CSSLDR

I picked up a 2013 RX F-sport this afternoon. Excellent ride improvement over the regular - just enough stiffness in turns without affecting ride quality, though I do believe the 18's may have a better ride w/dampers over the 19's

derfp2

These dampers are attached to the FRAME of the RX, not the suspension. It's kinda the same thing the Nismo 370Z has. Body sway will not be affected by installing these!!!!! Lexus/toyota installed these on the RX Fsport because after they kinda stiffen the shocks and springs to be able to reduce NVH inside the RX. Go to lexus website or lexus pressroom online and they describe it. Most of what these dampers do is a gimmick, they don't really do much, but sound good on paper. SO a damper attached to the FRAME of a car IS NOT GOING TO REDUCE BODY SWAY. Thicker swaybars will reduce body sway, but I think the RX Fsport has the same size swaybars front and back has the RX awd. So the decreased sway on the RX Fsport is due to the stiffer shocks and springs front and back. How could a lexus dealer sell and install these part to some of u a say "yes, this will reduce sway, now give me the money" it's unbelievable. It's like someone selling devices to increase MPG on cars...

ecr72

I doubt these two members, especially dolphin who has been looking for a way to reduce body roll for a long time, are just imagining their vehicles ride better with the damper.

As for Lexus dealers selling them to the public, I don't think the dealers are advertising them to do anything. People came to them with a theory and a part number looking to order the part. They would be stupid to turn away business simply because they don't "think" it will work. Especially since it appears the addition of this part does provide some benefit.


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Clutchless

I have not looked at this thread in a long time and just read all the developments. My other car is a CT200h FSport Special Edition and like the RX350 FSport, comes with those cross frame dampers. They are actually like strut tower cross bar braces to stiffen the chassis and tighten up handling. What Lexus did is add a small damper in the middle of the bar to reduce NVH. I added strut tower braces to my 94 Mazda MX6 and they did really stiffen up the body flex and handling as they reduce suspension geometry changes under cornering, but did not really reduce body roll. It took a bigger rear sway bar to make a difference in body roll. So the car may feel a lot better with the cross bars, but body roll is not really reduced. I think more bang for your buck may come from either FSport shocks and struts or the older Sport Suspension option shocks and struts that were available in 2010 and 2011. Also will these things bolt to 2010-2012 model year vehicles?

Also I looked at the Strut Tower bar from Ultra Racing that someone posted a link for in August. The photo is of a Japanese version for a right hand drive car as the brake fluid reservoir is on the right. I contacted the seller to inquire if they actually had a US left hand drive version. They never responded. I then looked at the Ultra site and learned the part is for the 2009 model!

Clutchless

Could someone who installed the front damper bar post photos or the instructions so we can see where it bolts to the vehicle? I am trying to determine if the 2010 etc have the mounting holes to allow installation.

mbrahmer

Clutchless is right saying that body roll needs a bigger sway bar and firmer shocks to achieve the desired result.

Dolphin

Interesting positions... of course, there is a lot of variables at play here...such as weight distribution of the various vehicles, FWD, AWD, Hybrids, rim diameter, quality of tire, etc. All can increase / decrease body roll... so how much improvement you notice with the dampener is prob. a function of your starting point.

Regardless...I can only share my experience after 5k miles... my experience is similar to Lexus ls post on the previous page... a noticeable improvement.

I have been getting some 13RX loaners, so this provides me a good benchmark for comparison... as I mentioned above, there is some variables... for example, on the 18" rims, the body roll is worse, so the difference is more noticeable vs. comparing the same to an RX with 19" rims. That 1" makes a difference... as the added tire sidewalls also contributes to the body roll.

Comparing my modified ride to a 19" rimmed 13RX, (I have the factory F Sport 19's) I would say the difference is most noticeable at higher speeds, 45-60 mph, such as off ramps, fast lane changes, etc. I can assure u, you can feel it.

vs. 18" rims, more noticeable, even at lower speeds....

and yes, as incorrectly mentioned above, Lexus does NOT market this part as a means to reduce body roll...its simply a replacement part for the 13 F sport. We confirmed with Lexus engineers before ordering, this dampener will help with body roll, but they wanted to be clear, there was no claims made on "how much"... as they never tested this. It took 4 weeks to get the part shipped from Japan...so surely Lexus is not marketing this part for reduced body roll.

I will be replacing my 19's with 20's and moving to an 8.5" wide tire, my guess is, this will further reduce body roll...will report back...

Dolphin

Regarding post above, opinions that mention dampers will have no effect on body roll...

Although I am very mechanically inclined, I would never try to predict how effective a part will be, by simply looking at a picture / diagram of the part. Suspension systems are quite sophisticated today, and unless u understand the specifics of the stresses applied to all the components during a turn (body roll), it's hard to assess the effectiveness of a newly introduced component. Of course, Lexus engineers have the benefits of dynamic CAD modeling systems that take the entire suspension system into the equation. These dampers were designed and implemented for good reason, no car maker uses senseless added components for marketing reasons. When I pioneered this mod, I relied on opinions of the Lexus design engineers on the effects it would have on body roll. I was not poking in the dark.

Being curious about a few of the above posts, I googled the subject and found a few interesting articles, linked below.

A small cut n paste of the relevant info below....written by Lexus CT 200h Chief Engineer Sam Sadakata


> no doubt that these dampers can improve handling significantly, making the car sharp, smooth, and fun to drive. They also help reduce road noise, as well as improve steering feel and comfort. “We’re really happy to have discovered such a great application for the lateral damper mechanism in the CT 200h,” says the chief engineer. “It’s a win-win result.”

http://drivers.lexus.com/lexusdriver...teral-Thinking

From Car and Driver report....

