BICYCLE REPAIR

Tools and Supplies
To build a bicycle wheel you need a spoke wrench, plastic mallet, Bicycle Research nipple driver or a small regular screwdriver, dishing tool (optional), grease and acetone.

You might want a bicycle truing stand, too (photo), which features indicators that make it easier to see wheel imperfections when you’re truing and tensioning. These are costly, however, so you might prefer to simply place the wheel in your bicycle frame or fork and true it there. Just use the brake pads as indicators resting your thumb on one as you get the wheel nearly true to see and feel the wobbles. This is the way I learned to true and tension wheels and it works fine. I now use the Park TS-2 truing stand, which I, and legions of professional mechanics think is the best available because of its durability and ease of use.

Choosing Components
Hubs: These days all bicycle hubs from major manufactures provide a stress-free spoke foundation. The main decision concerns drilling, or how many holes there are in each hub. The current norm for road and mountain wheels is 32, which is fine unless you weigh more than 185 pounds. Heavier riders or those planning to subject the wheels to hard use, such as loaded touring or stunt riding, should consider 36-hole hubs.

It’s OK to reuse old hubs (but not rims or spokes). Disassemble them and check the bearing races for pits or scoring, which mean the hub should not be used. Replace pitted cones and bent axles.

Another consideration with old hubs is how many times they’ve been rebuilt. V-shaped spoke impressions indicate a hub has been used at least twice with different lacing patterns, and the flanges could be weakened.

Rims: This is the main structural component of the wheel, and selection is critical. Choose according to your weight and riding habits. For clincher road wheels, 375- to 500-gram rims are sufficient for riders weighing up to 170 pounds. Heavier cyclists should consider stouter models. Tubular (sew-up) rims are somewhat stronger and allow use of slightly lighter weights.

Other choices include triangular (aero) or box cross sections, whether the rim comes with or without nipple ferrules, and if it has offset or centered nipple drilling. While the last 2 factors are not that important, keep in mind that aero rims ride harsher than box-section models (today called “double-wall” rims for some unknown reason). However, aero rims add strength and are a good choice for heavy use. In my opinion, Mavic makes the best rims.

Spokes: To simplify truing and tensioning, beginning wheelbuilders should use 14-gauge straight (non-butted) Wheelsmith or DT stainless-steel spokes and matching nipples. Butted spokes and aluminum nipples are lighter but require extra skill during truing and tensioning.

Proper spoke sizing is a prerequisite for durable wheels. I recommend after selecting your components to have shop personnel calculate the correct length for your setup. They should be happy to do this if you’re buying a set of spokes from them, and there’s a benefit to buying the spokes from them. If they get the length wrong, they’ll make it right, whereas if you calculate the wrong spoke length, you might not be able to return the spokes (depending on where you bought them).

There are formulas and programs for calculating spoke length, too, but it’s easy to make mistakes. If you’re planning to build lots of wheels, consider purchasing a spoke-length chart, or computer software or keep a record of what lengths worked for the rim/hub combinations you’ve used. These, as well as truing stands, books and other wheelbuilding tools, are available from bicycle shops, though some things will need to be ordered.

Front and rear wheels require different-length spokes. This is because the rear needs slightly longer spokes on the left to compensate for the offset of the cassette/freewheel. Buy 2 different-size bunches of 16 or 18 spokes for the rear, but 32 or 36 of the same size for the front. Mark the bunches accordingly to avoid confusion.

The crossing pattern also affects spoke length. I recommend 3 cross, which means each spoke passes over or under 3 others on its way from hub to rim. This makes for a strong wheel.

Preparing Components
To ease truing and tensioning, apply grease or thread compound to the spokes and grease to each rim nipple hole. For the spoke threads, I prefer Wheelsmith’s Spoke Prep. You must apply it carefully because too much will make it harder, not easier, to turn the nipples. After applying it must dry, too. When applied properly it will keep spokes from loosening and nipples from freezing for years. An alternative is linseed oil, which becomes tacky as it dries. Or, you can just lube the spoke threads with grease or oil, which will at least ensure that you can get the wheel nice and tight.

