Bouncy Ride

[thejimmyd]

I have a 2004 RX330. At low speed it feels like tires are not round. Just put on new tires from Goodyear. 235/55 R18 100V. Before putting them on we found that the 2 rear tires had cups in them. The ride then was very rough. Since new tires it has smooth out except at low speed. Anyone else have the same problem?

[pj8708]

Hi Jimmy and welcome to the LOC.

You've peaked my curiosity regarding the cupping on the two rear tires. Did the service people explain what caused that and did they fix the problem that was causing it? Did they tell you what they thought was causing the rough ride at low speeds?

My RX is a 2013 and came with Dunlap 235-55-R19's. It provides a nice smooth and mostly quiet cabin. I've also had a 2005, 2010, and currently a 2013 ES 350. The difference between the two vehicles in smoothness and quiet is definitely there. My 2013 came with Bridgestone tires, (sorry I can't remember the exact model) and they were not a good match in my opinion. I had the dealer take off the OEM Bridgestones's and replace with Michlen Primacy 18 inch. The Michlen Primacy are like riding in your favorite recliner.

Many other members also swear by the Michlens for an ES 350. My point is always dig around and research what people say are the best choice for them.

For me, you just can't get around the fact that the RX is a totally different animal. It will never be as smooth as an ES or LS, and it will never be as quiet as the other two models as well. Figure out the wear problem and do a search of our data base for some more input.

[RX400h]

Cupped tires generally indicate worn shock absorbers.

[thejimmyd]

Hi Paul. I'll start by trying to get some more facts in. We bought the car used and the salesman told my wife that the car had two tires on the rear that had low tread. He sent his men to get some tires and when they drove it they said the tires had "flat spots on them". That when the roads got warm and the tires got hot they would smooth out. That seemed to work at first. Then I noticed that the bouncing was getting worse. So we decided to put some other tires on it to see if that helped. I made the mistake of putting some used tires on it. Bouncing was still there. So I took it to my mechanic and had them check it out for the shocks and struts. He advised that the rear dynamic struts had just a little play. That it would not cause the car to bounce like that. He also said the rear tires that I had on it were cupped. I then went to Sam's club an had the tires put on. The bouncing was greatly reduced but continues at low speed. It would cost me over $2500 total to have the rear struts replaced because you can't replace just one. My thoughts are if this is something that is peculiar to the RX Models and I like them I will have to put up with it. I am not a mechanic and don't know if the struts were replaced (both front and rear) would that solve the problem?

[landar]

Hi Jimmy and welcome.

There is a lot to absorb in your post and I am not quite sure I understand all of it. But, assuming the car did have worn tires from the car lot, that indicates that there is something bad in the rear suspension or the previous owner did not replace all four tires at once. May not have rotated them either. Who knows.

So, you put used tires on the car and your mechanic said they were 'cupped'. But they are used tires so maybe that was partially from the last vehicle?

If the cupping was a result of your RX, then that indicates worn shocks/struts as Dave pointed out in the previous post.

What I would do, if I were you, is to take the car to a reputable alignment shop and have them thoroughly go over the suspension system. They should be able to pinpoint the culprit and perhaps be able to correct it right there. They may charge a small fee to look it over but that may be well worth it.

[lenore]

Yup go for an alignment shop, these cars are generally very smooth and quiet.

[gwgang]

Just for future reference.

I had feathering, not outright cupping at my rea tires.  Turns out my driver side rear lower control arm had rusted due to road debri.  The bushing had seized.  I was rotating tires left to right during that 5k miles interval.

[gwgang]

I hope this post is still helpful to the OP.  I just had the rear struts replaced, including strut mounts and boots.  It cost $270 in parts, and my local mechanic charge $500 to install them and rear alignment.  I am in NYC, so you know the labor charge is high.  You don't have to buy from the Dealership for the struts.  KYB is the OEM for the RX400h.  I bought my parts from partsgeek.com because their shipping is lower to my location.  You can also check out rockauto.com if their shipping is cheaper to your location.

 

The OP's problem is most likely struts.