A micro servo weighs 9 g or less and fits small foam planes and 1:18 cars. Look for 1.5 to 2.5 kg-cm of torque and speed near 0.10 sec per 60 degrees. Metal gears survive crashes better than plastic gears. Check the spline count before you buy horns. Compare weight, torque, and gear type first.
How small is a micro servo?
A micro servo weighs 4 to 9 g and measures about 23 mm long. A sub-micro servo weighs 4.4 g and suits the smallest foam models.
A 9 g servo is the common size for park flyers under 500 g. It fits a 23 mm by 12 mm mount pocket in most foam wings.
How much torque does a micro servo give?
A 9 g analog servo gives about 1.8 kg-cm of torque at 4.8 V. That moves control surfaces on planes up to 500 g.
A metal-gear micro servo gives 2.5 kg-cm at 6 V. The extra torque helps when the surface is large or the speed is high.
Which micro servo suits a foam plane?
The SG92R is a 9 g analog servo with 2.5 kg-cm of torque. It fits most foam plane aileron and elevator mounts.
The MG90D is a 13 g digital servo with metal gears. It holds center better than an analog servo on fast models.
Which micro servo suits a small RC car?
A 1:18 car steers well with a 9 g servo near 2 kg-cm. The car is light, so the servo sees little load.
A 1:16 truck needs a metal-gear servo with 3 kg-cm or more. Metal gears survive curb hits that strip plastic gears.
How do you fit horns and linkages to a micro servo?
Count the spline teeth first: many micro servos use 21 teeth, while standard servos use 25 teeth. A horn that fits one spline will not fit the other.
A 4-point aluminum horn set gives four arm choices in one pack. A 1.5 inch arm gives fast response, and a 2.25 inch arm gives more throw.
How do you power micro servos?
Four micro servos draw about 1 A together under normal load. A 3 A BEC covers that with margin to spare.
Digital micro servos can spike to 1 A each when stalled. Feed them from a 5 V source rated 3 A or more to avoid brownouts.
Frequently asked questions
Can I use a 9 g servo in a 1:10 car?
No. A 1:10 car needs 6 kg-cm or more, and a 9 g servo gives near 2.5 kg-cm. Use a standard servo instead.
What does kg-cm mean on a servo?
It is torque: 1 kg-cm lifts 1 kg on a 1 cm arm. A 2.5 kg-cm servo lifts 2.5 kg on that same arm.
Are digital micro servos worth the extra cost?
Yes, when the model flies fast or needs precise centering. For a slow park flyer, an analog servo works fine.
How long do micro servo leads run?
Most micro servos ship with a 15 cm lead. Add a 6 inch extension for wing mounts and a 12 inch extension for tail mounts.
Parts used
SG92R Analog Plastic Composite Gear Micro Servo, $8.00. US stock, ships fast from NY, USA. Towerpro SG92R Analog Plastic Composite Gear Micro Servo. Torque: 2.5 kg/cm at 4.8V; Speed: 0.1 sec/60deg at 4.8V; Gears: plastic composite.
MA-90 Metal Gear Micro Servo, $8.00. US stock, ships fast from NY, USA. Torkstar MA-90 Metal Gear Micro Servo. Torque: 1.3 kg/cm (18.1 oz/in); Speed: 0.10 sec/60deg at 4.8V; Dimensions: 24 x 12.2 x 30 mm.
SG50 5g Micro Servo, $9.00. US stock, ships fast from NY, USA. Towerpro SG50 5g Micro Servo. Torque: 0.6 kg/cm (8.3 oz/in); Speed: 0.1 sec; Weight: 5g.
MG90D Digital Metal Gear Micro Servo, $14.00. US stock, ships fast from NY, USA. Towerpro MG90D Digital Metal Gear Micro Servo. Weight: 13g; Gears: metal; Digital: True.
SA-44 4.4g Metal Gear Sub-Micro Servo, $10.00. US stock, ships fast from NY, USA. Torkstar SA-44 4.4g Metal Gear Sub-Micro Servo. Torque: 0.8 kg/cm (9.3 oz/in); Speed: 0.12 sec; Dimensions: 20 x 26 x 8.0 mm.
1250MG Metal Gear 25g Mini Servo, $18.00. US stock, ships fast from NY, USA. Power HD 1250MG Metal Gear 25g Mini Servo. Torque: 3.5 kg-cm (48.6 oz/in) at 6.0V; Speed: 0.14 sec; Dimensions: 31.0 x 16.3 x 29.5 mm.
DSM-44 Digital Metal Gear Micro Servo, $22.00. US stock, ships fast from NY, USA. Power HD DSM-44 Digital Metal Gear Micro Servo. Torque: 1.6 kg/cm (18.0 oz/in); Speed: 0.07 sec; Dimensions: 22 x 8.7 x 22 mm.
Towerpro MG92B Digital Metal Gear Micro Servo, $17.00. Towerpro MG92B digital metal gear micro servo. 3.5 kg-cm torque, 0.11 sec/60 deg, 13.8g. A metal-gear step up from the SG92R.
4-Point Aluminum Servo Arm Horn Set with Rudder Angle Ball Link, RC Aircraft, 2-Pack, $8.37. 4-point aluminum alloy servo arm horn set with rudder angle ball link for RC aircraft, racing drones and airplanes. Two triangle horns plus glass fiber plate, ball link and hardware. Ships from NY, USA.
25T Extended Metal Servo Horn, $7.99. Extended 25T metal servo horn arm for RC car, boat, and airplane servos. Red or black. Ships from NY, USA.
Servo Arms, Extensions and Testers
Related buying guides on Quality RC Parts
How to Choose Micro Servos for RC Planes and Cars
How to Choose the Right Servo for Your RC Plane or Car
How to Choose Servos for RC Planes and Cars
Browse all the guides on the Quality RC Parts Drone Guides hub, or start at the Quality RC Parts store.
Sources
Quality RC Parts stocks parts in New York, USA and ships in-stock orders in 1-2 business days.
Last updated: 2026-11-10.