The Spokin' Word: All About Motorcycle Wire Wheels
The ins and outs of lacing and truing spoked wheels.
By Evans Brasfield,
Motorcycle Cruiser/December 1997.
Spoked wheels are popular with cruisers because of their classic style, but
customizers like spoked wheels for their flexibility. The look of a stock
wheel can be dramatically altered simply by changing the spokes or their
pattern. Builders install oversized rims with low-profile tires or fit
smaller rims with big, fat tires. The hub usually remains the same and the
spokes and rims are changed. The process for attaching rims to hub is called
lacing, and the steps are the same whether replacing spokes, rims, or both.
When we contacted Kennie Buchanan, owner of
Sun Rims California, Inc., to see
if he would like to walk us through how wheels are laced and trued, he said
that our readers would better understand how the spokes interacted with the
rims if they knew what went into manufacturing rims.
From the Straight and Narrow
Sun Rims start out as six-foot long bars of extruded 6061 aluminum. The bars
already have the shape of a rim's cross-section, with the channel for the spoke
nipples and the shoulder for the tire bead to seat against. The bars get cut to a
rough length and are run through the rolling machine for their first bend. After
the first bend, the excess aluminum is cut off the ends so that when the bar
meets the rolling machine a second time, it will be as close as possible to the
final diameter.
The fireworks of the rim-building process take place at the butt welder. The
two open ends are clamped with 80,000 psi of pressure and moved slightly apart.
Extremely high voltage is applied to the clamps on either side of the gap (We
asked Buchanan how high the voltage was, and he responded that he'd have to do
the math to come up with the actual number but that the voltage was high enough
to badly injure or kill someone unlucky enough to get personal with it), and
although the current is applied to opposite ends of the same piece of metal, the
path of least resistance is across the gap between the ends. The machine starts
with a pop as the electricity makes the initial jump across the gap. The sparks
and smoke continue for several seconds as the arcing electricity heats the
aluminum until it is molten. At this point, the butt welder slams the molten ends
together, showering the floor with sparks and bits of liquid aluminum. The
bulging seam glows as the rim leaves the butt welder. According to Buchanan, the
weld is as strong as any other part of the rim.
The expander stretches the newly formed rim to a preset internal diameter
while assuring that the rim is true. Although the expander is a deceptively
simple-looking machine that essentially drives a cone shaped wedge down the
center of a circular group of plates, it is extremely accurate and can be
adjusted to expand and true rims ranging from 16 inches to 23 inches. The
properly sized rims then move to the rim grinder to have the seam from the butt
welder ground flat, allowing the seam to be invisible in the finished product. At
this point, the polished rims get their first polish before moving on, all other
rims visit the automated rim driller to be given the correct hole pattern for
their specific application. Since spoked wheels vary the number of spokes from as
little as 28 spokes to as many as 200 spokes, precision drilling of the spoke
holes and their relative angles is paramount for true wheels. The automated
drilling machine drills and countersinks up to four holes simultaneously and
rotates the rim for each additional set of holes. After the holes have been
drilled and deburred, the rims move on to the chromer, anodizer, or polisher.
Lacing Up
While manufacturing rims is an industrial process, involving large, heavy,
precision machinery, lacing rims is still an art practiced by craftsmen, though a
bike owner can do it too with some patience. Truing wheels, even in the era of
high technology, is largely done by eye, using only a spoke wrench and other
simple tools.
Preparing the parts to be used in lacing a hub to a rim makes the job quicker
and easier. Pros lay out and count--nothing would bring the job to a halt quicker
than not having enough spokes or nipples--all the parts necessary for lacing a
wheel. The nipples should all be lined up, standing on end, to receive a drop of
thread lubricant to ease the threading process. The spokes' threads will also
receive a drop of lubricant once they've been laid in the hub.
Place the hub on its side on a workbench (or wheel stand if you are lucky
enough to have access to one). Our Vulcan Classic hub incorporates 48 spokes.
