Car not stable at speed.

[i-s]

Perhaps too late to be of any help, but...

When our car was serviced in late summer they said one of the rear shocks needed replacing (2015 GS Premier with AVS), at a cost of over £400. We had it done, and afterwards the "floatiness" that I complained about above was largely gone, so it could be that. 

[Vlady]

14 hours ago, i-s said:

Perhaps too late to be of any help, but...

When our car was serviced in late summer they said one of the rear shocks needed replacing (2015 GS Premier with AVS), at a cost of over £400. We had it done, and afterwards the "floatiness" that I complained about above was largely gone, so it could be that. 

Hello i-s, good to have you back! I thought you have left the forum. 😞

I checked this with Lexus Glasgow when I noticed that "floatiness", the luck of directional stability and they couldn't find anything, they said they have never seen a failed shock on GS Mark4. I thought the issue was in wheel alignment but I did that with Lexus and nothing really changed after that. 

Since then I have done 2 MOT's with Lexus and 2 Battery Health  Checks so I assume if there was a leakage/sweatiness in the shock-absorbers they would spot it.

Thanks for a suggestion though, when I am in the garage next time I will ask them to check it again.

[Steven Lockey]

I do always drive with the shocks in sports mode, but get absolutely none of this. 
In fact it seems to absolutely ignore winds, particularly when compared to my last cars.

It may be while the shocks are fine, they were misaligned and the car is riding far too high?
I guess that could cause this kind of effect as the GS has quite a high weight for it's profile
so should be less affected by winds than most cars.

[Mihanicos]

Before doing any alighnment work you should check all the suspension components and eliminate any play  between the members. Similarly for the steering wheel, all ball joints and wheel bearings. Also have the shock absorbers checked. Also check that the tyres are a fairly true circle and their steel belt is good.  

Chris.

[Vlady]

Thanks guys for advices above, none of the faults were spotted before, the car covered so far 53k miles, when I spotted this type of riding the car had about 35k miles and it was about 2.5 years ago, I am not sure how careful it was checked by mechanic but I would assume that for that mileage on the car there should be no play on joints or in steering mechanism. Tyres were new also, plus i have no knocking noises coming out from suspension or any play in the steering.

@Steven Lockey i agree with you, with the mass car carries it should be pretty planted on the motorway and not affected by the wind but it is. May be I should start driving in Sport mode too. 🙂

 

[Adge]

I bought my GS300h a month ago.  On the M27 I was struck by how much the car steering was affected by wear in the motorway lanes.  Near-side lane and indentations caused by lorry wear were the culprit.

[Vlady]

14 hours ago, Adge said:

I bought my GS300h a month ago.  On the M27 I was struck by how much the car steering was affected by wear in the motorway lanes.  Near-side lane and indentations caused by lorry wear were the culprit.

HI Harry, what car did you have before? Was the old car experiencing the same on M27? Was windy too on top ob bd road surface?

[Adge]

Jaguar XF and jaguar S type.  They  also “drifted” when nearside lane was worn.  The wheels are in the slight grooves in the road and which, in a way, become like rail tracks.

[Mike_Mac]

Hi guys! I'm coming a bit late to this topic, but have found the same 'wandering' nature to my GS430 throughout my brief ownership, especially on M-way/A-Road driving. I had a lot of other issues to deal with before getting to that, but it had always been high on my list to investigate. Up front it felt like a degree of tram-lining on certain, rutted, roads, but more than that I thought there was alignment issues or worn suspension bushes, so am getting mine into a friendly local place to check all those before doing anything else.

Regarding shocks, I've recently installed a full set of Tein Adjustable coilovers, as one of my OE shocks had failed (worked out cheaper!!), which I've used to lower the car slightly, as well as firm up the damping slightly and can't say it's improved things - although a worn shock certainly wouldn't help. The other factor I'm going to look at is tyres, as they can make a big difference and the ones on there now (came with the wheels) are fairly 'low-rent'!

I'll be really interested to see what others come up with and will post on here if I find anything.

