SoSmellyAir

Has anyone managed to combine cogs from two donor cassettes to make a custom 11 speed cassette (preferably a 12-28 cassette) which shifts perfectly smoothly?

I tried doing so with an Ultegra 11-28 cassette and an Ultegra 12-25 cassette, but the downshift from one donor cassette to the other misses fairly often, as detailed in this other thread.

Bike Forums - View Single Post - Custom 12-28 cassette (my post)

Custom 12-28 cassette - Bike Forums (the entire thread)

I would sincerely appreciate any pointers. Thank you.

gsa103

Cheap, reliable, light. Pick 2. Buy the DA cassette if you want reliable shifting. Bodge something together if you don't want to spend the money. The reason you can't get perfect shifting is that the teeth profiles are optimized are across the entire cassette so that it releases and switches at an optimal spot. It's likely that when you're trying to get across the 17-19 shift, the shift points aren't clocked properly.
The only way you might be able to get it working better is to shave the keying on the upper cog set. That would let you adjust the offset of the cassettes with respect to each other. You'd have to look at the tooth profiles and try to guess the offset.

SoSmellyAir

Sigh, I hear you. I would have immediately bought an Ultegra 12-28 cassette if Shimano makes such a product. I would even have bought one, albeit reluctantly, at a Dura-Ace price level. I bought the two Ultegra "donor" cassettes at $70 each; the Dura-Ace 12-28 was available then for under $200. But two issues (in addition to the extra cost) swayed me against a Dura-Ace cassette:

(1) It uses a carbon composite carrier for the two largest cogs, and another carbon composite carrier for the third to fifth largest cogs. Whereas, the Ultegra cassette uses an aluminum carrier for the three largest cogs, and a carbon composite carrier for the fourth and fifth largest cogs. Evidently, the carbon composite material is not strong enough to withstand the forces on the two largest cogs. Many online customer reviews complain of creaking in the two largest cogs; a few even managed to crack the carrier.

(2) Its five largest cogs -- where I will spend most of my ride because I am weak and slow, and somehow manage to ride uphill and upwind both ways -- are made of titanium, which wears faster than stainless steel. I have worn titanium watches and their wear show that this metal is much softer than stainless steel. Whereas, all cogs in an Ultegra cassette are stainless steel.

As I did not want to spend more money for less reliability, trying to "bodge" it was my only option.

Thanks, but I don't think my level of tinkering extends to that level of ingenuity.

At this point, I am rather resigned to not having a 12-28 cassette. But I am still curious why it did not work when cog markings matched perfectly.

Racing Dan

An other solution is to combine a 11-25 with a 46/30 crank. Arguably better in fact.

Bicycle Gear Calculator

SoSmellyAir

Thanks. Have thought along similar lines, i.e., 48/32 chain rings (like an eTap AXS bike) with the 12-25 cassette. Having only used the 12T cog once or twice since switching to the Ultegra cassette, I doubt I need more than a 4:1 top end. And, at the bottom end, 32 over 25 (1.28) splits the difference between the 34 over 25 (1.36) that I am currently getting by on (side benefit: firmer legs) and the 34 over 28 (1.214) original goal of the custom cassette. But I do not have the experience or the required tools to remove crank arms, which seems to be necessary to swap at least the small chain ring. But definitely keeping that option in mind when it comes time for new chain rings.

burnthesheep

I didn't believe gsa103. So I pulled up the cut sheet from Shimano for the R8000 line of cassettes.

Sure dang enough the cogs have different part #'s depending on what the jumps are and on what cassette the cog belonged to!

I guess you'd have to figure out how to put them together in a way that the A/B/C/D part # of the cog matches for each gear change to something in their range.

Mind blown, I thought a cog was a cog was a cog for the same model like R8000. Guess not.

https://si.shimano.com/api/publish/s...001-03-ENG.pdf

SoSmellyAir

As discussed in the other thread, I followed the exact cog sequence, including the alphabet after the number, for the Dura-Ace 12-28 cassette, and it still did not work perfectly.

GrainBrain

I went with the SRAM 11-28, I really like it coupled with my 46/30.

