Wheel spacing is an important part of any ground-up bike building project. It also must be addressed when customizing an existing bike. With the vast selection of frames and wheels available today, there is no way any manufacturer can fit every different wheel combo to their frame and provide exact fitting wheel spacers.

Some frame manufacturers provide a wheel spacer for the left side of the wheel, most of the time this spacer is longer than needed and the exact length is left up to the bike builder to decide and cut to length. The most common reason that the frame builder only provides the left side spacer is, because the rear caliper mount doubles as the right-side wheel spacer. Again, there are a number of different width caliper mounts, mainly depending on the style of caliper you choose.

Another factor is especially true of the new crop of wide frames designed to fit the wide tires. Some frame builders widen or offset only the left side of the frame for belt clearance. Mix in the different width of custom wheel hubs and the need for drivetrain offset. The next thing you know you are in wheel spacer hell.

Generally motorcycle wheels should track one directly in line with the other. That's why motorcycles are called, in some circles, a single-track vehicle; however, this is not always the case. Harley-Davidson offsets the rear wheel on some of their Softail models as much as a half inch to the left, to move the center of gravity back towards the center of the motorcycle. As of this writing we know of three different offsets for the Softails. The different offsets can be found in your service manual in the chassis section, titled vehicle alignment (page 2-30 in the H-D service manual for 1997-1998 Softail models, H-D part number 99482-98). Be sure to check the correct service manual for your particular model.

If building a ground-up bike based on a Softail-styled chassis, then buy a service manual that closely relates to what you're constructing. Another point to keep in mind while your fitting a rear wheel to a new frame is, the location of the fender mounts. (If you're building a rigid, it is simple fitting fender struts or a sissy bar to the frame to support the rear fender. Just center the wheel and go. Remember to build fender mounts that clear the disc rotor and the drive pulley or sprocket. Also make sure the tire can be moved for belt adjustment.)

On Softail-style frames, the fender mounts are usually drilled and tapped holes at the top of the frame, just under where the seat will sit. When we fit a wheel to a frame, we like to check first where the fender struts or rails will locate in relation to the wheel and tire combo. Sometimes offsetting the wheel is necessary to be centered in the fender and so you won't have to carve up a set of custom fender rails. Again, this all depends on the way the frame was designed and built. By placing the wheel in the center of the fender rails you'll be able to see if the frame is offset or not. If once it's in the center of the frame rails, it's not in the center of the swingarm, then it's offset. Keep it in the center of the frame rails.

The above description may sound confusing and complex, but it really isn't. With the aid of some photos and the loan of a frame, wheel and tire at Mike Powers Customs in Burbank, CA, we can show an easy way to set-up, measure, and make new rear-wheel spacers to get you up and rolling.

The following procedure can be applied to almost any style of bike. One last note... ideally, wheel spacers should be square, meaning that each end of the spacer should be parallel. The optimum tool for making wheel spacers is a lathe; however, some patience with a hacksaw and file or grinder will get the job done.

01: At Mike Powers Customs in beautiful Burbank, CA we worked with a new ground-up project bike. The frame is a Diamond 250 series, Softail style chopper with six inches out and six inches up. The rear wheel is a Superior with a custom, wide hub laced to a 9-inch wide 18-inch diameter rim. The tire is 250-40X18 Avon Venom.

02: First thing is to place the frame somewhere solid. Mike uses a scissors lift with the frame strapped to the lift. Now slide the axle through the swing arm and wheel. Push or pull the axle all the way forward or back to insure the axle is parallel to the swing arm pivot shaft and perpendicular to the frame centerline.

On To Page 2........