Front Tyre wear/Camber Angle

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moggiegeek
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Front Tyre wear/Camber Angle

Post by moggiegeek »

Been noticing unusual pattern of tyre wear. Front offside worn on outside edge. Steering fine and light. NSFront not worn in this way. Garage says Toe in not likely to be causing this problem.
Car has had new chassis rails on the front both sides and Nearside King pin and trunions replaced complete with Poly bushes.
From the front the car appears to have tyres tucked inwards where they contact the road. Is it possible:
a) that more spacers are neccessary to correct Camber angle on Offside Front
b) that replacing kingpins and trunions complete with poly bushes on Offside front will rectify the problem
c) that a) and b) need to happen
OR is something else going on?
Help appreciated
JOWETTJAVELIN
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Re: Front Tyre wear/Camber Angle

Post by JOWETTJAVELIN »

Check the basics first: tyres inflated to correct pressure? N.B. Some people say radials should have different pressures to the figures quoted in the manual, which were of course for cross-plies (I am still on cross-plies so unsure of radial pressures).

Find a quiet road, head the car in a straight line and let go of the steering wheel. Does the car wander or keep going straight?

No idea about trunnions etc I'm afraid but no doubt the more experienced members will help you there. :)
bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

Indeed - you need 30/32 psi in radials -and if you live in a town / city with many roundabouts, then the nearside front tyre will take a pounding on the outside edge. Try to get a handle on the camber angles using a spirit level - on a flat piece of ground obviously..........
Last edited by bmcecosse on Sat Jul 21, 2012 9:51 am, edited 1 time in total.
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fussyoldfart
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Re: Front Tyre wear/Camber Angle

Post by fussyoldfart »

moggiegeek wrote:Been noticing unusual pattern of tyre wear. Front offside worn on outside edge. Steering fine and light. NSFront not worn in this way. Garage says Toe in not likely to be causing this problem.
Car has had new chassis rails on the front both sides and Nearside King pin and trunions replaced complete with Poly bushes.
From the front the car appears to have tyres tucked inwards where they contact the road. Is it possible:
a) that more spacers are neccessary to correct Camber angle on Offside Front
b) that replacing kingpins and trunions complete with poly bushes on Offside front will rectify the problem
c) that a) and b) need to happen
OR is something else going on?
Help appreciated
I have just had my '67 in the alignment shop following chassis leg(s) replacement and quite a bit of shim was required to correct the camber on one side (left in this case). The cause was probably imprecise location of the chassis leg(s). They would seem to be slightly offset to the right so the right side has slightly negative camber (good, that's what I want.) but the left side needed shims to make it match. Unless the chassis legs were installed with a proper alignment jig an error in either direction could produce improper camber. In your case it seems to be too much positive camber.
Fussyoldfart in Welland Ontario.

mike.perry
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Re: Front Tyre wear/Camber Angle

Post by mike.perry »

If there is an obvious camber angle to the front wheels check if there are horseshoe washers between the eyebolt bushes and the lower suspension arms, if not then try adding one each side, some cars have them, some do not.
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MarkyB
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Re: Front Tyre wear/Camber Angle

Post by MarkyB »

I thought they were ordinary, if rather thick washers, mine need this treatment too.

"Once you break something you will see how it was put together"
bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

They are much BETTER if solid washers are used (mine are flat plates) - but BMC rather foolishly used a horse-shoe shaped washer (for easy installation) - and this encourages water ingress = rot.... :oops: :cry:
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moggiegeek
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Re: Front Tyre wear/Camber Angle

Post by moggiegeek »

Thanks for the info. Looks like the camber angle is wrong due to chassis repairs being unjigged. What should camber angle be?
Also now have various ships on order ( circular not Horseshoe). what is simplest way to instal them? keep the help coming...
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Re: Front Tyre wear/Camber Angle

Post by Alex'n'Ane »

Unfortunately full round washers are a pain to install, hence the use of U shaped ones! Get a variety/a few U shaped washers made up, then go down to your local 4 wheel alignment garage (I can recommend a very good one if your in the north-west) Or if not have a look on here.. http://www.alignmycar.co.uk/ for one. They should have the factory setting programmed into the aligner, iirc its something slightly odd like 1 deg of positive camber :s but they can just set it to roughly (depending on how many/precise your spacers are) the amount of camber you want. Probably around -0.3deg or something along those lines. Others will give you advice on here i'm sure. They will also do the toe at the same time to get it straight/slight tow in. Will vastly improve the handling. Expect to pay around £70 or so to do the job, obvs depending on how awkward the job proves to be regarding bolts, tre's etc..
___Anne___

bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

Standard setting is usually slightly positive camber - this is hopeless. You should set at 1 degree negative camber for best response. Be sure to reset the tracking (1/8" toe IN) It's partial suspension strip down to fit the very necessary shim washers.
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IslipMinor
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Re: Front Tyre wear/Camber Angle

Post by IslipMinor »

Definitely use full washer/shims. Very roughly 1/8" or 3mm of shim will alter the camber by 1°, but also make sure that after adding all the shims there is enough thread on the eye bolt to allow the full engagement of the nut, after fitting the spring washer.

