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Rear Wheel Camber Etc & Lpg Conversion


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Hi All,

I just did a service on my LS430 2002 (air-ride suspension) and whilst underneath I noticed that the extreme insides of both rear tyres were badly worn - a feature that was missing when I bought it - around 6 months ago and before the lpg conversion.

I took it to WIM (Wheels in Motion), who just happen to be on my doorstep. As soon as they felt the tyres and saw the lpg filler the diagnosis was camber. This is probably exacerbated by the fact that I'm a private hire driver and usually have several passengers with copious quantities of luggage.

Pete, you'll probably know the answer to this but I believe that a full gas tank can weigh around 90 kg?

Anyway, they replaced the tyres but we quickly realised that it would not be possible to adjust the camber without replacing the No. 2 lower arms with the shorter versions mentioned in the manual.

We did notice that the toe-in needed increasing and this will have contributed slightly to the wear but the main culprit appears to be camber.

I don't really have a specific question, I'm just fishing for any info. in this arena so feel free to chip in with anything relevant.

Many thanks

Mike

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Hi All,

I just did a service on my LS430 2002 (air-ride suspension) and whilst underneath I noticed that the extreme insides of both rear tyres were badly worn - a feature that was missing when I bought it - around 6 months ago and before the lpg conversion.

I took it to WIM (Wheels in Motion), who just happen to be on my doorstep. As soon as they felt the tyres and saw the lpg filler the diagnosis was camber. This is probably exacerbated by the fact that I'm a private hire driver and usually have several passengers with copious quantities of luggage.

Pete, you'll probably know the answer to this but I believe that a full gas tank can weigh around 90 kg?

Anyway, they replaced the tyres but we quickly realised that it would not be possible to adjust the camber without replacing the No. 2 lower arms with the shorter versions mentioned in the manual.

We did notice that the toe-in needed increasing and this will have contributed slightly to the wear but the main culprit appears to be camber.

I don't really have a specific question, I'm just fishing for any info. in this arena so feel free to chip in with anything relevant.

Many thanks

Mike

Mike

Now I don't like speaking ill of anyone and I let it go at the time but they did cost me a fair bit of money.....

I can't believe a suspension specialist would say that.... your car has air suspension.... it automatically adjusts the ride height to the correct setting no matter how much weight you put in the back... the LPG tank full or empty plus luggage plus three passengers will make no difference to the rear camber. If you didn't have self levelling suspension then yes, the lower the rear got the more it would effect the camber.

The tyres on mine were wearing on the inside edge, this is partly due to the characteristics of the car and also the toe-in, mine was out as well.

I know WIM are the bee’s knees as far as the IS is concerned but I doubt they are any better than any other garage with regards to the 430... I emailed and spoke to them at length about revised settings for the 430 to aid driver feel and relieve the tyre wear issues.... I was assured they would sort it with one visit, I presumed they would work out the correct settings for the car based on suspension design, length of wishbones etc etc. I was assured twice that they would sort the car, so I drove over 200miles to see them and low and behold they did nothing, the settings they had were the standard ones as supplied to anyone, they found my front camber was out and went on and on about the serious effects this would have, so I booked my car in with Lexus to have the bottom arm mountings replaced with the adjusted ones... well the service manager phoned me, stated he had checked the settings, found all of them out to some degree (three days after WIM had set them, and no I hadn't hit a curb) including the camber. He had contacted Lexus GB technical dept who had stated that this was not an issue as far as they were concerned and that it was negligible with regards to tyre wear. He advised not to waste my money and said to try it now it had been set up correctly, well I did another 5000 miles before I sold it and there was no uneven tyre wear showing front or back.

So my advice is, get Lexus to check and if necessary adjust the suspension and then forget about it.

