Uneven tyre wear on multi utility vehicle

we are having aproblem of uneven front tyre wear on a utility vehicle.the front suspension is of double wishbone type nd rear rigid axle with leaf springs.The front toe variation,track changes and camber changes during bump and rebound are controlled within limits.the other problem that we are facing is the toe disturbance after running the vehicle.upto what value toe disturbance can be tolerated?and what could be the causes of toe change after some km running of the vehicle?

 

[GregLocock]

Which part of the tire is wearing excessively? If it is the outer shoulder then change the static camber setting or the toe setting. I can't tell you what toe disturbance is acceptable, I'd have thought that a vehicle that was set to the optimum shouldn't move to outside the acceptable tolerance during the life of one tyre in normal use. The causes of toe distrubance are surely just the obvious mechanical things - either the hardpoints are moving, things are wearing, or the adjusters are self-adjusting. I suppose the wheel bearings could be an issue as well.

Bear in mind that a slightly overloaded tire will wear much faster than one that is correctly loaded.





Cheers

Greg Locock

 

Thanks for the reply Greg Locock.The wear pattern is not same for all tyres,there is scatter.as fa as moving of the hard points is concerned,we are thinking of how to measure that ,since even a movement or deflection of 0.5 mm in centre link can cause a large toe variation.we are suspecting the ball joint play in steering and suspension joints.what is the norm for acceptance?.Also the position of pitman and idler arm ball joints in Z direction is very sensitive to toe variation in bump and rebound,so we r trying to control that also...it's an very interesting problem...thanx again for ur reply

 

[GregLocock]

Our tolerance is plus or minus 9 minutes, ie 0.15 degrees Cheers

Greg Locock

 

[ProEpro]

I have found simalr problems to be caused by a combination several things.

Overloaded / incorecet tires
under inflation
loose parts

The last one was the hardest to find. The slop could be anywhere in the system. Any loose parts should be coreceted. Any slop in the steering system will cause problems.

If you have a decent tire supply they should have an aplication engineer to help you. If they don't switch brands. Michelins Engineers are very good.

If you need to discuss this in detail contact me off line. ProEpro

http://www.whitelightdesign.com