Originally Posted by
Steve B.
If you have a short cage 105 rear derailer, by the time you change that and a cassette, it might be near the price of a Shimano GRX 48/31 crank. Might need a new b-bracket with it. Do some research on the crank spacing to make sure it works with the current 105 front derailer and b-bracket.
A 200 dollar crank vs 30 dollar cassette + 34 dollar 105 5800 DR + 30 dollar chain........ I don't think so. Unless you know somewhere to get cranks cheap. Those are new prices. Personally, I wouldn't buy any used.
edit... yeah I'm probably being a little harsh, and the OP should consider if they need the low gearing that would give.
For myself, I just think it might be too low a gearing, depending on what part of Maine the OP is riding in. As well, when going downhill, I like to pedal and have a little resistance even though I might not be adding to the speed of just coasting.