Rough ride on new IS 250

If your car has low profile tires, they will give a harsher ride than conventional tires.

Ray,

I asked the service guy if the demo car has the same tires; and he said they all had what they call "summer tires" as mine.

Ray O wrote:

I checked the Lexus web site, and here are the potential tires installed:

The IS 250 AWD has 225/45 VR 17 all season tires on the front and rear.

For the IS 250 RWD

The standard tires are 225/45 VR 17 in the front and 245/45 VR 17 all season in the rear.

The optional tires are 225/40 YR 18 in the front and 255/40 YR 18 summer tires in the rear.

All of the tires listed above are low profile tires, which tend to give a rough ride. The optional summer tires are lower profile than the all season tires and they should grip and handle better than the standard tires, at the expense of an even harsher ride.

I also see there there is an optional sport tuned suspension, which will give a harsher ride than the standard suspension.

Low profile tires and stiff springs are very much in vogue, and a lot of people don't seem to mind they tradeoffs from that style, like a harsher ride and greater likelihood of tire and wheel damage when hitting a curb or pothole.

what do you expect? Kiddie tyres, not for adults. Not for real people. Sorry.

Check the tire pressures against what the handbook recommends for your style of driving and adjust. All IS250's seem to come with tire pressures at maximum, i.e. they are set for a fully loaded car travelling at high speed.

Oldun

Ditto this, my wife's GS300 came with over inflated tires, 5 Lbs over in each tire. I'm guessing this was done to help seat the bead when installed. Check on the door jam of the driver side and you should see a sticker that lists cold tire pressure and the size tire installed. Make sure they're at the right pressure.

And cold tire pressure is best measured after sitting overnight.

The cars are shipped with the tires inflated to the tire's capacity so that they do not develop flat spots when tied down on the ship, trains, and transporters. The dealership is supposed to set proper tire pressure during pre-delivery service.

I recommend 4 or 5 psi over the factory recommended tire pressure to prolong tread life. The ride will be slightly harsher as a result.

That all makes perfect sense but there's no reason a new GS should be delivered with tires inflated to 41 psi (cold) when the max stamped on the tire is 40 psi and only for seating the bead. The door sticker states 33 psi cold. My assumption is the dealership delivered the car at the wrong pressures, even after I specifically asked if the tires are at the correct pressures while standing in the customer delivery stable. I'll bet this is not uncommon.

As I mentioned before, the cars are shipped with high tire pressures for reasons other than just seating the bead.

The door sticker

Your assumption is probably correct; I do not know how common it is for dealerships to deliver cars with the incorrect tire pressures.

The dealer set my tires to the correct pressure (33 lb) when I took delivery of my new GS300, and the ride was noticeably harder than when we test drove a similar car at the dealer.

I do recall that when "pushed" on the test drive, the car seemed to "mush" in a hard turn, and I got more tire squeal than I expected from the front outside tire, so I suspect that they demo cars with lower than specified tire pressures to give that "soft luxurious feel" that sells cars to anyone other than a "driver."

As there are more "passengers" than "drivers" out there, this may be good marketing strategy, but it does not show the car off as well to those of us who actually like to "drive". :-)

the lifetime of the tread a bit while increasing the probability of fatal blowouts in traffic. If they would only install high profile tires in the first place, they would not have to risk the lives of the owners with this overinflation problem. Has anyone talked to their congressmen and senators about this totaly arrogant and killer like approach to the American consumer? Where is the concern for safety?

Sue the bastards!

Increasing the tire pressure reduces the probability of fatal blowouts in traffic.

That would be crazy. Unlike most people these days, I actually know something about cars. Little things like improper tire inflation could be a problem for those "I just pay someone else to do it" folks. In addition to drag racing I also drive in many SCCA events so I'm a major do-it-yourselfer when it comes to my family's personal vehicles. But unfortunately there's a lot of people that never even check their own tire pressures.

Its a sports sedan, not a luxury vehicle. I have a 350 and its pretty stiff as well. as far as the demo you drove, it probably has the same feel, its just your imagination.

Anyone read or personally experience anything along the lines of:

1. Tires getting harder or softer over the first few thousand miles of use.

1. Springs or shocks having a 'break in' period, i.e., their character changing over the first few hundred or thousand miles of use, or after driving over a rough road for the first time?

2. Inflation pressures varying significantly from one side of the car to the other, depending on which side is in full sun and the other isn't?

1. The temperature of the pavement affecting the ride?

2. Noticeable changes in ride, handling, acceleration with the addition of only one additional passenger or having a passenger move from one seat to another?

I know some of these sound...well, ridiculous or neurotic.... but anyone who's been into audiophilia will understand that these questions represent the very tip of the iceberg..........

Given properly inflated tires your #2 "break in period" for suspension components will be commonly experienced. Hot-rodders also claimed that with their high performance shocks/struts on the tracks.

The Lexus IS is supposed to much stiffer. But magazine reviews termed the suspension as harsh (there is a fine line between firm and harsh). It's also my belief that Toyota's suspension systems aren't very well designed.

But don't people in most areas (at least in the US) allowed to test drive the vehicles they will purchase?

Is it still your belief that a GS has Macpherson strut suspension, and that there's a Lexus model based on a Corolla?

Are your beliefs ever based on anything like easily researched facts, or do you prefer to just go with your gut feeling?