So I'm looking to buy a 36-hole rear road hub, to build up with a Ritchy 36-hole asymmetrical rear rim that should make for an extremely durable wheel. While 32-hole rear hubs are very common, 36-hole rear road hubs can be hard to find. I can get Ultegra on sale for $55, but have found Tiagra for less than $30.
So my main question is a more general one than 36-hole rear cassette hubs. How much meaningful difference exists between Tiagra, 105 and Ultegra cassette hubs? (I've linked to Shimano's webpage for each hub.) There's a slight weight difference of 15g between Tiagra and Ultegra, which is basically meaningless. Durability is the real question. Here are the design differences:
- 105 and Ultegra seem to have better seals than Tiagra - but I expect Tiagra's are plenty good seals; 105 and Ultegra have an "internal grease sleeve" on the freehub
- Ultegra says forged hub shell (on Shimano's website); 105 and Tiagra just say "aluminum" (they don't say that it's not forged, but they don't say that it is either, and Ultegra says forged hub shell)
- 105 and Ultegra have "super polished" bearing races; Tiagra doesn't
So the basic diffs are that 105 and Ultegra have better seals and bearing races, while Ultegra improves on 105 with a forged hub body.
I'm wondering how much difference, in terms of frequency of service, chance of pitting, and chance of breakage there actually/functionally exists between these hubs, though.