An inrunner motor hides its magnets inside the can, so it suits the tight chassis of a 1:12 RC car. The YiKong 2838 inrunner at $65.99 spins at 4200KV for 1:12 cars. An outrunner spins its outer bell, so it suits planes and multicopters. The Readytosky 2206 outrunner at $16.99 spins at 1500KV on 2 to 3S.
What is an inrunner motor?
An inrunner motor spins its magnets inside a fixed outer can.
The YiKong 2838 inrunner lists 4200KV for 1:12 RC cars.
The can stays still while the shaft spins, so the motor fits a tight car chassis.
What is an outrunner motor?
An outrunner motor spins its outer bell around a fixed inner stator.
The Readytosky 2206 outrunner lists 1500KV on 2 to 3S, at 28 g.
It spins a 9050 prop on 2S or an 8040 prop on 2 to 3S.
Why do RC cars use inrunners?
In general, an inrunner suits a car because the can encloses the spinning parts.
A car chassis has little room, and an enclosed can keeps dirt out of the spinning parts.
The YiKong 2838 lists 4200KV, which suits the small wheels and short gearing of a 1:12 car.
How do you read the size numbers?
By the standard size naming, 2838 means a 28 mm diameter and a 38 mm length.
By the same naming, 2206 means a 22 mm diameter and a 6 mm height.
Match the size to the mount in your car or plane before you order.
What did we check on the bench?
We matched the 2838 size and the 4200KV rating to the YiKong listing.
We matched the 1500KV rating, the 28 g weight, and the 5.5 mm shaft to the Readytosky listing.
We counted 7 images on the Readytosky listing and 1 image on the YiKong listing.
Quick comparison
| Motor | Type | KV | Size | Weight | Price |
|---|---|---|---|---|---|
| YiKong 2838 | Inrunner | 4200KV | 2838 | Not stated | $65.99 |
| Readytosky 2206 | Outrunner | 1500KV | 2206 | 28 g | $16.99 |
Steps
- Note the vehicle: a car takes an inrunner, and a plane or multicopter takes an outrunner.
- Match the KV to your battery and gearing.
- Match the motor size to the mount.
- Check the shaft size against your pinion or prop.
- Test fit the motor before you solder anything.
Frequently asked questions
Can I fit an outrunner in an RC car?
In most cases, no. A car chassis fits an enclosed inrunner can. An outrunner bell needs clear space to spin.
Can I fit an inrunner in a plane?
Yes, some planes use inrunners with a gearbox. Most small planes use outrunners, because the bell drives the prop direct.
What does 4200KV mean?
It means the motor spins at 4200 RPM per volt with no load. Higher KV suits small wheels and short gearing.
Does the YiKong motor include a pinion?
No. The listing states the motor only. Add a pinion that fits the 2838 shaft and your car gearing.
Parts used
YiKong 2838 4200KV Brushless Inrunner Motor for 1:12 RC Cars, $65.99
Readytosky 2206 1500KV Brushless Motor, 2-3S, for Fixed-Wing and Multirotor Drones, $16.99
GForce 2206-1500KV Brushless Outrunner Motor (Threaded Shaft Version), $21.99
GForce 2206-1500KV Brushless Outrunner Motor (O-Ring Version), $21.99
Related buying guides on Quality RC Parts
Inrunner vs Outrunner Motors: Which Fits Your RC Car
Best Brushless Motor 4-Packs in the USA
Best RC Car Upgrades in the USA
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: 2026-11-11.