2015 base model. I’m looking to swap out my rear coil springs on my suspension to increase the amount of rear weight I can apply in the back and on the trailer hitch. I already upgraded to Bilsteen B6 shocks. I’m having difficulty identifying a stiffer, more heavy duty replacement coil. Anyone have experience in this?

 

I think this has been discussed before. I found a thread that states the hybrid has the same rear springs as the 350, but think there is a thread that discusses spring rates. Maybe the 2013-19 Highlander has stiffer rear springs. https://www.clublexus.com/forums/hyb...-as-rx350.html

See this thread with regard to towing as the RX is not really a good tow vehicle. https://www.clublexus.com/forums/rx-...er-towing.html

 

These should fit on the rear springs although they are listed for the 2014 Highlander but should fit the RX as it has the same rear struts. https://www.etrailer.com/susp-2014_T...on_Enhancement

I found these threads on the Highlander forum

https://www.toyotanation.com/threads...#post-14211442

​​​​​​https://www.toyotanation.com/threads...#post-14141933

 

I saw someone retrofit 4th gen RX rear springs, they should be stiffer along with 3rd gen RX450h springs. The 14-19 Highlander rear springs are an option too (use same perch), but I don't think they'd be an upgrade. We have one in the family and the spring rate feels like jello - I think it may actually be softer than the RX.

 

Maybe look at the Air Lift 1000