Car not stable at speed.

[Vlady]

Hi all,

When I drive on motorway it feels like the car moves with the wind so you always have to correct it with the steering wheel. I noticed this a while ago but hoped that wheel alignment will fix it and then I had another wheel alignment done last Friday but the issue is still there, I thought it is the wind but I drove my wife's Citroen and it stays solid on motorway and my GS doesn't. I remember my BMW felt much more secured at the motorway speeds without much input from steering wheel. 

Even by changing the radio channel the car can move a meter within the lane!

The car was with Glasgow Lexus twice within last 2 months (tyres change and wheel alignment) and they could see anything being worn or damaged.

I mentioned this a while ago in specific thread I created that when you follow my car it looks like it is on sea waves (I saw it, my boss saw it), I thought it is a super comfort suspension but the issue above makes me think that I do have an issue.

I checked the tyre pressures (36psi all 4 wheels) and there is no visual leaks in shock absorbers.

I expect the car to be like an iron on the road being that heavy but it feels like a boat!

Does anyone have an idea what it can be or it is a GS specific thing and this is how it should be?

Any ideas are welcomed! Thanks

[i-s]

I have two thoughts on this topic. 

1) The GS is pretty "floaty". I REALLY notice this when I go between it and the Tesla. On the same piece of road the Tesla makes me think is flat with some bumps and surface roughness the GS makes me think is undulating continuously. The body is constantly moving up and down, it never seems to "settle". This is reduced quite a bit by setting to Sport+ as it firms up the damping, but this isn't a brilliant solution because although it mostly cures the float, it's then far too harsh on bump compression. This is ultimately part of the trade-off of the car I think - floaty or firm. The movement is slow - less than 1Hz. However, I've not found it to lead to flightiness on the motorway. 

2) There's wheel alignment and there's wheel alignment. A proper 4-wheel alignment done using a properly set up Hunter Hawkeye run by a skilled operator is a world apart from someone sticking some lasers on the back wheels and getting a toe angle set. I have seen people going around and around having "alignment" after "alignment" and never solving their problems, yet then being solved by a hunter machine. If you're not getting a print out like this then you need to find a hunter and get it done there:

Ultimately all that may do is rule alignment out as an issue, but at least it will give you peace of mind on that front. It could, however, be a camber or caster issue, which would not be revealed by older style "laser" alignment (which can merely set front toe angle relative to rear). 

[Vlady]

@i-s thanks for the suggestion and for confirming some of mu thoughts. I have the same print out from Lexus Glasgow showing what was wrong with wheel alignment before and after so I hope it was done properly.

My GS apart from floaty feels like it is trying to be blown away by the wind i.e it's directional movement forward is affected by the wind if that makes sense not by much but you can feel it.

I think I can rule out wheel alignment, well, not sure what else it can be!

[i-s]

I'm glad to hear that your dealer is doing that job properly, good. Yes, if you're all in the green on the after print then wheel alignment is not the cause. 

I've not found the GS to be particularly sensitive to winds. However, all my previous cars were large estates, so maybe I'm just used to that... One thing though; my Honda wasn't particularly sensitive to winds.... except one time when I had a bunch of stuff in the boot (about 100kg). The change to the aerodynamics on the motorway were noticeable - suddenly the car was upset by breezes where it never had been before - presumably the lowering of the rear end, raising of the front channeling more air underneath and giving rise to greater front-end lift was the issue here. Do you have some unusual amount of stuff in the boot (although I'm sure the GS should self-level)? 

Is there possibly some other upset to the aerodynamics? For example, was the engine undertray removed for servicing and not replaced? Has one of the front wheel spats (small vertical flat piece of plastic that sticks down about 1" from the body, in front of the tyre) got damaged or folded?

Otherwise, it may unfortunately come down to your shocks approaching the end of their life - not totally surprising on a 6 year old car, but you'd hope for longer. This was long an issue for 3GS 450h, so maybe it's true for 4GS too. 

