Wheel Balancing

[Chris KC]

Once again seem to be an exception on this forum and I do find it worth while balancing A7 wheels. They are often considerably out and this shows at the speeds I travel. I use a home made balancing jig similar to what you would use to balance a grinding wheel with, this seems sufficient even for A7 racing application in my experience.

Interesting Ian; but I can't quite picture how you mount the wheels - presumably on a mandrel of some sort, but does it pass through the wheel centre (thus supported at either side)?

[dickie65]

My front wheels are slightly out of balance when spun on the axle without the brakes dragging but its not noticable on the road at 55mph.
I do find that my Blockley tyres are prone to flat spotting which is noticable till they get warmed up I store the car with 3 Bar in the tyres !

[Ian Williams]

Yes Chris, I made a mandrel that incorporated an old hub, that was first balanced, and then wheels are mounted to the mandrel. the balancing frame is set level and uses overlapping bearings on each side as a toolroom grinding wheel balancer has. It works for me. Prior to making this fixture I found some motorcycle shops were able to balance A7 wheels for me. I know some readers of this forum will not see the point. However my view is that with the limited performance an A7 has every small loss we can eliminate adds up to a worthwhile gain. Added to which if you travel at speeds above 50mph an out of balance wheel, particularly at the front, can at times cause alarming handling issues. Even below 50mph they will sap power, as will any out of balance rotating/reciprocating component. To make a real difference though we need to go beyond simply balancing wheels but look at dragging brakes, bearings, incorrect set up of carburation, ignition etc etc.... its a long list. But get it all right and it is worth the trouble as I and other like minded enthusiasts have proven time and time again.

[falcott]

Good points all. One of my front wheels always comes to rest in the same place, and this with new tyres. The car has seen 75mph, so I'd better get it looked at. There's no use inducing front end issues at that speed.

[Chris KC]

Yes Chris, I made a mandrel that incorporated an old hub, that was first balanced, and then wheels are mounted to the mandrel. the balancing frame is set level and uses overlapping bearings on each side as a toolroom grinding wheel balancer has. It works for me. Prior to making this fixture I found some motorcycle shops were able to balance A7 wheels for me. I know some readers of this forum will not see the point. However my view is that with the limited performance an A7 has every small loss we can eliminate adds up to a worthwhile gain. Added to which if you travel at speeds above 50mph an out of balance wheel, particularly at the front, can at times cause alarming handling issues. Even below 50mph they will sap power, as will any out of balance rotating/reciprocating component. To make a real difference though we need to go beyond simply balancing wheels but look at dragging brakes, bearings, incorrect set up of carburation, ignition etc etc.... its a long list. But get it all right and it is worth the trouble as I and other like minded enthusiasts have proven time and time again.

Thanks Ian. I don't doubt the benefits at all, though equally I quite understand it makes no odds for many owners. I may yet give it a try, though as you suggest, it's but one item on an ever-increasing list - nowadays I find I have far more time available for thinking up things to do than for actually doing them!

[Hugh Barnes]

Ah, the joys of retirement... :^)

[Tony Griffiths]

Thanks, everyone, for the experience and advice. It's all greatly appreciated and adds even more to our A7 'database'.

[Ian Williams]

I put my ideas into practice, nothing I say on this forum is an armchair theory unless I state so, and to be clear I tried all of this long before I retired Hugh, I am only 61 now!