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Full machine-readable index: https://core-electronics.com.au/llms.txt # Tamiya 70168 Double Gearbox Kit **Type:** Product page · **SKU:** POLOLU-114 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia) **Page:** https://core-electronics.com.au/tamiya-70168-double-gearbox-kit.html ([markdown](https://core-electronics.com.au/tamiya-70168-double-gearbox-kit.html.md)) Tamiya’s double gearbox packs two independent gear trains into a compact and affordable package that is great for small mobile robots. Each side can be assembled to have one of four gear ratios: 12.7:1, 38:1, 115:1, or 344:1. ## Pricing - **Price:** $35.20 (inc GST) — $32.00 AUD, exc GST - **Quantity discounts:** 10+ $30.72 (exc GST) · 25+ $29.76 (exc GST) ## Availability & dispatch - Out of stock — the product page offers email notification when it returns. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=POLOLU-114:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/POLOLU-114:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description | [![](https://core-electronics.com.au/attachments/localcontent/0J2740_2836672411b.jpg)](https://core-electronics.com.au/attachments/localcontent/0J2740_14796b1d286.jpg) | |---| | Tamiya 70168 double gearbox kit – clear. | #### Overview The Tamiya double gearbox is a compact unit with two independent motors and gear trains. The kit includes two motors and all gears and parts to build any of the four possible gear ratio configurations (12.7:1, 38:1, 115:1, and 344:1). Although it is not typical, it is possible to assemble each side with different gear ratios. There are two possible output axle locations (for any given gear ratio, only one output location is possible). #### Color options - [70168 double gearbox](https://core-electronics.com.au/tamiya-70168-double-gearbox-kit.html) — This gearbox is **solid gray** and comes packaged in a box. - [89918 double gearbox](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-1677) — This gearbox is **clear** and comes packaged in a plastic bag. #### Complementary products The output shafts included in this kit are 3 mm hexagonal axles that are 10 cm (about four inches) from tip to tip. The axles work with any of the [Tamiya wheels](https://core-electronics.com.au/category/35/tamiya-wheels) Pololu carry, giving you many options for your robot speed. The low-voltage motors run on 3-6 volts and draw up to a few amps, making them perfect candidates for the [DRV8833 motor driver carrier](https://core-electronics.com.au/drv8833-dual-motor-driver-carrier.html). Motor overheating can be caused by excessive stalling, even at very low voltages. Pololu recommend that you use stall-detection sensors, or just watch your robot, to make sure that it doesn’t stall for more than a few seconds at a time. For motor specs, see the Mabuchi motor FA-130 (#18100) data sheet (58k pdf). Note that you can replace the motor in this kit with a [lower-current, higher-voltage motor](https://core-electronics.com.au/brushed-dc-motor-130-size-6v-11-5krpm-800ma-stall.html) if you want to use this gearbox with controllers such as the [qik 2s9v1 dual serial motor controller](https://core-electronics.com.au/pololu-qik-2s9v1-dual-serial-motor-controller.html), [TB6612FNG dual motor driver carrier](https://core-electronics.com.au/tb6612fng-dual-motor-driver-carrier.html), or [Baby Orangutan B-328 robot controller](https://core-electronics.com.au/baby-orangutan-b-328-robot-controller.html). #### Comparison to the Tamiya twin-motor gearbox | [![](https://core-electronics.com.au/attachments/localcontent/0J2739_2040550ac4b.jpg)](https://core-electronics.com.au/attachments/localcontent/0J2739_67497774a08.jpg) | |---| The double gearbox is very similar to the [Tamiya 70097 twin-motor gearbox](https://core-electronics.com.au/tamiya-70097-twin-motor-gearbox-kit.html), as shown in the picture to the right. The gear ratio options of the two products complement each other well, but the mounting holes and overall dimensions vary slightly. The double gearbox is shorter and wider than the twin-motor gearbox, and the gears are a bit smaller and wider. This should make the double gearbox a bit more robust, though Pololu have not heard any reports of the twin-motor gearbox gears breaking. To compare all Tamiya gear box kits, see the Tamiya Gearbox Gear Ratio Comparison. **Note:** The double gearbox is a *kit*; assembly is required. To use the kit in robotics projects, you need to connect the motors to your own robot controller. **People often buy this product together with:** | [![Tamiya 70111 Sports Tire Set (2 tires)](https://core-electronics.com.au/attachments/localcontent/0J224_3965103e5f.jpg)](https://core-electronics.com.au/tamiya-70111-sports-tire-set-2-tires.html) | [Tamiya 70111 Sports Tire Set (2 tires)](https://core-electronics.com.au/tamiya-70111-sports-tire-set-2-tires.html) | |---|---| | [![Tamiya 70145 Narrow Tire Set (2 tires)](https://core-electronics.com.au/attachments/localcontent/0J226_279093ace2.jpg)](https://core-electronics.com.au/tamiya-70145-narrow-tire-set-2-tires.html) | [Tamiya 70145 Narrow Tire Set (2 tires)](https://core-electronics.com.au/tamiya-70145-narrow-tire-set-2-tires.html) | |---|---| | [![Tamiya 70144 Ball Caster Kit (2 casters)](https://core-electronics.com.au/attachments/localcontent/0J263_3658dbdf90.jpg)](https://core-electronics.com.au/tamiya-70144-ball-caster-kit-2-casters.html) | [Tamiya 70144 Ball Caster Kit (2 casters)](https://core-electronics.com.au/tamiya-70144-ball-caster-kit-2-casters.html) | |---|---| **General specifications** | Typical operating voltage: | 3 V | |---|---| | Gear ratio options: | 12.7, 38, 115, 344 :1 | | No-load motor shaft speed @ 3V: | 12300 rpm[1](https://core-electronics.com.au/#note1) | | No-load current @ 3V: | 150 mA[2](https://core-electronics.com.au/#note2) | | Stall current @ 3V: | 2100 mA | | Motor shaft stall torque @ 3V: | 0.5 oz·in[3](https://core-electronics.com.au/#note3) | | Color: | gray | **Notes:** 1A theoretical speed of the gearbox output shaft can be computed by dividing this speed by the gear ratio.2This is the no-load current of the motor when disconnected from the gears in the gearbox; the no-load current of the entire gearbox with the motor connected will be slightly higher and will vary depending on the gear ratio.3A theoretical torque of the gearbox output shaft can be computed by multiplying this torque by the gear ratio. **Documentation and other information** - ![](https://core-electronics.com.au/attachments/localcontent/0J359_5820399a29.jpg)**Tamiya Gearbox Gear Ratio Comparison** Table comparing the gear ratios available in the many different Tamiya gearboxes Pololu carry. - ![](https://core-electronics.com.au/attachments/localcontent/0J323_208447dbc8.jpg)**Tamiya “Toy” Motor Testing by Adam Borrell (a.k.a nexisnet) (Printable PDF)** Adam, who posts under the username nexisnet on the Pololu forums, has performed a detailed series of experiments to determine how operating voltage affects the lifetime of the Mabuchi FA-130 motor, which happens to be the motors used in the Tamiya 70168 Double Gearbox, 70167 Single Gearbox (4-Speed), 70097 Twin-Motor Gearbox, 70093 3-Speed Crank-Axle Gearbox, 70110 4-Speed Crank-Axle Gearbox, and 70103 Universal Gearbox. **File downloads** - **Mabuchi motor FA-130 datasheet (see model #18100) (58k pdf)** ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/t/a/tamiya_70168_double_gearbox_kit__pololu_114__00.jpg)