Long story short. i bought a 2017 luxury with 50,000 miles for too much at beginning of covid. I hated the suspension (the test drive didnt give it away). The bouncing and unplanted feeling especially on the highway was concerning. Through the help of knowledgeable people on this forum I changed a few things. I put bilstein 4600 all around. and put on the michelin defender LTX. This changed the entire feeling of the suspension. Better in all aspects. I am going to go with 6112 coilovers on the front soon. Still bounces to much. I have a question regarding the rear. I still feel the rear suspension shimmy bounce and jump around too much. So today i transported a few hundred pound of stone in the back and the rear felt great. It was composed planted and smooth. Still have it back there I liked it so much. How can i reproduce that? Would changing those airbags to coils help the cause? I feel the air bag suspension is contributing to the bouncy unplanted feeling of the rear?

 

Love this post ... in my observation, the majority on this forum want a "comfortable ride" ... many wanting "marshmallow" where any connection to the road is muted to the point of being disconnected. For me "comfortable ride" means "being in-control" and "planted" ... where the vehicle responds in a precise manner. No, the GX is not a sports car ... but IMHO Lexus dumbed down the suspension for the "comfort crowd" to the point where it is close to impossible to live with ... the as-delivered OEM shocks and the absolute garbage Dunlop or Bridgestone tires combine to provide a totally disconnected driving experience.

While counterintuitive ... I have found that E-Rated tires combined with Bilstein 4600's or 5100's solves the above. The stiffer sidewall does not mute road conditions ... so the Bilstein's (or any shock) can provide a more precise and confidence inspiring response. The Michelin Defender LTX Tires are made for the Lexus GX ... fantastic tires ... but after running the E-Rated version there is no going back. Short of this, try running your tires at 36-PSI versus the 32-PSI recommendation ... and if you like the improvement ... E-Rated tires at 45-PSI will be a significant further step in that direction ...

I also have Timbren bump-stops installed ... the OEM are anemic ... speed bump violence is now a thing of the past.

 

... further ... Air Bags or Springs as I'm sure you know simply provide a spring rate ... so I would first focus on the Shock / Tire combination before possibly converting the rear to a higher spring rate spring. Eibach is a good source ... that supplies to ToyTec ... a resource where you may want to give their technical department a call ... they are not just a catalog reseller of parts ... they specialize in the Toyota Body-on-Frame vehicles and do installations at their facility. Very knowledgeable ... nothing lost in making a quick call.

 

Thank you for the response! I run the defenders at 39 pounds. I have tried all different pressures and I found 39 is the sweet spot. I am still curious about the rear suspension with the airbags and the 4600s. The backend shimmies and bounces almost like I’m bouncing on a balloon. Not planted what so ever.That is why I think the airbags are the problem. any suggestions are appreciated! Maybe replace with coils?

 

Are you guys running stock rims on your GX?

 

For me ... the Toyota 7.5" wide wheels are too narrow ... even when running 265 tires ... too much side wall "bulge" ... way too much tire wall flex when cornering. IMHO the ideal wheel width is minimally 8.0" or even better 8.5" ... with a wheel offset that positions the edge of the tire tread in vertical alignment with the edge of the fender. Looks more commanding and planted without being aggressive ... and significantly improves steering response. The stock Toyota wheels are way too inboard ... a "Soccer Mom" stance.

 

Personally ... had a GX with air bags in the past ... since purchased a GX with coils ... the latter is my preference ... and eliminates any future repair complexity and cost. Unless one tows ... the rear leveling feature is not important ... with coil spring "Helper Bags" (Firestone) being a good intermediate option.

 

Have you changed the suspension settings to see if that helps? Id imagine sport setting would help a lot with the bounce. I've only driven 1 GX on air (rear suspension only) when it was new and I always preferred that over the spring suspension. I noticed way less brake dive and a much more stable ride (variable dampening?). Again that was new, I've driven a handful with spring suspension and none have compared including my new 2022.