Originally Posted by
ultraman6970
IMO you can do it all with a 42 unless you cant climb the stairs or you are old with weak knees. I bet you have a 32 cog in that cassette too, we did not have those back in the day when the cranksets were 52/42
I love these dismissive statements about how others should be able to use certain gears because "...back in the day..." You bring your 42T small ring to nearby Maryland or West Virginia and we'll see how well it works.
To the OP: If your crank has a 110 mm bolt circle you can fit a 34T chainring. I did the same thing for my son when he didn't want to use a triple but wanted a lower gear than the 52/42 provided. His crank was an older SR with a 110 mm BCD so it worked. The early Sora triple cranks were 110/74 and if you have one of these, you can make the change.