If you own a second or third-generation Lexus IS, RC, RC-F, or the IS-F, you are probably familiar with their problem of severe front tire wear. It is especially bad with the nose heavy, wide tired, and powerful IS-F. Our Project IS-F wore the inside edges of the front tires so quickly that we could not run ultra high-performance 200 treadwear summer tires on it. These would wear out in as little as 7000 miles making running tires that matched the car’s performance an expensive proposition. We aligned the car to maximize tire life, running only 1.2 degrees negative camber in the front and zero toe at close to the stock ride height. We were forced to run hard 300+ UTQG all-season tires on the car to avoid going broke and even these would wear out in 12 to 15k miles!
Running this sort of tire on a high-performance car like the IS-F was not fun and it really put a damper on driving pleasure. However, it was this or go broke as wide 19″ tires are not exactly cheap.
Speaking to the guys at FIGs Engineering, they told us that they had found a solution to the tire wear issue. You see the rear lower control arm bushing on these cars is huge and soft being fluid-filled. This bushing allows so much movement of the lower control arm that it causes the toe settings to dynamically change over an inch toe-out in some situations causing severe scrub and tire wear as well as making for sloppy handling. They had come out with a low-compliance rear bushing and an optional front bushing to clear this up. They also said that these parts would make a big difference in handling as well.
The FIGs Engineering rear control arm bushing comes in 80 and a harder 90 durometer polyurethane. We opted for the harder 90 durometer bushing. The hard polyurethane replaces the OEM soft gushy silicon fluid-filled bushing. The rear bushing is where most of the problem is and is relatively easy to replace. If you were to replace just one bushing to help with tire wear, just the rear bushing would solve most of your problems. For the more serious cars that see track duty and really sticky tires, FIGs offers these parts with zero compliance sperical bearings as well!
The bushing is a direct bolt in replacement and is machined with features such as the inner sleeve with the conical mating surface to match up with the set on the lower control arm pivot perfectly.