2018 Alta Redshift MXR Dirt Bike Torque Specs

2018 Alta Redshift MXR Dirt Bike Torque Specs

Shop parts for a 2018 Alta Redshift MXR Dirt Bike.

The 2018 Alta Redshift MXR represents the top of the Redshift motocross lineup, stepping up to 50 horsepower and 147 ft-lbs of torque at the countershaft — a meaningful jump over the standard MX model. Weighing in at approximately 259 pounds thanks to a comprehensive weight reduction effort, the MXR was engineered to compete with 350cc four-stroke motocross bikes. Upgraded WP AER 48 air fork, revised rear shock valving, and improved linkage dynamics separate the MXR from its siblings. With that much power on tap from a dead stop, every bolt and nut on this machine needs to be torqued with precision.

Upgraded Components That Affect Fastener Specs

Several key differences between the 2018 Redshift MXR and the standard MX model are worth noting from a torque perspective. The front fork changes from the WP 4CS to a WP AER 48 air-sprung unit, which uses the same triple clamp interface but offers different internal architecture. The rear shock receives revised valving and linkage dynamics with a short-body reservoir. These suspension upgrades don’t change the torque values for the mounting hardware, but they do make it even more important to follow proper tightening sequences — the AER 48’s performance is highly sensitive to fork tube alignment in the clamps.

Like all Redshift models, the MXR is fully electric. No spark plugs, oil drain plugs, cylinder head bolts, flywheel nuts, or clutch hub nuts are part of the equation. Maintenance revolves around the drivetrain, chassis, suspension, brakes, and the integrated aluminum bulkhead.

Drivetrain & Wheel Hardware

The MXR runs Warp 9 Elite wheels with a 21-inch front and 19-inch rear, wrapped in Dunlop MX3S tires — an upgrade from the Bridgestone Battlecross X30 rubber on the base MX. The single-speed drivetrain channels 147 ft-lbs through the chain and sprockets, placing substantial load on every drivetrain fastener during hard acceleration.

Given the MXR’s higher torque output compared to the standard MX, chain and sprocket wear happens faster under aggressive riding. Check rear sprocket bolt torque as part of your regular pre-ride inspection and apply medium-strength thread locker when installing new bolts.

Suspension & Chassis

The WP AER 48 air fork on the 2018 Redshift MXR is one of the most respected air forks in motocross. Its light weight contributes to the MXR’s overall 259-pound figure, and its infinite spring rate tunability through air pressure adjustments makes setup fast. The fork tube to triple clamp interface remains the same as other WP-equipped models, so pinch bolt torque values are identical. The rear shock features improved valving tuned specifically for the MXR’s power delivery and reduced weight.

With the AER 48, fork height in the clamps directly affects steering geometry and front-end feel. After setting your desired fork height, tighten the lower clamp pinch bolts first while the front wheel is on the ground, then secure the upper clamp. This prevents the tubes from being pulled out of alignment by the clamp sequence.

Braking Hardware

Brembo supplies the entire brake system on the 2018 Redshift MXR — two-piston caliper with a 260mm rotor up front, single-piston caliper with a 240mm rotor at the rear. Steel-braided lines are standard. At 259 pounds, the MXR is light for its power output, which means braking zones can shrink dramatically once a rider learns to trust the motor’s instant response.

Disc bolts should always be installed with medium-strength thread locker and tightened in a star pattern. The front 260mm rotor is especially sensitive to uneven clamping force, which can induce warping and brake pulsation over time.

Bulkhead & Motor Housing

The Redshift MXR’s bulkhead is the same integrated aluminum unit found across the Redshift family. It serves as the motor casing, cooling jacket, inverter enclosure, and gear reduction housing all in one. The upgraded 50-horsepower motor sits inside this bulkhead, and while the higher output doesn’t change the bolt torque values, it does increase the operational stresses the bulkhead absorbs during riding.

Dry vs. Wet Torque on the MXR

Every torque value in this article assumes dry, clean threads — no oil, no grease, no thread locker present. Dry torque is the standard for most dirt bike fasteners. When thread locker, anti-seize, or lubricant is applied to the threads, the friction between mating surfaces drops and the same wrench setting produces significantly more clamping force. This is the “wet torque” condition, and on the MXR’s aluminum components, it can mean the difference between a properly secured bolt and stripped threads. Reduce your applied torque by 15–20% whenever thread locker or lubricant is used.

Over-Torquing and Under-Torquing Risks

The 2018 Redshift MXR’s lightweight aluminum construction makes over-torquing especially dangerous. Stripped threads in the frame, bulkhead, or swingarm can render components irreparable. Warped brake rotors from unevenly or excessively tightened disc bolts introduce pulsation that compounds over time.

Under-torquing carries risks that are harder to detect until something goes wrong. A countershaft sprocket nut that backs off under the MXR’s 147 ft-lbs of drivetrain torque can damage the output shaft and chain in seconds. Loose linkage bolts degrade rear suspension performance gradually, making the handling feel vague and unpredictable through rough sections of track.

Thread Locker Guidelines

Apply medium-strength (blue) thread locker to the following fasteners on the 2018 Redshift MXR:

• Rear sprocket bolts
• Front and rear brake disc bolts
• Linkage connecting rod bolts
• Subframe mounting bolts
• Skidframe / skid plate bolts

Keep thread locker away from axle nuts and the swingarm pivot bolt. These fasteners depend on high clamping force and are designed for regular removal and reinstallation.

Picking the Right Torque Wrench

The fastener range on the 2018 Alta Redshift MXR spans from about 10 Nm for small brake hardware up to 100 Nm for the rear axle nut. A click-type wrench in the 3/8-inch drive size covers most of that range and provides the satisfying, unmistakable click that signals you’ve reached the target. For smaller fasteners under 15 Nm, a 1/4-inch drive digital wrench gives the precision needed to avoid over-tightening delicate hardware. Beam-type wrenches remain a dependable and affordable option for riders who want simplicity without batteries or calibration schedules. Between a 1/4-inch and 3/8-inch drive set, you’ll have the MXR fully covered.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.