> The RX350 F Sport is intended for buyers who previously found the RX line too staid for their active lifestyle, whether real or imagined. Via the use of what it calls a lateral damping system, Lexus claims to have improved steering response, agility, and ride comfort while dramatically reducing vibration and twist. Basically, the system—a claimed Lexus first—eschews traditional fixed suspension bracing, instead using a specially tuned damper to connect the front suspension towers and another linking the rear-subframe rails. This setup is said to allow lateral suspension movement while absorbing torsion, body flex, and fine vibration. <end>

So after experiencing the standard RX350, my modified RX350 and the RX350 F Sport.... I feel more confident stating the damper is a very nice addition to the RX350. I considered the stiffer shocks, but for me, the F Sport was bit too hard of a ride...bumps transferred through a bit too much...(although I could live with it) the RX is surely not a sports vehicle... acceleration, braking, cornering, etc. The stiffer shocks gives a sports car suspension, but the RX lacks all the other components of a sports car... of course, that is just my take on the subject. The damper seems to address body roll, while leaving the plush ride mostly intact. Regardless of the type of ride you prefer, body roll is never a desirable feature.

For those considering this mod... drive an RX350 at hwy speeds and do a quick lane change. If you find the body roll acceptable in this maneuver, then I would not suggest the upgrade. If like me, you find the body roll during this maneuver very annoying, u will prob. be happy with the damper upgrade.

I am careful not to mention the RX450, as it might not react the same due to differences in center of gravity and weight distribution. And so far, the only two upgrades discussed here, are for RX350 FWD.

Dolphin

An interesting update for this thread, as I am sure it will hang around for a long time for those looking to improve RX body roll / cornering...

I replaced my factory 19" F Sport rims with 20" rims. Replaced the Dueller 19" with 20" Mich. HP's. I was expecting another improvement in cornering performance.... unfortunately, the opposite occurred. The HP sidewalls are not as stiff as the Duellers, these details MATTER! The increased rim size did not compensate enough for the softer sidewalls. Def. a mistake for me, as the ride was already plush enough, if a do-over was possible, I would have went with 20" Duellers.

These rims also offer 1" wider width... other than slightly nicer appearance, as the wheels are not buried so deep in the wheel well, no noticeable benefit. I am sure the larger footprint on the road will yield better traction.

johnl617

Thanks for all the info guys. I am thinking about picking up the dampener for my 2011 AWD RX. Just wanted to know where the install points were. I am not as mechanically inclined as some of you are, but I am willing to give a crack at it. Any help is appreciated.

SteveCraig

Stiffer sway bar is the only practical way to reduce body roll. Attached to the frame/under -body components, they limit travel on the control arms.
Car leans right, RH arms & spring compresses & LH side expands.
Sway bar, attached to the control arms, will twist to a given degree allowing movement of the arms.
Stiffer bar ( thicker) will resist twisting as much, reducing the RH compression & LH expansion.
Generally, the stiffer sway bar you use will present as a somewhat stiffer ride. Even under light cornering loads, the bar will resist more vs. a stock set-up.
Shocks may help smooth out the ride but they do not support the car & only provide dampening from road surfaces.
Stiffer springs are another ball-game by themselves. I'm thinking a damper will absorb more road input & dampen only torque steer effects.
Remember it's not the individual parts you put together but how the combination, as a unit, works for you.

johnl617

Did any bite the bullet and bought the sway bar mentioned in the previous threads? I wonder if there is vendor selling any sway bars for the RX….

Clutchless

I think Johnl617 meant dampener when he stated sway bar above. I too am interested in installing this on my 2010 RX350. I need to remove the under cover to see if it has the same mounting points as 2013.

There are no aftermarket anti-sway bars available for the RX350. I have looked far and wide and consulted several vendors who cater to this forum. I tried stiffer bushings but they made little difference and did not fit well so I removed them.

I think the dampener, bigger wheels and the H&R wheel spacers as covered in another thread are our best options. When your shocks wear out consider the stiffer Sport ones or FSport ones.

B2001AS

Can someone post pictures of the dampers installed on the car?

vlad_a

I'm going to point out the obvious, that many suspension modifications, in the name of handling, will deteriorate the ride quality, and may do the opposite of their intentions.

For example, installing stiffer sway bars will reduce body roll. However, at the same time, will diminish traction during turns because the vehicle will now be trying to lift up the outside wheel while fighting centrifugal forces tilting the body. The car will feel quicker, but in really, it isn't. Sway bars will also alter understeering and oversteering tendencies of the vehicle. By default, manufactures tune suspensions to understeer because it is easier to correct and get a feel for when the traction limit has been exceeded. Stiffening rear sway bar will introduce oversteer, which is much harder to control in FWD vehicle.

One may install more aggressive shocks. Yes, the traction will be improved because wheels will be forced to follow the road surface and not bounce. Unfortunately, so will your body. Go too stiff, and the plush Lexus ride will turn into a vomit maker. 2IS 350 is an example of an over-damped setup. Civic Si would be another. Riding on concrete pavement during winter becomes a torture. If this is selected route, be sure to get adjustable units.

And then, there are springs. Soft springs will provide comfortable ride, but increase body roll and bounce. Stiffer springs will do the exact opposite, so the body roll will be reduced at a cost of comfort. Lowering, essentially, has a similar effect, as it does require more aggressive springs to prevent bottoming-out.

Now, the springs can be progressive in their action. They will stay soft on small bumps and will be stiffer on big bumps. They feel less natural, but could offer a good compromise between comfort and sport.

What is the point I'm trying to make? Just that tuning the suspension is a rocket science. It is very easy to make it worse and much harder to improve it... and that RX is not that bad for what it is intended to be.