Yes, I have searched, but cannot find an answer to this specific question... Recently had a wheel alignment done (to my Eunos, not the Zed), and because the required new tyres had to be delivered from off-site, the alignment was done with the original (badly scrubbed) tyres on while they were waiting for the new tyres. Every other alignment I have had was AFTER the new tyres were fitted, so I queried the effectiveness of their approach, and the guys said: "Trust me!", which of course immediately raised my suspicions. I know that the equipment is fixed to the wheel, so in theory the condition of the tyres should have no effect (ie only wheel angles being measured, not wheel/tyre angles.) Is this correct? (Laser/computer alignment equipment used)
Your right, But... if the tyres are worn from too much toe out/in or camber, therefore wearing the tyres more on one side than the other. When the new tyres do go on they will be out by some degree of measurement, because the new tyres will be the same across the tread contact area in relation to the rim. Thus, giving a different reading compared with the older tyres which would have had the angles slightly changed due to the wear. How much will depend on how much wear was on the old tyres. Cheers Kerry :zlove:
Whilst not completely at odds with your reasoning Kerry, in general... Wheel alignment is a mechanical adjustment and worn tyres will subsequently change or 'deform' (eg: contact patch on road with vehicle weight applied) according to the aligner's adjustment and tyre pressure. Having said that, it is usual to have an alignment done AFTER new tyres are fitted to achieve the BEST alignment on a vehicle which may have slightly worn steering and/or suspension components. Particularly with very low profile tyres run at high pressure.
Thanks for the answers, guys. The wheel people assured me that the laser equipment only measures wheel angle, regardless of tyre wear, because the tyre sits on a pivoting disc which compensates for uneven wear. I guess it is more of a problem with the older, mechanical, alignment systems. But I'm 'old school' enough to still be a bit worried. I guess I'll have to wait and see what the wear pattern is like.