[Vlady]

Mike welcome. I did wheel alignment couple of times and one of these times was after putting on 4 New Goodyear tyres (not a budget tyre) and the car wonder on the road, it just does not have linearity to its movement, basically if you look left or right during driving the car will change direction Slightly, Even on motorway I Always try to catch a car especially if it is a bit windy. 

I also had a chance to drive behind my car and noticed that the rear of the car behaved like on the waves. Lexus checked suspension and shocks and nothing is Worn (car has done at that point about 40K miles) or leaks.

Yesterday I Tried to drive the car in SPORT setting which helped a bit but still not even close to other car I drove. Considering the car weights almost 2 tonnes it should behave on a motorway more like a train not a boat.

[Mike_Mac]

3 minutes ago, Vlady said:

Mike welcome. I did wheel alignment couple of times and one of these times was after putting on 4 New Goodyear tyres (not a budget tyre) and the car wonder on the road, it just does not have linearity to its movement, basically if you look left or right during driving the car will change direction Slightly, Even on motorway I Always try to catch a car especially if it is a bit windy. 

I also had a chance to drive behind my car and noticed that the rear of the car behaved like on the waves. Lexus checked suspension and shocks and nothing is Worn (car has done at that point about 40K miles) or leaks.

Yesterday I Tried to drive the car in SPORT setting which helped a bit but still not even close to other car I drove. Considering the car weights almost 2 tonnes it should behave on a motorway more like a train not a boat.

Cheers Vlady! Yes - that's exactly what I'm experiencing too. The alignment and checking of bushes/tyres is primarily to make sure the baseline is sound before moving on.

Ref shocks, because I've got the Teins, I can now adjust damping to a reasonable degree, so that will allow me to test different variations between front and rear jounce and rebound bias and see what differences that makes. I feel the anti-roll bars don't help either and body-roll is one of the first things I want to get at in the future, along with chassis stiffness too. 

I'm just composing a build thread now where I'll keep track of it all, but I have lots of plans for this car, all centered on ride and handling, just need to save for a bit and wait for better weather to start spannering. Your thread just prodded me into actually starting to type stuff out!

[Mihanicos]

Given that all suspension components and members are in a good condition without any play and that all tyres are of the same make and type, the car should hold the road and not be affected by side winds. A heavy car like the one in question should go straight ahead without holding the steering wheel for about half a kilometer, assuming a level surface and no strong side winds.

The wheel geometry is the key to road holding. The modern electronic alignment equipment needs calibration so the set values correspond to the actual true values of the various parameters.

There is non electronic equipment that uses absolute methods of measurement that are not subject to wear or adjustment. When an alignment is done using this equipment, the car goes like a train and the slightest command from the steering wheel, the car obeys precisely.

The person who is doing the wheel alignment must know what he is doing and what every adjustment does and which way it influences the behaviour of the car. Looking at the wear of the tyres, he will know the cause and  he will compensate within the range given by the manufacturer.

Sadly there are very few of them left nowadays.

Chris.

[Vlady]

@Mihanicos I did twice wheel alignment at Lexus garage both times and none of them helped the matter unless I both times I got the same mechanic who doesn't know how to use hie equipment to a full potential! 🙂

As I mentioned above, a while back, even my wife's Citroen C4 (MPV) 7-seater was much more stable on motorway than the GS and C4 had very soft suspension.

May be there is something in my suspension but Lexus Glasgow couldn't find a fault with it.

[Mihanicos]

Try a professional who only does alignment and uses equipment with spirit levels to measure camber and caster and tow in/out on a board for each wheel. (Car rolls on the board )

The equipment fitted on each wheel for alignment must be set to absolute vertical and horizontal otherwise anything off vertical and horizontal will be included in the wheel adjustment.

Having done that initial setting, the front wheels are turned 20 degrees on either direction. At this point the camber and caster are adjusted to specifications. Tow in/out is the last to adjust.

A small range of tolerance is given for each parameter. A true experienced professional uses this to compensate the geometry for better road holding, tyre wear etc.

