KEEPING YOUR BIKE ON THE STRAIGHT AND NARROW.
How to make sure your bike’s rear wheel is properly aligned for top performance and durability.
Most of us don’t give it a second thought. But a misaligned rear wheel can create serious handling issue, lead to rapid, uneven tire wear, and wreak havoc on drivetrain sprockets and chain. Fortunately, it’s pretty, um, straightforward to make sure everything is in line.
Heading different directions.
So what do we mean by “alignment?” Quite simply, we’re talking about the rear wheel’s position relative to the bike’s frame and swingarm. The rear wheel should be perfectly parallel with the frame and swingarm of the motorcycle. But, because the chain adjusters on each side of the bike’s rear wheel can be adjusted independently, it’s relatively easy to make slightly different adjustments to each when adjusting the chain. That, in turn, angles the rear wheel a little in one direction of the other. Over the course of multiple chain adjustments, that angle can become significant enough to cause problems.
But wait a second. You make sure that you turn each adjuster evenly. And you’ve been using those tick marks stamped on the swingarm by the factory to make sure you adjust each side evenly, right? That’s what we call a good start. Unfortunately, it’s not quite accurate enough. The tick marks are not perfectly accurate and they’re often spaced too far apart to provide anything more than a rough alignment.
To be more accurate, here are some ways you can be sure your bike’s drivetrain is in alignment and performing the way it should. Start by making sure your bike is vertical, either on the center stand or atop a shop stand or paddock stand. In order of preference and accuracy, here are three distinct ways to get yourself back in line …
One for good measure.
Here’s an accurate, straightforward way to measure alignment. Grab a tape measure, measure from center of the swingarm pivot (where the swingarm attaches to the fram) back to the rear axle. Take the measurements on both sides of the bike and compare your numbers. If the measurements are the same, you’re set. Done. Easy peasy, right? Unfortunately, not all bikes are set up to make it easy to make that measurement. Stuff gets in the way. Exhaust systems, foot pegs, bodywork. If your bike is one of those, don’t sweat it; there’s another simple method to measure your bike’s drivetrain alignment.
A sight for sure eyes.
Snag a simple chain alignment tool that is designed to help make a visual alignment. These tools are available from suppliers such as Motion Pro and are typically less than 20 bucks—a small investment for a tool you’ll use for years (and a lot less expensive than replacing a worn tire and drivetrain). The tool is simply a clamp with a straight rod that extends forward. Remove the bike’s chain guard, clamp the tool onto the top of the rear sprocket and then, from directly behind, visually inspect if the rode aligns with the bike’s chain. If it isn’t perfectly parallel with the chain and angles off to one side, loosen the axle pinch bolts and axle nut and then tighten or loosen the chain adjuster on either side until the rod is perfectly aligned with the chain. Of course, make sure chain tension is right. Got it? Tighten everything back up, take one more glance at the rod and chain alignment to make sure everything’s still good. The remove the tool and reinstall the chain guard. You’re good to go.
Get strung out.
Can’t get to the swingarm to use the tape measure method and don’t have a visual alignment tool? Okay, you can always go old school and do a parallel straight-edge measurement. All you need is a length of string longer than the length of your motorcycle. With the bike upright and with the front wheel on the ground pointed straight ahead, tie off the string to stationary objects in front of and behind the motorcycle. The idea is to stretch the string taut parallel to the bike and as close to the wheels as possible without touching. The string should also be as close to axle height as possible. With the string running parallel to the bike and extending beyond the front and rear wheel, measure the distance between the string and each wheel at both the leading and trailing sides of the tire. That should give you four distinct measuring points (two at the front wheel and two at the rear). With everything as closely aligned as possible, you will now be able to determine if the rear wheel is aligned properly. Make adjustments to the chain tensioners individually until the measurements are equal at the front and rear edges of the rear wheel/tire.
Have questions? Don’t hesitate to reach out to us directly to get the expert answers. And be sure to check out all of the great high-performance sprocket and chain products for your bike at sunstar.com