Switching from 52/39 to 50/34 - Cassette matching advice

rflynnr

So. Having acquired a second-hand groupset in pretty decent condition (following some helpful advice elsewhere on this forum), I find myself with a Shimano 105 R7000 50/34 crankset. I've never run a compact before but I was simply going to run with an 11-speed 11-30 cassette that came with the groupset. However, the seller also threw in an 11-25. I've always thought of cassettes that top out at 23 or 25 as just for proper racers so wasn't seriously considering it.

However, I just ran the numbers on a gear ratio calculator and an 34 chainring/25t cog has a more or less identical ratio to what I used to run as my lowest gear: a 39 chainring with a 28t cog. (In fact 34/25 will be slightly lower than 39/28.)

Although not quite the cyclist I might have been 20 years ago, I've never really felt the need for anything lower than 39/28. Given this I'm thinking about trying the 11-25 cassette over the 11-30.

But here's the question: should I expect the new setup to feel markedly different even if the gear ratios are essentially unchanged?

monkeyslayer

Been on a 34/25 for years and it gets me up the mountains with no major problems, tho the second bike has a 34 /32 and I love it and feel far better on longer spins in the hills. Its those wall type roads where you'll really feel it on the 25, plus in the long run your hips will probably thank you for the occasional jaunt into the 28 or 30 if you have it.

07Lapierre

It really depends on what terrain your cycling on and also if you intend racing. Its usually better to have low gears and not need them than to need lower gears and not have them ;)

nicksnikita

11-30 all the way. Spin to win.

Worst case scenario you hate it, you can switch in your 11-25 and shorten your chain a touch.

rflynnr

The people have spoken. 11-30 it is. Thanks all.