All I did when my original bearngs failed was take them to a bearing factor and asked for a direct equivalent, the box in the picture is what they had in stock. Details are
here. I don't think there is a great problem with the original MMC supplied bearings but it is really easy to destroy any of these bearings in service as I mentioned before plus there is one particular other way of destroying bearings in this type of hub and that is to fit them and then realise that the centre spacer is still sitting on the bench at which point you have to drift one of them back out by hammering with a drift on the inner race at which point you have just destroyed the bearing, you need to throw it away and find another new one!.
