Originally Posted by
Ryan_M
Ok I know this is going to be a lot like asking you what my favorite flavour of icecream is but... I'm strongly considering building a road bike and I have to (more or less) blindly pick gearing when ordering the groupset so I'm hopeful some input will give me something to go on. FWIW I'm likely going to go with an Ultegra R8020 groupset.
Currently I have what started as a Giant Roam 1 but I've done a lot of work to it including a full Deore XT drivetrain 38/28t rings and a 11-42t cassette and that works well for me on that bike for the trails and light offroad we do. I definitely use those lower gears because the GF lives in escarpment country and my knees don't like standing and grinding up hills so I sit and spin, however a road bike is going to be lighter and more efficient so maybe I don't need as low? Also my natural cadence is 95-100RPM and I like a close ratio cassette. I wouldn't say I'm a particularly strong rider and I'm 183cm 85kg, more of a fitness rider. Our short rides are about 40km with better rides being 70-110km.
Again I know it's nearly an impossible question to answer but I'd appreciate anything to go on.
Thanks!
Close ratio cassettes generally do not provide sufficient range, especially on the low end.
The current setup of your Giant Roam 1 offers much lower gearing (28T:42T) than even the Ultegra GRX groupset (30T:36T). Perhaps before ordering your new Ultegra groupset, you ride your current bike (as lightly loaded as possible) to your GF's location and see if you can get make it there and back without using, for example, at least the (physically) largest (42T) cog, and preferably the two (physically) largest (37T and 42T) cogs in your current 11-42 cassette. If yes, the math shows that a 46/30 chain ring set and a 11-36 cassette should work.
Or you can just order a 46/30 chain ring set with a 14-28 cassette and (a) hope for best or (b) ask your GF to relocate to somewhere less steep.