kappy

We have an IS300 that is a much smoother/softer ride that our new IS250. We test drove a 325XI and the IS250 on the same day. The 325 was a much more enjoyable ride. Not as much bounce and smoother acceleration. Unfortunately I was over ruled on the BMW.

Prior to the IS300 we had an Audi TT. Talk about riding on a granite slab.

pelorojo20

Hey I came from an Integra also In fact all I had ever owned were integras, an '87 and a '94. I feel like I've gone from a propeller-driven plane to the space shutte.
I had the same problem here in Texas so I special ordered and specified the 17" wheels. I think the ride is noticeably smoother and definitely quieter with the 17s vs the 18s I test drove. Wheel size was one of the dealbreakers for me as far as getting a car that was in stock vs. special order. Plus, the tires should last longer and even if they don't they tend to be less expensive.

I haven't driven the ES350 but the ES 300 & 330 my parents drive feel like a library on wheels.

al503

I would describe the ride in my 350 w/sport as somewhat 'choppy', not bouncy.

I'm also coming from a g35 coupe that was lowered with stiffer springs and had 19" wheels with about the same sidewall height as the stock. The word choppy wouldn't even enter my mind with the G though.

With that said, I really don't mind the ride that much as I'd rather have the car be too stiff than not enough. If what the others have said about it softening up a bit after a few K miles holds true, I'll be very happy (until I get springs or coilovers, that is.)

Gainesvill

Any resolution to this? My car feels like it is bouncy also.

I can feel constant small subtle bumps, the kind that bounces your thighs up and down just slightly.

My car has Dunlop 5000M. My previous BMW mechanics (not dealer, this is independent shop) have said that Dunlops never make a round tires.

I had problems with my BMW Dunlop SP 2000 (bounces, vibrates,etc) from day 1. I did not know and dealer will not acknowledge. Replaced tires, and it is gone.

I am considering to replace my tires with Michelin.

Mike_TX

No known resolution as of yet.

My 350 has the "bouncy", jerky", "jittery, "jiggly" (choose your adjective) ride, too, and the best I've been able to do is reduce my cold tire pressure to 30psi. Helped a little, even though I hate getting those rims that much closer to the pavement. Thank goodness I have wheel and tire insurance!

I too am surprised Lexus couldn't engineer a suspension that handles well yet doesn't bruise your internal organs.

4TehNguyen

iTrader: (1)

found the IS to be very smooth during test drives, but I currently drive a lowered 215/35/18 car now (which is still pretty comfortable for me, took 45 min trips to school with no qualms), its all a matter of perception

If you want to change out your 18" with 17" that will help a lot. Sidewall thickness means a lot to ride quality

Mike_TX

As an update, I went out after penning my last post and lowered my cold tire pressure to 28psi. Drove it around the block, and that 2 extra pounds seemed to help a bit (I already took it down to 30 week before last).

When it gets cold, I'm sure my TPMS will sound off, since they are usually set to about 26-27 and the cold will reduce the pressure. In the meantime, though, I'll enjoy the extra margin of comfort.

I'm almost convinced some 2IS's ride a lot harsher than others. Like others posting about this, I'm no wimp, and I've had cars with real "sports" suspensions. My IS, though, isn't so much a sports suspension as it is a primitive suspension. It handles absolutely NO better than cars I've owned that pamper you much more on choppy roads. Hell's bells, my Acura TL smothers bumps and dips TONS better than the IS, and it will take cloverleaf offramps every bit as fast.

(BTW, I have the Bridgestone Potenza RE050's and I don't have the Sport Pkg. Don't know how these tires compare to the Dunlops.)

Mike_TX

UPDATE:

For those with the jiggly or otherwise harsh ride - and with the 18" Bridgestone Potenzas (non-Sport Pkg.) - I've found the "sweet spot" at 28psi cold tire pressure. I had already lowered the pressure to 30psi and found that it helped the ride quality a good bit (maybe 15 or 20%). Surprisingly, an additional 2psi had an amazing additional effect ... I'd say it improved the ride an additional 20% or more!