Good Luck

Pete

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Its hard to believe that a car like the LS has such a design fault where Lexus engineers couldnt get the setup correct. The LS430 may have a bias for inner tyre wear but why would the suspension arm need replacing with a modified one ? i'm not saying the advice given was wrong but what is the underlying reason ? The amount of weight referred to above isnt really seem like something that would put this kind of car's suspension under stress.

I would stick with Lexus's own suspension settings.

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Thanks Guys,

Yes it is interesting that they haven't commented on the fact that it has air-ride suspension, because, thinking about it, as you say Pete, if it's working correctly the camber shouldn't be affected by the load.

However, that doesn't mean that the camber is correct, simply that it wont be affected by the load.

A question that springs to mind is: "should the camber be measured with the engine (air-ride) running" or "cold"? It's not mentioned in my manual; simply that there are different camber specs for air-ride and non air-ride models.

According to WIM's equipment, the camber on the rears is -1deg 44' (left) and -1deg 57' (right). This compares with the spec for air-ride which is -1deg 33' +/- 45'. This is a little splayed of the spec but well within the recommended tolerance.

The toe-in however is -0deg 03' (left) and +0deg 06' (right) Totalling +0deg 03'. The spec is for a total of 0deg 18' +/- 12' so the toe-in is obviously well out (so to speak).

My feeling is that I should get the toe-in fixed and observe how the wear goes with the new tyres.

Does that make sense?

Kind regards,

Mike

PS Are you saying that it's a common feature for LS430s to wear rear tyres on the inside?

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Hi

Goldfinger

A lot of cars have adjustable camber, the LS430 has a fixed bottom arm with a replaceable mount, they come in three different sizes to adjust the camber, this will be set when the car is first made but with time all the bushes wear a bit and the camber will change, hence the availability of different sizes.

The amount of correction is minimal, if I remember right about 1/2 to 1 degree...

Mike

One other thing that occurred to me, get the ride height checked as this could be the reason for the incorrect camber...

Pete

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Thanks Guys,

Yes it is interesting that they haven't commented on the fact that it has air-ride suspension, because, thinking about it, as you say Pete, if it's working correctly the camber shouldn't be affected by the load.

However, that doesn't mean that the camber is correct, simply that it wont be affected by the load.

A question that springs to mind is: "should the camber be measured with the engine (air-ride) running" or "cold"? It's not mentioned in my manual; simply that there are different camber specs for air-ride and non air-ride models.

According to WIM's equipment, the camber on the rears is -1deg 44' (left) and -1deg 57' (right). This compares with the spec for air-ride which is -1deg 33' +/- 45'. This is a little splayed of the spec but well within the recommended tolerance.

The toe-in however is -0deg 03' (left) and +0deg 06' (right) Totalling +0deg 03'. The spec is for a total of 0deg 18' +/- 12' so the toe-in is obviously well out (so to speak).

My feeling is that I should get the toe-in fixed and observe how the wear goes with the new tyres.

Does that make sense?

Kind regards,

Mike

PS Are you saying that it's a common feature for LS430s to wear rear tyres on the inside?

Mike

Sorry I was posting as you were

That amount of incorrect camber is nothing, the wear will have been caused by the toe-in, did WIM put it right or leave it?

All big heavy cars seem to wear the inside of tyres, front or back... well all the big ones I've had did........

Pete

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Hi All,

I just did a service on my LS430 2002 (air-ride suspension) and whilst underneath I noticed that the extreme insides of both rear tyres were badly worn - a feature that was missing when I bought it - around 6 months ago and before the lpg conversion.

I took it to WIM (Wheels in Motion), who just happen to be on my doorstep. As soon as they felt the tyres and saw the lpg filler the diagnosis was camber. This is probably exacerbated by the fact that I'm a private hire driver and usually have several passengers with copious quantities of luggage.

Pete, you'll probably know the answer to this but I believe that a full gas tank can weigh around 90 kg?

Anyway, they replaced the tyres but we quickly realised that it would not be possible to adjust the camber without replacing the No. 2 lower arms with the shorter versions mentioned in the manual.

