Traxxas 90T 48-Pitch Spur Gear for 2WD Models 4690

The Traxxas 4690 is a genuine 90-tooth, 48-pitch composite spur gear for compatible Traxxas Torque-Control slipper clutch assemblies.

It is used as a standard replacement gear on selected 1/10-scale Traxxas 2WD vehicles and may also be fitted as a gearing option on other compatible Bandit, Rustler, Slash and Stampede models.

When used with the same motor pinion, a larger 90-tooth spur gear generally produces a lower overall gear ratio with stronger acceleration, improved low-speed response and reduced motor load. Top-speed potential is normally lower than with a smaller spur gear.

Features

• 90-Tooth Spur Gear: Provides a lower gear ratio than smaller compatible spur gears when used with the same pinion
• 48-Pitch Tooth Profile: Matches compatible 48-pitch motor pinions
• Torque-Control Slipper Compatibility: Designed for selected Traxxas Torque-Control slipper clutch assemblies
• Composite Construction: Provides low rotating weight and economical replacement
• Gearing Adjustment: Allows acceleration, top speed and motor load to be tuned for different conditions
• Direct Replacement Application: Used as a factory replacement part on selected Traxxas 2WD models
• Accessory Gearing Option: Suitable as an alternative ratio on selected compatible vehicles
• Genuine Traxxas Part: Manufactured for compatible Traxxas transmission and slipper-clutch dimensions

Specifications

• Brand: Traxxas
• Manufacturer Part Number: 4690
• Product Type: RC spur gear
• Tooth Count: 90 teeth
• Gear Pitch: 48 pitch
• Material: Moulded composite
• Colour: Black
• Clutch Compatibility: Selected Traxxas Torque-Control slipper clutches
• Drive Configuration: Primarily selected two-wheel-drive models
• Typical Vehicle Scale: 1/10
• Quantity: One spur gear

Compatibility

Replacement part for selected versions of:

• Traxxas BIGFOOT No. 1 Officially Licensed Replica
• Traxxas BIGFOOT Officially Licensed Replica
• Traxxas Ford F-150 Raptor 2WD
• Traxxas Rustler 2WD
• Traxxas Slash 2WD
• Traxxas Slash 2WD Unassembled Kit
• Traxxas Stampede 2WD

Accessory or optional gearing part for selected versions of:

• Traxxas Bandit
• Traxxas Bandit VXL
• Traxxas Drag Slash 1967 Chevrolet C10
• Traxxas Drag Slash Ford Mustang 5.0
• Traxxas Rustler VXL 2WD
• Traxxas Slash Brushless 2WD
• Traxxas Slash VXL 2WD
• Traxxas Stampede VXL 2WD

Traxxas model names may cover multiple generations, transmissions and factory gear ratios. Confirm that the vehicle uses a compatible 48-pitch Torque-Control slipper clutch and check the recommended gearing chart in the owner’s manual before ordering.

Includes

• 1 × Traxxas 90-tooth 48-pitch spur gear

Required to Complete

• Compatible Traxxas Torque-Control slipper clutch assembly
• Compatible 48-pitch motor pinion
• Suitable hand tools for transmission and motor adjustment
• Replacement slipper pads, bearing or clutch hardware if the existing components are worn

FAQ

What does 90T mean? It means the spur gear has 90 teeth.

What does 48P mean? It means the gear uses a 48-pitch tooth profile. It must be paired with a compatible 48-pitch pinion gear.

Will this gear work with a 32-pitch pinion? No. A 48-pitch spur gear must not be meshed with a 32-pitch or Mod 1 pinion.

Does a 90-tooth spur gear increase acceleration? Compared with a smaller spur gear used with the same pinion, a 90-tooth spur normally increases wheel torque and acceleration while reducing top-speed potential.

Will this spur gear make the vehicle faster? Not usually when replacing a smaller spur while retaining the same pinion. A larger spur creates a lower gear ratio that normally favours acceleration and cooler running rather than maximum speed.

Can changing the pinion alter the result? Yes. The final gear ratio depends on both the pinion and spur tooth counts. A larger pinion raises the ratio, while a smaller pinion lowers it.

How is the gear ratio calculated? Divide the spur-gear tooth count by the pinion-gear tooth count. For example, a 90-tooth spur with a 16-tooth pinion produces a spur-to-pinion ratio of approximately 5.63:1 before the transmission’s internal ratio is considered.

Does the slipper clutch come with the spur gear? No. One spur gear is supplied. Slipper pads, pressure plates, spring, shaft, nut and other clutch components are sold separately unless otherwise stated.

Does a pinion gear come with it? No. A compatible 48-pitch motor pinion is required separately.

How tight should the gear mesh be? The gears should have a small amount of backlash. They must rotate freely without binding while remaining close enough that the teeth cannot skip under load.

Can paper be used to set gear mesh? A narrow strip of ordinary paper placed between the gears can provide a useful starting point. Rotate the gears to remove the paper, then confirm slight backlash around the entire spur gear.

Why did the spur gear strip? Common causes include incorrect gear mesh, loose motor screws, debris inside the gear cover, damaged pinion teeth, excessive slipper-clutch tightening or drivetrain binding.

Should the slipper clutch be fully tightened? No. Follow the vehicle manual for the starting adjustment. An excessively tight slipper clutch can increase shock loads on the spur gear, driveshafts and transmission.

Will this fit a Slash 4X4? No. This part is primarily for selected Traxxas 2WD Torque-Control slipper systems. Most Slash 4X4 configurations use different spur gears and drivetrain components.

Can it be used with a brushless motor? Yes, on listed compatible models and with an appropriate pinion and slipper adjustment. Motor temperature should be checked after gearing changes.

Important Notes

• One spur gear is supplied.
• The slipper-clutch assembly and motor pinion are not included.
• Use only with a compatible 48-pitch pinion gear.
• Do not combine 48-pitch, 32-pitch or Mod 1 gears.
• Confirm the vehicle model, transmission and slipper-clutch type before ordering.
• Traxxas model names may cover multiple generations with different factory gearing.
• Consult the vehicle owner’s manual for approved pinion and spur combinations.
• A larger spur gear generally increases acceleration and reduces top-speed potential when the pinion remains unchanged.
• A smaller spur or larger pinion generally increases motor load and operating temperature.
• Check motor and ESC temperatures after every gearing change.
• Avoid optional high-speed gearing in thick grass, sand, repeated stop-start driving or hot ambient conditions.
• Set a small amount of backlash between the pinion and spur gear.
• Rotate the spur through a complete revolution when checking gear mesh because moulded gears may have minor variations.
• Ensure the motor screws are secure before operating the vehicle.
• Inspect the motor pinion for damaged or sharp teeth before installing a new spur gear.
• Remove stones and debris from the transmission cover and gear area.
• Check the slipper pads, bearing and transmission for binding if spur gears repeatedly fail.
• Do not lubricate exposed plastic spur and pinion teeth because lubricant can attract abrasive dirt.