During winter all of my bikes are in a cramped, frigid garage. There isn't room to swing a wrench to remove parts to bring into the house. Among everything I do, I find motorcycle projects help keep me going through the rough spots; either thinking about bikes, riding them or working on them. Rebuilding a wheel seemed like the ideal winter project.
I looked through our club Roster for a wheel builder close to home but there were less people with that skill listed then in previous years. The one I did find was too busy but took the time to describe how I could do it myself - over the phone. I've seen various diagrams and descriptions over the years but it always seemed daunting. I was in no hurry to get this wheel up for next summer so I decided to give it a try. Here is what Canadian Vintage Motorcycle Group (CVMG) member Keith Morgan of Toronto described along with my own first-time experiences in building a simple disk-brake front wheel re-using its stock alloy rim. Since this article was written I've used the same method for building a half-brake BSA front wheel and a BSA rear wheel with an offset. All spokes came from Buchanan's Spoke and Rim with accurate length which also helps the process considerably.
1. Many bicycle shops sell a donut-shaped spoke wrench. File the largest spoke wrench slot a bit wider to suit spoke nipples on your motorcycle wheel. Many large auto supply retailers that sell bicycles may have them too.
2. Strip disks, axles and/or brake plate from the wheel leaving the hub and the rim bare. Place the wheel on newspaper or cardboard to trace the spoke pattern for future reference. Record which side of the wheel is the right or left side, brake side or plain side, the direction of rotation and the left and right offset and right side of the hub if not obvious. A scribe in an unseen spot is best as marker pen may disappear when cleaning/polishing.
3. If re-using an old rim check it for "waves" and "hops". Mark these spots, inside the rim, with a felt-tipped marker or scribe. Make a photo of the wheel if you have some simple way to blow the image up for future reference (scanner and computer printer).
4. Measure hub-to-rim offset, in a number of places, on both sides and record information on tracing.
Figure 1.Stripped wheel showing rotation direction.
5. Loosen all spokes first then remove the spokes. As more spokes are removed it becomes harder to remove rusted nipples; they all must be loose before you remove them. Keep a set of sample spokes including their original location as reference, especially if spokes are of different lengths, to compare to replacement spokes. Once you have a few reference spokes don't be afraid to cut other spokes out of the wheel if the nipples are too rusted to remove easily.
6. Find a flat surface like your kitchen table and check waves that were previously marked. Are they still there? If waves are still there they will have to be removed when wheel is rebuilt. Unless hops or waves are caused by dents most should be gone as most are caused by loose spokes. Manufacturing tolerances for many rims are plus or minus 1/16" - not .001" that a dial indicator may show. Even a new rim may vary in width by 1/8" in width over its entire diameter, an old rim may vary by more - it doesn't matter when the tire is on the rim as tires vary too. The best indicator of rim condition is how smooth the tire seat is, not the uneven edges of the rim.
This is not a hard job. Spokes and rims are designed to make things easy for persons or machines assembling a spoked wheel. There is a pattern, which is easily found as soon as the first spokes are placed, that makes things easier. Compare the angle of the spoke to its intended location on the rim - the spoke should not be bent in any way.
1. Put two dabs of oil on each spoke thread and run nipple to the bottom of the thread. The nipples should thread on easily by hand. If any are tight, work the spoke nipple back and forth until they are loose or try swapping with another spoke. Free-running nipples are critical (alright, control your imagination).
2. Begin assembly according to marked spoke locations, your image or paper tracing. I loosely assembled all the spokes on one side of the wheel turning each nipple 2-3 turns onto the spoke just to keep them in place. The other side was done the same way but I found I had to undo some of 1st side's spokes to swing some of the 2nd side's spokes in place. That's another reason why the first side was done up loosely.
3. Tighten each nipple until spokes are few turns below the top of the nipple (up to the base of the screw-driver slot. The spokes should still be loose and the hub should rattle, if they aren't back each nipple off an equal amount so there is a common reference depth before starting to true the rim.
4. Check rim offset. If adjustment is required, tighten spokes on one side of the wheel a little at a time to adjust (no more than « turn) then check again. Always turn each spoke an equal amount.
Figure 2. First side complete - hub and spokes loose.
5. If rim and hub are in the approximate final location (correct offset) begin tightening the spokes in an orderly manner marking your start point. Move around wheel tightening each nipple one turn, then a half turn, then a quarter turn until spokes begin tighten.
6. This is where the sound part starts; when plucked like a harp string each spoke should make a similar "thunk" sound. The sound of the plucked spoke becomes important as it will be used to true rim and gauge torque. Don't even think about dial indicators as they will waste endless hours at this point.
7. Oops - another tool is required. To get the correct torque a wrench at least six inches long is required. I had to run to my favourite auto supply again and buy a long 6mm combination wrench. You may need a similar ¬" wrench for your wheels. If you were really planning ahead a spoke wrench can be purchased from most spoke suppliers.