[royoftherovers]

2 hours ago, Vlady said:

Hi all,

When I drive on motorway it feels like the car moves with the wind so you always have to correct it with the steering wheel. I noticed this a while ago but hoped that wheel alignment will fix it and then I had another wheel alignment done last Friday but the issue is still there, I thought it is the wind but I drove my wife's Citroen and it stays solid on motorway and my GS doesn't. I remember my BMW felt much more secured at the motorway speeds without much input from steering wheel. 

Even by changing the radio channel the car can move a meter within the lane!

The car was with Glasgow Lexus twice within last 2 months (tyres change and wheel alignment) and they could see anything being worn or damaged.

I mentioned this a while ago in specific thread I created that when you follow my car it looks like it is on sea waves (I saw it, my boss saw it), I thought it is a super comfort suspension but the issue above makes me think that I do have an issue.

I checked the tyre pressures (36psi all 4 wheels) and there is no visual leaks in shock absorbers.

I expect the car to be like an iron on the road being that heavy but it feels like a boat!

Does anyone have an idea what it can be or it is a GS specific thing and this is how it should be?

Any ideas are welcomed! Thanks

Power steering on the blink Vlad ?

[Vlady]

14 hours ago, royoftherovers said:

Power steering on the blink Vlad ?

I hope not John, how can I check it? I do not feel it being inconsistent or when you rotate the wheels it judders or pulsating. 

[Vlady]

15 hours ago, i-s said:

I'm glad to hear that your dealer is doing that job properly, good. Yes, if you're all in the green on the after print then wheel alignment is not the cause. 

I've not found the GS to be particularly sensitive to winds. However, all my previous cars were large estates, so maybe I'm just used to that... One thing though; my Honda wasn't particularly sensitive to winds.... except one time when I had a bunch of stuff in the boot (about 100kg). The change to the aerodynamics on the motorway were noticeable - suddenly the car was upset by breezes where it never had been before - presumably the lowering of the rear end, raising of the front channeling more air underneath and giving rise to greater front-end lift was the issue here. Do you have some unusual amount of stuff in the boot (although I'm sure the GS should self-level)? 

Is there possibly some other upset to the aerodynamics? For example, was the engine undertray removed for servicing and not replaced? Has one of the front wheel spats (small vertical flat piece of plastic that sticks down about 1" from the body, in front of the tyre) got damaged or folded?

Otherwise, it may unfortunately come down to your shocks approaching the end of their life - not totally surprising on a 6 year old car, but you'd hope for longer. This was long an issue for 3GS 450h, so maybe it's true for 4GS too. 

I heard about 3rd Gen having shocks issues, I have asked Lexus to have a look at them and they found nothing (visually) and told me they never had a GS (4th Gen)with faulty shocks. My car is 7 years old but covered only 44441miles (I noted last night) :).

I have almost nothing in the boot and will have to check these little flaps you are talking about, I don't expect them to have such an effect though, could it be? I always wondered what are these for! 🙂

I guess it will be one of the mysteries this issue until something brakes, as they say do not fix it if it ain't broken!

My wife never mentioned that she felt the same effect on motorway and she took it to Sterling last Saturday so may be it is in my head and I just expect more linearity from the car?

[Thackeray]

Did changing the tyres have any effect? Was it better or worse with new tyres? Did you change the brand of tyre?

Maybe some brands of tyre make the GS more stable than others.

[Cotswold Pete]

2 hours ago, Vlady said:

I heard about 3rd Gen having shocks issues,

I had a bit of a problem with drift (and tramlining on LS), and it was only when I had new shocks and ARB bushes sorted on front end the problem went away.

Although the LS is a bit of a wallow-mobile, since the new shocks it does corner much better, and I think we mainly just get used to the gentle decline in steering and road-holding performance, though it sounds like your situation is somewhat dramatic.

Based on experience I would say that cheaper tyres do show up the effects of worn suspension more so than more expensive brands, but a tight running gear setup is not so botherered by cheaper tyres.

[Vlady]

1 hour ago, Thackeray said:

Did changing the tyres have any effect? Was it better or worse with new tyres? Did you change the brand of tyre?

Maybe some brands of tyre make the GS more stable than others.

Hi William, I have changed the brand of tyres but I had similar issue with my old ones, actually it is a bit better with new tyres and freshly done wheel alignment.

