Originally Posted by
seeker333
In the past, Shimano has claimed borozon-hardening on only its premium lines, specifically XT, XTR, Ultegra and DA. Lately their product descriptions make no mention of it, so perhaps its been discontinued, expanded to all products, or they've decided it's an ineffective marketing point and chose to not advertise it. Maybe the limited success of third-party marketing of "ceramic" bearings has effected their decision to use or advertise borozon (which is a ceramic too).
Although borozon has been used successfully for years in mining and tooling applications, I'm not sure the benefits are significant in the case of MTB hubs used for touring. To most cyclists it's simply pixie dust that helps them justify paying 100% more for a hub they want that's probably only 1% better.
I've got 7,000 miles on a non-borozon Deore hub so far, with no sign of wear. My best performance on XT hubs are 22,000 miles, but they started developing an erosion track at about ~17,000. Ask me again in 2 years and I'll be able to make a more informed comment on Deore vs XT hub bearing race wear.
Well, I did read a message a while back from someone claiming he compared Deore hubs to (if I remember correctly) Dura-Ace (or minimum 105, not completely sure) with 20 years of use and said the road hubs were very smooth while the Deore hubs, not as much. But he said the Deore was ridden much rougher on a mountain bike.
No one attempted to answer my earlier question as to why there are more parts next to the bearings of XT hubs (as per technical document drawings) and if it really represents an advantage or not.
I really think Shimano should at least attempt to list detailed descriptions on their site for parts. I mean who can tell when a hub has a steel axle and an aluminium one?
I'm also puzzled by the number of bearings. When I look at technical documents on dynamo hubs, the number of bearings varies but seems to be higher in the higher-end dynamo hubs. If larger bearings were really better at carrying a larger load, why would they use smaller bearings on higher-end parts? Ah well, maybe people don't have the anwers but wondering anyway.