Let us know what you think of the 20s when you sample them. Though I haven't (yet) sampled a big GM body-on-frame SUV with the 20s (or a Lexus LS with them), nothing else I've sampled with 20s has what I'd call a smooth ride. Those big 20s, for example, ruined the Cascada's ride...I would have been interested in that car with, say, 17s (maybe 18s) on it, but, with the standard 20s, no dice. The Lacrosse, for example, offers optional 20s and a Hi-Per suspension option....and almost nobody out in the public actually bought that option, despite some reviewers from the auto press pushing it.

 

The 20s on the S Class don’t ruin the ride.

 

Calty has certainly applied Akio's new formula of "no more boring cars" to the 5LS' styling.
I can't wait till you test drive new 5LS.
Be sure to tell us if they have also applied Akio's new formula of no more boring cars to the 5LS's chassis, ride and refinement.

I would always encourage everyone to give feedback to TMC to be helpful to guide them in the right direction, and to tell it as it is, rather than just turn a blind eye, sweep it under the carpet, and pretend that the styling, ride and refinement is okay, when it is not.
Just switching to another make or model is not really constructively helpful to Toyota Motor Corporation.

The Germans are able to achieve both comfort & sportiness by having at least two different spring & damper packages to cater for different tastes.
I wonder if 5LS has done the same, because my 4GS uses the same spring & damper part numbers in both Luxury & F Sport.

I know that wife's refteshed IS200t has different base & F Sport suspension rates.
The spring/damper rates for the base model IS200t is a touch firm, but that is ok for the age group that purchase IS.
LS is normally purchased by a much older age group, because young don't want nor can they afford full size, so I wonder if Lexus has matched suspension rates to age group of full size luxury 5LS buyers?


It's not really the 20" on its own, but the entire package added together including: the overall weight, wheelbase, track, center of gravity, unsprung weight of the tires and wheels, waistline height & amount vertical space for suspension travel, spring rates for roll resistance, damper rates to control float, plus rubber compound, tire carcass construction & stiffness, tire pressures, all the way down to suspension subframes with oil-filled hydraulic subframe mounts.
.

 

the size of the rim is irrelevant, it's the sidewall height that impacts ride quality more. my jeep has 20's but the side walls are large so it's fine. but a civic with slammed 20s and 'rubber band tires' as you would say, well that ride sucks. the cascada is a small convertible so not surprising it rides rough.

 

In addition to side wall height, it is also the profile/aspect ratio, because the lower the profile, the stiffer the side wall must be to hold its rectangular shape.

 

The “profile/aspect ratio” and the sidewall height are the same thing

 

Yes, I agree. In most cases, though, all else equal, the larger the wheel diameter, the smaller the sidewall height....particularly if engineers have to keep the overall size of the tire/wheel assembly within the limits of what can be fit inside the wheel-wells with proper clearance.

 

I would also add that springs and shocks also have a very significant part of it. So tired of hearing that the wheels and rims are always the blame. Word is the new LC is magical in comfort mode. How big are those rims? Although my parents have 20in rims on their 4Runner, it rides well. There is a bit of a bounce to the ride compared to my 4,Runner which has 17in rims.

Ride quality can be very subjective to the individual.

 

That's why I addressed my comments with an "all else equal" clause. Gotta compare apples wth apples.

 

Wheels have a big impact when it comes to impact harshness which is why they get blamed a lot.

I also do not buy that the LC is “magical” in comfort mode. I’ve heard it rides similar to a GS, I intend to drive one soon.

 

No.
The profile [nee aspect ratio] is the "ratio" between the sidewall height and the tread width.
The sidewall height is the sidewall height.

For example on an E Class/4GS, often instead of using OEM 235/40R18, some users choose 245/40R18 which is actually OEM for E Class.
The profile and aspect ratio are the same, so the carcass will the the same rigidity for the same make and model of tire.

However, the E Class OEM actually has more sidewall height; the greater the sidewall height, the greater the comfort & quietness.
However, people who do this swap will increase the rolling circumference of the 4GS, and they'll actually be driving faster than their 4GS speedo indicates.

 

To be picky, the rim size does in fact count.
The bigger the rim size, the heavier the unsprung mass, so everytime the wheel/tire combo hit a bump, more mass x velocity = momentum is imparted onto the body of a motor car.

That's why if we test drive ES and RX back to back, using the same platform, everytime we hit a bump, the vertical force is thrown into the cabin of the RX much more so than the ES.
The higher the speed over the bump, the greater the vertical force.

NB. You will find that the most comfortable riding SUV's are the small little CUV's, or SCUV's like Toyota C-HR, not just because of their small lightweight unsprung wheel/tire combos, but also the lower center of gravity for less uncomfortable pitching and rolling.

That's why engineers go to great lengths to reduce the weight of the alloy wheel.
Formula 1 racing car wheels are incredibly light.


Also, the heavier the wheel/tire combo, the slower the acceleration from 0-60.
Many people don't realize this.
Below, the 15" wheel/tire combo is only 40 lbs, while the 19" wheel/tire combo is 54 lbs; nearly 50% heavier!

In this chart below, notice how big wheels eventually causes slower 0-60 acceleration times as acceleration for 15" starts at 0-60 in 7.6 seconds, while acceleration for 19" falls to 7.9 seconds.

Imagine you had to spin a disc with your hands; the heavier the disc, the harder it is to spin.
Also, the heavier the disc, the more momentum it holds at any given speed, so the harder it is to stop spinning...

 

I understand all this, but it’s semantics. When we discuss sidewall height, we are discussing aspect ratio. It’s the way sidewall height is delineated on a tire. Tires with larger aspect ratios generally have taller sidewalls.

 

Tire experts do not talk like that, simply because a 235/40R18 has the same aspect ratio as a 245/40R18, yet the latter has a taller sidewall height.

It is common for 4GS owners to move to a 245/40R18, not because they want additional sidewall height & comfort, but moreso because they are after a particular model of tire that is only available in 245, and is not available in the 235 size.
.

 

We’re not tire experts. We’re laypeople discussing cars on an Internet forum.