The tires you should use depends primarily on whether your bike will be driven with or without the sidecar. Because a sidecar bike can't lean, tires designed for sidecar operation need to provide maximum contact area when the bike is perpendicular to the ground. Tires for solo use are generally not ideal for sidecar use because they will not provide as much contact area as they could to assist braking/turning with the added weight of the sidecar.
Generally the dimensions of tires suitable for a CJ have a width of 3.5" to 3.75" and a diameter of 19". Some tires which are 4.0" wide are also suitable, but not all; tires which are too wide will rub against the drive shaft, either constantly or when the bike is heavily loaded or hits a bump.
Another source for tires is JC Whitney, they have a collection of blackwall and whitewall tires which may be suitable..
Depending on what you're willing to spend, there are also Continental, Metzler, and other German brands.
Adding whitewalls to your tires can be accomplished by paint. The PLA used to paint the sidewalls of their tires white. A suitable paint for painting tires is found here.
Lacing wheels is not difficult. The best instructions for lacing wheels are in Sloan's The Complete Bicycle Book, of which there are several editions. The thing to remember is that there are two different lengths of spokes, one for the brake side and one for the other side. This makes the spoke pattern different from a bicycle.
Here is a step-by-step way to properly lace a wheel:
Clean the rims and wheel hubs well with a degreaser and dry them. If there are paint chips, touch them up now. It's easier to do this before the wheels are built up.
Start by taking the short and long spokes and dividing them into piles of 20 each. Put a rubber band around each pile. You will need 20 long and 20 short spokes for each wheel.
Take off all the spoke nipples and clean both the ends of the spokes and the nipples. When the bikes are fumigated before leaving China a little steam gets into the spoke nipples causing some surface rust. This is no big deal. Place 20 nipples in each of eight zip-loc bags. This way you won't loose them or knock them over.
Place the hub large-flange (brake side) up on a workbench. Put a short spoke in every other hole from the underside up and fan out the spokes. The spoke heads will be down, or to the inside of the wheel. If you look carefully, you will see that every other hole has the paint chipped a little bit. Try to get the head ends of the spokes into the chipped holes. This is the way the wheels were originally assembled, and it means less paint touch up.
Place the rim around the hub and spokes, flat on the bench. You will notice that the spoke dimples in the rim are pointed either forward or backward, and every other one is either up or down. That makes four different kinds.
Take a short spoke and stick it into an up and forward hole. Put a nipple on the end of the spoke and give it a couple of turns to hold it.
Take the next spoke around the flange (remember it's every other spoke, since you have put in only half of the spokes so far) and stick it into the next up and forward facing hole, which is four holes over. Put a nipple on it and give it two complete turns. Work your way around until you have all ten spokes in place, all of them in the up and forward holes.
Next, IMPORTANT! rotate the hub against the rim so that the spokes are at an angle to the rim and the hub and the nipples are all seated in their wells in the rim. Now insert a set of 10 spokes from top to bottom in the other ten holes. The spoke heads will be on the outside of the wheel. Take one spoke, seat the head, and fan it around until it crosses the spoke next to it. If it forms a nice 'X' and lines up with an up and backward hole, great, insert it in the hole and install the nipple. If it doesn't line up, you crossed the spoke in the wrong direction. If you crossed the spoke in front, rotate it so that it crosses the spoke in back. It should now line up with a hole and you can install the nipple. Do all ten spokes making nice 'x's. Do not tighten anything yet. You want to hub to be able to flop around in the rim.
Turn the wheel over. The small flange has ten double keyholes, rather than 20 discreet little holes. Insert a long spoke in the middle of a key hole from underneath the flange and pull it to the right, into position. The spoke head will be facing you (up). Rotate the spoke until it lines up with a hole in the rim. This should be (remember, you flipped the rim over) and up and back facing hole. Insert the end of the spoke in the rim and put on a nipple, giving it only one or two turns.
Put in the next spoke in the next keyhole clockwise in the hub. You can actually go counterclockwise if you wish, but I like to go clockwise. This spoke should line up with an up and back rim hole four spaces (empty or filled) on the rim from the first hole. Install a nipple. Work your way around until all ten spokes are in place. Sometimes the spokes fall out at the flange ' don't worry, just stick them back it. Once everything is in place and tight, nothing will fall out.
Now you're ready for the last ten spokes, and these will be the hardest, although this is still not rocket science (and I can say that because my father really was a rocket scientist. No lie.) Take a spoke and stick it head down through the middle of the key hole and pull it to the left with the head facing down. You may have trouble getting the head of the spoke in place. Try holding the spoke almost vertically and lining up the head with the small part of the keyhole. This usually works to get the head in place. A few spoke heads are a little larger than they should be, and you can adjust them slightly with a file. Once the head is in place, count 15 spaces (filled and unfilled) from the other spoke in the keyhole with the head up. The spoke should line up with an up and forward hole in the rim. Insert the end of the spoke and screw on a nipple.
