My next train will consist of 10 cars, each car weighting about 600g. In order not to overload the locomotive I decided last autumn to equip the train wheel set with ball bearings. At that time I found only the solution using modified train wheel holders from Legopold https://www.flickr.com/photos/162569845@N05/25210157997/ and the solution using technic bricks from legoman666 https://www.eurobricks.com/forum/index.php?/forums/topic/140479-ball-bearings/.
My cars are 7wide, the solution using technic bricks requires covering the wheels, but this will exceed 7wide. Using the first method results in a significantly different wheel holder height and I do not like that.
So I decided to develop my own solution (if Legopold had invented his improved method https://www.eurobricks.com/forum/index.php?/forums/topic/174266-improved-method-to-equip-lego-train-wheel-holders-with-ball-bearings-no-cutting-of-the-wheel-holder-required/ earlier I probably would not have looked for another solution).
This is my result:
I milled out the locations for the ball bearings:
Except the ball bearings I used only original LEGO parts.
For comparison: on the left side the original wheel set, on the right side the wheel set with ball bearings
The ball bearings are steadily joined to the axle.
Due to the ball bearings the cars now run more smoothly and I do not regret my efforts.
Ludger