The wheels and tires you put on your bike have as much to do with the final look as anything else. In both a visual and functional sense, the importance of the wheels can’t be overstated. Though there is certainly a functional aspect to wheels, when it comes to choppers the visuals are the single most important thing many riders consider.
Wheel types
What many of us simply call “billet” wheels are actually two or three different types of aluminum wheels. True billet wheels are carved from a billet (or a solid chunk) of aluminum. Most billet wheels are manufactured from 6061 T6, the first four digits identify the alloy while the T6 number refers to the heat treating specification.
Cast is the other major type of aluminum wheel. The alloy in this case is generally 356 aluminum. The expense of buying forged billets of aluminum is eliminated through casting, though tooling costs are considerable. Most cast wheels have a rim that is an integral part of the assembly instead of being a separate piece bolted or welded to the spokes. Because there may be some porosity in the cast material, chrome plating is more difficult with a cast wheel.
At one time billet wheels used spokes (or a center section) cut from forged aluminum, bolted or welded to a separate rim assembly. Currently there are at least two methods of manufacturing a true billet wheel with an integral rim.
With “split and spin” a large round disc of billet aluminum is set into a special lathe or fixture. The fixture spins the raw disc of aluminum while a bit comes in at the edge of the spinning billet and carefully splits the aluminum at the edge. By carefully splitting and rolling this edge, two rim halves are formed at the edge of the spinning aluminum billet. After the rim is formed the incomplete wheel is moved through a series of CNC lathes and mills where the spokes are fashioned.
A one-piece billet wheel with an integral rim can also be created in a forging operation. In this case a rather large disc of billet aluminum is forged between a pair of dies. The extremely high pressure gradually molds the aluminum disc into a shape resembling a wheel with a crude rim at the outer edge. After the dies have “forged” the disc into this basic shape, the rough wheel is machined to the final shape.The forging operation creates some advantages, it makes for very dense aluminum that polishes easily, and it creates a strong radial grain pattern.
Wire Wheels
The wire wheels offered for sale today come in 40, 80, 120 and 240 spokes with rims of aluminum or steel. Diameters include 15, 16, 17, 18, 19 and 21 inches. Widths start at about two inches for skinny 21 inch front rims and go to at least nine inches for 15 and 16 and 18 inch rear wheels. Spokes come in steel or stainless steel, in round, square and twisted configurations. The most common spokes used today are 6/8 gauge, though heavier gauges are available. Not all spokes are the same in terms of quality either. The best spokes come with well-known brand names, including one of the best known brand names in the world – Harley-Davidson.
At the center of the wheel is the hub, available in steel or aluminum. Not all hubs use the same spoke indexing pattern, the Motor Company has used at least 3 different indexing patterns over the years including one that started in 1997. In addition, not all spokes fit all hubs. The hub must match the bike, i.e. wide or narrow-style fork and single or double-disc brakes. The hub manufacturer will suggest spokes, some are quite specific as to which spokes must be used with which hubs.
When discussing spokes the name Buchanan comes to mind. This maker of polished stainless spokes does the manufacturing in the US, the spokes are available in various shapes including conventional round spokes as well as twisted-rectangular designs. Buchanans can also lace up almost any imaginable rim and hub combination for those hard to find, or hard to fit, situations.
When it comes to rims, the names Excel and Sun come to mind, both manufacturers of high quality aluminum rims. Available either as rims or as part of a wheel assembly, sizes range from skinny 21 inch wheels to relatively wide 16 and 18 inch rims meant for the rear of that fat-tired two-wheeled hot rod.
There are also some very nice rims manufactured from chrome plated steel. These come raw or already assembled in any size you can imagine. Arlen Ness offers his own “Fat 40” wheels made up of their own chrome plated rim and radius design hub, laced with fat, heavy-duty spokes. Landmark and American Wire Wheel offer 80 and 100 spoke wheel assemblies with straight or twisted spokes and chrome plated hubs and steel rims. Some of these can even be run tubeless, as the area where the spokes come through the rim has been sealed with an epoxy-type material.
Custom Chrome has some very sharp wheels assembled from chrome plated steel hubs matched up to stainless steel rims. These 40 spoke wheels come in a variety of 15 and 16 inch sizes. We should also mention that not all rims are laced up in a traditional criss-cross pattern. Also available are the radial spoked wheels, where the spokes simply radiate out from the hub to the rim. Most of these either use more than 40 spokes or very large, heavy duty “spokes” measuring 3/8 inch or more in diameter.
Before deciding which style of spoked wheel to buy, consider that conventional spoked wheels get their torsional strength from the fact that the spokes criss-cross and do not run straight out from the hub to the rim. Forces or acceleration or deceleration are absorbed by spokes under tension. Radial spoke designs give up that design advantage though most use 80 or more spokes, or spokes that are much larger than the typical 6/8 gauge.
In the end, if you can’t find the wheel you’re looking for, you aren’t looking hard enough. They’re all here, from simple 40 spoke rims with chrome plated steel rims, to fancy 220 and 240 spoke designs. Consider all the criteria before buying wheels. That includes cost, weight and the wheel’s ability to handle the expected braking and acceleration loads.
