever seeing a non-zero bushing on a car from the factory (though I certainly haven't seen them all).
Jeff
Do you know if those paint marking colors are an accurate way to tell or is there a different way? I would assume chances are very high that I have 0 offset, but I am not the first owner so I'd ideally still like to check.
Also if anyone is interested in trying these out, it seems like now might be a pretty good to purchase them. At Bell Lexus, they already marked 27% off MSRP and then there is an additional 10% off just for September. So for both it comes to $112 shipped, which is even a bit better than the sources I found straight from Japan. I was going to wait for the spring to get them, but I may purchase them now even though I still probably cant actually install them until spring.
Are you referring to the inner bushing of the toe control link? Just an FYI, this is not the lower control arm...it is a separate component.
Here it is circled the GS F parts diagram, it’s like a donut with offset wings on both sides. Every reference to it I have heard and the aftermarket replacement parts call it the “lower control arm bushing”. The Lexus parts catalogue calls it “Bracket sub-assembly, lower arm”. Isn’t 48620/40 the lower control arm?
Here it is circled the GS F parts diagram, it’s like a donut with offset wings on both sides. Every reference to it I have heard and the aftermarket replacement parts call it the “lower control arm bushing”. The Lexus parts catalogue calls it “Bracket sub-assembly, lower arm”. Isn’t 48620/40 the lower control arm?
My bad. I thought you were talking about the rear suspension where the toe is adjustable.
So I poked my head under to try and take a picture of each side. I found the paint dots they were talking about, but still haven’t confirmed what they mean. The chart that I copied from the IS forum that posted in my original post is kind of confusing. Like they have listed black dot under all three offsets for the right side.
Driver’s side: blue dot with a yellow line and maybe a bit of a pinkish/red line unless that’s just the color fading
Passenger’s side: black dot with yellow line
So overall I’d assume they are 0° offset, but still don’t know for sure. Maybe I’ll try and email Bell Lexus with the photos and see what they say.
So I talked to Bell Lexus about it, they are familiar with this upgrade and said they sell a lot of these GS F bushings for people wanting to do this. They said they do not have a definitive way to decode the paint dots either, or even with the VIN, however they said the blue and black dots like the pictures above matches exactly what they have in stock for their GS 350 0-offset bushings that are still sealed in their parts bags. In addition, they said that they only ever use 0-offset in their own service department and have never had a problem. Also the offset in these bushings can only change the caster a tiny bit. I think the stock caster is supposed to be like 8° (which is what is should be at with a 0-offset bushing), but even if you installed the +/- 20 offset ones it only changes the caster something like +/- 0.33°. So in conclusion, if you car is at stock high and everything, you should be fine to order the 0 offset.
Forgot to update this thread as well. I ended up installing the positive offset GS F bushings (part # 48075-24080 for the right side and 48076-24050 for the left) and have been running them for nearly a year or so. They have been awesome and I would highly recommend for a bit of sportier feel! The car is more responsive to the steering inputs now, definitely less of a delay and rubber-band feeling to the steering now. In addition to that, the positive offset bushing increased caster and it actually made a surprising by difference in the steering weight now. In terms of steering weight, basically bumped everything up one mode so the steering in Eco now feels like normal and normal feels like sport, and sport is now heavier as well. For me, its perfect as heavier steering feel is one of the things I was trying to accomplish.
Now on to negatives, there is a slight impact on ride quality. Over road imperfections like pot holes and expansion joints, the impact feels a bit more sharper vs the float over anything feel of stock. Its honestly not bad though and not by any means rough. I noticed it more when I initially installed them and I am not sure if I just got used to it or now they are broken in or since it was winter when I installed them maybe the temperature was effecting the bushing rubber a bit or maybe even just the roads where just in rougher shape at that time of year. But at this point, the difference is so small that I am not sure if it was any smoother before.
Overall, I would HIGHLY recommend this upgrade for sportier drivers. That said, I am glad I did not go with any more aggressive with any of the poly bushing solutions, and if you live anywhere that experiences snow and has bad roads, I'd recommend you try these before going that route.
Just a tip - Harder Urethane steering rack Performance bushings would be about the same handling steering feel increase, without the rougher ride quality. I have these on my car, much more responsive to input and stays where you put it.
Just a tip - Harder Urethane steering rack Performance bushings would be about the same handling steering feel increase, without the rougher ride quality. I have these on my car, much more responsive to input and stays where you put it.
Do you have a RWD? I don’t think they have steering rack upgrade parts for AWD unfortunately. I actually bought some Think Design steering rack collars from Japan exact with that idea in mind that were basically supposed to compress the OEM bushings making them stiffer. I made it all the way to removing the steering rack bolts only to find out that it wasnt going to be compatible with the AWD steering rack unfortunately.
I've done this mod on my '08 IS with RC-F bushings. The harshness seems to go away overtime. Tire wear is noticeably better for such a simple mod. I've been thinking about doing the same to my GS. I haven't had my GS long enough to know whether it suffers from the same inner tire wear as the IS... Can anyone report if the inner portion of the GS tires wear out extremely fast? Basically, what happens with the IS, is that the steering rack is in front of the suspension and the tie rods angle forward. When the brakes are applied the soft stock bushings allow the suspension arms to rock rearward. This pulls the tie rods back. Because the tie rods normally sit angled forward, when they are pulled back the also push the tires outward which creates excessive toe out and inner tire wear.
I've done this mod on my '08 IS with RC-F bushings. The harshness seems to go away overtime. Tire wear is noticeably better for such a simple mod. I've been thinking about doing the same to my GS. I haven't had my GS long enough to know whether it suffers from the same inner tire wear as the IS... Can anyone report if the inner portion of the GS tires wear out extremely fast? Basically, what happens with the IS, is that the steering rack is in front of the suspension and the tie rods angle forward. When the brakes are applied the soft stock bushings allow the suspension arms to rock rearward. This pulls the tie rods back. Because the tie rods normally sit angled forward, when they are pulled back the also push the tires outward which creates excessive toe out and inner tire wear.
my rear tires wore out faster than my fronts…….when I did have a set of tires on long enough for them to wear out. I have A 2013 rwd.
09-20-20, 08:02 PM
GS F/RC F LCA Bushings
