Which is a better group and why?
Both shift just fine. Choose based on ergonomics, cost, and availability. SRAM is sexy. Shimano is more commonly available, though they both use compatible cassettes. There’s not really that much of a difference to be concerned over. You’ll be equally as fast with Shimano Sora, Dura Ace, Campy Record, or SRAM Rival/Force/Red. YOU as the ENGINE make much more of a difference.
But to answer your question, I personally like Rival over 105. Rival feels more like Dura Ace, and 105 feels like, well, 105. But 105 is still a great gruppo, and I’d be happy riding either one. Also, if you have bar-end shifters (like on a tri bike), the difference is very small. But if you are using the 105 or Rival brake shifters, I like the feel of Rival over 105.
Also a big cost difference currently between the two. SRAM rival is really hot right now and as a result priced accordingly. As hard as this may be to believe you can get almost brand new Dura Ace 7800 for less than what would pay for the 2009 Sram Rival components. The one advantage of Dura Ace or even down to 105 is that is has been proven to last for a very long time and be very reliable.
And definitely a big difference if you are going for TT set up versus standard road as SRAM rival brifters are going for upwards of $230 on ebay right now.
Thanks for the replies. I’m doing a TT build right now and trying to stick on a budget. 105 seems to be a lot cheaper. I’ve gotten brand new 105 parts cheaper than used rival stuff.
I have found the same thing as I am doing a road build right now. I would just say to keep your eye out on classifieds on here for parts.
Buy the most expensive RD and chain you can afford for your TT bike. Those are the two items that have the highest power losses in grouppos.