chikoo

Does anybody have the ride height information that I can use to find out whether my suspension is OK or not?

Folks with 2008-2010 IS250 with less than 30K, please respond by measuring the ground clearance from the rocker panel to the ground. Please....

Thanks!

XhyDra

iTrader: (8)

From my experience driving multiple IS's ranging from brand new to 10k, 15k, 35k, 48k and 100k there's a significant change after 35k. I'd say it feels more like the suspension is slapping the bushings on hard bumps. From 60k - 100k there's little to no difference in feel. At around 10 - 35k the suspension still feels supple and stiff as far as bumps are concerned.

I've replaced suspension after 60k and although the shocks and springs were brand new, the car still exhibited this "slap" like sensation that is obviously transferred to the door seals giving the impression that everything is harsh. When all it is with the door seals is age. The rebound lessened but there was still a sence of not as oem new feel to it.

I will attribute the loss of comfort and luxury to bushings on the suspension components. Almost every single connection part is partnered with a rubber bushing.

Sadly they don't sell individual bushings for most of the suspension components.

chikoo

Should I ask the dealership to replace bushings?

chikoo

Any one with any updates on this matter? Xhydra thank you for the details. That really helps.

sallydrive

Second this. Mine has about 60K on it, and I recently got a loaner with about 10, and it is SO much softer and smoother...

chikoo

I have contacted (via email) Lexus Customer Service regarding this issue. Waiting for them get back to me.
I would urge anyone whose IS is under warranty and experiencing the same issue of deteriorating ride quality after 35K miles to contact Lexus and get their attention on this detail.

XhyDra

iTrader: (8)

I'll try to put the bushings into perspective in different scenarios.

When the car is built the bushings within the control arms and joints are new and stiff, these bushings are pre-loaded and torqued to spec. This basically sets a resting point for the bushings, which is stock height. When the car is standing still the bushings are at their neutral position, due to the factory pre-load.

Over time from all the flexing the bushings do in bumps and the over all weight of the vehicle during hard cornering they slowly begin to lose their rigidness. This can be best seen in swaybar bushings, they deteriorate over time and the vehicle seems to sway a lot more. Hence the F-Sport bushings are a lot stiffer than the OEM ones.

Heat and cold affect the rubber bushings, so does weather conditions. If the vehicle is mainly outside all day every day the rubber bushings will go out a lot quicker than a well garaged vehicle.

In my observation this can be seen in the rubber sleeves on the front suspension shocks. The rubber sleeves on a non garaged car at around 100k are practically falling apart the rubber is completely deteriorating and cracked. You take this into account for the rest of the suspension components and you get an idea where I'm going with this.

Although the bushings are made of a stronger rubber compound they are none the less wear and tear. If you ever take apart the IS suspension you can actually tell how much flex the bushings have because on the front you're able to push the lower control arm up and down. If you let it go it rests in the neutral position that the bushings were pre-loaded in. On the rear arms it's the same thing, except you have countless more individual arms, such as the camber arms and all have pre-loaded bushings as well.

One would say that tires have a lot to do with the ride quality and I agree, but there are a lot of different aspects to tires. When they're cold they might feel rough but once heated up they're at their optimal ride. The same can be said for bushings, in cold weather the rubber reacts different to warm weather so under both climate conditions on used old rubber bushings you'll experience different ride comforts.

All this from my experience with many of these cars.

Older model GS's had a problem with the lower control arm bushings, and newer better quality made bushings were released by the Daizen aftermarket company and the results were night and day. I'm not saying this is the case here but surely it's a contributing factor to the lessening ride quality.

So basically worn bushings allow more stress to be transmitted to the shock making it absorb a little extra than it used to because of wearing bushings.

I have noticed on some IS's that have race spec suspension with very stiff dampening that although the ride is stiffer the dampening setting alone compensates for the worn bushings because as everyone knows with expensive suspension although stiff, it is still very comfortable.

chikoo

Xhydra, you are saying all the right things. I sure hope Lexus is reading this and sincerely taking the initiative to help us out.

cchase231

I don't think he is saying there is anything necessarily wrong, it's just the bushings wearing out as they would on any car. Although, on this car (or any luxury car) I would expect them to maintain their integrity longer than they seemingly do. I could understand the bushing's premature wear on a car like mine since it sees 4 seasons and is driven on some of the worst roads in the country. But, I do find it curious that xhydra has noticed the same wear on most ISs in the same mileage range. I would venture to guess that the composition of the bushings or suspension design comes into play somehow. I highly doubt Lexus will be very sympathetic or admit that anything abnormal is happening, but hey, you never know. As far as a remedy, I am not sure if he is saying the smooth ride can't be restored because of a lack of availability of the individual bushings or if it is just not possible because of the shear number of bushings, or both.

Joeb427

iTrader: (1)

chikoo,the measurement from the bottom of the rocker under where the front door meets the back door on my '10 IS350 with 1300 miles(yes,1300 miles) is 7-7/8" give or take a 1/16".
I know you're looking for a 250 number but no one replied so here's a 350 with stock set up.

chikoo

Thanks Joeb. My car is at the dealers right now for another related (yet unrelated issue...dash rattles...which is amplified due to this harsh ride). Lexus customer service did get in touch with me and informed me that they have advised the dealership to look into this. No guarantees though. I am not very hopeful as the dealership has already visually inspected the suspension and visually there is nothing wrong. Maybe this time with this information, their search might be a bit more focused.

chikoo

XhyDra

Is it possible to visually tell if the bushings in question are worn out and need replacement?

stanjohn12

Can you please tell us what tires you're running now ? Mine is the Bridgestone Potenza RE 050 and it's really noisy inside on rough roads. I'd say mostly tire noise on rough roads rather than loose interior materials but haven't checked fully yet.

Will drive my car entirely without listening to music tomorrow to find the exact noise.

chikoo

I have the stock Turanza ER33 50% tread life left.

chikoo

Update: Lexus Customer service called back and reported everything is "normal". Picking up my car today, sadly.