Check Out: The Art and Science of Wheelbuilding

Mike Holt at RK EXCEL America, cranking away on his latest wheel.

Have you ever wondered what goes into building a custom wheel for your bike? So did we, which is why we met with Mike Holt at RK EXCEL America Inc., and he gave us the low-down on how they assemble their wheels. To accommodate customer demands for rim and hub configurations, as well as for rim and hub colors, they custom-build their wheels on site, as well as doing special projects like wheels teams like Red Bull KTM.

These days, wheels are much stronger, and stay together much more consistently, compared to when they were one of the major limiting factors in how hard you could ride. Better materials, designs and construction methods all contribute to making them nearly bulletproof…as long as they're well maintained. You may not need to chase the spoke tension after each ride, though you will need to keep on top of it, especially when your bike is new.

While we were in RK Excel's Oceanside, CA, offices, Mike built up a Talon Ultra Lite II 36-spoke front wheel with a Talon Ultralite II Nickel hub, and Excel Takasago Signature Series rim, and Excel Spoke and Nipple Kit.

Ingredients in the wheel Mike built included a Talon Ultralite II Nickel hub, Excel Takasago Signature Series rim, and an Excel Spoke and Nipple Kit. The spline drive spoke wrench is also shown.

Mike started out by selecting the individual components, and prepped the spoke threads by brushing them with a high-performance waterproof grease. That ensured that the nipples would tighten evenly during the wheel building process, and would also prevent a chemical reaction between the aluminum nipples and stainless steel spokes over time. Mike  also mentioned that it doesn't take a lot of lube to get the job done, just enough to coat the threads lightly and evenly.

Mike preps the spokes for building by brushing on a small quantity of waterproof grease.

The wheel builders at RK Excel always lay out the hub and rim so that the Excel logo is on the disk side for easy identification of wheel size. The wheel Mike was assembling was fairly simple, since all the spokes were the same length, and he laced it in four segments, following the same order that he always uses during assembly… disk side outer, disk side inner, and then non-disk side outer, and non-disk side inner. Other wheels can become more complicated, with two, three, and sometimes even four different lengths of spokes per wheel, depending on the wheel size, hub design and offset.

Mike explained that 99% of their wheels use a cross-three pattern, for a good mix of strength and flexibility. He also mentioned that the biggest cause of fractured aluminum around the spoke holes on the rim or rim failures are spokes that have been overtightened.

Lacing the wheels is the fastest part of the job, and thanks to the (mostly) straight pull design of the hubs, it appeared nearly impossible to goof up.

As each spoke was dropped into place, the nipples were just finger-tightened on each spoke by a few threads to give the wheel some room to move during assembly. On the 36-spoke wheel, there were nine spokes per section, and Dan was counting out the reps as he installed each one, something he could be hear repeating during tightening. Watching him quickly work his way through the individual parts, it seems as if the wheel practically built itself, as the spokes fell into the right places quickly and easily. Mike noted that some mini wheels take a bit more muscle, and occasional spoke bending, because the spokes are so much shorter, along with the reduced space between the hub and rim.

During initial assembly, the nipples are threaded onto the spokes only a few threads.

After all the spokes were in their proper place, Mike used a variable-speed drill equipped with a screwdriver tip to tighten each nipples, leaving only a couple threads visible on each spoke, and once that was completed, he hand-tightened them individually to the point where no threads were visible. RK Excel has carefully calculated spoke length for each wheel's configuration, so it's easier to note that the spokes are evenly tightened by how many threads are visible. Once all the spokes were tightened evenly, that's when the truing began in earnest.

Even the straightest wheels are junk if they don't have the proper offset to keep them tracking straight and true in the center of the fork or swingarm, and the offset varies by brand and model. Here Mike checks the offset (26.5mm on this wheel), by running a straight-edge across the face of the brake disk surface, and measuring the distance between it and the edge of the rim.

Watching Mike work his magic on the wheel was a testament to his patience. Using a dial indicator, he methodically began working out the extremes of side-to-side movement, while working around the wheel to slowly but consistently tightening the spokes. He always follows the same pattern…inners on each side, outers on each side. Back and forth, all while counting the repetitions. Nine spokes on the inner disk side. Nine spokes on the inner non-disk side, and the same for the outer spokes.

Mike uses a dial indicator to straighten out both the side-to-side and roundness of the wheel. After the wheel has been straightened from side-to-side, it's time to check the roundness.

Once he'd worked through the initial round of straightening, it was time to check the offset, which was spec'd at 26.5mm. Mike checked this by using a straight-edge across the mounting surface of the disk brake, and using a ruler to measure the distance between the edge of the rim and the straight-edge. The initial measurement came in at 25mm, so he had to work on tensioning the non-disk side to pull the rim further away for additional offset.

The spline drive nipples allow wheel builders to easily make small adjustments without having to take full quarter-turn "bites" with the wrench.

With the cross-three pattern, one small turn will move the wheel approximately a half-millimeter. Rather than do it all at once, using the inner/outer pattern, Mike used two passes on the first round of inner/outer tightening, and then one additional inner/outer round to achieve the movement he was looking for.

With the initial rounds of side-to-side straightening done, and offset check completed, as well as the tension on the spokes increasing, it was time to move on to the inside of the wheel, to check the roundness. Mike didn't do just one side, but each side of the wheel.

In the final stages of assembly, the spokes on this wheel were torqued to 46 inch-pounds. Total output for him on a good day? About ten wheels. That's assembled, trued, and packaged for shipping.

Once the wheel has been straightened to within spec, it was time for final tensioning, which is 46 inch-pounds for their spoke sets and rims. Mike was using one of Excel's spoke torque wrenches, and suggested checking your bike's owner's manual for the specs on your wheels.

Mike shows off the finished product...but getting there takes plenty of hands-on labor. This is no machine-built production line wheel.

As the spokes reached their desired tension, any further straightening was handled by loosening spokes, instead of additional tension, since they don't want to go too tight.

Excel's Spoke Torque Wrench set.

Wheelbuilding has been described as part science, and part art. Watching Mike work, you can definitely see that as he works over sections of spokes, rather than individual spokes to achieve the straightness that he's looking for, or in how he describes tightening or loosening one section will affect a section on the opposite side of the wheel. Bringing it all together smoothly is definitely an art learned via practice and experience.

For more info:

RK EXCEL America Inc.
2645 Vista Pacific Drive
Oceanside, CA 92056
(760) 732-3161
www.ftmbiz.com