Work your way around, one spoke at a time. A few of the spokes may take a little bending to get them in position. The wheel will begin to firm up as you work your way around and the rim will no longer be on the work surface. It will be more-or-less in the middle of the hub.
With all the spokes in place you are ready to start truing the wheel. If your spoke nipples have a screwdriver slot in the head, you are in luck. If not this next step will take a little longer, but not much. Tighten all the short spokes so that the end of the spoke is even with the end of the nipple. You can use your fingers, an electric screwdriver, or a wrench. I like to use a 4' adjustable wrench. There is a spoke wrench in the tool kit - it's a notch in a funny look tool that has two pins in the other end and a 27 stamped on it. The 27mm is the wrench you need to tighten the spare tire nut on the sidecar. By tightening all the short spokes first you will get the wheel nearly round right off the bat, and you will also get it 'dished' correctly - more about that later.
Now tighten all the long spokes so that they are not flopping around. If you do these two steps, some of the steps below will be a lot easier, and maybe even unnecessary.
Mark a spot on the rim with masking tape right in the middle of where two spokes from the small flange attach to the rim, one position apart. The spokes will be parallel, one from each side of the flange. One will be a heads up spoke and one a heads down spoke. Do the same thing directly opposite on the wheel. Now mark two spots at right angles to the first pair of marks. You should now have four marks each 90 degrees from each other, evenly spaced around the wheel. Take a ball-point pen and mark the tape marks 1,2,3 and 4. Marks 1 and 3 will be opposite, and 2 and 4 will be opposite.
Tighten the two spokes at position one three turns each. Then tighten the spokes at position 3 three turns each. Now tighten the spokes at position 2 three turns each. Finally, tighten the spokes at position 4 three turns each.
Flip the wheel over and do the same thing with the spokes coming from the large flange at points one through four. This will keep the hub pretty well centered in the wheel.
Now go around the wheel and tighten all the rest of the spoke three turns each, working in opposite pairs if possible. If any spokes on the small flange fall out, put them back in. Dishing: It is important that the wheel be 'dished' correctly, or you will break some short spokes. By now you will have noticed that the large flange is not at 90 degrees to the hub ' it's at an angle pointing in to the center. You want to adjust the spokes side-to-side so that both the inner and outer short spoke shanks do not touch the flange at its outer edge. If you tighten all the short spokes first, you will probably be pretty close. The ideal is to have the gap between the spoke shanks and the flange be the same for both the inner and outer spokes. You can achieve this by tightening all the short spokes and loosening all the long spokes, or vice versa, to move the rim back and forth to change the angle of the spokes. The spoke angle for the long spokes is unimportant. The hub will not be in the center if you dished it correctly. Remember that there is also a brake plate that is part of the hub. When you add that, the wheel will be more-or-less in the middle.
OK - back to the main program - The wheel will still be a little loose. Repeat the last three steps as many times as necessary until the spokes are reasonably tight. They should 'ping' when tapped with a screwdriver and not 'thunk.'
Once all the spokes are reasonably tight and the spoke nipples well seated in the dimples in the rim, it is time to mount the wheel and spin it. You can make a truing jig (drawing attached) that makes the job easier, or you can mount each wheel on the front or sidecar axle. If the sidecar body and fender are already attached to the sidecar, you will have to use the front axle. Screw the front axle in place. The front axle has a left hand thread. When you spin the wheel it will wobble from side to side (run out) and up and down. You will need to attach some indicators to the fork to gauge your progress. A piece of wood taped across the fork above the wheel will work well enough for up and down movements. Tape it in place so the wheel just barely rubs at its highest spot. Tape a couple of 1/4'x20 nuts attached to a long bolt to the fork at the rim level so that when you screw in the bolt it just touches the edge of the rim.
You want to get the up and down variation of the rim to within a couple of millimeters from true. Do this by adjusting pair of spokes. Tighten spots opposite a high spoke and loosen spokes at the high spot. Do this no more than one turn at a time. The wheel rims are usually a little out of round at the weld, so as long as you are not going to go 90 mph, a 2mm variation will not be noticeable.
Next, true the wheel from side to side. Adjust spokes from opposite sides of the wheel to move the rim back and forth. This takes time and patience, but you can get the rim very close to perfect. I figure a millimeter of run out is close enough, and I can usually get better than that.
Re-check the spokes to make sure none go 'thunk' and you're done.
