On Tue, 07 Jul 2020 13:49:28 -0500, Jim Joyce
wrote:

On Tue, 7 Jul 2020 09:23:07 -0400, Wade Garrett wrote:

I love my 2016 Toyota Avalon Limited....except for the rough ride. You
can feel most every bump, expansion joint, pavement crack and manhole
cover on the road. Even shallow potholes slam and are a teeth-jarring
experience! The tires are inflated to the door sticker pressure and
there's nothing wrong with the suspension.

I know Toyota gave this trim model a "sportier" suspension with
225/18/45 skinny tires on 18 inch wheels to improve handling- rather
than go with the fatter 215/17/55 on 17 inch wheels on the lower trim
models.

I'm curious why the slightly wider tire is a "skinny" tire while the
slightly narrower tire is a "fatter" tire, but I'll put that aside.

Fatter - not wider. More "meat" between the rim and the road

Doing the math, the 225/45-18 is approximately 659.7mm (25.9") tall when
new, while the 215/55-17 is approximately 668.3mm (26.3") tall when new,
with a difference of about 1.3% between the two. Sidewall heights are
101.25mm vs 118.25mm, respectively, but I don't think the harsh ride is due
entirely to tire size. Tire construction could still play a role, with some
tire models having a stiffer sidewall than others.

You say there's nothing wrong with the suspension, but if I needed to tame
a harsh ride that's where I'd start, especially with the shocks. Spring
rates could also be a contributor.