All in all, I now feel my ride quality is perhaps as much as 35-40% better than when delivered (with 33-35psi in the tires).

Now, a few caveats and disclaimers:

1. If you do this, you do it at your own 'risk', since it is lower than the recommended pressure. However, I personally have zero concern that 28psi presents any risk at all, since it's more than adequate to maintain the tire/wheel integrity. You might see slightly quicker tire wear, depending on your driving style and road conditions, but these tires aren't destined to last long anyway. If you drive very aggressively, lower pressures may affect handling, cornering and/or traction.

2. When cold weather comes, you may get a TPMS light, since most of these systems are set to alert at 26-27psi. If it annoys you, it may be necessary to add a couple pounds of air to shut it up. Otherwise, a few miles of driving should warm up the tires enough to turn off the alert.

3. ADJUST THE PRESSURE ONLY TO COLD TIRES. Tires pick up 3-4psi or more from the heat generated by driving, so make the adjustment only after the car has sat for several hours. First thing in the morning is the best time. If you bleed your pressure to 28psi with warm tires, you may find you have more like 24-25psi when they are cold. And that's too low.

But for me, I can say I'm MUCH happier with my IS than I was a couple of days ago. It no longer feels like it's going to forcibly eject me, or to turn that gallon of milk to butter before I can get home from Kroger. In other words, it finally feels civilized.

Frisco

I had my TPMS go off at 33 and 35 psi. But it went from a really hot day to a really cool day over night. I just reset it for the lower pressures and all has been well. I think the high pressures are to protect the wheels more than anything. These things are like rubber bands without much tread to wheel distance. A pothole at low pressures might bend a wheel. But I agree, just lowering mine 2 PSI helped some.

lobuxracer

iTrader: (2)

I bent the OEM 17s on my Supra three times in the last 10 years. One time, it was bad enough to crack the inner lip on the rim. I discovered the problem at 135 mph. I was lucky it didn't fail catastrophically. I'm not so confident the 18's on the IS will be round for years to come.

Also - note especially for Mike - I finally experienced exactly what you described on a short but very noticeable piece of road in my area. Yes, the ride was awful and a cup of fresh cream would go to butter in about 10 miles if the stretch were that long. I am very confident a reduction in the high speed damping would sort it out pretty easily. Yes, it is disappointing, but thankfully, it isn't common on the roads I normally drive.

TimboIS

Definitely not worth the risk, or the loss in fuel economy.

Mike_TX

LOL. I'll eat the cost of the extra gas (if any) from the lower pressure ... it has transformed my IS from a buckin' bronco to a real pleasure. I mean, I really almost can't believe how much better the ride quality is at 28. Even the difference between 28 and 30psi (which is less than 7%) is astonishing.

I also don't think there's really any other risk involved. I've tried some higher-G maneuvers in the last day or so and it handled beautifully. In fact, it "stiffened" up the steering a little more, too ... and the IS's steering is overboosted and needs it.

And as for the wheels - I have insurance for those. If I were to go on the highway for any distance, I'd increase the pressure a few pounds, but for around town 28 is the ticket!

Mike_TX

I got the TPMS this morning, too. We had a little front come through, so I guess that affected the atmospheric pressure or something. It was a good excuse to go ahead and re-initialize my sensors for the lower pressure bogey, so I should be good to go now.

Mike_TX

Hey, Lobux! Glad you se what I mean. LOL. But as I've noted above, I have it pretty well conquered now.

As for the rims on your Supra, there's a big debate over on another forum about the value of wheel and tire insurance. Some of the uninformed don't even seem to believe you can actually ruin a rim!

lobuxracer

iTrader: (2)

I think I'll see if I can get a Penske or Ohlins shock that will work on the IS. They're infinitely adjustable if you don't mind changing washer stacks. I think I can lick this problem...

Sad to say, it's possible to bend any rim. Wheel Techniques is always backed up just because this is true. So is my local source, Precision Wheel. It's about a week to get a wheel straightened here in Sacramento.