|No.|| 15034 (Hex hole set)|
15111 (Round hole set)
15259 (DR hex hole set)
15269 (DR round hole set)
15287 (RC hex hole set)
15338 (DR HG set)
94389 (AO 620 set)
94752 (AO 520 set)
15519 (HG round hole set)
|Release Date|| 1988 (Hex hole set)|
1992 (Round hole set)
June 24, 2000 (DR hex hole set)
September 26, 2000
July 17, 2002 (RC hex hole set)
March 26, 2004 (DR HG set)
2010 (AO 620 set)
May 28, 2010 (AO 520 set)
December 15, 2018 (HG round hole set)
|Parts type||Ball bearing|
Resin (for cages in later revisions)
In earlier days of Mini 4WD racing, the driveshafts were supported by four pair of plastic bearing with eyelets made out of brass. However, since the driveshafts are in hexagon shape, they can easily wears down the eyelets on the plastic bearings. The 620-sized ball bearings replace those standard plastic bearings and minimizes the power losses.
Endurance of the ball bearings varies depend on the sets. The earlier, hexagon-shaped hole and round-shaped hole bearing were known to be easily breaks compare to the recent ball bearing sets. This is because unlike the other sets, those two are manufactured using press-molding process. Since Late 2019, the metal cage inside the bearings has been replaced by the low-friction resin cage.
Since the existence of the Mini 4WD PRO series, the small, 520-size ball bearing sets were made available for the counter gears.
It should be noted that some ball bearing sets were sold as AO parts rather than as GUP.
- R/C Mini 4WD Hex Hole Ball Bearing Set (4pcs.) on Tamiya Japan (Japanese)
- Round Hole Ball Bearing Set (4pcs.) on Tamiya Japan (Japanese)
- AO-1011 620 Ball Bearings (2pcs.) on Tamiya Japan (Japanese)
- AO-1017 520 Ball Bearings (4pcs.) on Tamiya Japan (Japanese)
- HG Round Hole Ball Bearings (4pcs.) on Tamiya Japan