I have an 11-32 11-speed 105 5800 cassette on a gravel bike and would rather have a 12-13-14-15-16-18-20-22-25-28-32 than the 11-12-13-14-16-18-20-22-25-28-32 that I have now. It looks like all I need to do is buy a 12-25 5800 and combine cogs.

The red cogs would come from the 12-25 and the black cogs would come from the 11-32: 12-13-14-15-16-18-20-22-25-28-32. Is it really that easy?

I've reviewed the Shimano Dealer pdf, see: [PDF]Cassette Sprocket (11-speed) - SHIMANO Dealer's Manual / User's ...
si.shimano.com/php/download.php?file=pdf/dm/DM-CS0004-02-ENG.pdf

Aren't 10 useful gears enough?

I don't know about 11 speed. I am doing the same with 8 speed SRAM cassettes.
I looked at the Shimano Doc and looks like you would need to use the last 3 smallest cogs at least.
Looks like it would be easy..... but some of these cassettes have a rivet or long screw in there holding them together. I prefer the 12 cog as smallest myself.

I'll be able to use the 3 riveted cogs from the 11-32 without disassembly. Look on page 6 of the document.


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I like a tight set of cogs in the 12-13-14-15-16 progression, This covers speeds from 15 to 31 mph with a tight 90 to 100 cadence, if I change from the small chainring to the bigger chainring at about 21 mph. I don't like the 14 to 16 jump on flatter routes. The 15 is far more useful than the 11. Enough said.

basically you are buying the 12-32 to get the 12 lockring and the last 3 cogs...12,13,14.
Then you can change the others to what you want.
A plus ....if some of the middle cogs get worn, you have extra.
A minus.... when the 15 wears you buy another cassette just to get the 12-15.

fify. The pluses outweighs the minuses.

Yes it will work. Harris Cyclery/Sheldon Brown has done this expensively for 9 speed cassettes, but I am unaware of many people doing it for 11 speed cassettes. I believe the thought is that with 11 cog the steps are so small you don't need to do custom. But no reason why you have to ride what the manufacturers want.

Theoretically you could just replace single cogs. For example you could buy a Shimano 12T cog designed for the 1st position (includes integrated spacer) and 1 tooth change to the next larger cog (13T). Ideally you would change the current 14T cog, which is designed for a 2 tooth change to the next larger cog, with a 14T cog designed for a 1 tooth change. You would also need a 15T cog designed for a 1 tooth change to the next larger (16T) cog. Unfortunately the larger cogs (14T, 15T) are not available individually unless you found someone disassembling a cassette and selling them individually.

Good luck finding that perfect gearing. Just be careful, chasing that dream can lead you down a rabbit hole.

Yes, I won't be an expensive project, a 12-25 5800 cassette is about $35. Probably easier and cheaper to get the entire cassette that to special order individual cogs. Although I might later just buy the 15 cog to refresh the 13-14-15-16-18 portion of the cassette.

I like the idea just because for me the 11T cog is entirely useless. I mean, if my big chainring were 44T I might use it, but not if it's 50.

Right now my commuter bike has a 39-30 double with an 11-speed cassette on a 10-speed freehub that I made work by dropping the 11T gear. Even with this combination I could hit 30 mph by spinning a 110 cadence if I really felt the need to (but since it's a commuter I don't).

go for it; the experiment will cost less than $100- and if it works, the enjoyment/pleasure value is far greater.

My favorite 8 speed is an 14-32, 14T Miche 1st position, 8sp Shimano 13-26 and a 32T Shimano from an 11-32.

Subscribed. Let us know how it works.

Cog timing
In the past, different Campagnolo cassettes had the same cog teeth with different circular tooth positions. So there might be a 16A and 16B. This was designed to do the best cog shifting with different neighboring cogs. But riders would mix and match two cassettes, and reported that the "wrong" cog worked reasonably well.

The Shimano 11 speed cassette dealer's manual pdf is here.
From page 6, a chart of the cogs for the different cassette sizes.

I see that 11-32 has 16B, and 12-25 has 16A. You could try the combo cassette with either of them and see which has a better shift.

The merged 12-13-14-15-16-18-20-22-25-28-32 has a great shift pattern.
The 11-32 has large gaps in the 20-25 mph range. That's where I need close shifts to try to hang on to my faster group rides.

The missing 11 cog has two uses:
It allows a rider to stay in the 34 chainring and 12 cog past 20 mph, without being completely cross chained.
Pedaling at speeds higher than the low 30 mph range. Or it's kind of nice to soft pedal at an easy cadence on long moderate downhills.


With a 12 smallest cog, the riders will want to shift out of the 34 chainring and 13 cog around 18 mph.

Attached: the 12-32 combined cassette and the 11-32 standard cassette.

12-32 combined.JPG

How did you install a 11 speed cassette on a 10-speed freehub? Did you end up with 10 or 11 cogs?

I'd try this!
12-13-14-15-16-17-19-22-25-28-32.

Here's the Mike Sherman Gear Calculator link for this setup. All the settings are stored in the URL, so you can make changes, click Bookmark Gear Set, then save the page as a bookmark.
And all the charts update on the fly as you change cogs, cadence, or tire size.

It has bigger gaps in the 14-18 mph range, but the 34 chainring covers these very well.

17-19:
the 11-28 has 17B 19E 21D
the 12-25 has 17C 18D 19F 21B

I'll be interesting to see if the shifting is noticeably any worse.

A cassette can't line up the teeth all the way around, anyway. There has to be sections where they are optimal and others where the chain won't hit the next cog smoothly. Maybe the tooth shapes are modified on certain portions of the circle to improve this? I've never heard of any discussion of the cassette tooth designs.