Each flange on the hub consequently needs 24 spokes. The holes on each flange are
offset and can be divided relative to their location to the outside of the wheel
into an outer and inner row. Slip the spokes into the holes on the upper flange
then go around the hub making sure the inner row's spokes all face the same
direction and the outer row faces the opposite direction. On our Classic's rear
hub, we had the inner row pointing counter-clockwise and the outer pointing
clockwise. At this point, lubricate all of the spokes' threads.
Lay the rim over the hub. If the hub that the rim will be laced to is heavily
offset, use pieces of wood to raise the rim so that its center line is on
approximately the same plane as the midpoint between the flanges on the hub.
Starting with the outer row of spokes, take one spoke and rotate it until it
lines up with a hole at the very tip of the spoke. If the spoke could line up
with one of two or three holes, take a pen and insert it into the hole in the
rim. Since the holes have been drilled at an angle, only one of the hole angles
will cause the pen to line up with the spoke in question. Slip the nipple through
this hole and loosely thread the nipple onto the end of the spoke. Do not tighten
the nipple more than a couple turns. Slack will be required to maneuver the other
spokes into position. Count four holes clockwise on the rim, and the next outer
spoke (clockwise) should line up with this hole. Thread the nipple and continue
with the outer row. The inner row will lace in the same manner.
One way to be certain that the spokes are going to the correct hole is to
count the number of spokes it crosses. On the Classic, the spokes will only cross
once; other wheels may have several crosses. Turn the wheel over and thread the
spokes in as with the other flange. Starting with the outer row, lace the wheel
following the same steps as with the ?revious side. Once all the spokes have been
threaded to nipples, the nipples will need to be tightened on all the spokes so
that each nipple just barely covers the threads. Before doing so, go around the
rim and place a drop of oil (regular 30 weight will work fine) under the head of
each nipple. Next, choose a group of four spokes (two from the upper flange and
two from the lower) and run the nipples up on these spokes until they cover the
threads--and no further. Find the four spokes directly on the opposite side of
the wheel from the first group of four and tighten them similarly. After those
four are run up on the threads, go to the center of the hub and choose a group of
four spokes 90 degrees from the first two sets and repeat the process. Then run
up the rest of the remaining nipples onto their spokes. The loose-laced wheel is
now ready for truing.
True Stories
Truing spoked wheels is really just a process of averaging out errors. No
wheel needs to be absolutely perfect, and trying to make a wheel that way with a
dial gauge will only lead to undue stress. Remember the wheel isn't what contacts
the road, and the tire will cancel out small wheel errors while bringing its own
set of small errors to the game. With this in mind, good wheelwrights will simply
use a surface gauge to check visually for a wheel's bumps and wiggles and then,
using a spoke wrench, make the rim run as round as possible.
Place the wheel on a truing stand or take an axle and clamp it in a vice so
that the wheel will be horizontal (the axle is vertical) when placed on it. Go
around the wheel with a spoke wrench and put a little tension on each spoke.
Next, put the surface gauge in position and give the wheel a spin. The
loose-laced wheel will wiggle in one of three ways: It will roll from side to
side, it will have either a hump or dip, or once the other problems are
addressed, the entire rim may sit either too high or low, relative to the hub.
Since side-to-side motion (which is an up-and-down motion if the wheel is
positioned horizontally on the axle) is the easiest to remedy, start by finding
the center point of the twist. Spokes will pull the rim sideways when they are
tightened so tighten the spokes that would pull in the opposite direction as the
twist. For example, if the rim is high in one section (assuming it's on the stand
horizontally), tighten the spokes on the bottom side of the rim. Do just the
opposite for low sections. Only turn the nipples in the center of the high point
one or two of the flat sides and nipples at the outside of the imperfection one
or no flats, depending on the severity of the side-to-side roll. Several small
adjustments may be necessary to fix the problem.
