Whether you call them wire wheels, knock-offs or even Rudge-Whitworth spline-drives they need to be in good condition to be safe. They have to carry the drive power from the engine to the road, as well as the braking force from the tires back to the car. If your splines are in bad shape, you are “along for the ride” and you will not like it.
Not all MGs came from the factory with wire wheels, though it was a popular option. In addition, many cars have been converted from disc-type wheels to wires over the years. I do not want to frighten anyone unnecessarily, but the condition of wire wheels and their mounting hubs is really important. I love wire wheels, as well as their race-heritage cousins, knock-off alloy wheels. Besides being an important part of the “sports car” mystique, they look neat.
A little anecdote I like to recall happened in San Diego, where I lived for a time. As I walked through the parking lot after work one day, I saw I had a flat tire. My friend laughed good-naturedly and told me he’d see me tomorrow. He then headed across the lot towards his own car. I was able to jack up my car, bonk off the wheel with the flat, slip on the spare, snug up the nut, drop the car and heave the bits back into the boot before he reached his car on the other side of an (admittedly) large parking lot. Figuring that I would be indisposed for quite a while, imagine his surprise as I was able to fire up the little GT and pull out right in front of him and beat him out the gate. To call it a jaw-dropper was no exageration, as he had never seen knock-offs in action before! So, back to the inspection.
You will need to jack up the car to check out the wheels and hubs. If everything is tickety-boo, this will take almost no time. If the wheels and hubs are well-cared-for, a couple of good bonks with either a rubber dead-blow or lead hammer (which should come with the car, I might add, and not one of those wretched copper ones), should free up the nut, wheel-nut, knock-off, spinner, or whatever you want to call it. Then the wheel should pull straight off of the hub. Neither the wheel nor the hub should have worn splines. If the splines are properly shaped and well-lubed, you are good to go. Pop the wheels back on and move on.
However, if the nut is frozen or the wheel is stuck, you have evidence that they were not cleaned and lubed, and you can bet that the wheel, hub or both will need to be replaced. If, once the nut is off, the wheel wobbles while still on the hub, you know you have worn out splines either on the wheel, hub or both.
If you already own the car, or want to go further with this inspection, its time to get a bit dirty. You will need a pan of some sort, like an oil drain pan, a supply of solvent, such as paint thinner or Stoddard solvent, gloves, and a scrub brush. Once you have the wheel off, scrub off the grease and dirt from the hub and the inside of the wheel, so that you can inspect the metal. First check the wheel, since it is easiest. From the back side, run your finger along the top of the splines from the outside inward. The innermost 3/8” or so do not contact the drive splines and are always in good shape, and make a perfect reference. If you feel short, sharp splines that jump up to become taller, blunt-topped splines at the rear, you have worn wheels. Just how worn takes some judgment, but new splines are either flat or rounded on the top, not sharp. See here for a sketch on BWW's site.
Now inspect the hub splines. These wear all across, so they do not have the unworn reference area. But still, good splines will not be sharp on their tops. Badly worn wheels and hubs are dangerous! When they fail, the wheel will spin on the hub, unwind the nut, and the wheel will come off! This usually occurs during hard braking, but can occur at any time. As you can imagine, this is bad.
If the wheels and hubs look good, apply a thin coat of grease to the splines and the tapered faces before reassembling them. Also, before lowering the car, grab the front wheels, top and bottom and try to wiggle them. If you have movement, the wheel bearings need to be rpaired. I can also mention that now is also a good time to check the brakes. More on that later.
If your wheels or hubs are bad, on the other hand, you need to think about the cost of replacement. And, no, you cannot simply swap them around, putting the best wheel on the worst hub, etc. Bad wheels on a good hub will wipe out the hub, and vice versa. If you have already bought the car, I have the unhappy job of telling you that you need to fire up the checkbook and plunk down some money for new hubs and wheels. Wheels start at around $200 each and go up, depending upon number of spokes, and whether they are chrome or stainless. There are also alloy wheels with spline-drive centers available. One can easily spend $2000 and upwards on a set of hubs and wheels, not forgetting a spare for the boot. So, if you are looking at a car to purchase, factor this into any negotiations. Often the seller is the third or fourth owner and has no idea that the wheels even need any maintenance. They figure that if no spokes are falling out, they are “good”. Better to know what you are getting into before purchasing a car. If you already own the car and just got the bad news, its still better than finding out the hard way as your wheel passes you on the off-ramp and you get to go for a wild three-wheeled ride …