By Carl Heideman
Dec 9, 2008
| Posted in
Tires & Wheels
| From the July 2003 issue
| Never miss an article
One of the things that distinguished the classic British sports cars from many of their contemporaries was their striking wire wheels. Usually laced with 48, 60 or 72 spokes, these wheels offered a performance boost as well as visual punch.
Back before the advent of today’s “mag-style” wheels, racers chose wire wheels for two reasons: They were lighter than the available disk steel wheels, and the single knock-off nut made for fast tire changes. Non-racers sought them out because they provided an elegant enhancement to any car’s looks.
Of course, these pluses are offset with some inherent minuses. Wire wheels require maintenance, and lots of it. Their “knock-offs,” the big nut that fastens the wheel to the car’s hub, must be kept tight. Spokes need to be tightened periodically. The wheels themselves must be trued to eliminate wobble, known as runout. Wire wheels get dirty and can be hard to clean. Finally, they are more expensive than their steel disk counterparts.
Beyond maintenance, there are other issues, like broken spokes. The single largest issue with wire wheels, however, is the condition of the splined hub. The splines in the hub wear, especially if the wheel is not tight enough (which it rarely is).
The wear on the wheel’s hub will wear the axle’s hub, which will further wear the wheel’s hub, creating a vicious circle that eventually allows the axle’s hub to spin within the wheel—a very dangerous situation. In the best case, this will happen on a rear wheel, and the car won’t accelerate properly. In one worse case, the hub will spin the knock-off loose, and the wheel will come off. In another worse case, the wheel will keep spinning on the brakes, and the car won’t stop. These are not good things. Fortunately, there are solutions.
On some cars, like big Healeys and Triumphs, the hubs bolt on at the lug nuts and are easy to replace. New pinch nuts should be used if hubs are replaced.
Properly installed and maintained, wire wheels can provide your car with great looks and performance. Becoming familiar with the different components can help you understand these creatures.
Wire wheels are actually a system of sorts, containing the axle hub, the wheel hub, the spokes, the rim and the knock-off nut. Each component requires its own special attention, but, fortunately, most enthusiasts can tackle the necessary tasks at home. Most of the action takes place around the hub.
The axle hub actually holds the wheel to the car; the piece is splined and threaded to accept the wheel hub and the knock-off. The center of the wheel sits on the splines and is held in place by a large nut, commonly called a knock-off.
Front hubs usually bolt to the front brake drum or disc, while rear hubs can be bolted or pressed onto the rear axle. Cars with pressed-on hubs are notorious for suffering bent, twisted or broken axles; Spridgets—especially those with worn differential assemblies—seem particularly susceptible to the problem.
Everything revolves around the hub, which has four basic components: the mounting area, the tapered seat that locates the wheel, the splines and the threads for the knock-off. These hubs are pretty beefy, but the splines do wear, and occasionally the knock-off threads get damaged. Damaged hubs and/or axles should be replaced as there is no cost-effective way to repair them.
Note that different hubs are used for each side of the car. The left-side hubs have a right-hand thread pattern, while the right-side hubs use the reverse, left-hand thread pattern. This ensures that the knock-offs won’t loosen themselves while traveling forward. There are two common safety concerns here: One, sometimes the hubs get switched side-to-side; and two, sometimes people will tow a car backward on a tow dolly, which should never be done with a wire wheel car.
There are two common types of knock-off nuts, which hold the wheel on the axle hub. Earlier knock-offs are winged, usually with two prongs (or ears), while later ones replace the wings with a large, hex nut mandated by U.S. federal safety regulations. The winged nuts are best removed and installed using a heavy hammer, while special, large wrenches are available for the hex-style fasteners. (Some purists refer to these wrenches as spanners, in the British mode; the same types also call a knock-off a knock-on.)
The preferred method for tightening knock-offs is to use a “knock-off hammer” against one of the ears (or against a wrench fitted to the hex-style knock-offs); ideally this is one with a soft metal face to prevent cosmetic damage. Original knock-off hammers typically had wooden handles fitted with iron heads holding faces made of brass, bronze, copper or rawhide so they wouldn’t scar the knock-offs.
