How I Make Custom Wheel Spacers

A step-by-step look at measuring and machining one-off wheel spacers for a 1977 Shovelhead customer build.

This one's all about wheel spacers. We're building this 1977 Shovelhead for a customer, and we just got these wheels and tires set up. Now it's time to make our wheel spacers so we can mount the fender and bend the handlebars after this. Store-bought spacers never land exactly where you need them on a custom build, so I machine my own — here's how I do it, start to finish.

Step 1. Align the wheel sprocket with the transmission sprocket

Before I measure anything, the wheel has to be straight and exactly where it needs to be between the axle plates. I like to use a piece of flat bar laid across the rear sprocket to line it up with the transmission sprocket. When the flat bar sits flush against both, your chain line is dead straight and the wheel is centered where it's supposed to live.

Step 2. Grab a telescoping gauge

I like to use these little telescoping gauges to measure the width for my wheel spacers. They're super cheap, and they work great for this application. You compress the gauge, slip it into the gap, and let it expand to fill the space — then lock it down and it holds the exact dimension.

Step 3. Measure the gap

Get in there and measure the gap between the bearing and the axle plate. As you can see, this gap is pretty small, so I wouldn't be able to measure it with a tape measure or a ruler that easily. Obviously anything's possible, but this is how I like to do it — the gauge expands to fill the space and gives you a solid, repeatable measurement.

Step 4. Record your measurement

Pull the locked gauge out and measure across it with calipers. This one came out to 0.5545". Write it down — that number is your spacer length, and you don't want to be second-guessing it once you're standing at the lathe.

Step 5. Repeat for the right side spacer

Same process on the other side of the wheel. I like to go through and get all my measurements up front — that way I can just go to the lathe and start making spacers without running back and forth to the bike.

Step 6. Start turning — roughing pass

I'm starting with a 2" outer diameter piece of 6061 aluminum. I wanted this spacer to have a big shoulder on it that covers the bearing area and butts right up to the sprocket, so there's no gap in between — it all looks like one seamless piece. From there, I rough it down toward my finished dimensions.

Step 7. Finish pass with a circular cutter

For the contour on the shoulder, I like to use a circular cutter. Super easy — you just run it into the work and it leaves a nice, clean radius. One smooth finish pass and the profile is done.

Step 8. The finished left side spacer

Here's the finished left side spacer installed. The shoulder flows off the sprocket and covers the bearing area just like I wanted — looks pretty good in there. No washers stacked up, no gaps, just one clean piece that fits exactly.

Step 9. Repeat for the front wheel

I then repeated the same process for the front wheel on the springer — align, measure, machine. These front spacers run longer, and since I had some room to play with, I added a few grooves for a little extra flare.

Step 10. The finished front spacers

Here's a close-up of the finished front spacers. The grooves dress up all that extra length between the hub and the springer leg, and the fit is dead-on against the bearing. Little details like this are what separate a custom build from a bolt-together bike.