The Super Speed Gear Sets (Japanese: 超速ギヤセット, Chōsoku Giya Setto), formerly known as Special Ratio Gearing Sets, are the series of Mini 4WD Grade-up Parts released by Tamiya since July 23, 1995.
The Super X set, unlike the rest of the Super Speed Gear sets, was released as a AO (Afterservice Original) parts release.
The gear sets has the designated gear ratio of 3.5:1, which offer the highest top speed at the expense of acceleration. All releases, with the exception of the MS set and the Super X set, includes a ball bearing for the counter gears. MS set includes a pair of polymer sleeve bearings, while the Super X set doesn't include any kind of bearing.
For the Special Ratio Gearing set and Lightweight Ratio Gearing set, the G16 spur gear and G15 counter gear were molded in the same colors as a pair of motor covers that were included in those sets (Mustard and gray respectively). The former includes the motor covers for Type-5, Zero and Super-1 Chassis, while the latter includes the motor covers for Super-FM and Super TZ Chassis. Later releases includes the light blue G17 counter gear and the yellow G18 spur gear.
In current race regulation, the light blue G17 counter gear and yellow G18 spur gear cannot be used on Type-5, Zero, Super-1 and Super-FM cars and requires the gears from the first two gear set releases.
The Super X set and the TR-1 set comes with a hooked counter gear shaft, while others comes with a straight counter gear shaft. The Super XX and Super-II set is the only gear set that comes with both straight counter gear shaft and hooked counter gear shaft.
The gear set usually comes as default for most Mini 4WD cars with small diameter wheels starting with Max Breaker, the first in the Aero Mini 4WD series. Mini 4WD cars that has the gear set equipped includes Blast Arrow, Z Wing Magnum and Spin Cobra Premium.
- Gray-colored version of G15 gear included in Lightweight Special Ratio Gear Set differs from mustard-colored one, included in earlier-released Special Ratio Gear Set, by having four holes to reduce weight.
- Special Ratio Gearing at Tamiya Japan
- Lightweight Special Ratio Gearing at Tamiya Japan (Japanese)
- Mini 4WD PRO Super Speed Gear Set (for MS Chassis) at Tamiya Japan
- Super Speed Gear Set (for Super XX and Super-II Chassis) at Tamiya Japan
- Special Ratio Gearing at Tamiya America
- Lightweight Special Ratio Gearing at Tamiya America
- Mini 4WD PRO Super Speed Gear Set (for MS Chassis) at Tamiya America
- Super Speed Gear Set (for Super XX and Super-II Chassis) at Tamiya America