8. Mount wheel on its axle and support in some manner such as shown in Figure 3 with no side-to-side play.
9. Turn the stereo off. Turn the TV off and send the kids out to play; they need fresh air and you need silence.
10. When turned the wheel should run close to true. Begin tightening the spokes an equal amount all around the rim again. When you have completed one revolution check the sound of each spoke along with how tight the hub is. If one spoke is loose resist the temptation to turn it beyond the `sound' of a similar spoke.
11. Check the hops and waves that were previously marked. Are they still there? This indicates that the rim was bent in some way during spoke installation (it was checked for straightness before lacing wasn't it?) requiring careful adjustment of spokes to remove these spots (see next section).
Figure 3. Quick wheel truing stand. Hockey stick pieces are screwed to the 4x4" which is clamped to the bench. The other side held in 2x2" mounted in a vice to allow free width and height adjustment. Various washers and spacers are used to keep rim and hub away from the stand and vice.
12. Each similar spoke should sound the same. "Thunks" will change to higher-pitched "things." Mark spokes that have a higher pitch then the others. If you are tone-deaf and can't hear the difference in the sound go by the feel. Mark "tuned" spokes with black marker to use as reference as you move around the wheel.
13. If the hub is solid and offset is close (within a 1/16" as measured with a straight edge) then the wheel can be trued completely by sound at this point unless there are hops and waves that must be removed (see next bottom of this page). If rim offset is off to one side or the other tighten the spokes on one side only by an equal amount before loosening spokes on the other side by the same amount. When everything is in the position you want it to be, tighten spokes again, carefully, until they all sound the same. A wood dowel or other object that won't mar the spoke may be required to check the sound as you may not be able to pluck the spoke like a harp string at this point. On a wheel with a half-brake hub the short spokes on one side will sound different from longer spokes so similar length spokes should be `tuned' to match other similar spokes.
14. When hub is solid check each similar spoke's sound. A high note indicates a correct spoke while a low note indicates a loose spoke. Tighten to adjust the sound to be similar to the average of the tight spokes of similar length.
15. Rotate the rim. It should be running true at this point. If all spokes sound the same go around the wheel one more time and tighten each spoke by a tiny amount (1/8 turn or less). Check the sound of each spoke again. They should sound similar to each other (you can spend hours at this; accept a tolerance in the sound if all spokes are tight and the rim is true). Go around the wheel one more time and tighten each nipple by a tiny, but equal amount. That long handled wrench is critical. A wheel's strength is based on the tight adjustment of all spokes, not just a few. Spokes are also designed to stretch by a small amount for optimum strength of the wheel.
Are the waves and hops still there? Most should be gone at this point. If using an original rim those variations should be gone as they were probably the result of loose spokes, minor dents or variations in the original rim. Before final tightening (steps 13 and 14) decide if they are annoying. Only you can determine whether they are important before adjusting spokes any further because this can be the frustrating part. Check the rim seat too; it may be true while the edges are not.
How big are these waves? If they are greater than 1/6" then adjustments can be made to remove them. Before adjusting any spokes check the other side of the rim to see if there is an equal wave in the same direction as rim width may vary. There may be a wave on one side only or it may be a bulge (both sides wider) or narrow section (again, on both sides, in). Many rims have bulges or narrow sections as part of the original manufacturing process, particularly close to the weld. If one side is straight, don't touch the wave. Adjust only if a wave on one side is matched by an equal wave going the same direction on the other side.
Hops are easy to see but hard to adjust. Is the hop on the outer edge of the rim or on the part the tire is seated on? Where you measure is important as the edge of the rim may be dented or subject to normal manufacturing variations while the seat where the tire sits is true. If there is a hop, and it is less than 1/16" it can be left alone - you'll never remove it unless you want to spend endless hours at it. If greater then 1/16" mark the centre of the hop and begin from the inside moving outwards in both directions.
Figure 4. Adjusting for a "Hop." Each spoke is marked with the number of turns to loosen (or tighten) along with centre spoke locations. Similar markings are put on the other side.
Adjustment must be made from the center of the hop two spokes at-a- time (not counting the spoke at the centre of the hop). Mark the spokes that have been adjusted and the amount each was turned using sound as a guide. Remove the hop without touching spokes on the opposite side to check the effect before adjusting on the opposite side. Loosen no more then 9 spokes before checking with each set of loosened spokes. Once the hop is removed use the sound method to begin tightening spokes on the opposite side. Note that loosening 9 spokes on one side may require tightening 11 spokes on the opposite side, working from the outside to the centre of the location opposite the hop.
Geoff Collins is the proprietor of Ed G Cranks, Toronto, ON Canada
ED G Cranks www.offsetcrank.com