To make it clear right from the beginning – the modification does not convince me. It is about to equip the train wheel holder (2878c01 or 2878c02) with ball bearings to make everything more smooth. But, if it is not convincing me, why I still consider and write about it? Because I have some wheel holders from one of Legos® competitors. And they are really loud.
It is a squeaking noise and it is just too much to ignore it. If we talk about Lego® originals, we don’t have this noise issue, at least, if I talk about my 50 wheel holders, I have in my collection. But the 10 competitor wheel holders I have - all of them have a noise issue. So, I think it has something to do with the quality and the exact measurements. I found out, that the cut-out for the axle on the holder is half a millimetre shorter than the Lego® ones and so, the axle is in permanent contact with the wheel holder – in principle, the axle rubs against the plastic and this generates the noise. The cut-out on the Lego® wheel holder is deeper, so the axle somehow is free.
Anyway, back to the question, should you modify the wheel holders? If you have a noise issue – yes! If you can run your trains without issue, don’t touch it. In my point of view, it isn’t worth the effort. To have a really perfect result (long rotating wheels with almost no friction), your work must be very precise and the bearings must be from very good quality. I modified 10 wheel holders and for 50% of it, I can say the result is really good. Smooth rotating wheels for a long time. But 50%, it’s like before, except the noise is gone. And I think, I am really a perfectionist – at least this is the feedback, I always get. So from this side, I think, I did it properly, but still just 50%.
But if you are still keen, below you can download the PDF where I will show you my method. But even the changes on the wheel holder are minimal, you can’t sell it anymore as “original”. But maybe you are not a seller, so you don't mind.
Videos before and after the modification, as well as the comparison of both variants:
Download the instruction for free:
Disclaimer: I am not responsible for any damages or injury on parts and humans happen while following this instruction. Everything you do is your responsibility and under your personal risk.