Different motor manufacturers label their motor sizes in different ways. Here's how to compare them.
Metric Size: used by chinese manufacturers such as Hobbywing and Surpass. the first 2 numbers are the can diameter in mm, the last 2-3 numbers are the can length in mm
Castle Creations size: first 2 numbers are diameter in tenths of an inch, last 2 numbers are a marketing scale loosely correlated with motor length and power.
Tekin size: similar to metric size on their 1/8 motors but they don't count the fins in the diameter and doing armature length instead of can length?
Reedy and Traxxas sizes: Mostly mabuchi sizes but they get a little freeform
| Traditional Mabuchi Size |
Metric Size | Castle Size | Tekin Size | Reedy Size | Traxxas Size | Intended Use | Typical Shaft Size(s) |
|---|---|---|---|---|---|---|---|
| 1620 | N/A | N/A | N/A | N/A | 1:24 crawler | 1.8mm (0.07") | |
| 1626 | 1:28 | 1.8mm (0.07"), 2mm (0.08") | |||||
| 130 | 2025 | 1:24-1:18 | 1.5mm, 2mm (0.08") | ||||
| 180 | 2030 | 180 | 1:24-1:18 | 2mm (0.08") | |||
| 190??? | 2037 / 2038 | 0808 | N/A | 1:24-1:18 | 1.5mm, 2mm (0.08") | ||
| 280 / 370 | 2431 | N/A | 370 | 1:18-1:16 | 2mm (0.08") | ||
| 2435 | N/A | 1:18-1:16 | 2mm (0.08") | ||||
| 2445 | 280 | 1:18-1:14 | 2.26mm (0.089") | ||||
| 380 | 2848 / 2850 | 1007 | 380 | 380 | 1:18-1:12 | 3.175mm (1/8") | |
| 390 | 2858 | 1010 | 390 | N/A | 1:16-1:12 | 3.175mm (1/8") | |
| 540 | 3650 / 3652 | 1406 / 1410 | 1:10 Pro2 | 540 | 540 | 1:12-1:10 | 3.175mm (1/8") |
| 550 | 3660 / 3662 | 1412 | 1:10 Pro4 / Pro4 HD | 550 | 550 | heavier 4wd 1:10 | 3.175mm (1/8"), 5mm (0.197") |
| 560 | 3665 | N/A | N/A | N/A | N/A | heavier 4wd 1:10 | 3.175mm (1/8"), 5mm (0.197") |
| 560 | 3668 / 3670 | 1415 | 540XL | 1:10-1:8 | 3.175mm (1/8"), 5mm (0.197") | ||
| 750 | 4268 | 1512 | 4030 | 680 / 1:8 buggy | N/A | 1:8 buggy | 5mm (0.197") |
| 775 | 4274 | 1515 | 4038 | 1:8 truggy | 775 / 2200kV | 1:8 truggy | 5mm (0.197") |
| 4288 | 1520 | N/A | N/A | Traxxas 2000kV | 1:8-1:6 | 5mm (0.197") | |
| 4985 | 1717 | 1200XL Big Block | 1:8-1:6 | 5mm (0.197") | |||
| 4990 | 1721 | N/A | 1:7-1:5 | 5mm (0.197") | |||
| 5687 / 5690 | N/A | 1:6-1:5 | 8mm (0.315") | ||||
| 56112 / 56118 | 2028 | 1:6-1:5 | 8mm (0.315") | ||||
| 70120 / 70125 | N/A | 1:5-1:4 | 8mm (0.315") |