Use an upside-down nipple threaded onto the end of a spoke to grease rim holes. Just dab it in the grease and apply. This is especially important on rims without ferrules because nipples bind against the aluminum.


Lacing
Because rear wheels are more complicated to build, my directions focus on them with occasional comments for front ones. If you’re using old hubs, inspect the spoke holes. On some models every other hole is countersunk. If so, install the spokes so that the bend (not the head) is against the countersink.

1. Place the rim flat on a workbench with the valve hole opposite you. Insert one of the shorter rear spokes into any hole in the rear hub’s cassette-side flange. It can be put in from the inside (head in) or outside (head out).

Looking at the 2 rim holes straddling the valve hole, determine which is offset toward the top, push the spoke end in (photo 1), and thread a nipple 4 turns. On rims with centered rim holes the spoke can be placed in either one next to the valve.

2. In the same direction you installed the first spoke, place 7 more into the hub (8 for 36-hole wheels) using every other hole. One at a time, place these spokes into every fifth rim hole (counting from spoke to spoke; photo 2) and add nipples. You should have a hub and rim joined by 8 spokes (or 9 for 36-hole wheels).

3. You must have parallel spokes at the valve stem to provide clearance for pump heads. To achieve this, twist the hub to wind the spokes in the proper direction before adding the second set. Determine which way to twist from the location of the spoke nearest the valve hole. If it’s on the left twist the hub to the left (counterclockwise; photo 3). If it’s on the right, twist to the right. To hold the hub in place, insert a spoke through the cassette-side flange in the opposite direction of the first set of spokes. (If they were installed head out it should be placed head in.)

4. As you bring the spoke toward the rim, it must be laced through its neighbors If you are installing head-out spokes, each one must go under the first 2 it crosses and over the third. Head-in spokes go over the first 2 and under the third (photo 4). Then place it in the rim, centered between the spokes already in place, and add a nipple. Be careful not to kink the spoke or scratch the rim.

At this point it saves time to turn the nipples from outside the rim with a Bicycle Research nipple driver or small screwdriver. But don’t tighten them more than 4 turns because you don’t want to add any spoke tension yet. Finish lacing the cassette side by placing the remaining 7 (or 8) spokes through the hub, interlacing them, and adding nipples.

5. To make lacing the other side easier, seat the spokes in the hub by pressing the head-in ones with the palm of your hand or tapping them near the hub with a plastic mallet (photo 5).

6. Lay the wheel on the workbench with the empty flange facing up. The next spoke’s position is trickiest to locate. It should be parallel to the first one you installed and next to the valve hole in the rim. To find it, stand the wheel with the valve hole at 12 o’clock (photo 6). Insert the threaded end of a spoke into the rim hole next to the valve and thread a nipple 4 turns. Let the spoke hang by the nipple in the rim. It will point to the correct hub hole if you align the hanging spoke parallel to the one on the other side of the valve (the first spoke you installed).

Pick up another spoke and put it into the hub from either side to mark the hole. (If your hubs are countersunk, insert the spoke accordingly.) Remove the hanging spoke and finish lacing the marker spoke through its neighbors and into the rim, then install a nipple. It might be necessary to flex the spokes to lace them into position, but as long as you don’t actually bend them this won’t affect their strength.

7. Add the next 7 (or 8) spokes, filling every other hub hole (photo 7). Lace them into every fifth rim hole counting from left-side spoke to spoke, and add nipples. Finish lacing the wheel by installing the last 8 (or 9) spokes. Put them through the hub in the opposite direction of the set you just installed, and lace them to the remaining rim holes.

Seat the head-in spokes as before (photo 5). Also, seat the head-out spokes by pulling each one outward with your fingers or by prying them with a screwdriver handle placed below the cross. Seat the nipples in the rim by grasping parallel spokes and squeezing gently.