We did notice that the toe-in needed increasing and this will have contributed slightly to the wear but the main culprit appears to be camber.

I don't really have a specific question, I'm just fishing for any info. in this arena so feel free to chip in with anything relevant.

Many thanks

Mike

Mike

Now I don't like speaking ill of anyone and I let it go at the time but they did cost me a fair bit of money.....

I can't believe a suspension specialist would say that.... your car has air suspension.... it automatically adjusts the ride height to the correct setting no matter how much weight you put in the back... the LPG tank full or empty plus luggage plus three passengers will make no difference to the rear camber. If you didn't have self levelling suspension then yes, the lower the rear got the more it would effect the camber.

The tyres on mine were wearing on the inside edge, this is partly due to the characteristics of the car and also the toe-in, mine was out as well.

I know WIM are the bee’s knees as far as the IS is concerned but I doubt they are any better than any other garage with regards to the 430... I emailed and spoke to them at length about revised settings for the 430 to aid driver feel and relieve the tyre wear issues.... I was assured they would sort it with one visit, I presumed they would work out the correct settings for the car based on suspension design, length of wishbones etc etc. I was assured twice that they would sort the car, so I drove over 200miles to see them and low and behold they did nothing, the settings they had were the standard ones as supplied to anyone, they found my front camber was out and went on and on about the serious effects this would have, so I booked my car in with Lexus to have the bottom arm mountings replaced with the adjusted ones... well the service manager phoned me, stated he had checked the settings, found all of them out to some degree (three days after WIM had set them, and no I hadn't hit a curb) including the camber. He had contacted Lexus GB technical dept who had stated that this was not an issue as far as they were concerned and that it was negligible with regards to tyre wear. He advised not to waste my money and said to try it now it had been set up correctly, well I did another 5000 miles before I sold it and there was no uneven tyre wear showing front or back.

So my advice is, get Lexus to check and if necessary adjust the suspension and then forget about it.

Good Luck

Pete

The Target data offered by Lexus for the 430 has never been in desput, so i would assume your car would have been returned to that?... the bit i don't understand is you say you had tyre wear but we did nothing, then Lexus did nothing but the tyre wear went?

This 430 is visibally low at the rear and has camber wear but there's no oem camber adjuster... any ideas?

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Tomorrow morning I'll take some measurements of the gaps between the wheel arches and the tyres with and without the engine running.

I agree that the car is sloping uphill when stopped without the engine running. Is this normal for this model; I wouldn't have thought so? Not cosmetically attractive! What could be causing it?

I've just had a look at the "air-ride" section of the manual and it gives precise details/specs. of how to measure the height of the vehicle at the front and back, ie. ground to centre of lower arm mountings (presumably inner mountings). Also specs of allowed differences between front and back (around 1 inch).

It then gives the procedure for adjusting the vehicle height (front and rear seperately) by altering the adjustable "height control sensor links" that, unsurprisingly, link the lower arms to the ride height control sensors.

It also gives a scheme for testing the operation of the air-ride system generally. I'll try to go through all this in the next few days and decide the best way forward.

This is suddenly starting to make sense.

Many thanks again for all the input.

Mike

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The Target data offered by Lexus for the 430 has never been in desput, so i would assume your car would have been returned to that?... the bit i don't understand is you say you had tyre wear but we did nothing, then Lexus did nothing but the tyre wear went?

This 430 is visibally low at the rear and has camber wear but there's no oem camber adjuster... any ideas?

Hi

What I said was

I booked my car in with Lexus to have the bottom arm mountings replaced with the adjusted ones... well the service manager phoned me, stated he had checked the settings, found all of them out to some degree (three days after WIM had set them, and no I hadn't hit a curb) including the camber. He had contacted Lexus GB technical dept who had stated that this was not an issue as far as they were concerned and that it was negligible with regards to tyre wear. He advised not to waste my money and said to try it now it had been set up correctly, well I did another 5000 miles before I sold it and there was no uneven tyre wear showing front or back.