I had wheel alignment at the dealer of my previous car, not a Lexus but a german car, and it was going like boat after that. I had to go to a professional like I described to put it right.

Chris.

[royoftherovers]

1 hour ago, Vlady said:

@Mihanicos I did twice wheel alignment at Lexus garage both times and none of them helped the matter unless I both times I got the same mechanic who doesn't know how to use hie equipment to a full potential! 🙂

As I mentioned above, a while back, even my wife's Citroen C4 (MPV) 7-seater was much more stable on motorway than the GS and C4 had very soft suspension.

May be there is something in my suspension but Lexus Glasgow couldn't find a fault with it.

Have your tyres been put on the wrong way round? Directional tyres must be fitted correctly.

[Vlady]

14 hours ago, royoftherovers said:

Have your tyres been put on the wrong way round? Directional tyres must be fitted correctly.

John there are directional and all of the them are the right way. I am pretty sure the issue not in tyres.

[Steven Lockey]

Hmmm, perhaps take it to a suspension specialist. 

Just did a run down to Southampton from London area so a good 1.5 hours down the motorway and lets just say I wasn't going slowly 😉

When in the howling wind, car was dead stable. Road camber did cause a slight sway but thats kinda to be expected in any car at speed.

It can feel a bit 'floaty' in normal suspension mode when you hit a bump, but the car is still in full contact with the road and full control.

[royoftherovers]

3 hours ago, Vlady said:

John there are directional and all of the them are the right way. I am pretty sure the issue not in tyres.

Twas just a thought I had over breakfast matey.

[Mike_Mac]

Personally, based on previous experience, I'm suspecting worn bushes in suspension arms as the likely culprits, now that I've been able to drive the car again today and spend a bit more time observing this issue (thanks Essential journeys!).

As said these cars are reasonably weighty and the arms take a pounding over time. A long time ago I had a Supra that had over 100K and it was genuinely frightening at times - the back end had a mind of its own on rutted roads. I changed all the rear arms (cost a packet) but that solved it. The ones that came off weren't falling apart or anything, but there was movement...

Driving home tonight, I was reminded of that in the way my front end likes to schmooze about depending on the road's camber. Don't get me wrong, it's not horrific and is usually 'ok', but it's definitely not 'right'. 

Alignment can be spot on, tyres can be spot on, shocks can be spot on, but if the bushes are goosed... thoughts? 🙂

[Vlady]

11 hours ago, Mike_Mac said:

Personally, based on previous experience, I'm suspecting worn bushes in suspension arms as the likely culprits, now that I've been able to drive the car again today and spend a bit more time observing this issue (thanks Essential journeys!).

As said these cars are reasonably weighty and the arms take a pounding over time. A long time ago I had a Supra that had over 100K and it was genuinely frightening at times - the back end had a mind of its own on rutted roads. I changed all the rear arms (cost a packet) but that solved it. The ones that came off weren't falling apart or anything, but there was movement...

Driving home tonight, I was reminded of that in the way my front end likes to schmooze about depending on the road's camber. Don't get me wrong, it's not horrific and is usually 'ok', but it's definitely not 'right'. 

Alignment can be spot on, tyres can be spot on, shocks can be spot on, but if the bushes are goosed... thoughts? 🙂

Michael I 100% agree with you, it must be a suspension if everything else is checked and adjusted correctly. I am just a little bit surprised that the Lexus that covered only 40k miles would have an issue with suspension, well, my wifes Citroen needed new anti-roll bars at 30k miles and my friends Superb needed something done in it's front suspension as there was knocking sound @20k miles, but this is Lexus we are talking about so I would never expect that but probably could easily happen so needs another proper checking. 

At the moment I do not travel far or often so it doesn't bother me much but if we go back to "normal" it will. 

I kind of trying to reprogram my brains for a fully electrical vehicle but time will tell if this will happen.

[Cotswold Pete]

20 hours ago, Mike_Mac said:

Alignment can be spot on, tyres can be spot on, shocks can be spot on, but if the bushes are goosed... thoughts? 🙂

Certainly get the ARB bushes looked at, my LS at about 170K was making the missus sick (I noticed nothing much), but got the front bushes down a year ago (as garage said although okay!!, would tighten up the car.  

