evan326

Hello, I've been reading here a while but haven't said much.
I've got a CAAD 12 105 that came with a 11-28 cassette. I've been eyeing the 11-25 Ultegra cassette though. I live a few miles out side Richmond Va, it's relatively flat here. I never find my self using the 28, and rarely the 25 cog. On the steepest hills here I'll use the 23 here and there purely out of laziness. I figure by dropping the 28 cog, and adding a 16, I would be gaining a more useful gear and getting rid of one that is just serving as added weight now.
What are the holes in my logic?
Thanks!

Da Reef

Probably won't make much of a difference either way.

doctor j

If you don't need the 28T cog for climbing, the the 11-25 makes sense. Having the 16 for fine adjustments when cruising would be nice.

OldTryGuy

I use the 16 in my 12/28, 12/25 and 12/23. Very useful.

Athens80

With the CS-5800 11 speed 12-25 you'd get 1 tooth gaps from 12 to 19, and have 21, 23 and 25 for climbing:
12-13-14-15-16-17-18-19-21-23-25.

With a 12 tooth small cog instead of 11 you'd max out pedaling 110 rpm on the flats at 37.5 mph instead of 41 mph. If pedaling 41 mph on the flats is essential for you and you can't do 120+ rpm then you wouldn't want to settle for starting with the 12 tooth.

You'll need a new cassette soon just because of wear, even if you don't need one today. I'd stick with the 105 group, pocket the savings compared to Ultegra, and get the 12-25.

rpenmanparker 

Yes. I vote for the 12-25. Get both the 16 and 18. Another advantage to this is your cassettes will last a lot longer due to two extra dogs right in the middle of your most used part of the cassette. You have just been throwing away unused cogs at both ends when the middle of the cassette wears out.

smarkinson

If you don't need the 28 do you really need the 11?

The 12-25 does give you a couple of extra gears in the middle where you're most likely to use them.

The other thing to consider is to make sure you don't end up cross chaining too badly. If you use the big ring and the 23 a lot then losing the 28 means you will effectively be one cog further up the cassette which may (or may not) introduce cross chaining problems. That's something you will need to keep in mind.

Here is a comparison between 11-28 and 12-25 on the HTML5 gear calculator:
HTML5 Gear Calculator

evan326

Thanks for the input everyone.
If anything I think I would run into less cross chain situations. I said that I RARELY use the 23, not a lot. I'm not trying to brag, there aren't very many long inclines here! With the price and weight difference between 105 and Ultegra, I'm fine paying another $30 for slightly higher spec. I didn't think of 12-25, I'll check that out some more.

jitteringjr

I used to live in the Libby area of Richmond's near west end just outside the fan and I used a 11-23 at the time and was fine with it. Didn't even use the 11 much. That was with a 39-53 crank btw. I think a 12-25 or a 11-25 would do nice.

evan326

Thanks for the local input!
I'm about 8 miles from the city near Varina. The capital trail goes right in front of my house which is great
smarkinson, that tool you linked to is great, thanks!

FlashBazbo

You asked if there was any reason NOT to change. Nobody has given you one. I will help you out: Don't change if you ever plan to ride in an area hillier than where you live.


I realize that bit of "wisdom" may be obvious. My "range" every year extends from plains to mountains and from Oklahoma to Tennessee. Still, I occasionally like to tinker with gearing just to change things up. Of course, if you never plan to ride outside your limited area, even my "reason not to change" doesn't hold up.


Get what you want. And keep that 11-28 in a ziplock bag in case you decide go to uphill someday.

jitteringjr

Fwiw, I have gotten by in the Colorado mountains with a 39-25 as my smallest gearing for ten years. Although now that I am in my middle 40s, I decided to go to a compact 34-50 crank when I wore my chain rings out. I have two Cassettes: 11-25 and 12-30 and I pick the one more suited to the ride I plan, but I haven't even picked the 12-30 for outside rides and only have used it on the trainer so I can stay in the big ring there. Definitely keep the than cassette around.

DaveLeeNC

Where I live we don't have many long climbs. I have an 11-27 on my 'race wheels' and 12-25 on my bullet proof wheels. When on the bullet proof wheels I really don't miss the 11 when on the BigRing, nor do I miss the 27 when on the SmallRing.

HOWEVER ...

I do miss the BigRing-25 and the SmallRing-12 without cross chaining. And I don't care much about the missed intermediate gears, so the next time I need to replace the cassette on my bullet proof wheels.

dave