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Caster angles


V8david
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Hi all. The front right tyre of my RRC is wearing bloody quickly around the inside shoulder.

I took it to have the tracking/wheel alignment checked and was told the caster angles were out on the front wheels but they were (obviously) non-adjustable.

(I would have thought that wear on the inside shoulder would've been caused by camber rather than caster...?)

I have replaced the steering rods and track rod ends (pre alignment), the swivel bearings, and set the preload. New steering damper and props, and polybushed throughout.

The readings were:

Nearside front caster: 0.27 degrees (tyre wear on this side is fine and even so not bothered)

Offside front caster: 1.32 degrees (tyre wear shocking!)

So my question is, what is there left to be wrong?!?!?

Is it worth replacing the wheel bearings as a last ditch attempt?

ALSO... been reading on the defender forum about setting the tracking yourself with string. Does anyone know the toe in/out in mm to set the tracking with this method?

AND FINALLY... Also on the defender forum (interesting place that! :lol: ) there are posts about setting the swivel preload with the seals in place. Does anyone have the figures in lbs or kg for swivel preload on a RRC?

Think that's all for now.

Cheers.

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Castor out by that much?

Perhaps the axle tube is bent, or the sub axle? The swivel ball damaged on that bad side?, or the swivel ball isn't a Range Rover one, I'm not sure if they are all the same. ie I believe that the swivels from a 90 will physically fit, but are they the same? It could be a dodgy aftermarket swivel ball that's been fitted at some point. Also I don't know what the factories tolerances were like on things like this......

Range Rovers are toe out, 1.2mm-2.44mm, or as I prefer to say, 0.10"- 020" :blink:

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Cheers mate. i guess the caster being out also explains the shaky steering over bumps when i fitted a bilstein steering damper. I went back to the original to get over that having replaced pretty much everything.

So the next question is where the hell do I take it to have everything checked so someone can finally tell me the culprit? Failing that do I just but a known good second hand axle and overhall it? I'm sick of chewing tyres!

Anyone know anyone or anywhere I could get it all checked?

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Could the problem also explain why I'm STILL getting vibration at 50-60mph, despite replacing the possible culprit of the props? It's like a humming vibration.

So I've got vibration at speed, dreadful inner shoulder tyre wear on the front right, new christ knows what and still no joy. The reading for the left caster (mentioned in the first post) is also out of tolerance (according to the data sheet from the tyre place). So basically both ends are fooked (right more than left though). So....... I don't know......... get another axle I guess.

I'm waffling/ranting now because this is F**#@NG pissing me off! I just want to take a 30yd run up and kick the car into the river.... F**#@NG money pit.

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What are the front radius arm bushes like and have they been put together correctly? If you have polybushed them you might have messed it up! If one side is effectively longer than the other it could easily create some of the problems you have.

Unlikely but are the hockey sticks bent?

Stick the front end on axle stands and thoroughly check for loose wheel bearings, wheel nuts, bent wheel rims etc. Are the spring seats on the axles at the same angle? Get someone to turn the steering while you make sure nothing is loose and that the steering joints are fine. Even though you did the work check that all the bushes including panhard rod are in the right place and tightened up correctly. While you are at it check the rear radius arm bushes and the A frame ball joint, they can have some strange effects if worn.

Good luck.

Mike

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Cheers Mike, I'll give it all the once over.

Thing is the uneven tyre wear was on it when I bought it before I did any of the work. So through the process of elimination (albeit a very bloody expensive process) all that's really left is to start replacing axle parts. If not the axle. I guess it's up to me where I start. At least if I buy new parts and then end up buying another axle :blink::(:blink::huh::o:blink: (can't believe I've just written that!!!), I can stick all the new bits on the axle.

Patience is really wearing thin....

I think the frustrating bit is, if I take say, a stub axle off, hold it up to the light and stare at it's shiny shaft.... how the f**k do I know if there's anything wrong with it? Even more so, take off a swivel ball, how do I tell if there's a problem?!?!? Stick it in my swivel ball testing machine I suppose...

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It's quite feasible for the axle tube to be bent.

We had one on here (I think) years ago with tyre wear only on the inside edges.

Turned out the rear axle was bent.

We had a Disco in the club with a bent front stub which caused similar symptoms.

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It's quite feasible for the axle tube to be bent.

We had one on here (I think) years ago with tyre wear only on the inside edges.

Turned out the rear axle was bent.

We had a Disco in the club with a bent front stub which caused similar symptoms.

When you say the tyre wear was caused by the rear axle being bent, it was the rear tyres that were wearing funny wasn't it?! Please don't tell me a bent rear axle can cause front tyres to wear funny! I'll be even more lost then! All the readings for the rear wheel alignment were fine anyway.

So where can you get something like that checked? Is there a bent axle checking facility anywhere?!

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Sorry, yes I meant in this case the rear tyres :ph34r:

:lol: Thank god for that!

I think now after much deliberation and waffle I'm going to start with swapping the stub axles. I've managed to locate a pair to try next week so i'll let anyone who's interested know how it goes. Failing that I think he's got an axle case to try. And beyond that I think i'll try another RR.

Cheers all, will update when I have more info!

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Notwithstanding the Castor angle being out of spec I would suggest its camber thats causing the tyre wear.

Although it was on my car with independent front suspension I have experience of camber angle shredding the front N/S tyre down to the canvas on the inside edge. The camber wasn't out by much and certainly not visually detectable looking from the front etc.

