$7 Minimum Shipping — USA Addresses See checkout for all options. Insurance automatically added to all USA orders over $50. $13 Minimum Shipping — All Phone Orders Worldwide shipping — see checkout for shipping options.
A special note to gear purchasers for non-model aircraft purposes. We get many inquirys about asking if these gears will fit a Childs X-G-Wiz-Go toy or will repair a home kitchen device or etc. We are model aircraft experts, if it's a model aircraft gearbox, we can help figure out the part on the phone if your stuck. If it's a toy or special project outside the hobby, I can't begin to guess if our gear will mesh with your gear in your device. I can't tell from a photo what pitch your gear is. If your trying to fix a special item, my best suggestion is to purchase all the gears that look similar and have a go at it. Most gears are a few dollars or less.
Himax Gearbox Driveshaft with E-clip for ACC3966 & ACC3937. Priced per one shaft, e-clip and one plastic spacer. This is a shaft for the Himaxx gearbox that comes with the 2015 and 2025 motors and fits all other 20mm motors.
Himax Threaded Gearbox Driveshaft with E-clip for ACC3936, ACC3937. Priced per one 3mm threaded shaft, nuts, washer, e-clip and two plastic spacers. Use on ACC3937 & ACC3966.
Himax 3966 Gearbox Driveshaft 2mm E-clips. These are very easy to lose when dismantling your gearbox. (for 3mm shaft gearboxs) This listing is priced for 5 individual clips in one pack.
Ball bearing set for ACC3937 (24mm) gearbox and ACC3966 (20mm gearbox) from Himax. Contains 2 each 6x2.5x3mm (OD/Width/ID) flanged bearings. Genuine factory parts. Genuine Japanese bearings.
Himax Gearbox Driveshaft with E-clip for ACC4966. Priced per one shaft, e-clip and one circlip spacer. 38.5mm long. For late model gearbox with 4mm shaft included with many 2015 and 2025 20mm inrunner/gearbox systems.
OUT OF STOCK
SKU Number: MPIACC4966-5
Himax Gearbox Parts
Himax outrunner gearboxes rely on a spur and pinion set that wears over time, and this category supplies the replacement gears that restore a worn drive. Keeping a spare set on hand means a stripped gear does not ground the model for long.
Complete Gear Sets
Full gear sets are offered in three reduction ratios: 4.4:1, 5.3:1, and 6.6:1, each built for the ACC3966 gearbox. Changing the ratio lets you tune the same motor for a larger, slower prop or a smaller, faster one.
Spur Gears Only
If only the larger gear is damaged, spur-gear-only replacements in the same three ratios fit the ACC3966 and ACC3937 gearboxes. Replacing just the spur can be the economical fix when the pinion is still in good shape.
All of these gears are wear items in a working gearbox, so builders who fly often tend to keep a set on the shelf. Confirm the ratio and the gearbox model number stamped on your unit before ordering a replacement.
Choose the ratio and part that matches your Himax gearbox below.
 "Himax Ball Bearing Set for 3937 & 3966 Gearbox")
 "Himax Gearbox Shaft for ACC4966 Gearbox")