hovbuild

It,s not too hard to see the difference if you "push" the car. We have owned some hot cars and I used to do some track driving with a rs6 back a few years ago. The ride is a bit harsher like if you can complain because it is still pretty good.. IMO the look of the 19" wheels makes a difference also. I just hope that a new England pothole doesn't play havoc with my rims.

JDR76

That's just the thing - If you push it. So let me quantify my statement a little better. I have tested both the 18" and 19" wheels and driving the way I would drive an RX, I cannot see any improvement in handling. The 19" wheels still have a fairly substantial sidewall - they're not low profile. I found that the suspension gives before the tires do in the RX. YMMV

EMSLEXUSRX

The ride quality on less than perfect roads has been the only downside to driving my 2010 RX for the past four years. Everything else on the car has been fantastic. The interior still looks brand new. When I take the RX on longer road trips, it's wonderful on the highway. But back home when I'm driving on the crappy streets of Tampa, I usually grimace when going over uneven faults in the road and sometimes feel like the fillings in my teeth are gonna come loose.

In the near future I'm going to talk to my service guy at Lexus to see about replacing possibly the rear shocks or springs in my 2010 RX.

I remember back in 2012 driving a 2012 RX350 for two weeks while some warranty work was being done on my '10 RX. Now, mind you, both vehicles have the 19-inch wheels. The 2012 RX ride was much better than the ride of my '10 RX around town!

CapeDave

But back home when I'm driving on the crappy streets of Tampa, I usually grimace when going over uneven faults in the road and sometimes feel like the fillings in my teeth are gonna come loose.

This is exactly how I feel in my 2012. Except Cape Cod, not Tampa

vlad_a

If the problem is experienced at certain types of roads and at a specific speed, then it has to do with the shocks. The rebound frequency needs to be shifted by decreasing or increasing rebound force. Too bad nobody makes adjustable shocks for the RX350/RX450h.
I wonder if putting heavy weight in the trunk will make the ride more comfortable in this scenario.

CapeDave

This sounds like the crux of the problem. I am going to do some experiments. Just got my baby detailed, looks great! I'll throw a bunch of kitty litter bags in the back and give it a try.

There really is a pathetic lack of shock choices for the RX. What is up with that?

garygve

I removed the rear shocks today on my 2015 RX350 to see how stiff the rear spring really is. The spring is not the cause of the hard rear suspension, I was able to push down on the rear bumper fairly easy to get the car to bounce up and down. I took the car for a ride over various roads just to see how it felt, it road smoother over bumps but of course it would continue bouncing with no shocks. The hard ride is the shocks, they are gas charged and that is where the harder rear ride is coming from.
Its too bad there is not much choice for different aftermarket shocks, I think with a softer type rear shock absorber the RX350 would have the ride that some of us are trying to obtain

CapeDave

I am very impressed that this forum seems to have narrowed down the issue to the shocks. That at least gives us hope. I am pretty sure I will be getting some kitty litter tomorrow. That could just dampen the responsiveness enough to make a difference. Maybe not solve the issue entirely, but any relief would be most welcome.

hovbuild

Ok now put a softer shock n the car and take it to the track. Do some fast maneuvering like in a panic situation and see how much you give up for a softer ride......Don't forget to test first with the original in. Also do a timed lap and see what you will lose because of the "softer" ride you want. I am sure for a safety concern that your assumption that a softer shock will give a better ride will make the car more likely to lose control under certain driving conditions. I would bet the farm Lexus and all other car builders would make this their major concern balancing the ride to the safety. Don't forget all cars are designed for their intended uses, the RX is a SUV with a decent load capability and includes towing. JMO

garygve

Found some QA1 shocks #DS701 that might work on the Lexus RX350 they are adjustable so you can adjust them to the ride that you want. To adjust I just have to reach around the front of the tire and turn the ****. I have a slight rattle when I go over a bump because the 1/2" hole at the ends of the shock is bigger than the metric bolt, will have to work on trying to correcting that. I got these from a local guy that does custom street rods, so if I can't correct the rattle I can return them.

CapeDave

Again, speaking for me personally, it is not necessarily a "softer" ride I am after. It is one where I feel that the shocks are at least doing a decent job of smoothing bumps. To me, there is a big difference between a soft ride and a "less harsh" ride.

I agree that any major changes to the suspension opens up an entire Pandora's box of potential issues. Which is why I am going to try the 100 pounds of kitty litter in the back to see of it "flattens out" the ride at all.

tqh

Wow, garygye is the man, you removed the shocks! Is it a big job?

garygve

No its only 2 bolts, I used a impact wrench but you can remove them with a socket wrench. Its pretty easy to remove the bolts once you take off the tire.

CapeDave

OK, I have about 100 pounds of kitty litter in the back of my RX. Hard to tell becasue everything is so subjective and there are many variables. But early results are encouraging. The litter (I use the best) was over $100. Which I knew was not going to waste. But still, more than I usually buy.

But as the guy was helping me load it, I told him what I was doing. He said he had bags of 40lb sand for about 6 bucks. Ouch!

So, I recommend those for any who want to try this for themselves

tqh

I do notice when I drive with 4 passengers, the [RX 350 AWD] does feel a bit smoother over bumps, but not enough. It may sound like a sick joke but I prefer the suspension feel of my wife's Camry 2009. I don't think there's anything wrong with my RX - it's suspension is the smoothest compared to the GLK's (horrible!), Q7's and X5's I tested but still not like the Camry's.

garygye, do you think replacing the shocks is something that doesn't tend to break other things in the car? I mean "replacing the rotors" is pretty isolated, while "replacing a transmission cooler" will carry a higher chance of breaking other expensive things if not done right.