I'm guessing that the shifting will be decent, and being in the middle of the cog set might help, too. See the example cassette photo attached.

I agree with your general summary, but some of the important details need to be explained by me so that you can see a difference in gear range.

It's a gravel bike and I'll be using tires in the 700x38 or larger tire size. The chainrings will be 46 & 33, using a Cyclocross crankset and installing an aftermarket 33t inner ring.

I'll stay on the big chainring on flat or downhill sections. I'll probably climb hills that are less than 4% without changing to the 33 chainring, I'll just stay on the 46 chainring and 28 cog on milder climbs.

Once the climb reduces my speed to 10 mph or less, I'll shift to the smaller 33 chainring and stay on that chainring until I hit 20 mph again. I'll be able to use either chainring in the 10 to 20 mph range, but will use the bigger ring as the preferred default.

Oh, I missed that this was a gravel bike. My comments were for road riding.

Here' your setup in the gear calculator: 38c and 46/33

Attached is the speeds at high cadence. The 33 ring has much better shifts in the 15-20 mph range. If the road ahead looks like 20 mph or less, I'd stay in the 33 ring.

The cassette choices do depend on your expected speed ranges. For me, on gravel, I'd be optimizing my 5-15 mph range, instead of the 15-22 mph road range. Lots of choices.

See attached:
12-13-14-15-16-17-19-22-25-28-32 My example for fast road rides.
12-13-14-15-16-18-20-22-25-28-32 This looks better for gravel, a more consistent set of shift gaps. This is your original plan.

I ended up with 10 cogs. I removed the 11T cog, used a lock ring from a 12T cassette (10-speed) and put a 2mm spacer behind the cassette. (This was inspired, BTW, by Gevenalle's HOUP -- an ingeniously simple product that is fantastic for its intended use.)

In case anyone is curios, this odd setup I'm using was driven by the confluence of a number of factors:

1) I wanted hydraulic road brakes, so I needed to go 11-speed.
2) I wanted 32-spoke wheels and at the time Shimano's only 11-speed road disc hub was the 28h CX75.
3) I wanted to keep the 30T small ring on my crank, but the RS685 hydraulic STI's are double only, so I removed the 50T chainring from my triple.

I've seen some articles that recommend removing one of the inner cogs to make an 11-speed cassette fit on a 10-speed hub. I think this is because the 12T cog on an 11-NN cassette isn't serrated and has an indent that accommodates the 11T cog. I haven't had a problem with this. As long as the lock ring is given sufficient torque it holds in place just fine.

It is possible to use the 3 cog spider groups together. I build this cog for my trip to Utah using brass shims to get them separated.

You can get 11, 12 and 14 small cog cassettes, I have not seen anything that starts with a 13.

https://www.bikeforums.net/road-cycli...-cassette.html

Is it possible to build a 12-34 11-speed? A 12-13-14-15-16-18-21-24-27-30-34 would be interesting. I know Shimano road cassettes are bot offered with the larger cogs needed, can mountain cassettes be combined with with road cassettes?

I tend to be conservative and stay within the 32t limit for the Ultegra long cage RD.

I have read some people have made the 34 work in 1x11 or 2x11 setups.

YMMV on this based on your chainstay length and your hanger offset and alignment to the axle center.

I believe so. The spacing of the cogs is identical for the Shimano road and MTB cassettes. The problem is the Shimano 11 speed MTB cassettes have large cogs of either 40, 42, or 46 teeth (in fact none of the 11 speed cassettes even has a 34T cog). The closest Shimano 11 speed cassette to what you are asking for is the CS-6800 Ultegra Cassette 11-12-13-14-16-18-20-22-25-28-32 (see the following for a listing of the Shimano 11 speed road cassettes 2016-2017 SHIMANO Product Information Web. The listing of teh Shimano 11 speed MTB casesttes are at 2016-2017 SHIMANO Product Information Web.

Fun fact, as reported by Lennard Zinn the spacing of 11 speed Shimano, SRAM, and Campagnolo cassettes are the same (see Lenard Zinn Drivetrain compatibility hidden in plain sight | VeloNews.com.

Have fun considering all you options (with 11 speeds they are closing in on infinity) but don't loose sleep agonizing about the ultimate gearing.

I should mention that though the cog spacing on 11 speed cassettes are the same, the cassettes are not readily interchangeable on hubs like they once were. See the thread titled "10sp road vs 10sp mtb freehub and casette?" for a good discussion of the problems. The manufacturers are really trying to make parts from different groupos/manufacturers not play nice together (and they are doing a good job unfortunately).

I’m considering a Franken-cassette - Shimano 11sp r8000 Ultegra, to go with 52/36 mid-compact crankset.
my thoughts are to take a 12-25T cassette, and an 11-32T.
like the idea of single tooth increments from the 12 so 12-13-14-15-16 and was wondering if using a 17 but then going to 20-22-25-28-32 - would the 3-tooth strep between 17-20 be too big? - I note of course that 22-25-28 are also 3 tooth increments, with final 28-32 being 4T difference.

I could use the 18T instead which would be 16-18-20, but I have a feeling that 17T would come in handy for my riding/cadence/road-speed.
it’s for a road bike, variety of terrain, some quite lumpy hence the desire to go to 32T.

appreciate any thoughts.
thanks,
david

You'll definitely notice a bigger jump than the other smaller cogs going from 17 to 20. Remember as the cogs get larger each tooth added has less percentage of change than with the smaller cogs such as a 25 to 28 will be less of a jump than a 17 to 20.

12-13-14-15-16-17-19-22-25-28-32