Put together your own
You don’t have to buy an already assembled spoked wheel assembly. Hubs, rims and spokes can be purchased separately and screwed together to create your own unique wheel, or a wheel with a certain amount of built-in off-set. Though lacing up a hub and rim isn’t exactly rocket science, it is a job that requires a certain amount of experience particularly when it comes to the truing. In short, if you can’t find what you want already assembled, this is one job better left to professionals.
Tires
First, the technical stuff. All tires have an epistle written on the sidewall though few of us take the time to do any quality reading. Here’s what all those letters and numbers really mean.
Let’s look at a Avon 160/70R17 79V AV56. The first numbers give the approximate section width of the tire in millimeters. The width of the tire through a section just outside the rim and not the width of the tire at its widest point. The second number describes the profile. The number 70 means the tire is 70 percent as tall as it is wide. A 40 would represent a very low-profile tire, one that is only 40 percent as tall as it is wide. The number, seventeen, represents the applicable tire diameter. V is the speed rating, R indicates radial construction, 79V is the load index, a numerical code associated with the maximum load a tire can carry at the speed indicated by the speed symbol.
In the example above, V is the speed symbol, the maximum speed at which the tire can carry a load corresponding to its load index. The TL means the tire is tubeless and must be mounted on a tubeless-type rim. Tubeless tires can be mounted on a tubeless rim or a tube type spoke rim with a tube. The exception to this is the pre 1977 Harleys which had a different type of rim and need tube type tires. The AV56 is the model specific identification code. “It is a reinforced construction and works well on the Deuce with the AM41 21 on the front,” said Sukoshi Fahey, Avon Sales Manager. “We also have the sizes 180/190/200 in 17. And the tire comes with a road hazard warranty on the rear.”
The speed ratings
All tires carry a speed rating. These ratings start at S, good up to 112 miles per hour; H, good up to 130 miles per hour; V, good up to 149 miles per hour and W, good for 168 + miles per hour. Looking through the Avon chart again, tires rated VR or VB can be run at up to 240 km or 149 mph, the ZR can operate at speeds up to 149 miles per hour while W rated is good to 168 plus miles per hour, faster than most of us will ever ride a motorcycle, much less a chopper. There's also Y for 186+ (300 stand for 300 km/ h).
We should talk a little about the profile of the tire we put on the rear of our new chopper. The 250/40X18 from Avon uses a very short sidewall, while the 230/60X15 uses a much taller sidewall. A few points about these two tires, especially in light of the types of bikes being discussed here.First, the look of the two tires is very different. The 230 has a more traditional profile while the 250 looks more modern, like something you might find on a new Corvette or lowered Toyota. Second, the two tires have nearly the same diameter. To quote Craig Knapp from Hoppe and Associates, the sales, technical and marketing office for Avon, “We designed the 250 to have about the same overall diameter as the 230, that way it fits current frames, fenders and swingarms.”
Craig adds, “To clarify the 230/250 further, the 230’s taller sidewall and stiffer bias-construction can allow for lower air pressures to soften the ride when used on a hardtail. However, this practice can exaggerate the squared-off feel and handling characteristics the 230 exhibits when compared to a higher-crowned tire like the 250. Despite its width, the 250 has the more rounded contour – and in most cases will provide an easier and lighter cornering feel. With the 250 being of radial construction, its low sidewall height makes using low air pressures a somewhat risky proposition over rough roads! The 250 is used OE on Big Dog and Big Bear motorcyles. The Avon 230 is OE on Boss Hoss bikes, so they can stand the weight.”
Just a few more points to make with regard to tires: Front and rear tires have different shapes and should be kept on their respective ends of the motorcycle. There are also tires which are universal – fitting both front and rear such as the Roadrider AM26.
The tire data book mentioned earlier is available from all the manufacturers and will provide information as to the recommended rim width for a certain tire, the overall diameter and circumference of the tire as well as the maximum load. Automotive and motorcycle rims adhere to slightly different specifications, meaning an automotive tire used on a motorcycle rim might not center correctly resulting in a very lumpy ride. A car tire used on a m/c rim could come off the rim.
Automotive tires also have those square shoulders which makes turn-in challenging at best. Finally, most 17 inch tires are meant for the sport bike market and are of a smaller total diameter than the 15, 16 and 18 inch tires mentioned above. Meaning they may not fit typical V-twin frames, fenders and gearing scenarios as well as the tires meant for this market.
How toBuild a Chopper
Author: Tim Remus
Publisher: Wolfgang Publications
Choppers are back in a big way. This book from Tim Remus and Wolfgang Publications helps builders choose the right stretched frame, aftermarket V-twin engine and radical chassis components. Interviews with long-time builders like Donnie Smith help put the chopper in perspective and give sound advice to new builders. Three start-to-finish photo sequences document and explain the assembly of a chopper in the shop of Arlen Ness, Donnie Smith and American Thunder.
Eleven chapters cover History, Frames, Engines, Suspension, Sheet metal, Wiring, Wheels, Tires and Drivetrain choices. With 144 pages and over 250 photos (over 50% in color) this book contains the information needed to choose and assemble your own very unique chopper.
Available for $24.95 + $5.50 S&H from from Wolfgang Publications, 217 2nd St. North, Stillwater, MN 55082, by phone at 651 275 9411, or on the web at wolfpub.com.