This was after you had "set up" the car.

Pete

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Tomorrow morning I'll take some measurements of the gaps between the wheel arches and the tyres with and without the engine running.

I agree that the car is sloping uphill when stopped without the engine running. Is this normal for this model; I wouldn't have thought so? Not cosmetically attractive! What could be causing it?

I've just had a look at the "air-ride" section of the manual and it gives precise details/specs. of how to measure the height of the vehicle at the front and back, ie. ground to centre of lower arm mountings (presumably inner mountings). Also specs of allowed differences between front and back (around 1 inch).

It then gives the procedure for adjusting the vehicle height (front and rear seperately) by altering the adjustable "height control sensor links" that, unsurprisingly, link the lower arms to the ride height control sensors.

It also gives a scheme for testing the operation of the air-ride system generally. I'll try to go through all this in the next few days and decide the best way forward.

This is suddenly starting to make sense.

Many thanks again for all the input.

Mike

Mike

It is very easy to adjust the rear ride height if it is low...

rearls430.jpg

When I set up mine to the exact specs the rear does look lower than the front.... seen this on other 430's to....

Pete

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Thanks Pete,

I'm trying to understand the effect of raising or lowering the ride height on the rear camber.

At present my understanding is - that as the upper arm is considerably shorter than the lower No.2 any alteration in ride height will cause the upper part of the hub to move more than the lower, thereby affecting the camber. And, further, because the upper arm is angled downwards (towards the wheel) a lowering of the ride height will push the upper part of the hub outward more than the lower part, hence reducing the negative camber.

The upshot of this view seems to indicate that by lowering the ride height the wheels will be more upright and cause less wear on the inside.

Does this make sense?

Mike

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This morning I tested the air ride system and it does indeed raise and lower the car within the specs - this is a good start!

Next I need to check the vehicle height (as defined by the specs) because, as stated in my previous post, I feel that too high a rear will give camber wear on the inside. I know it LOOKS low at the back but that's only in relation to the front - also, it's bound to be low at rest because of the gas installation, this is corrected by the air-ride when it's running.

Then I want to experiment to see how ride height affects camber by adjusting the height and observing the resulting alignment.

Finally, I realised that I had been focussing entirely on GEOMETRY so far. I then considered that although my inside rear wear may have been caused in some part by incorrect toe-in and maybe some extra camber this would have probably been exacerbated by the extra weight of the lpg tank installation and the fact that I mainly have the car fully loaded with passengers and luggage - air-ride may correct the geometry BUT the weight is still there and must surely increase any wear effect that is present.

Mike

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This is so interesting! I just checked the ride height against the specs. As I suspected, in spite of the back appearing much lower than the front (judged by the gap between tyre and wheel arch) the reality is that the back is actually higher than the front (using the Lexus definition).

But the really interesting bit is that back left is 3cm higher than spec. with the left being 2cm higher. The front is also higher by the same amount. I've just checked to make sure I hadn't left the ride-height in "high" btw - lol!

Pete, perhaps you could help me here. You mentioned in your photo that lowering the position of the bolt lowered the suspension on the rear. Do you know if shortening the link length on the front has the same effect or is it the other way around?

Thanks

Mike

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Mike

just read the above.... I'm just on my way out but the higher the back the more the wheels will tuck in so reducing inner wear... when the VIP boys lower there cars into the weeds they get very severe inner edge tyre wear not the other way around, yes the front is easy to do, I'll post some info and pics later...

There are left hand threads on the front links so go carefull if you have a go in the meantime....

Pete

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Thanks Pete, I understand that this may apply to some cars HOWEVER I think the geometry of the LS430 at the back is such that it will be the other way round.

