It's now a couple of months riding in the Eibach springs and Sachs struts.

Too me the ride is awfully bumpy, with "thuds" in the rear all the time as it can't absorb drips and potholes in the road.

After driving my wife's 2005 Dodge Grand Caravan over the same locally pummpy roads, and not feeling these massive thuds and impacts, I just can't stop thinking how uncomfortable the Lexus is and that that's not the way a Lexus should drive. Since I've only owned the RX for two years, I wonder if this vehicle ever drove smoothly over road inspections when new.

I thought maybe it's the rear struts and springs. Changed those twice already with no good results for a more comfortable ride.

How I'm thinking rear control arms could be a slight cause but to what extent.

Last option is to sell.

Any thoughts?

 

If your alignment is off at the back (too much toe-in / out between both sides etc), it'll ride badly. But, if not changing those won't make a difference. Those Caravans ride really soft, even with my original springs and shocks, the Caravan rode a lot softer, but they also handle like a wet noodle compared to the much stiffer & sportier RX. The stiffness is definitely going to be from the springs, as the Sachs shocks are pretty comfortable

I would not get a 3rd gen or newer RX if you think a 2nd gen is stiff, as those ride a LOT worse!

 

Interesting.

I just got the front alignment done after tie rods and new control arms installed. Aside from the rear front facing and rear facing control arms, the entire suspension is brand new. Went with Delphi tie rods, control arms and end links.

You'd suggest getting the rear alignment as well to possibly improve the "rear thuds" and harsh ride?

Just thinking economically and time wise, I've spend alot already. However, aside from the suspension riding 2 out of 10 for comfort, I like the vehicle and would keep it if I can figure out this allusive suspension comfort issue.

Prior aftermarket struts were harsh, now the Eibach and Sachs I can't say are worse, basically the same.

Grand Caravan, 2016 Sonata and friends Ford Edge go over the same dips, cracks and bumps just with a whole lot less jarring thuds and jolts. Bumps will always be there in the road but they shouldn't be brought to my attention is the way I want to drive.

 

Those are all going to ride softer than the RX even when stock. Do you have pic of alignment sheet before & after? Even if it was just a front alignment, the machine should have a full read out of the car's alignment - if not I'd see if they have it on file. If the toe and rear camber is in spec at the back, I would probably leave it alone as the rear arms are a lot of labour $$$ to get replaced due to seized bolts in the bushing collars.

Your only other options I'd say are to get the Moog 1999-2003 RX300 rear springs (Only one left in stock on Rockauto) LESJÖFORS 4249102 - abt 80 dollars for pair, or some used RX rear springs from the junkyard or eBay.

 

I will request the alignment sheet.
Rear tires have been installed for 2 years and wear evenly, nothing odd that I can tell.

Rear and front springs from 1st Gen RX will fit flawlessly into 08 RX?

These springs ride soft?

 

Yes, they will fit front and rear. I have 1999-2001 RX300 front and rear Eibach springs on my RX350. The factory RX300 springs will retain the factory height. Every RX300 I have been in felt pretty similar to a gen 2 in terms of spring rate, they use the same suspension setup as a 2nd gen apart from the sway bars (RX300 has much smaller / thinner ones). I don't think they make a replacement aftermarket non-lowering front spring for the front of an RX300 though sadly

 

I'll try to work with the Eibach springs to get them to ride well before nixing the idea.

When I spoke with Eibach USA install team an hour ago (asked to be transferred to them from the technical support team) the man advised the harsh ride is due to installing the pro kit on Sachs aftermarket/non-OEM shocks which will inhibit the spring as they try to compress because the valving isn't designed for such short compressions and is hitting the harsher/stiffer valving too early. The pro kit is only designed to fit over OEM shocks or performance shocks like Koni or Bilstein performance lines. If installed on aftermarket copy of OEM shocks, the ride will be impacted, usually resulting in rough ride. That's basically word for word of the conversation.

Not sure what to think about that because alot of the road imperfections here in NY are cracks, with sharper edges and I don't think require the strut to compress all that much. The job seems to me more to be compliant to the road very rapidly and absorb the impact. I thought copy of OE shocks should be similar enough, maybe I'm completely wrong.

Did the 2nd Gen RX ever ride silky smooth like the ES series of that time for example?

I'm not investing in OEM shocks and I already have the Eibachs.
Backup plan is tk follow your suggestion and go with junk yard OEM springs for front and possibly rears if I can't get Moog springs easily.

 

My RX never came even remotely close to the ride of an ES or even a Camry. At the end of the day they have to make it at least stiff enough to compensate for heavy these cars are vs. the lighter & longer wheelbase ES. The stock shocks also aren't designed to be lowered by that much either, and will suffer the same complications as the Sachs, KYB or other brands i.e. reaching the stiffer valving sooner in the stroke. Bilstein / Koni would be your best bet, but they don't make them for these.

 

Will 1st Gen RX struts fit 2nd Gen RX? I found good deal on those.

 

Rear - yes,

front - not entirely sure, at the minimum you'll need different sway bar links

The RX300 rear struts increase ride height by about 6mm (higher spring perch)

 

Rears will be a direct bolt on or needs the 2nd Gen RX mount?

 

Needs the 2nd gen mount and 1st gen RX rear sway bar links (or 2011-2018 Ford Fiesta)

Almost forgot about that

Fronts will need at least the mount and sway bar links, not sure how the rest fits

 

Next mod that this 4200lbs vehicle should of came with, Do the gen3 BBK, easy direct bolt on, pr of reman calipers, pads/rotors & since you have the brake system open, replace the brake hoses w/ oem style or SS hoses & flush the system out w/ new dot 3. One look at #1005 gen2 pads vs #1324 gen3 pads will show you as well the 2 different calipers. For the rear you'll need the gen 2 Hylander('08-'13) rotors/pads/reman calipers.

 

Thanks MattRX for all the pointers! I swapped the mounts and purchased Suspensia 1st Gen RX sway bar links (would have liked Delphi as I've used this brand numerous times and appreciate the very solid quality).
Installed the new rear (1st Gen RX) and front (2nd Gen RX) Monroe Quick Struts. I took the RX on a long & thorough test drive down the same bumpy/cracked up roads which until today used to cause me to cringe. It's amazing how much smoother and more subtle the the bumps/cracks are and aren't brought to my attention all that much. Honestly, the Eibach stiffer springs weren't the issue, they were pretty good. Like what MattRX mentioned is that the non-performance strut is much quicker to hit the stiffer valving due to the slight ride height drop to the point it made a significantly harsher ride on city cracked up roads. The Monroe's are SO MUCH smoother than the prior FCS rear struts (Very harsh) and no name brand front struts from when I purchased the vehicle. Still not sure how this RX drove when new or with the original struts, however I'm very happy with the comfort level now.

I'm keeping the RX and very happy about that!

 

SO glad you finally got that sorted out! Enjoy your now comfortable RX!