Gearing

1_reaper

Hi. Not sure if I've put this in the right section? Anyway I'm coming back from a couple of injuries shoulder& knee which means I can't really get out of the saddle on climbs much and I'm not the strongest of climbers. Anything over 10% and over and I'm struggling. I was thinking at the moment I've a standard sram red chain set. Now is there much difference in changing the chain set to a compact or keeping the chain set and swapping the 25-11 rear cassette to a 28-11 (if the derailleur can take it?) Thanks

ai_1

It's very easy to compare gears:
Below is just the basic ratio which IMO is all you need. In cycling it's common to talk in "inches per pedal revolution" but that's unnecessary unless wheel size comes into it and I presume you're sticking to your 700c!

Your smallest gear at the moment as I read your post is 39/25 = 1.56
If you keep the standard double and get an 11-28: 39/28 = 1.39
If you went to compact and keep the existing 11-25: 34/25 = 1.36
If you change to a compact and get an 11-28: 34/28 = 1.21

These numbers correspond to the number of revolutions of the back wheel for each revolution of the pedals. At the moment you turn the pedal once and the rear wheel turns 1.56 times. (The inches terminology mentioned earlier just multiplies this figure by the circumference of the wheel to give the distance travelled per pedal revolution).
You can see that going to a compact with the existing cassette will give a slightly easier gear than just changing the cassette but both are significantly smaller than your current set-up. Doing both would of course give you a significantly smaller gear again.

Hope this helps

dw300

This is the best gear calculator I've used for Android. Mess about with it if you have a compatible phone/tablet.

To make it easier to use, go into the setting and 'deselect all' for tire size, chainrings and sprockets etc, and only select the ones that youll ever use.

There's also a gear comparison thing which is great.

https://play.google.com/store/apps/details?id=com.gearcalculator&hl=en_GB

drlodge

Changing your gears will make a big difference IMO, changing the rear cassette for a 11-28 is the cheapest option.

I have a compact and changed the cassette from 12-27 to 12-29, those extra 2 teeth make a difference on the steepest hills or when I'm tired. A bottom gear of 39x25 is really not that low so no wonder you're struggling on hills.

okgo

12-27 would be better, the gaps on an 11-28 might be a bit large. Most people do not need an 11 anyway.

ai_1

okgo wrote:

12-27 would be better, the gaps on an 11-28 might be a bit large. Most people do not need an 11 anyway.

I agree the 11 is usually unnecessary but the 28 may be useful. I don't know why you never see 12-28 cassettes. That's what I'd buy!
If you've an 11 speed then 11-28 is fine. With 10 speeds the gaps are a little bigger but it still works fine and it depends whether you're picky about your exact cadence!

drlodge

Ai_1 wrote:

I agree the 11 is usually unnecessary but the 28 may be useful. I don't know why you never see 12-28 cassettes. That's what I'd buy!

You need to convert to Campagnolo then...12-27 or 12-29 available ;-)