How To Upgrade Your Vehicle with a Metal Gear Servo
Traxxas offers a wide variety of metal-gear servos both as standard equipment in select models and as upgrades for all models with composite-gear servos. Metal-gear servos offer greater strength and durability compared to servos with composite gears. Some metal-gear servos may also deliver greater torque and responsiveness. In this article, you’ll find all the specs you need to make the best choice for your machine and budget.
Don’t need a new servo just yet, but you’d like to add metal-gear durability to your model? You can upgrade many Traxxas servos by removing their composite gears and replacing them with metal versions. Traxxas offers conversion kits that make it easy—more on that later.
Don’t need a new servo just yet, but you’d like to add metal-gear durability to your model? You can upgrade many Traxxas servos by removing their composite gears and replacing them with metal versions. Traxxas offers conversion kits that make it easy—more on that later.
Upgrading to a metal-gear servo is a great way to boost durability—and an opportunity to give your machine more steering power, too.
Traxxas’ most powerful servos feature an aluminum mid-case to increase rigidity and dissipate heat.
Servo Sizes
Most Traxxas servos fit into three size categories: Standard, Micro, and Sub-Micro. Standard servos are most common, hence the name. Some vehicles, such as Summit and TRX-4 trucks, use both Standard servos (for steering) and sub-micro servos to operate other functions including 2-speed transmissions and remote-locking diffs. But don’t worry about remembering which size your model requires; when you look up your model in the Traxxas Model Showroom and click the Accessories tab, all the servos listed under Motors & Electronics will be compatible with your model.
Most Traxxas servos fit into three size categories: Standard, Micro, and Sub-Micro. Standard servos are most common, hence the name. Some vehicles, such as Summit and TRX-4 trucks, use both Standard servos (for steering) and sub-micro servos to operate other functions including 2-speed transmissions and remote-locking diffs. But don’t worry about remembering which size your model requires; when you look up your model in the Traxxas Model Showroom and click the Accessories tab, all the servos listed under Motors & Electronics will be compatible with your model.
With the exception of the Maxx and X-Maxx, all Traxxas models use Standard, Micro, and/or Sub-micro servos. The dimensions for these size categories have a little bit of wiggle room, but the lengths shown are typical.
Understanding Servo Torque
The higher a servo’s torque rating, the more power it has to push and pull the steering system’s linkages for authoritative control. That extra power is especially welcome for larger, heavier models and their larger, heavier tires. If you’re trail-trucking, a higher-torque servo makes it easier to push away from obstacles and steer with precision when low speeds and high grip require more tire-turning strength. Extra torque also puts a greater load on the servo gears, which is why Traxxas high-torque servos have metal gears. Servo torque is measured in ounce-inches and indicates the force (measured in ounces) that the servo can apply via a one-inch lever. If you find that hard to visualize, no worries—all you need to know is the higher the torque number, the more powerful the servo.
The higher a servo’s torque rating, the more power it has to push and pull the steering system’s linkages for authoritative control. That extra power is especially welcome for larger, heavier models and their larger, heavier tires. If you’re trail-trucking, a higher-torque servo makes it easier to push away from obstacles and steer with precision when low speeds and high grip require more tire-turning strength. Extra torque also puts a greater load on the servo gears, which is why Traxxas high-torque servos have metal gears. Servo torque is measured in ounce-inches and indicates the force (measured in ounces) that the servo can apply via a one-inch lever. If you find that hard to visualize, no worries—all you need to know is the higher the torque number, the more powerful the servo.
The #2255, #2275, and #2250 servos are Traxxas’ most powerful metal-gear “standard” servos.
Converting Your Composite-Gear Servo to Metal Gears
It’s easy to convert a composite-gear servo to metal gears, and it’s a smart durability upgrade whether you do it as a preventative measure or wait until you wear out your current gears. Your servo will operate just like it did before the gear swap, but it will be much more resistant to gear damage and the metal gears offer much longer service life than the composite parts.
Traxxas metal gear sets make it easy to upgrade your current composite-gear servo with the strength of an all-metal geartrain. 
This chart lists all the available metal-gear conversion kits and their compatible servos.
How to Upgrade a Composite-Gear Servo to Metal Gears
The specific steps for upgrading each Traxxas servo vary, but the steps below cover all the essentials. We chose the #2075 servo and 2072X gear set for our example upgrade, as it’s a very popular servo that outfits a variety of Traxxas models and is very metal-gear-worthy with its potent 125 oz-in torque output.
The specific steps for upgrading each Traxxas servo vary, but the steps below cover all the essentials. We chose the #2075 servo and 2072X gear set for our example upgrade, as it’s a very popular servo that outfits a variety of Traxxas models and is very metal-gear-worthy with its potent 125 oz-in torque output.
The metal-gear kit replaces all the composite gears and includes a fresh tube of lithium grease.Step 1: Center the Servo
Power up your model and transmitter. Turn the transmitter’s steering trim knob to the zero position to center the servo, then switch the model and radio system off.
Power up your model and transmitter. Turn the transmitter’s steering trim knob to the zero position to center the servo, then switch the model and radio system off.
Center the servo before you remove it.Step 2: Remove the Servo
Servo removal steps vary with each model, but at a minimum you’ll need to remove the servo output arm or servo-saver and take out the screws securing the servo to the chassis. You’ll also need to open the receiver box to unplug the servo from the receiver. Click here for a how-to article and video detailing a servo-swap with the Slash.