Truing and Tensioning Tips
You should now have a laced wheel with parallel spokes at the valve hole, interlaced spokes, seated heads, bends and nipples, and very little tension. Check the crossing pattern one last time. Also, ensure that alternate spokes lead to different hub flanges.

Remember that when viewed from outside the rim, clockwise turns tighten and counter-clockwise turns loosen spokes. Always use this perspective or it can get confusing and you might tighten when you mean to loosen and vice versa. Also, turn nipples in small increments. Half a rotation is plenty.

To simulate riding stresses and relieve spoke wind-up that can occur while truing and tensioning, it’s important to stress-relieve the spokes after each step by squeezing parallel pairs around the rim with your hands.

When the wheel is done the rim should be centered between the axle locknuts. It’s easy to move the rim off center if you don’t check it regularly while building. Several manufacturers make dishing tools that allow you to measure this. The Park TS-2 truing stand, which I mentioned earlier, automatically centers the rim.

It’s also possible to center rims by simply reversing the wheel in the truing stand or bicycle frame as you work. If you do this and adjust the spokes to keep both sides of the rim the same distance from one of the truing indicators or brake pad, it will be centered.

Truing
Place the wheel in a truing stand or bicycle frame. Starting at the valve hole, spin each nipple onto the spoke with the nipple driver or a flathead screwdriver until only 4 threads are still exposed. This should supply just enough tension to straighten all the spokes.

Spin the wheel. Adjust the truing indicators (or brake pad) so they barely brush the rim. Study the rim as it spins and decide which section needs to be moved. Use the spoke wrench to adjust the nipples in this area. It’s crucial during the early stages to gently bring the rim into true and round by loosening instead of tightening. For instance, to move the rim left, loosen spokes in the area leading to the right hub flange instead of tightening ones leading to the left. As the wheel straightens, bring the indicators closer to the rim and continue.

To correct vertical movement, adjust the truing indicator under the rim (if you’re using your bike frame for truing, rest your thumb on the brake in such a way that you can view the gap between it and the underside or top edge of the rim as the wheel spins). Work on flat spots first, loosening an even number of spokes in the area to allow the rim to move outward. Gently tighten an even number of spokes to bring down high spots.

If you let the truing indicator brush the underside of the rim, you’ll know when it’s perfectly round because it will stop scraping. If you prefer to sight the space between the indicator and rim, a light background will help. Place a piece of white paper on the workbench in your line of vision.

When the wheel is round move the indicators beside the rim and perfect lateral trueness again. Alternate correcting lateral and vertical movement, and flip the wheel occasionally to check rim centering. Eventually you should get a round, straight rim with low spoke tension.

Tensioning
Increase tension by starting at the valve hole and working around the rim, turning each nipple. For the rear wheel, which has less tension on the left, turn the right-side spokes a half turn and the left ones a quarter turn. This helps center the rim. For front wheels, turn both sides a half turn at a time.

If a centering adjustment is required, first loosen all the spokes leading to one side of the hub a quarter or half turn (every other spoke) and then tighten those leading to the other side by the same amount.

After each tensioning sequence, adjust the rim’s trueness, roundness, and centering. In general, remember to turn the nipples a little at a time, and move the rim by loosening one side and tightening the other instead of doing just one. Also, stress-relieve the spokes after each truing.

With each successive tensioning step the rim should need less truing. After adding 4 or 5 rounds of tension it should be strong and the spokes tight enough not to loosen, which is the mark of the good build.

It takes experience to recognize proper tension by feel. It helps to squeeze spokes on hand-built wheels at a shop or check those of another bike. On rear wheels you’ll notice that left-side spokes always feel looser than right ones.

Other options are to buy a spoke tensionometer (available at shops) or take your new wheels to a shop and ask them to critique your work.

The last step is clean-up. This is important because wheelbuilding lubricants can contaminate brake pads and some may deteriorate tires. Thoroughly clean the rim, hub, and spokes with a rag dampened with acetone or other solvent. Good job!