If the rim has a hump (a place where it rises away from the axle) in one
section, tighten the spokes at the center of the hump on both the top and bottom
of the rim. Dips usually occur when the spokes in a section are too tight, and
loosening the top and bottom spokes slightly, should improve things.
To determine if the entire rim is too high on one side or the other, the
distance between the edge of the rim and the hub needs to be measured on both
sides. Place a straightedge across the top of the hub or the rim, whichever is
higher (the Classic's hub was higher in our case) and measure the distance from
the edge of the hub (or if it is not symetrical, the flange) to the edge of the
rim. Flip the wheel in the stand and repeat the process. If the difference
between the sides is 1/16 of an inch or greater, the entire wheel needs to be
adjusted. Slightly tighten all the spokes on the side with the greatest gap and
slightly loosen the spokes on the side with the least gap. Now go back to measure
the differences. Once the difference is less than 1/16 of an inch, double-check
to make sure the wheel is true. Some minor adjustments may be necessary.
Hoop Dreams
Our representative wheels for?this article were a set of Vulcan 1500 Classic
hubs. Jon Sprenger, an R&D guy at Cobra, slipped our hubs in with a batch of
Cobra's parts to get chromed. When the hubs returned, he painted all of the rough
cast sections of the hubs, like inside the hub where the cush drive will reside,
glossy black for a nice custom look, since those sections don't readily accept
chrome.
For our custom rims Buchanan suggested 18-inch (instead of the stock 16-inch)
rims with low-profile tires. A quick call to
Avon Tires revealed that we should
be able to fit these new hoops under the stock fenders if we used an Avon
150/70VB18 AM23 ($195) tire on the rear 4.0 x 18 rim. The front 3.5 x 18 rim
required a trick from the Harley customizing world. We will install an Avon
130/70VB18 AM23 ($165), which is a rear tire, and then flip it so it rotates
backwards from the way it would as a rear tire. This will enable the tire to
direct the braking loads (which travel from the opposite direction from the
drive loads on a rear tire) into its carcass as intended.
In the looks department, we chose Sun Rims' bright, buff polished aluminum
rims laced to the hub with stainless steel rippled spokes from Buchanan's. The
front rim cost $254 and the rear $277. These prices included hand drilling for
our custom-sized wheels. The polished stainless steel ripple spokes add $354 to
the cost, and lacing and truing labor were $84 each. The result was two
unique-looking wheels that we can't wait to see on our Vulcan Classic.
THE TRUE PATH: WIRE-WHEEL MAINTENANCE
Every bike with wire-spoke wheels, be they aftermarket or original equipment,
will need some wheel maintenance sooner or later. We asked Gary DuPape of
Wheel Works what knowledge he's gained
in his 20 years in the business which he can pass on to riders who want to keep
their spoked wheels round and true.
According to DuPape, riders should clean their wheels regularly. That's the
best way to prevent big problems. While cleaning, grab groups of four spokes and
squeeze them. If done enough times you will develop a feel for the spokes'
tension and notice when they start to loosen. Also, broken spokes or small cracks
in rims will be noticed before they lead to other problems. A broken spoke should
not be replaced individually and forgotten. It could be a sign of a problem.
Consider buying a new set (How about those fancy ones you've been eyeing?) and
have the wheel completely trued.
Every time the tires are changed, the wheel should be checked for trueness on
a truing stand with the tire removed. While properly trued wheels shouldn't
suffer from spoke "settling" after the wheel has been laced, new wheels should be
checked after their first 500 miles or so. If a loose spoke is found, tighten it
up snugly but not so tight as to influence the shape of the rim.
Eventually, spoked wheels will need to be retrued. Spokes are subjected to
constantly varying stresses, and they stretch over time, causing looseness.
DuPape says that only through regular spoke observation and maintenance can
riders stay on the true path of motorcycling.
This article originates from here
and includes larger photos.
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