TEN THINGS ABOUT YOUR BIKE’S AXLES

(1) Axles. Although they are simple, your front and rear axles play a key role in your bike’s handling. They absorb energy from the wheels and transfer it into the suspension. Factory teams and manufacturers test with axles of different diameters and materials, all to affect the overall handling of the bike. 

(2) Position. Your rear axle position changes every time you tighten your chain. Whenever you install a new chain, factor in chain stretch when measuring your cut point so that once the chain is worn in, your rear axle will be where you want it. Your rear axle position affects the bike’s stability, rear shock sag and stiffness. If your axle is at the end of the swingarm, you’ll have a longer wheelbase, creating more leverage on the shock and therefore more stability. A shorter chain and wheelbase are better for sharp turns and apply slightly less leverage on the shock, making the shock spring feel stiffer. 

(3) Factory. The JGR MX team was so particular about the rear axle position that they would pick an ideal sprocket ratio that positioned the rear wheel in the right spot. Then, instead of changing the number of teeth on the rear sprocket, they would change the internal gear ratios inside of the transmission. Now that’s next-level factory!

(4) Size. Axle diameter is the most important factor when it comes to handling. A smaller axle provides more flex and bump absorption, while a large-diameter axle creates more stability under a load. KTM went from a 25mm rear axle to a 22mm axle on its 2023 models to increase flex. We’ve heard that everyone at KTM wanted this change except Roger DeCoster. Smaller axles, whether front or rear, provide more comfort, but they aren’t as consistent under the heavy loads experienced in Supercross whoops and rhythm sections. More comfort is a good thing for everyone who isn’t racing Supercross, especially on the new KTM chassis. 

(5) Factory forks. While a smaller axle allows more bump absorption, bigger axles create more stability under a load. The factory KTM/Husqvarna/GasGas teams often use 52mm WP Cone Valve forks, which riders like for their hold-up, especially in Supercross. Voila! These forks originally came with massive 30mm axles, but now come with a 25mm front axle, also contributing to front-wheel stability. 

(6) Fork offset. For its 2015 models, KTM changed the front axle offset from 35mAm in front of the fork center line to 33mm. They didn’t change the triple clamps (like we normally do for offset changes); instead, they moved the front axle 2mm rearward in the fork lugs (but had to downsize the stock KTM axle from 25mm to the current 22mm axle, which is still standard on Austrian bikes today. 

(7) Titanium. Stock axles are made of steel, but factory teams often use titanium axles to reduce weight and fine-tune the chassis feel. Reducing unsprung weight is a plus, but titanium axles also affect the feel because titanium is softer than steel. On the rear wheel, a titanium axle can provide more flex, creating added traction over acceleration bumps. Surprisingly, factory mechanics have reported that titanium axles have the opposite effect when used on the front wheel, creating more rigidity. 

(8) Swingarm pivot. In addition to titanium axles, factory teams have also tested with titanium swingarm pivots; however, most riders prefer the feel of the stock steel swingarm pivot bolt because the titanium version creates a soft “hingey” feel with too much flex. 

(9) Fixed axle. The Japanese brands use a floating rear-axle design, while the Austrians use a fixed rear axle with the left-side axle block being fixed onto the axle. The fixed axle makes for a faster wheel change in a pinch, but it can hinder rear-wheel action over bumps because the axle is stuck to the block that sits inside the swingarm. 

(10) Floating axle. Not every MXA test rider can tell the difference between a floating rear axle and a fixed one, but our pickiest testers noticed an improvement when replacing the stock fixed KTM/Husky/GasGas rear axle with Ride Engineering’s rear axle kit (which replaces your stock axle with a YZ250 axle with Ride Engineering blocks) and Works Connection’s Elite Axle Block kit (which modifies your rear axle into a floating design). The concept was designed for Ryan Dungey, and the KTM, Husqvarna and GasGas factory teams still use it today.