Later cars came with the better lead-headed hammers, and several wire wheel suppliers offer excellent modern versions. A five-pound, shot-loaded plastic shop hammer can also be used. Buy either one and save your copper hammer for your concours tool kit.
The wheel should be raised slightly off the ground before the knock-off nut is tightened or loosened. Once the wheel is raised, one uses just enough force to tighten the knock-off, not so much as to move the wheel laterally inward against the pavement.
How tight is tight enough? Jim Judd from British Wire Wheel sums it up well: “After getting the knock-off tight, put the car back down on the ground and note the relation of the knock-off to one spoke. Then give the knock-off a good, sharp whack. If it doesn’t move relative to the spoke, it’s tight enough.”
The wire wheel itself is made up of an outer rim, the inner hub and the spokes connecting them. Outer rims lose their trueness and get bent from curbs or other collision damage. Inner hubs, just like axle hubs, are susceptible to spline wear. Spokes will break from time to time, as well as lose their tension. If a wheel has good splines on the hub, it may be worth having it trued and balanced. Worn splines mean it’s time for a new wheel, and usually a new hub as well.
Later MGBs with Salisbury axles use a hub that bolts to the axle, not to the wheel studs like Triumphs or Austin Healeys. The four studs hold the brake drum to the hub.
Wire wheels require periodic maintenance, so checking the hubs and wheels should be a standard procedure. The easiest parts to inspect are the spokes. First look, then feel each wheel for broken or loose spokes. Spokes usually break at the nipple or at the hub, but rarely in the middle. The break is often hard to see if it’s behind the hub or within the nipple. Nonetheless, the spoke will be loose if broken.
To help locate a bad spoke, take a small block of wood or even a hammer and lightly tap each spoke. If it makes a “tinging” sound, it is tight. If not, it is loose. Hold off your temptation to tighten the loose spokes until you have finished your inspection.
Next, check the wheel for trueness. Jack up the car and secure it on jackstands. Find a suitable tool rest (a jackstand works well) and hold a screwdriver or other pointed object right next to the edge of the rim while slowly turning the wheel. If the wheel isn’t true, the gap between the tool and rim will change as the wheel is spun.
If the wheel moves side to side, then lateral runout is present; if the rim moves up and down, then it is suffering from radial runout. If the wheel stays pretty true—1/8 inch or so of deviation—it’s probably going to be okay with a tune up. But if it’s got a big wobble, then it’s going to need a lot of work—or replacement.
Now comes the most important inspection, the splines. Remove the wheel from the car and clean away the grease from the splines to allow a good visual inspection. The splines should be slightly rounded at their peaks, not sharp. They should also be symmetrical.
The inner 1/4 inch of the splines does not contact the hub, so you can compare that portion to the rest of the spline surface during your inspection. Clean the hubs and inspect them the same way you inspect the wheel. Remember that worn splines are dangerous, so this is an important inspection.
If the splines on either the wheel or axle hub are worn, the only solution is replacement. Further, if you put a new wheel on a worn hub, or vice versa, the new component will quickly wear out. So the best and safest recourse to worn splines is new wheels and hubs.
If the wheels are in pretty good shape, and you want to true them up and paint them yourself, see the sidebar on reconditioning the wheels.
Dayton’s wire wheels can be used with modern, tubeless tires. Silicone sealer on the spoke nipples plus modern rim styles prevent loss of air.
If the wheels can’t be saved, then it’s time for new ones. In many cases, purchasing new ones is less expensive than rebuilding old ones.
In any search for replacement wheels, the first question is often whether to purchase used wheels or spring for new ones. Allen Hendrix from Hendrix Wire Wheel gives this advice to those looking at used wheels: If someone is selling their wire wheels, there is usually a reason beyond a need for cash. It’s probably not because the wheels are in great shape and the seller just decided to get new ones.
Most used wire wheels are junk. Unless you can inspect them carefully first for hub condition, spoke condition and runout, you’ll probably be disappointed. Nonetheless, we’ve just told you how to make these assessments, so it might be worth a try.
If you decide to buy new wheels, there are several factors to consider. If you’re restoring your car to concours specifications, then you’ll probably want to get wheels of the same brand, size and spoke configuration as the originals. If you’re looking for upgraded performance, looks or both, you have the factors of size, number of spokes, finish (chrome or painted), tubed or tubeless, and more. Here’s a rundown of the factors you should consider.