SoSmellyAir

gsa103 is right. Regardless of whether I put the transition between the two donor cassettes at the 17T to 19T shift or the 16T to 17T shift, when I spin the custom cassette slowly by hand under a light shining at an angle, I can see an incongruity in the reflected light at the transition. After reading his post, I now realize that the incongruous reflection I had observed was due to the angles of the surfaces on the teeth.

alexdi

Edco, Recon, and Token have all-steel 12-28s in 11. More details.

SoSmellyAir

Thank you! Learn something new everyday. On a first glance most of the reviews are from a few year ago and pertain to people using older wheels with 10s freehubs in 11s systems. Do you have any experience with any of these cassettes?

alexdi

I do not. I doubt they shift quite as well as Ultegra, but they will be lighter. There are also various 12-27 cassettes you might consider.

Greatestalltime

So I can’t just put an 11 in the place of the 12 on a 12-25?

SoSmellyAir

Based on my tinkering to date, I highly recommend against doing that. You could put a cassette together as you have described, but the downshift from 11T cog to the 13T cog will miss fairly often, and even when it shifts onto the 13T cog, a two teeth jump at the small end of the cassette would be too much disruption to your cadence. If you want a 11-25 cassette you can just buy one, no need to cobble together one yourself.

Greatestalltime

I’ve had 11-25 and don’t like it without the 18.

52-18 is highly used and just right for me.

SoSmellyAir

What cassette are you using now?

My bike came with 50/34 chain rings and an 11-32 cassette, which never felt right. So, as described in my post in the other thread (Bike Forums - View Single Post - Custom 12-28 cassette), I bought both an 11-28 cassette and a 12-25 cassette. Comparing the latter two cassettes:
(a) I never use the 11T cog (in the 11-28 cassette), so I will readily give that up to have the 16T cog (from the 12-25 cassette);
(b) The 18T cog (from the 12-25 cassette) is much appreciated, giving me a single tooth jump from 12T through 19T, but I would consider having a 28T cog instead.

SoSmellyAir

Thank you. The only 12-27 cassette I have found is Campagnolo Chorus, which necessitates swapping the freehub too. So will probably stick to the Ultegra cassettes I now have.

faulker479

I wonder how well the DA 12-28 actually shifts? I'm sure it's fine, but I have never known anyone with one.

I would be interesting to see which Ultegra 17t matches the ramping of the DA 17t in the 12-28. And then also compare the ramping of the 16t and 19t of each.

SoSmellyAir

I am sure it shifts fine. Given that a Dura-Ace cassette is priced at 3x to 4x of an Ultegra cassette, can you imagine the outcry if it does not?

I tried to match the Dura-Ace cassette by using the Ultegra cogs with the same markings (i.e., the alphabet, e.g., A, B, C, D, etc. after the number denoting the number of teeth) not just for the 17T cog, but for the whole cassette, and that still did not work.

Greatestalltime

I’m on a 52-36 with a 12-25. On an 11-25 I don’t like the skip from the 19 to the 17. Also, when it’s windy I’m on that 18 quite often.

Im on the 52 98% of the time where I ride at home/not on vacation.

SoSmellyAir

Yes, among the current generation of Ultegra cassettes, 12-25 is my favorite for my local terrain.

Symox

I did this with a pair of 105 10 speed cassettes and it worked perfectly. I had a 12-27 and a 11-25 and combined to make a 11-27.
However I found a used Dura Ace 11-28 cassette and couldn't resist

Ken2

Look at Miche cogs/cassettes (www.miche.it). Italian company, makes mix 'n match almost limitless choice between 11 & 36T. They shift well and are competitive with Ultegra for weight & price.

Chain Reaction Cycles carries the most popular sizes in complete cassettes, or try Lordgun Cycle for more choices. Make sure you order 11sp Shimano compatible, since Miche also makes 9 & 10sp for both Campy & Shimano fitment.

I have 12-30 on one road bike, and 11-28 on another. You can plot the ratios you want--I have the important 16 & 18T cogs on both of these. Oh, and one other detail: you must use Miche cog spacers (included), since Shimano spacers are just slightly wider.

Dave Shaper

I did that on my 12-25 to make a custom 11-25. Don't miss the 12, it shifts fine, and I'm a lot faster top-end.