Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing wheel balancing

Nevermind, I forgot this was in the general forum, not the M3W forum.

Not at all - you're comments apply to 4W spoked wheels too!
It's just as important to get the balance right!

Hehe, thanks, but I have now made a thread in the M3W forum, as I wasn't sure if it was even relevant to this.

It's here, if people want to read it:

http://www.talkmorgan.com/ubbthreads.php/topics/150601/Bumb_steer_and_vertical_angle_

This is how I understand it having had a long talk with wire wheel friendly technician. The problem with using standard cones is that there is no guarantee that the inner face of the splined hub (where it bells outwards from the splines) is accurately flat compared to the rims of the wheel - it doesn't need to be because this face does not locate the wheel on the hub, it is the inside of the splined portion that does that. The accuracy is better in modern wheels (eg from factory or MWS), very poor in older/classic wheels. Thus the inner cone on a balance machine may (if lucky), or may not, locate the wheel accurately flat - resulting in run out which may be axial (rim wobbles in and out laterally) or circumferential (rim wobbles up and down i.e. eccentric). If this amount of wobble is large it will be evident visually, but it can be quite small and within the range that can be balanced out on the machine. If balanced on the machine and put back on the car, the wheel will now be located accurately on the hub by the splines, and thus be out of balance when driven, indeed all four wheels could well be out of balance. Sorting this out is difficult, because when the wheel is put back on the machine, the location may be slightly different, resulting in a new balance point, which is still off when put back on the car. Compare this to a standard steel or alloy car wheel, where a (usually accurate) circular hole is present in the flat face of the wheel centre, and a cone will locate this accurately, so a wheel balanced off the car will usually be in balance when put back on the car. Balancing on the car is possible, but is only correct for one location, so if you take the wheel off and move it by one stud or a few splines, or put it in another location, it cannot be guaranteed to be in balance.

Accurate, correct balance makes a big difference - mine was recently done in house by Beamish Morgan, who are co-located with the Aston Martin Workshop and between them know a bit about this.

Please note I am not an engineer.

Nigel

Thank's Nigel very informative but about as clear as mud to read , thank goodness I read stuff like this everyday . Now I know why the mog was acting like it did .

Hi Folks,
Just to say Thank you to everyone for their thoughts and comments regarding fitting and balancing. They certainly give food for thought, so to speak. I live close to Paul Harris, so will be giving him a call.
Thanks again, Mark.

And the real problem is that most tyre fitters do not understand the problem.

Exactly!

Another point is decent well fitted tyres need fewer weights than "Ditchfinders" fitted by "Tyre Sheds-r-us"

The Chen Shins the three wheeler came with had a plethora of weights on the spokes and weren't even round, the Avons currently fitted have no weights.

Chen Shins? The mind boggles! All the M3Ws I saw at the factory had Avons.