Do you have to change both tyres to do the tracking alignment accurately?

[Submariner1]

I am going to WIM to have the tracking and suspension geometry checked/adjusted.
Note this is the full job, where they previously changed the castor bolts and angle so one avoids the usual ‘designed in‘ MB drift to the left.
Do I have to change the right front tyre as well? this has circa 5mm tread depth and has the usual more worn outer edge.
Apparently the alignment tool hangs on the tyre, not the rim?

Note I have had the left front wheel re-powder-coated, straightened and also got a new front left tyre so it has about 7mm to 8mm tread depth. I slightly kerbed this left side at sub 5 mph. Resulting in scratch through clearcoat and in another place down to the powdercoat white i.e. under the silver - not down to alloy ! So hopefully minor movement if any.
The tyre was changed because it had a couple of nasty bulges on the inside, and the wheel was slightly buckled - I assume due to potholes - And not related to the wheel scraping incident.

 

[LostKiwi]

Ideally yes but given the difference in wheel size as a percentage is tiny it will make little difference.
Whilst the tool hangs off the tyre I think you'll find it uses the rim as the reference point (so straight rims are essential). Using the tyre as a reference point is far too fraught with potential errors.

 

[Submariner1]

Ideally yes but given the difference in wheel size as a percentage is tiny it will make little difference.
Whilst the tool hangs off the tyre I think you'll find it uses the rim as the reference point (so straight rims are essential). Using the tyre as a reference point is far too fraught with potential errors.

Thanks LK
The part about using the rim as a reference makes perfect sense. I was puzzled thinking uneven tyre wear, various profiles, different tyre bulges and pressures etc. Would make it very “subjective” .
My rims are untouched now, they just have to get inside the tyre protector rubber flange.

I have had 2 notifications one at MOT and One at Service Main Dealer, saying there was very slight Lower Swivel Joint play; but not worth fixing yet. Reconfirmed with Tech. Not worth doing yet, especially as I only do about 2,000 miles per annum. And the last year was only 1,670 miles.
Not sure what that would do to the tracking and castor angle? Hope not much, as the tyre wear was very even. No sign of scrubbing.

 

[Submariner1]

One other
Q. Would you feel wheel imbalance on the rear of a CL 500?
I noticed there are a few missing weights i.e. just the black sticky pads left circa 3 each wheel.
My tyre company confirmed they only remove old weights, never take off the sticky residue/double sided pads - to ensure they do not damage paint surface.
So you don’t know if it was a missing weight or the pad left on from the previous tyre change!
Both back wheels have had new tyres since all wheels were re-powdercoated.

Q. Any idea what would remove these pads cleanly without damaging paint surface?
Only thing I could think of was wifes cotton wool make up balls soaked in white spirit and taped on with masking tape, then remove and squeeze off.
I have been told Brake Cleaner removes them but suspect that would screw up the paint?

 

[axelcls]

Try a simple piece of wood, use it like a scrapper


Sent from my iPhone using Tapatalk

 

[LostKiwi]

One other
Q. Would you feel wheel imbalance on the rear of a CL 500?
I noticed there are a few missing weights i.e. just the black sticky pads left circa 3 each wheel.
My tyre company confirmed they only remove old weights, never take off the sticky residue/double sided pads - to ensure they do not damage paint surface.
So you don’t know if it was a missing weight or the pad left on from the previous tyre change!
Both back wheels have had new tyres since all wheels were re-powdercoated.

Q. Any idea what would remove these pads cleanly without damaging paint surface?
Only thing I could think of was wifes cotton wool make up balls soaked in white spirit and taped on with masking tape, then remove and squeeze off.
I have been told Brake Cleaner removes them but suspect that would screw up the paint?

Q1. Yes. I can tell if one of my wheels has lost a weight and also which one.

Q2. Isopropyl alcohol will remove most stickers without damaging paint.