Rubber Sealed Bearing Kit (Fits SCX24)

 

Number Of Bearings Included: 20

To be honest, you really do not need to waste your money on anything higher than ABEC 1 for radio control applications. The ABEC rating only tells us how close the bearings dimensional tolerances are (that is, how close the bearing is to the stated size). There are many other factors relating to the quality of a bearing (shielding, quality of materials, lubrication etc), and most of these factors will have much more of an impact on how fast your RC goes than the ABEC Grade of the bearing.

The ABEC rating system covers a few things, but to give you an idea we will just examine one of them - the eccentricity (out of roundness) of the track in the inner ring. For an ABEC 1 bearing, the maximum eccentricity allowable is 0.0075 mm (0.000295"). This is quite precise - more than precise enough for radio control applications. The figures for the other ABEC grades are:

ABEC 3: 0.005 mm (0.000197")

ABEC 5: 0.0035 mm (0.000138")

ABEC 7: 0.0025 mm (0.000098")

ABEC 9: 0.0012 mm (0.000047")

If a bearing is to be used in high precision, high speed machinery, these tiny variations can make a difference to lifespan, vibration, noise and performance. However, radio control cars and trucks are very, very far from the clean, shock-free environment of a machine shop. The moment you use a bearing in your RC, after 5 - 10 minutes of use the tracks won't just be eccentric, they will become irregular (albeit minutely) enough to be practically indistinguishable from one another. Your high priced ABEC 9 bearing might as well be the cheapest ABEC 1 bearing out there. 

Be careful of other companies claiming a higher ABEC spec. If the bearings are under $2 each for chrome steel versions, they are ABEC 1 rated, no matter what they claim.