The result a happier missus, and I also noticed any tram-lining gone.  It did not have huge tram-lining problem before, but my previous LS (with less miles on) I found tram-lining could be really horrible on certain parts of M5, wind or no wind and felt like car was going to lane-hop. That LS had most of the front suspension well past its use by date. 

Just looking at the ARB bushes is not enough, you need to wedge a bar in there and give them a good wiggle.

[Mike_Mac]

2 hours ago, Cotswold Pete said:

Certainly get the ARB bushes looked at, my LS at about 170K was making the missus sick (I noticed nothing much), but got the front bushes down a year ago (as garage said although okay!!, would tighten up the car.  

The result a happier missus, and I also noticed any tram-lining gone.  It did not have huge tram-lining problem before, but my previous LS (with less miles on) I found tram-lining could be really horrible on certain parts of M5, wind or no wind and felt like car was going to lane-hop. That LS had most of the front suspension well past its use by date. 

Just looking at the ARB bushes is not enough, you need to wedge a bar in there and give them a good wiggle.

The M5 is a good tram-lining tester route, isn't it!! 😄 

[Mike_Mac]

Just to update this topic with what I've found after replacing my Anti-Roll Bars with F-Sport ones (and bushes) and installing aftermarket coilovers (Tein Flex Z).

Different car! 🤗

The shocks and anti-roll bar bushes I removed were all very tired (which won't help handling), so I suspect refreshing those would have made a difference in themselves. However, I would strongly recommend upgrading too.

Why?

Because from the outset the GS Mk 3 has been noted for pronounced body roll and soft suspension. While suspension firmness is a personal thing, sometimes being too soft can actually adversely affect ride quality, in essence because the shocks and springs can't react quickly to the larger bumps and imperfections. Anything more than a little body roll, however, is never good; it alters the suspension geometry from the ideal, as the car's frame shifts, and generally results in an unsteady ride and poor handling.

Therefore, upgrading Anti-Roll bars (in my case to F-Sport ones) has been the biggest (positive) change I've had in a car. When combined with adjustable coilovers that allowed me to dial them in to exactly where I was comfortable it's a wholly transformed car for the better. Plus the cost of the coilovers (around £800-900 IIRC) was under half the price of a set of new Lexus shocks, so it's cheaper overall too. The bars were around £400 delivered from the US (PTR02-30101 will fit the GS 430 and I'm pretty sure the GS300 too). 

So, for just over £1,200-£1,300 you can transform the handling of your car, or for a lot less you can replace the ARB bushes and/or the coilovers and still reap a benefit (you'll need to buy a rear bar though, as the bushes are bonded on...). Ultimately it's a personal decision as to whether that's VfM, but I only wish I'd been in a position to do it sooner! 

HTH! ☺️

[essldn]

Two things that fixed unstable movement on my other vehicles. 

Front control arms suspensions replaced as they were worn.

Road force balancing along with alignment.

Road force balancing is different to normal wheel balancing as it uses your cars weight and Road condition to balance the wheels which ensures better balancing when the car is driving under load. 

[Vlady]

4 minutes ago, essldn said:

Two things that fixed unstable movement on my other vehicles. 

Front control arms suspensions replaced as they were worn.

Road force balancing along with alignment.

Road force balancing is different to normal wheel balancing as it uses your cars weight and Road condition to balance the wheels which ensures better balancing when the car is driving under load. 

I have asked Lexus Glasgow to check the suspension a few times and they never found a fault, in a last three years I have done 4 or 5 times wheel alignment and the car still not as direct as I got used to based on my previous cars. Lexus does well when you go well above speed limit though! 🙂

I have done just under 60k and I noticed this behaviour when the car was at 30k! So I can't say the suspension is/was tired. I got used to this by now, I think! 🙂

Road forcing balance - I never heard of it, does dealers do that or it needs to be a specific garage?

Thanks for the input Shane.

Vlad