Brand: The two common brands are Dayton Wire Wheels and Dunlop. While Dunlop was the original-equipment supplier of wheels for most British cars, these wheels are currently made in India. Although there were some quality issues at one time, these have been resolved according to Kelvin Dodd of Moss Motors, a Dunlop retailer. Several people in the field echoed that opinion when we spoke with them.
The other choice would be Dayton. These U.S.-made wire wheels feature decades of improvements, but they can cost more than the Dunlops and will be subtly different from original wheels, something to consider for those heading to concours events.
Painted or chrome: Painted wheels are less expensive, slightly lighter, and were original equipment on most British cars. Many buyers, however, prefer the look of chrome. Both Dayton and Dunlop use a chrome rim and hub fitted with stainless steel spokes for their “chrome” wheels. In the past, some wire wheels did have chrome steel spokes, which lose strength over time due to the effect of hydrogen embrittlement caused by the plating process. Therefore, chrome steel spokes should be avoided.
Number of spokes: The rule of thumb for looks and performance is that more spokes are better. For instance, although they were original to most British cars built before the early 1960s, 48-spoke wheels are the weakest. In the mid-1960s, 60-spoke wheels replaced 48-spoke wheels and now offer a good upgrade for earlier cars.
Generally only available for the higher-performance cars like the Jaguar XKE, Austin-Healey 3000, MGC and Triumph TR6, 72-spoke wheels are also a good upgrade. These wheels tend to be wider than 48- or 60-spoke wheels, so sometimes fitting the 72-spokes becomes an issue. Further, Allen Hendrix says that 60-spoke wheels are the best choice for many cars, since they offer the strength of additional spokes but have enough spacing between the spokes to offer easier cleaning.
Tubes or tubeless: Original-equipment wire wheels were always intended to be used with tube-type tires and inner tubes, and most new replacement wheels are also made for use with tubes. Finding tube-type tires isn’t so easy these days, however, so many owners wind up running tubes inside tubeless tires; this can cause chafing, especially when running radials. A chaffed tube can quickly become a flat tube.
Most Dayton wheels are available with a tubeless option, for which the factory puts a seal over the spoke nipples before leak testing them. With this option, conventional tubeless tires can be used without the worry of any chafing issues.
Ask around about tubes and you’ll hear conflicting advice. For example, Mike Edgerton of Dayton Wire Wheel says that tubeless wheels are almost always the best choice because of the chafing issue. Allen Hendrix says that tubeless wheels will leak sooner or later, so properly installed tubes will work better in the long run.
If you’re going to run a tube, there is a proper way to install it. First, as obvious as it sounds, the tube must be of the correct size. The average tire store tubes are slightly oversized and will often have folds in them as they inflate, so you’re better off buying tubes from a specialist. Jim Judd of British Wire Wheel recommends staying with a name-brand tube. (His shop uses Michelin tubes, which sell at retail in the $20 to $25 range.)
Installing the proper tube will be made easier with some talcum powder, which will provide lubrication so it will slide inside the tire. It’s also important to properly center the inflation stem in its hole in the wheel rim to prevent any rubbing. Finally, all burrs, imperfections and labels must be removed from the inside of the tire to ensure there is nothing to chaff and damage the tube. When ordering tires with tubes, get an extra tube and toss it in the center of the spare; that way, if you do have to have your tire repaired out in the boonies, you’ll have the right size tube.
Standard or Heavy Duty: Finally, Dayton offers heavy-duty wire wheels that are often used by racers. These wheels use the same hubs and rims as conventional wheels, but substitute a .225-inch spoke for the normal-duty .203-inch spoke.
Prices can vary greatly by application, manufacturer, finish, number of spokes, rim size and other options, but we can get some idea of the price differential by evaluating some available 60-spoke, 14x5.5-inch MGB wheels from British Wire Wheels. The painted Dunlop retails for $160 each, while the painted Dayton carries a $195 price tag. As expected, the chrome finish adds a few dollars: $240 for the Dunlop and $250 for the Dayton.
Examples of shiny new 48-spoke, 60-spoke and 72-spoke chrome and stainless wire wheels.