Finally, grind off the ends of spokes that stick out so that they won't puncture the inner tube. I use a cheap stone on the end of an old electric drill. If you have access to an angle grinder it will save you time, but be careful with it because it will cut very fast. If you have trued the wheels well, only a few spokes will stick out. Clean the inside of each wheel and put the rim strip back on before you mount the news tires. This is the single most time-consuming process in assembling the motorcycle.
Most general books on motorcycle maintenance have information on how to true wheels. The local library will have at least a couple of general motorcycle maintenance books. You can also follow the directions in Sloan's bicycle book, mentioned above.
Balance / Truing
Keeping your wheels properly dished/trued is critical for rideability and long term life of the wheels.
(Help Us: The truing/dishing instructions are just a repeat of the section about lacing, and thus not quite right, since they assume spokes are all loose initially, we need someone with experience to correct this!) (Help Us: Add your knowledge here!)
Follow these steps to dish/true your wheel:
Now tighten all the long spokes so that they are not flopping around. If you do these two steps, some of the steps below will be a lot easier, and maybe even unnecessary.
Mark a spot on the rim with masking tape right in the middle of where two spokes from the small flange attach to the rim, one position apart. The spokes will be parallel, one from each side of the flange. One will be a heads up spoke and one a heads down spoke. Do the same thing directly opposite on the wheel. Now mark two spots at right angles to the first pair of marks. You should now have four marks each 90 degrees from each other, evenly spaced around the wheel. Take a ball-point pen and mark the tape marks 1,2,3 and 4. Marks 1 and 3 will be opposite, and 2 and 4 will be opposite.
Tighten the two spokes at position one three turns each. Then tighten the spokes at position 3 three turns each. Now tighten the spokes at position 2 three turns each. Finally, tighten the spokes at position 4 three turns each.
Flip the wheel over and do the same thing with the spokes coming from the large flange at points one through four. This will keep the hub pretty well centered in the wheel.
Now go around the wheel and tighten all the rest of the spoke three turns each, working in opposite pairs if possible. If any spokes on the small flange fall out, put them back in. Dishing: It is important that the wheel be 'dished' correctly, or you will break some short spokes. By now you will have noticed that the large flange is not at 90 degrees to the hub ' it's at an angle pointing in to the center. You want to adjust the spokes side-to-side so that both the inner and outer short spoke shanks do not touch the flange at its outer edge. If you tighten all the short spokes first, you will probably be pretty close. The ideal is to have the gap between the spoke shanks and the flange be the same for both the inner and outer spokes. You can achieve this by tightening all the short spokes and loosening all the long spokes, or vice versa, to move the rim back and forth to change the angle of the spokes. The spoke angle for the long spokes is unimportant. The hub will not be in the center if you dished it correctly. Remember that there is also a brake plate that is part of the hub. When you add that, the wheel will be more-or-less in the middle.
OK - back to the main program - The wheel will still be a little loose. Repeat the last three steps as many times as necessary until the spokes are reasonably tight. They should 'ping' when tapped with a screwdriver and not 'thunk.'
Once all the spokes are reasonably tight and the spoke nipples well seated in the dimples in the rim, it is time to mount the wheel and spin it. You can make a truing jig (drawing attached) that makes the job easier, or you can mount each wheel on the front or sidecar axle. If the sidecar body and fender are already attached to the sidecar, you will have to use the front axle. Screw the front axle in place. The front axle has a left hand thread. When you spin the wheel it will wobble from side to side (run out) and up and down. You will need to attach some indicators to the fork to gauge your progress. A piece of wood taped across the fork above the wheel will work well enough for up and down movements. Tape it in place so the wheel just barely rubs at its highest spot. Tape a couple of 1/4'x20 nuts attached to a long bolt to the fork at the rim level so that when you screw in the bolt it just touches the edge of the rim.
You want to get the up and down variation of the rim to within a couple of millimeters from true. Do this by adjusting pair of spokes. Tighten spots opposite a high spoke and loosen spokes at the high spot. Do this no more than one turn at a time. The wheel rims are usually a little out of round at the weld, so as long as you are not going to go 90 mph, a 2mm variation will not be noticeable.
Next, true the wheel from side to side. Adjust spokes from opposite sides of the wheel to move the rim back and forth. This takes time and patience, but you can get the rim very close to perfect. I figure a millimeter of run out is close enough, and I can usually get better than that.
Re-check the spokes to make sure none go 'thunk' and you're done.
Finally, grind off the ends of spokes that stick out so that they won't puncture the inner tube. I use a cheap stone on the end of an old electric drill. If you have access to an angle grinder it will save you time, but be careful with it because it will cut very fast. If you have trued the wheels well, only a few spokes will stick out. Clean the inside of each wheel and put the rim strip back on before you mount the news tires. This is the single most time-consuming process in assembling the motorcycle.