From the BMC Morris MInor Workshop Manual, the correct toe-in for the tracking is 3/32" or 2.5mm, and with radial ply tyres this should be the maximum and can be down to 1/16" or 1.5mm. Too much toe-in causes tyre scrub.

The standard camber is 1° positive, but can very usefully be reduced to 0°, even a very small amount negative, but if you do change the camber angle, again make sure there is enough thread length left on the eye bolt. There should be at least 1 full thread showing beyond the end of the nut when it is fully tightened.

On our Minor we have 0° camber (slight negative of ~1° would be better) as there is no more room left for additional shims on the eye bolt. As a Minor is lowered the camber goes positive and we needed around 8-10mm of shims each side to correct this and get to 0° camber.
Richard


bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

It's been commented before that 'someone' should produce 'negative camber' eyebolts...
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mike.perry
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Re: Front Tyre wear/Camber Angle

Post by mike.perry »

Are you volunteering????
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bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

Don't have any facilities I'm afraid - but this would be a useful part to save messing about with washers - and the risky 'less than ideal' thread left on the end of the eyebolt!
Last edited by bmcecosse on Mon Aug 13, 2012 8:27 pm, edited 1 time in total.
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moggiegeek
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Re: Front Tyre wear/Camber Angle

Post by moggiegeek »

Brill asssiatance as ever. A couple of questions
1) Can I grind down the new spacer washers/shims to make them horseshoe like?
2) When adjusting toe in I don't need to split the balljoint - just loosen nut on steering rack arm and screw in/out?
Looking for sympathetic/knowledgable tyre and steering place in S london environs - any recommendations?
thanks you...
IslipMinor
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Re: Front Tyre wear/Camber Angle

Post by IslipMinor »

You can convert complete washer/spacers into 'U' shaped ones, but you will get corrosion into the chassis legs and then just a matter of time before that causes more serious problems.

No need to split the ball joint, but do make sure as you adjust the track rods, they can turn inside the rubber gaitor - the gaitor must not be twisted out of shape.

Before you start, turn the steering wheel fully to the left, or right, and note its rotational position, now turn it fully in the opposite direction and count the turns, it should be 2.5. Turn the steering wheel back 1.25 turns - is the wheel in the 'straight ahead' position? If so fine, if not, remove the wheel and reposition it on the splines so that it is.

Drive the car on a straight, flat road. Is the steering wheel in the straight ahead position? If so fine, but if not it is an opportunity to correct the error when adjusting the track rod ends (TRE's).
Richard


bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

Be sure to adjust both sides TREs equally to reset the tracking. Just make your own tracking gauge - most garages will rip you off horribly for this simple task......
Last edited by bmcecosse on Mon Apr 22, 2013 1:51 pm, edited 1 time in total.
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Alex'n'Ane
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Re: Front Tyre wear/Camber Angle

Post by Alex'n'Ane »

bmcecosse wrote:most garages will rip you off horribly for this simple task......
Define rip you off... It all depends how long it takes, and what equipment they have how long it will take!! Also making your own gauges does not allow for run out, which almost all minor wheels will have to a considerable degree by now!
___Anne___

bmcecosse
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Re: Front Tyre wear/Camber Angle

Post by bmcecosse »

I have heard of folks being fleeced for upwards of £50...... for 'laser check'...... Just repeat the check with home-made gauge a couple of times - if mine gives same reading 3 times - I think it's good enough.....
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moggiegeek
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Re: Front Tyre wear/Camber Angle

Post by moggiegeek »

To let you know how it all worked out. Fitted new kingpins both side and new trunions with poly bushes. Still knocking from suspension so new eye bolt bushes - the pin had cut through the bush to knock on the eye bolt itself. Then a very nice garage checked the camber and toe in on a fairly sophisticated machine and made no charge. Turned out that the camber angles were both out so reshimmed ( with circular not horseshoe washers ) to get just slightly positive on both sides. The shimming didn't take the eyebolt anywhere near the last few threads fortunately.
Added an anti roll bar - already has telescopic shockers front and rear before. Had toe in set to one eighth toe in and the result is great in terms of handling, lack of tucking in under cornering. Minilites duly added.
One thing I did not do is rebush the wishbone rubbers with poly - I used rubber again -I gather the stiffness poly imparts prevents the wishbones following their proper geometry and puts huge loads onto the chassis fixing points.
Must just hunt down that knocking from the rear suspension............ thanks to all for their help.
PS anyone got an inch and a half SU surplus to requirements?
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