Possible that its been shunted into a kerb sideways in the past also causing the castor angle to be out as well.

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Cheers Steve, good points.

Speaking of the word 'shunted', I think we may have got to the root of the problem. Having been in touch with the bloke I bought it off, turns out he was shunted in traffic (someone drove into front nearside) quite a while back now.

So that would explain the exact same tyre wear when I first looked at it, and also explain NIL improvement in any of the chracteristics even after hours, no, days of blood, sweat, blue air and £££££££s.

So I think it's safe to say something front axle wise is bent. I'll start with the stubs and then try the beam itself if necessary. I don't think there're any bends chassis wise.

The radius arms aren't bent (I don't think). But then any bend in the radius arms would immediately affect castor? Almost worth buying a 2nd hand front axle with radius arms and killing loads of birds with one expensive stone. Any thoughts?!

Steering rods definitely aren't bent, they're new, as are all the ball joints.

Really looking forward to getting this sorted :(

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As the car was shunted in the past, my guess would be the stub and/or swivelhousing got damaged. This would explain misalignement in both castor and camber.

Unless you can find a cheap axle (in good shape), it will probable be cheaper to replace just the swivel and stub, especially considering the new parts you have already installed.

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There is a simple method of determining chassis straightness, or otherwise, in the green bible. You just need a measuring tape and an assistant.

Please elaborate! I have the RR manual on CD if that's what you mean.

Cheers Escape, I can just about cope with that!

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Sitting here visualising the hub arrangement I would think that if anything was going to bend it would be the flange on the end of the axle tube.

Am I missing something that is weaker within the hub or swivel?

Steve

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Camber only needs to be out by a couple of degrees between the top and bottom swivels to have noticeable effect on tyre wear.

Easiest way is to get a spirit level and measure the degrees off vertical that the 'good side' wheel is and then do the same on the bad side.

We are looking for a calculation that results in the same measurement each side - if the ground slopes (not horizontal) then use trigonometry to factor this in - sounds complicated but not practicable to explain in a post!

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Camber only needs to be out by a couple of degrees between the top and bottom swivels to have noticeable effect on tyre wear.

Easiest way is to get a spirit level and measure the degrees off vertical that the 'good side' wheel is and then do the same on the bad side.

We are looking for a calculation that results in the same measurement each side - if the ground slopes (not horizontal) then use trigonometry to factor this in - sounds complicated but not practicable to explain in a post!

I will try that, I know what you mean! The alignment check said that the cambers were well in tolerance, and by the time they had set the toe out, the only thing out was the castors.

Thing is, as and when I swap parts over to try, I'll need to have an alignment check to see if it's worked. But that's £40+ a pop. I have a couple of ideas...

To check a stub axle, if you put it in a lathe and spin it, any bend will be obvious?

Also if you take a half shaft out and role it on a flat surface, a bend will also be obvious? Like checking a pool cue on a pool table.

That'd leave the swivels, and as steve_d said, the flange on the end of the axle tube, or indeed the tube itself.

So gradually moving forward...

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Right. Done some geometry checking today, thanks for the info Highway_Star ;) , and here's what I found...

Axle measurements check out ok and everything seems straight.

Checked the wheelbase. On the left side, the good side, the measurement is 100 inches. Spot on. Measured repeatedly, moving the car back and forwards, always 100". That's something I suppose :rolleyes: ...

On the right side, the chewed side, the wheelbase is between 2/16" and 3/16" shorter. This is consistent around the wheel. I moved it back and forwards repeatedly and measured it with the wheel in various positions. This explains the castor problem and tyre chew I reckon..

So... I've located an axle which i'm going to overhaul and make look pretty and swap over and see what happens...

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couple of other checks would also be worth doing if the swivel preloads are too loose the bearings will wear and cause the problem you have.

if the front or rear radius arm bushs are pollyed try retightening them as this will increase decrease the wheel base had mine four wheel aligned found the o/s/r 1/4" shorter added a spacer washer cured the fault.

is the car square? yes you have measured the wheel base waht about the corner to corner if the thrust line is out this will cause the problem.

are the wheel bearings ok silly but can contribute to the prob

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couple of other checks would also be worth doing if the swivel preloads are too loose the bearings will wear and cause the problem you have.

if the front or rear radius arm bushs are pollyed try retightening them as this will increase decrease the wheel base had mine four wheel aligned found the o/s/r 1/4" shorter added a spacer washer cured the fault.

is the car square? yes you have measured the wheel base waht about the corner to corner if the thrust line is out this will cause the problem.

are the wheel bearings ok silly but can contribute to the prob

Cheers mate. I put new swivel bearings recently and set them about 3 times! Good thinking with the washer on the radius arm bushes, that could be worth a try. Car's square! I was pi##ing about with the tape measure for hours this morning! Wheel bearings also good, checked them while doing the swivels.

Cheers for the thoughts though, will keep this updated as I go... Covers all sorts from steering shakes to tyre wear.

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  • 1 year later...

Just to draw a line under this tyre wear business if anyone's interested...

I got a replacement front axle off a mate (cheers Gav), swapped my diff over to new axle, fitted all new bearings, swivel balls and seals to new axle and fitted it to the vehicle.

Tyre wear seems to be even now (been waiting to update to see if the problem is fixed). So basically something in the area of the front axle was bent and knackering the tyre. No idea what but the moral of the story is...

If in doubt try replacing large sections of your vehicle and you're bound to solve the problem no matter how small!

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