Great handling starts with a superior frame, and we’ve made some big changes to our 2021 CRF450RX’s chassis. First, it’s lighter—over a pound and a half lighter. By making the frame’s main spars narrower, we saved weight, but more important we made the chassis more responsive by reducing lateral rigidity 20 percent. The result is a bike that gets into, around, and out of corners faster.
Designed in conjunction with the new frame, by using narrower main members (just like the frame uses narrower main spars), we’ve matched the swingarm’s lateral rigidity to the rest of the chassis. What you get is a balanced, fully integrated approach to frame stiffness, letting you get around corners faster and with better feel.
We totally redesigned the rear subframe to make it nearly three-quarters of a pound lighter, and along the way simplified its construction too.
Three key features changed here: The battery box is lower, for an improved center of gravity. Second, it’s also easier to service. And third, it’s now water-tight, so there’s nothing to worry about when racing in wet conditions.
We’ve increased the front suspension’s stroke by 5mm for 2021, for better handling and rider comfort. Also, we redesigned the axle holding fixtures at the bottom of each fork leg—that increases rigidity, and enhances steering precision and suspension performance. Finally, we retuned the suspension settings for a more compliant ride.
The CRF450RX is a perfectly matched package. With the frame and swingarm featuring a retuned lateral stiffness, and the fork legs featuring a new, stiffer axle fixture, we joined the two with new upper and lower triple clamps. Working in concert, they help improve and balance total rigidity, responsiveness and turning performance.
The 2021 CRF450RX’s new frame design gave us the opportunity to fit a new rear shock. We’ve optimized its shape to match the frame, and gave it new settings to work with the new chassis. The shocks valving resets faster for better response. In addition, we’ve fit a new steel spring that’s way lighter, cutting weight without cutting performance. And naturally, the RX gets its own shock settings optimized for enduro riding.
The 49mm Showa® fork is specially tuned just for the CRF450RX, and features a conventional spring design that helps increase the CRF450RX’s front-suspension precision, handling and feel.
The CRF450RX’s swingarm uses a special fabrication technique that lets us fine-tune the flex to work with the chassis and give you better rear traction and cornering precision.
Along with the single-muffler exhaust, naturally we gave the 2021 CRF450RX a new single-pipe header. We’ve completely changed the routing too, bringing it 74mm closer to the center of the bike. It’s lighter, and helps improve weight distribution.
Changing the muffler’s construction to a pressed-alloy design let us reshape it too, for better rider ergonomics and lighter weight. How much lighter? More than two and a half pounds!