I went from a bike with Ultegra/105 mechanical to Force eTap AXS. On a road bike, the answer is clear to me: Rival eTap, no doubt about it. A while ago I wrote this post comparing Shimano to SRAM that seems quite popular. I tried to be as objective as I could, although the main thrust was comparing eTap to Di2.
- Gear range and selection. You can put a 10–36 cassette on the Rival rear derailleur and the cassette works brilliantly. Coupled to a 46/33 cassette and you get a much easier climbing gear than with any road bike Shimano setup. And if you don’t need that small a gear, well, pick one of the other cassettes, 10–33, 10–30 or 10–28. And/or pick larger chain rings. Shimano’s gearing options are much more limited.
- You can mix and match SRAM’s electronic groupsets essentially at will with extremely few exceptions. You could switch to 1x, put a gravel 2x crankset on, etc. It will just work.
- Rival eTap has the same shifting mechanism as its more expensive brethren, so apart from weight, there is no penalty.
- Rival cranks allow for a cheap upgrade to a single-sided power meter. It is as cheap as or cheaper than a 4iiii one-sided power meter ($249 if memory serves).
- A great weight saving tip is to replace the Rival cranks with a Red crank, you get most of the weight savings for relatively little money.
- 1x compatibility (if that is your jam).
- My favorite features are that I can shift with my pinky and have it shift every single time as well as the ability to trim my rear derailleur while riding.
I also prefer SRAM’s hood and lever shape, but that’s personal choice obviously.
Why? You can get equivalent gearing with SRAM if you would like. A 48/35 crankset with a 10–33 cassette gives you roughly the same top gear as 53:11 and the same climbing gear as 36:34. Plus, you can get the same or easier climbing gears if you need or want to. Although I would not want to use Shimano’s 11-34 cassette for road riding as it has no gears at the top that are one cog apart. I’d probably opt for SRAM’s 11-36 cassette if I had to or make do with an 11-32 cassette.
My experience from riding my 1x12 road bike is that my 10–36 cassette coupled to a 42-tooth chain ring feels very much like my 11–32 cassette but with one gear missing at the top and several added to the bottom.
Except when you need more easy gears on your road bike, then you can do that with SRAM but you cannot with Shimano.