|The MGA With An Attitude
TUNING & TRUING WIRE WHEELS - WL-109
At 09:27 AM 3/1/04 -0500, Roger Dotson wrote:
>".... regarding wire wheel trueing. .... this particular one is a bit out of round ...., and it cannot be balanced out on the machine."
Review prior pages to determine that indeed the wheel wobbles, not just the tire. If the rim wobbles out of plain or out of circle more than 1/8 inch, then the wheel needs repair or adjustment. You generally have to dismount the tire from the rim to do any wheel repairs. Remove tire and tube, put the wheel on a front hub, and spin it.
If the wheel has some stretched spokes, it may have a relatively large wobble out of plane or out of round without having any local bending. In that case you may be able to true it up by adjusting the spokes. This works exactly the same as it would with a spoked bicycle wheel. Tightening spokes on one side pulls the rim toward that side, and slightly inward (radially). Loosening spokes on one side allows the rim to move the opposite direction, by virtue of tension of the opposing spokes.
If the rim is out of round, then you need to loosen all of the spokes in the area where the rim is too close to the hub, and then tighten spokes radially opposite on the wheel to pull the rim radially across center to push the low spot radially outward to match the rest. Then re-tighten the spokes previously loosened.
Once you get the rim to run true, concentric and with minimal wobble, then you gradually tighten the spokes until they all have about the same tension. Tighten a little at a time and all together to avoid warping the rim. Strike each spoke lightly with a small metal tool, and listen to the sound. A properly tightened spoke will ping. A loose spoke will thunk. Tighten any loose spokes until they will all ping with about the same tone. Spin the wheel again to check for final straightness. Continue to make any required small adjustments to the spokes until the rim will run true within 1/8" all around.
When finished, paint the wheel if it needs it, then reinstall the spoke cover, then the tire and tube, and balance the wheel.
Mind you, all of this tinkering with the spokes depends on being able to get the spoke nipples to turn on the threads. If the threads are siezed you might only twist a spoke until it breaks. When the threads are stubborn you might start by applying penetrating oil to both ends of the nipple, take a lunch break while it has time to penetrate, and then try again. If the threads are still stubborn, try heating the nipple with a propane torch to near dull red, allow to cool until any color disappears, then quench it with a very wet shop rag. If that doesn't get the thread to break loose, cut the spoke out and install new one. This process may become futile if you realize that a large number of new spokes may exceed the cost of a new wire wheel.
When wire wheels are in generally good condition in normal use, they like to have a little personal attention once or twice a year, or every 12,000 miles, whichever comes later (more often if you drive on rough roads or use the car for competition). Ding each spoke in turn with a small metal tool. They should all ping. If you find one going thunk, just tighten it up a bit until it pings like the rest of them. In this manner you can keep wire wheels in good tune indefinitely.
As a small aside, wire wheels are often inspected as a qualification to enter a driving competition event. General rule is that one loose spoke is frowned upon but will be allowed (usually after a small comment). But two or more loose or broken or missing spokes is grounds for instant tech failure, and your car would not be allowed to enter the event until you correct the situation (change the wheel or tighten some spokes). This is all in the interest of safety, yours and anyone around you. You should be constantly concerned about this anyway, and should never be driving a car with loose spokes. The moment you notice one loose spoke it should be fixed immediately. This is also a case of a stitch in time saves nine. If you continue to drive on a wheel with loose spokes it only gets worse, and the worse it gets the faster it deteriorates.
Find additional comments on trueing wire wheels:
From Lawrie Alexander on the Moss Motors MGA forum here:
From Eddie Saunders here: www.fbccsc.org/tech/spokewheels.pdf