I am very much a novice at this sort of thing but I think my specific reasoning here is sound. I am open to being proved wrong though, so I anyone can refute my suggestion logically I'd be more than interested to hear the reasoning - especially since I'm thinking of making adjustments to the suspension accordingly.

Thanks!

Mike

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When I read the opening post, I immediately wondered why LPG and "rear weight" was stated as the culprit.

Surely, if your car is running LPG, your petrol tank is most likely to be empty-ish and so the LPG weight is less of a problem. Unless of course the LPG tank itself is very heavy.

On my 1995 LS400, the rear tyres were excessivly worn on the inside edges..... down to the steel beads YIKES!. Upon closer examination, it was clear to see that the rear upper wishbone rubbers were badly worn. I have since replaced both rubbers on the wishbone with American replacements at about 35 USD a side, as Lexus GB were only able to offer complete wishbones at £280 GBP. EACH !!! Might be well worth checking for any play on the wheel Mike.

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Mike

If you jack the car up and let the wheel drop, i.e. raise the car, you will see that the wheel will tuck in at the bottom, not splay out, so if the car is running too low then the pressure will be on the inside of the tyre... hence inner tyre wear...

Now have a look at the inside edge of the passenger side tyre on here.... this was before I had it set up, my rear toe was out as well...

23072008103.jpg

To set the front ride height you can get to the link by putting the front wheels on full lock, you need an 8mm and 10mm spanner to loosen the turnbuckle, shorten it to lower the car and lengthen it to raise, it has a left hand thread on one end.... I took mine off as they were very stiff and the threads were a bit rusty, a good wire brush and some wd40 and you could spin them by hand.... adjust them a bit and then start the car and it will self adjust within about 2mins... sometimes longer....

See here

frontsensor.jpg

I would set the car up to the exact spec from Lexus and try it from there.....

I lowered the front of mine 30mm to level the ride and this put the castor out a bit.... looked more level though and drove fine....

29072008105.jpg

With yours being a "work" car I'd just set it as it should be...

Good Luck

Pete

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Thanks Pete, a picture is certainly worth a thousand words, I'll have to relook at the geometry if I'm to understand it properly - I certainly don't think I'll lower the rear to the spec. though (it's now 2.5cm high) as it seems that this will only worsen the active camber.

Returning to the toe-in, I see that it's presently showing a total of +0deg 03' as against the spec of 0deg 18' +/- 12'. I think I'll simply get the toe set to a total of say +0deg 20' and see what the effect is.

Thanks for all this input!

Kind regards,

Mike

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Simon,

That's a good point about the lpg tank. I do try to keep the petrol low. However the lpg tanks are very thick and heavy and, in addition I usually have many passengers and heavy luggage. Although this shouldn't affect a working active suspension, I've just realised that it will exacerbate any wear situation simply by virtue of pressing harder on the tyres. Another good reason for getting the geometry correct.

Thanks

Mike

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  • 4 weeks later...
Simon,

That's a good point about the lpg tank. I do try to keep the petrol low. However the lpg tanks are very thick and heavy and, in addition I usually have many passengers and heavy luggage. Although this shouldn't affect a working active suspension, I've just realised that it will exacerbate any wear situation simply by virtue of pressing harder on the tyres. Another good reason for getting the geometry correct.

Thanks

Mike

hi I am in same line of work (dead!)

good post on the tyre wear/ride adjustment. will get mine done. see u at lap?

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  • 10 months later...
Simon,

That's a good point about the lpg tank. I do try to keep the petrol low. However the lpg tanks are very thick and heavy and, in addition I usually have many passengers and heavy luggage. Although this shouldn't affect a working active suspension, I've just realised that it will exacerbate any wear situation simply by virtue of pressing harder on the tyres. Another good reason for getting the geometry correct.

Thanks

Mike

wow, a great reply. I used to stuck with thick lpg tanks and same problem. And yes I surely agree that the wheels geometry should be done correctly.

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