The larger rollers used in Speeditwins are more tolerant of imperfections than the needle bearings used in Mercuries. The bearing surfaces may be reground and yes – oversize rollers were available.
Good to know that oversize rollers were an option…… at least “back in the day”.
I wonder if the same cages were able to be used with the oversize rollers?
Thanks!
Prepare to be boarded!