49 minutes ago, Cotswold Pete said:

I had a bit of a problem with drift (and tramlining on LS), and it was only when I had new shocks and ARB bushes sorted on front end the problem went away.

Although the LS is a bit of a wallow-mobile, since the new shocks it does corner much better, and I think we mainly just get used to the gentle decline in steering and road-holding performance, though it sounds like your situation is somewhat dramatic.

Based on experience I would say that cheaper tyres do show up the effects of worn suspension more so than more expensive brands, but a tight running gear setup is not so botherered by cheaper tyres.

Pete, I have good brand new tyres (Good Year Vector 4-seasons Gen 2) so tyres shouldn't be a problem. May be the shock absorbers are on the way to die. Will see how it goes.

 

Thanks everyone.

[noby76]

I currently experience this in my MK3 GS300 and had this same behaviour in my previous MK2 GS430 aswell.. both felt wallowy during high winds mainly on the motorway.. i have just learnt to keep speed moderate during high winds on the motorway..  my Accord or previous cars were sometimes wallowy during high winds as well but seems to be more noticeable in the GS's for some strange reason. not sure if the "soft cushy" setup of their suspensions is a contributing factor.

[Britprius]

On 1/7/2020 at 1:53 PM, Vlady said:

Hi all,

When I drive on motorway it feels like the car moves with the wind so you always have to correct it with the steering wheel. I noticed this a while ago but hoped that wheel alignment will fix it and then I had another wheel alignment done last Friday but the issue is still there, I thought it is the wind but I drove my wife's Citroen and it stays solid on motorway and my GS doesn't. I remember my BMW felt much more secured at the motorway speeds without much input from steering wheel. 

Even by changing the radio channel the car can move a meter within the lane!

The car was with Glasgow Lexus twice within last 2 months (tyres change and wheel alignment) and they could see anything being worn or damaged.

I mentioned this a while ago in specific thread I created that when you follow my car it looks like it is on sea waves (I saw it, my boss saw it), I thought it is a super comfort suspension but the issue above makes me think that I do have an issue.

I checked the tyre pressures (36psi all 4 wheels) and there is no visual leaks in shock absorbers.

I expect the car to be like an iron on the road being that heavy but it feels like a boat!

Does anyone have an idea what it can be or it is a GS specific thing and this is how it should be?

Any ideas are welcomed! Thanks

I had this problem with my GS450H however I had never had the tracking checked or adjusted. The tyres front and rear were wearing evenly with no shoulder ware. I dialed in one turn of tow in on each track rod marking there original position first so that I could return to this position if required. The problem disappeared completely, and tyre ware was not impacted in any way.
I know this was not very scientific, but it did work, and has done now for about 2 years. It is worth a try as it will not cost anything, and can be reversed if it does not work for you.
I did post about it at the time, but I cannot find the post.

John.

[Vlady]

14 hours ago, Britprius said:

I had this problem with my GS450H however I had never had the tracking checked or adjusted. The tyres front and rear were wearing evenly with no shoulder ware. I dialed in one turn of tow in on each track rod marking there original position first so that I could return to this position if required. The problem disappeared completely, and tyre ware was not impacted in any way.
I know this was not very scientific, but it did work, and has done now for about 2 years. It is worth a try as it will not cost anything, and can be reversed if it does not work for you.
I did post about it at the time, but I cannot find the post.

John.

Thanks John, it might come to that that I will need that adjustment get done, not now as I do not have access to a ramp and need to take the car to the garage and convince them to do it!

It is weird though that wheel alignment is spot on and the car still does this thing! 

To be fair it is less windy today and the car felt better on motorway but not ideal, I still do not feel that stability on the road as I felt with my 5er! 

[i-s]

Can you take a photo of your print out? Just curious - if the car is in a zero-toe or very low-toe configuration then what John says could possibly help. A lot of car makers do very low toe configurations these days for fuel economy. 

[Vlady]

@i-s Will do when I get home tonight. 

Thanks

[Britprius]

1 hour ago, Vlady said:

Thanks John, it might come to that that I will need that adjustment get done, not now as I do not have access to a ramp and need to take the car to the garage and convince them to do it!

It is weird though that wheel alignment is spot on and the car still does this thing! 