Wire wheels require a delicate hand when being mounted with tires and balanced, so it’s very important that the tire shop uses the right equipment. Improvising at this step can mar the finish of the wheels or even compromise their structural integrity.
First, the mounting equipment must grip the wheel by its rim. Some shops have mounting equipment that features a pin positioned to stick through the spokes. However, if anything should slip, bent spokes will be the result.
Second, the shop must have the proper mount for the balancing machine. The wheel must be mounted by the conical part of the hub, not the rear part at the outside flange. The rear, outside part of the hub is not necessarily true to the conical part and its use will result in a poorly balanced wheel. If a shop doesn’t have this equipment, find another shop.
Before the tire is mounted, the back side of the spoke nipples must be covered. For tubeless wire wheels, this is done with a sealer. For tube-type wheels, this was originally done with a large rubber rim-band. These bands are still available today, but many people are switching to PVC tape. The tape comes in one- and two-inch widths and is wrapped around the wheel to cover the spoke nipples. Duct tape will work in a pinch, but probably won’t hold up well over time.
After mounting, some higher-end shops will also shave the tires to ensure that runout is appropriate beyond the rim, right to the edge of the tire. Hendrix Wire Wheel is one of these shops.
When it comes time to mount the wheel on the car, it’s helpful to use silver- or copper-colored anti-seize compound on the splines. The silver-colored anti-seize is the better choice because it matches the wheel color pretty well if it does manage to get flung out. Grease will work just fine, but is more likely to fling itself out through the nipple holes and get the wheel dirty. Putting silicone sealer on the inner nipples is a bad idea, as it will trap water and condensation inside the hub, which can cause big problems.
Once the tires are mounted, wire wheels still require more maintenance than conventional wheels, as the spokes and nipples stretch over time, requiring periodic tightening. As they stretch and get tightened, they can throw the wheel out of true, so the trick is to tighten them without messing up the true. This is best done by a pro, or with the wheel mounted on a truing stand.
Some experts say that a new set of wheels should be tightened and re-trued at about 500 miles, then again every 20,000 miles. Allen Hendrix is so adamant about this that he includes the service and the cost of the shipping in his wheel/tire packages.
Another maintenance issue surrounds the spoke nipples, as they tend to rust themselves to the spokes and seize. A good, but tedious, annual maintenance practice is to spray a lubricant/penetrant on each nipple, then turn it a quarter-turn loose and back.
Cleaning is the last maintenance issue. Wire wheels have a lot of surface area and pick up a lot of dirt. Additionally, if the splines are over-lubed, they’ll fling grease out to the spokes and rim, which will in turn catch even more dirt.
Until a few years ago, cleaning was always done using soap and water with scrub brushes and rags. Fortunately, the folks who manufacture wheel cleaners have come up with some great products that can make cleaning some wire wheels a spray-on/spray-off affair. Unfortunately, many of these products are caustic and damage paint, thus making them suitable for use only on chrome wheels. British Wire Wheel sells a chrome wheel cleaner that works so well that even the competition (Allen Hendrix) recommends it.
Replacement wire wheels are available that bolt onto the lugs, as shown here on an MGA. They’re not original, but cause no spline or knock-off problems.
While many classics came with wire wheels from the factory, a car originally fitted with traditional bolt-on wheels can be converted. How the conversion is done can follow one of several different paths: You can install bolt-on wheels, install bolt-on conversion hubs and knock-off wheels, or install factory-correct parts and wheels.
Bolt-on wire wheels are the quickest but least authentic way to convert; Dayton offers them in many sizes to fit most British cars. While they don’t offer the originality and true knock-off ease of traditional wire wheels, they are an attractive and easy way to convert a car. They also don’t have the spline wear problem that knock-off wheels can have.
The Dayton direct-bolt conversion is another option. A knock-off hub is bolted onto the original studs, allowing the use of a proper knock-off wire wheel.
Those seeking originality tend to convert the hubs themselves, exchanging parts designed for a stud-mounted wheel to wire wheel splined hubs. This can be a very straightforward operation for some British cars, like Austin Healeys, Jaguars and Triumphs: Just unbolt the disk hub and replace it with the splined hub. On Triumphs, the mounting studs have to be shortened. For other cars, like MGs, it’s more complicated.
