Shifting from a Tiagra BB to an Ultegra or Dura Ace BB? So after about 10,000 miles with my bike I bought in 2015 the bottom brackets have had enough. I need to switch them out, and considering they're quite cheap in retail and also does a lot of the heavy lifting I thought I could upgrade to a better series.

And here's where my problem is, I have no idea whether a BB I'm considering will fit the bike or not.

Here's the bike I have

It's a 2015 Nishiki Hyper Pro



The original Bottom Brackets are Shimano SM-BB4600, which seem to be the Tiagra series. (https://www.chainreactioncycles.com/se/en/shimano-tiagra-4600-bottom-bracket/rp-prod67221)




The Bottom Bracket I hope to upgrade to would either be

Shimano Dura Ace BB-R9100 (https://www.wiggle.se/shimano-dura-ace-bb-r9100-vevlager/)


Or the 
Shimano BB-R60 Bottom Bracket (Ultegra, 6800/105 5800, Hollowtech II) (https://www.wiggle.se/shimano-bb-r60-vevlager-ultegra-6800105-5800-hollowtech-ii/)



Would you say these bottom brackets are interchangeable? And if so, for me who mainly use the bike for a high pace 12 mile commute (in sun, rain or snow) each day, what BB would you recommend? Never mind the price difference, I only focus on durability and performance.
There are three current Hollowtech II road threaded BB designs (different model numbers of identical designs also exist).


BB-RS500 - this is the 44mm 16-notch cup design and weighs 92g 
SM-R60 - this is the 41mmm 16-notch cup design and weighs 77g 
BB-R9100 - this is the 39mm 16-notch cup design and weighs 65g


These measurements refer to the diameter of the bottom bracket cup, which is only a concern during fitting/removal. The bottom brackets themselves all fit the same frames.

Technically only the R9100 is considered 'Dura-Ace', the others are 'non-series'. In any case they are all interchangeable - you can use BB-RS500 with an R9100 crankset.

In general weight savings are the primary driver of the higher BBs. It would not be reasonable to assume that they are more durable.

However Shimano advertise that SM-BBR60 &amp; BB-R9100 use 'small ball bearings'. This is not necessarily a good thing, in that smaller bearings are weaker. However there are more of them. Still it would be reasonable to assume that the RS500 will be DIFFERENT in durability from the other two, but not necessarily worse.

My money would be on the RS500 if durability is a concern as the extra weight does not seem to be a bad thing in this context. It is possible there are design differences such as seals between the models, but I would not assume this without evidence.