Cassette advice - going 12-25 to 11-28

TKF

I'm considering changing my 12-25 cassette to a 11-28 and I'd be interested to hear user experiences. My reasoning is less to do with the upper/lower end and more due to the jump in ratios where I do a lot of my riding.

For example I'll be happily plodding along in 34x13 and doing 17-19mph. I want to change down and go a little faster but 34x12 is crossing right over and 50x19 is basically the same gear. But a jump to 50x17 drops cadence right down as there is no overlap in my normal spinning speeds.


However if I were to change to 11-28 I'd have more options and overlap in the 15-22mph range.


But above 22mph there is another gap. Not that I do 22mph+ terribly often without gravity assistance.

Has anyone gone for this cassette change and how did they find the increased ratio gaps?

drlodge

I've got Campag 11s 12-28 with 34-50 chainset, so there's either a 1 or 2 teeth sprockets difference. I have no issues with ratio gaps. Even the 12-29 only has a 3 tooth difference right at the bottom gears so I don't see an issue there.

I don't get why you think there are ratio gaps if your cassette is like mine with 1 or 2 teeth difference?

TKF

drlodge wrote:

I don't get why you think there are ratio gaps if your cassette is like mine with 1 or 2 teeth difference?

Because as shown at 19ish mph I have to jump 2 teeth which drops/jumps cadence by 10rpm and I find it ruins my rhythm at cruising speeds.

My question is more about the 21-24-28 gaps in the 11-28 cassette. I'm decidedly mediocre up hills and wonder whether a 3 or 4 tooth jump at the bottom would make things harder?

antfly

What you want is a 12-27, it is the 16 ring you would miss on the 11-28.

drlodge

TKF wrote:

drlodge wrote:

I don't get why you think there are ratio gaps if your cassette is like mine with 1 or 2 teeth difference?

Because as shown at 19ish mph I have to jump 2 teeth which drops/jumps cadence by 10rpm and I find it ruins my rhythm at cruising speeds.

My question is more about the 21-24-28 gaps in the 11-28 cassette. I'm decidedly mediocre up hills and wonder whether a 3 or 4 tooth jump at the bottom would make things harder?

21-24 is a bit big gap, wouldn't worry too much about 24-28 since that's just used for the steepest part of the hill as a "bail out" gear. I rarely use my 25 or 23 with the big chain ring, there are gears on the 34 ring that give the same or similar ratios and with better chain alignment.

drlodge

antfly wrote:

What you want is a 12-27, it is the 16 ring you would miss on the 11-28.

+1 that's what I have, 11 speed: 12-13-14-15-16-17-19-21-23-25-27.

Even on the Campy 12-29 cassette you still get to keep the 16 tooth, 12-13-14-15-16-17-19-21-23-26-29

TKF

antfly wrote:

What you want is a 12-27, it is the 16 ring you would miss on the 11-28.

How would that help in the gap from 50x19 to 50x17?

It's the gears around the 20mph mark that I'm trying to give myself options.

sloppyschleckonds

Hmmmm

drlodge

TKF wrote:

antfly wrote:

What you want is a 12-27, it is the 16 ring you would miss on the 11-28.

How would that help in the gap from 50x19 to 50x17?

It's the gears around the 20mph mark that I'm trying to give myself options.

Short of some custom cassette, you're going to get 2 teeth gaps around that area. I don't have an issues at all between the 50x19 and 50x17, its an 11.8% gap - the biggest one albeit on my 12-27 cassette.

antfly

TKF wrote:

antfly wrote:

What you want is a 12-27, it is the 16 ring you would miss on the 11-28.

How would that help in the gap from 50x19 to 50x17?

It's the gears around the 20mph mark that I'm trying to give myself options.

If you are talking about Shimano they are both 17-19 anyway, it's the 16t that is missing.

TKF

antfly wrote:

TKF wrote:

antfly wrote:

What you want is a 12-27, it is the 16 ring you would miss on the 11-28.

How would that help in the gap from 50x19 to 50x17?

It's the gears around the 20mph mark that I'm trying to give myself options.

If you are talking about Shimano they are both 17-19 anyway, it's the 16t that is missing.

Yes, but the 11-28 has a usable 12t which fills in the gap.

antfly

You're not making any sense now.

Oh I see what you are getting at. In practice though, I think you would miss the 16t more than the "usable" 12.

drlodge

antfly wrote:

You're not making any sense now.

34-12 fills the gap between 50x19 and 50x17 (I think)