To be fair it is less windy today and the car felt better on motorway but not ideal, I still do not feel that stability on the road as I felt with my 5er! 

You do not need a ramp or even remove the wheels this can be done on the floor by just turning the steering onto full lock either way to gain access to the track rod ends. 

John.

[Vlady]

Hi @i-s, I have attached below the screenshot of the Wheel Alignment report, does it tell you anything? To me if it is green it is good but what adjustment you mentioned can be done to make the car a wee more stable Thanks.

[i-s]

I am by no means an expert. 

Clearly there's nothing grossly wrong with your alignment. If I'm reading that correctly they reduced your toe angle quite a bit, from .9 and .7 to .2 each side. Basically my understanding is no greater than imparted by these pages, and playing project cars:

https://suspensionsecrets.co.uk/adjust-tune-toe/

https://suspensionsecrets.co.uk/camber-2/

As for alignment adjustments.... Again, I emphasise that I'm solely an armchair non-expert in this. Maybe increase front toe-in to 0.4 on each side, and reduce rear camber to around 1.2 on each side (and currently they're a bit mis-matched, obviously they didn't adjust as the before/after figures are the same). I've visually noticed the rear camber on our GS. This should increase the front-end stability at the cost of a little more steering effort/understeer, and increase rear grip a little (further increasing the understeer tendency, but should make for a bit more straight-line plantedness).

However, your original post didn't suggest that it's any worse after alignment, and going back and reading it again I feel like it is a dynamic issue that you're complaining about (ie body movement) rather than alignment. As I said, our 4GS has a similar nature of being constantly moving, undulating.... your colleague's "sea waves" is a good analogy. The 5er is a supremely competent car, and one with more of a sporting bias than the 4GS, so they've paid more attention to controlling body movement like this. I did notice a very similar kind of movement and feeling in a colleague's Merc C350e PHEV, but it is completely absent in the Tesla. 

But ultimately I think it's just the nature of the 4GS suspension setup. Give it a try out on the motorway at a location where you've experienced this issue before but put it into Sport+ mode, see if that solves it. If it does it simply comes down to the damper behaviour

[Vlady]

Good Morning @i-s, thanks for links above, i will read them to have better understanding what is going on. I noticed last night was not as windy and the car behaved better on motorway, I guess Lexus comfort suspension and the little Scottish wind do not go together well! 🙂

I will leave the suspension as it is for now as on paper wheel alignment is fine, when I get next time to Lexus (hopefully for Battery Check only) I will talk to them about it.

Thanks everyone for input, if you have any other ideas keep them coming please.

[westo3]

My GS is just 3 years old this month but had to have a new near-side rear shockfor its MOT. So suspension could be an issue.  Fortunately it was replaced under warranty. I wonder if it wasn’t under warranty they would have insisted I had the pair replaced!

[Britprius]

59 minutes ago, westo3 said:

My GS is just 3 years old this month but had to have a new near-side rear shockfor its MOT. So suspension could be an issue.  Fortunately it was replaced under warranty. I wonder if it wasn’t under warranty they would have insisted I had the pair replaced!

They could not "insist" on fitting a pair of shocks as the MOT only failed the car on one.
Obviously the other shock on the other side passed the test. I would say it is advisable to change them as a pair to give even stability on both sides of the vehicle. It comes under the same category as fitting one new tyre on an axle where the other tyre may only have 2mm of tread left as this would still be perfectly legal, and still pass an MOT.

John.

[johnatg]

Absolutely agree. Brake and suspension components and tyres should always be replaced in pairs - like for like each side.

[westo3]

Interestingly when I asked if they would do both shocks instead of just replacing the one they said it was not necessary as the car had only done 27k

[NemesisUK]

Similar advice to that from Mercedes, replace singularly below 80km, unless there is obvious faults/failure both sides. 

[olliesgrandad]

Apologies but just quickly read this post. I had an issue with my alignment check on my last RX450h in that the tyre centre set the tracking up based upon my private number plate. Unfortunately that was for my  previous 2015 GS300h. 

Luckily I spotted the model on the printout and they rechecked it. 

Fortunately the figures for the GS were identical to the RX and all was fine.