Servo removal steps vary with each model, but at a minimum you’ll need to remove the servo output arm or servo-saver and take out the screws securing the servo to the chassis. You’ll also need to open the receiver box to unplug the servo from the receiver. Click here for a how-to article and video detailing a servo-swap with the Slash.
Keep the servo’s output shaft in its centered position as you remove the servo.
Step 3: Remove the Top of the Servo Case
Use a no. 1 Phillips screwdriver to remove the four screws in the underside of the servo, then pull the case top straight up to remove it. If the output shaft and its gear appear to be lifting off with the case, press the output shaft back into position so only the case top comes off. We don’t want to remove any gears just yet.
Use a no. 1 Phillips screwdriver to remove the four screws in the underside of the servo, then pull the case top straight up to remove it. If the output shaft and its gear appear to be lifting off with the case, press the output shaft back into position so only the case top comes off. We don’t want to remove any gears just yet.
Four screws hold the servo together. If the screws have o-rings under their heads (like this 2075 servo does) make sure none are stuck to the servo case. If any are, just lift them off and slip them back onto their screws so you don’t lose them.
Step 4: Note the Gear Orientation
Even though your metal gear set includes an exploded view showing gear installation, you may find it helpful to snap a photo of the installed gears for later reference. Note any bearings, bushings, or o-rings that will need to be transferred to the new gears. In the case of our 2075 servo, we’ll need to reuse the bearing and o-ring on the output gear, and make sure the gasket that seals the case top to the main case is in position when we reassemble the servo.
Even though your metal gear set includes an exploded view showing gear installation, you may find it helpful to snap a photo of the installed gears for later reference. Note any bearings, bushings, or o-rings that will need to be transferred to the new gears. In the case of our 2075 servo, we’ll need to reuse the bearing and o-ring on the output gear, and make sure the gasket that seals the case top to the main case is in position when we reassemble the servo.
Snap a pic of the gears before you remove them, it might come in handy.
The arrowed o-ring and bearing will be transferred to the new metal gears. Note the that the output gear’s lug is centered between the sides of the case—we’ll install the new output gear in the same orientation.Step 5: Remove the Composite Gears
Each gear will lift straight up for removal. If your servo’s output gear is supported by bearings, the lower bearing may come off with the gear or be left behind on the case. Remove the bearing for use with the new metal output gear. After you’ve removed the gears, clean any leftover grease off the case and gear shafts. We’ll start fresh with the new lithium grease included with the metal gear set.
Each gear will lift straight up for removal. If your servo’s output gear is supported by bearings, the lower bearing may come off with the gear or be left behind on the case. Remove the bearing for use with the new metal output gear. After you’ve removed the gears, clean any leftover grease off the case and gear shafts. We’ll start fresh with the new lithium grease included with the metal gear set.
The output gear’s lower bearing may stay behind on the case (as shown) or remain inside the gear. Remove it for reuse. The lowermost gear will hang up on the motor-shaft support if you try to slide it off its axle. Just slide the axle out of the case to release the gear.
If you discover your servo’s case is damaged during the disassembly process or any of the seals need replacing, Traxxas offers the components separately. Just search your servo model here at Traxxas.com.
We’re ready to install the new gears. The output gear bearings, o-ring, and case gasket will be reused.
Step 6: Install the Metal Gears
Install the lowermost gear and its axle first, as shown below. Grease the gear teeth and shafts as you go so each has a good coating. Pay close attention to lower-bearing and keyed-insert installation for the output gear as detailed below. Install the output gear with its pin centered like the original composite gear’s lug, and don’t forget to reinstall the top bearing and O-ring.
Install the lowermost gear and its axle first, as shown below. Grease the gear teeth and shafts as you go so each has a good coating. Pay close attention to lower-bearing and keyed-insert installation for the output gear as detailed below. Install the output gear with its pin centered like the original composite gear’s lug, and don’t forget to reinstall the top bearing and O-ring.
Position the lowermost gear without its axle, then slide the axle through it. Then stack the rest of the gears in place following the included exploded view and/or your disassembly photo. Apply white lithium grease to the gears as you go.
Our 2072X gear set’s metal output gear features a keyed insert that must be pressed into place before installing the lower bearing.
Before installing the output gear, align the flats of its shaft with the sides of the servo case.
The metal output gear replaces the molded gear’s lug with a pin. Install the gear so the pin is centered between the case sides.
Step 7: Reassemble the Servo
Make sure the output shaft’s O-ring is installed and the case gasket is in place before you reinstall the case top. You may need to give the top a wiggle to help it align with the gear shafts. Press the case top straight down until it seats against the gasket and main case. Then reinstall the four screws we removed in Step 3 and tighten them until snug. Be careful not to overtighten them, or you may damage the tiny o-rings on the screws.
Make sure the output shaft’s O-ring is installed and the case gasket is in place before you reinstall the case top. You may need to give the top a wiggle to help it align with the gear shafts. Press the case top straight down until it seats against the gasket and main case. Then reinstall the four screws we removed in Step 3 and tighten them until snug. Be careful not to overtighten them, or you may damage the tiny o-rings on the screws.
Optional: add a label so you don’t mix up your new metal-gear servo with a composite-gear version when you’re swapping electronics among different projects.
That's a wrap! Plug the servo into the receiver, power up the radio system, and operate the servo to make sure it’s working properly before you reinstall. When you’ve confirmed all is well, button everything back up and go for a spin with your new metal-gear servo.