On MGAs, MGBs and Midgets, the front disk hubs can easily be swapped with the wire wheel splined hubs, but different rear axles were used to accommodate the different wheel offsets. Wire wheel axles are approximately two inches narrower than disk wheel axles, so to properly convert the car to wire wheels, the appropriate rear axle and emergency brake cable must be located.
There is another option for MGs, however, as non-original conversion hubs exist for the rear axle. They are thinner and feature relocated mounting areas to compensate for most of the offset change of the wire wheels. These hubs allow wire wheels to be fitted on the tube-type MGB rear axles found on cars from the late 1960s through 1980.
Prices can vary according to the job at hand, but using our MGB as an example allows some comparisons to be made. Going with the Dayton direct bolt-on kit from British Wire Wheel is the least expensive option, as the entire package—chrome wheels, caps, lug nuts and wrench—sells for $1240.
The Dayton knock-off conversion replaces the traditional studs with a single knock-off. The kit includes the bolt-on adaptor hubs, chrome wheels, knock-offs plus a hammer. Retail price at British Wire Wheel is $1500.
The final option is the factory original conversion kit, which includes four splined hubs, four knock-offs and a hammer. British Wire Wheel sells the kit for $695; add another $1000 for a set of chrome Dayton wire wheels.
So there you have it. Wire wheels are a large part of the sports car tradition, and require maintenance and care just as you would lavish on the rest of the car. Left unchecked, wire wheels can shake or even be dangerous, but given regular service and attention, these wheels will provide many miles of enjoyment and great looks.
Great article, my opinion: wire wheels for show cars and disc wheels for daily drivers. Wire wheels are more trouble then an old whore for drivers. Working on the winged knockoffs I wrap the wing nut with ~ .050 th'k aluminum before the hammer use, saves the chrome plating.
Very comprehensive article, good job! Should be considered mandatory reading for anyone owning a wire-wheel equipped car, regardless of origin.
To secure and protect the finish on my chromed knock offs, I use the two (2) hammer method...
I hold a solid rawhide mallet tight against a k/o blade, and strike the opposite end of that with any of the appropriate lead or copper k/o hammers I have on hand. Since I installed these center-laced wheels in 2010, I have periodically rotated the five (5) wheels/tires around the car, and the k/os still look as perfect as they were when I received them__zero dents, zero compromised plating.
And they look great, seeing far more street use than show fields.
In reply to rdstr :
I raced a set of Dunlop wire wheels in my Blackjack Special for decades (1975-2001) then sold it and it raced several more years with the same wheels and hubs.
Regular greasing of the hubs with anti seize, checking of the spokes, and polishing ensured I was safe diving into turn 5 at Elkhart Lake at 155 mph lap after lap. That was using sticky Dunlop race tires as wide as was allowed.
In 1971 I converted my MGTD to 48 spoke wire wheels I took off a used 1956 MGA. I not only have driven that across country I’ve also vintage raced that as well, again using Dunlop race tires. Plus all the touring and car events I’ve attended.
It is worth noting that the popular trend of replacing wire wheels with splined mag wheels has one negative aspect, although it does eliminate spoke tuning. The solid machined wheel centre that bolts into the mag wheel makes the wheel assembly heavier (unsprung weight) than the wire wheel, which has the splines milled into a lightweight sheet metal centre.
Wire wheels, with a little maintenance, can stand up to long use quite nicely. They did service even on powerful and weighty cars like the AC Cobras, Aston Martin DB series through DB6, Morgan +8, and many Italian cars (the hub sizes on the Borrani equipped cars was identical to the British one used by all but Jaguar).
I had a set of toothbrushes that I modified to clean the wire wheels on dad's XKE. He would give me a couple of bucks for detailing his car, then we would go get ice cream, a caramel apple or something. There are roads between Sacramento and a variety of ice cream and candy shops in the Sierra Nevada mountains and the foothills that are something to experience in an open car making a great noise. If you have kids, you owe it to them.
In reply to Toebra :
I used to bring the wheels into my living room on a big piece of cardboard to polish the chrome. One wheel at a time, I’d watch a show or movie and carefully polish each and every spoke. During commercials I’d take one wheel down and swap it with another. By the end of the evening the wheels and knock offs looked pretty nice.
Now that the shop is turning into a man cave I can watch from down there.
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