Creating a Dura Ace 9100 12-30T Cassette

Discuss light weight issues concerning road bikes & parts.
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mimesis
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Joined: Wed Jul 03, 2019 1:47 am

by mimesis

Dura Ace 9100 offers a 12-28 cassette, and an 11-30. I really like the idea of having a 30-tooth low gear, but I have no use whatsoever for an 11 tooth cog. (I don't get into bunch sprints these days.) I also really like having a 16-tooth cog, which is right in the "sweet spot" of the gear range. So I was thinking of buying a 12-28 cassette, and an 11-30, taking the 12-17 cogs from one, and adding the 19-30 cogs from the other. That would leave me with a 12-30 that I could use, and an 11-28 that I could sell to someone who likes that kind of thing.

Any thoughts about whether this would work? The only thing I've found from Shimano's site is that on the 12-28, the 17 cog is "17C," while on the 11-30, it's "17B." I suspect that refers to different ramping orientation. I'm not sure whether there'd be any noticeable impact on the shifting.

by Weenie


Pierre86
Posts: 25
Joined: Mon May 13, 2019 3:53 pm

by Pierre86

mimesis wrote:
Wed Jul 03, 2019 9:32 pm
Dura Ace 9100 offers a 12-28 cassette, and an 11-30. I really like the idea of having a 30-tooth low gear, but I have no use whatsoever for an 11 tooth cog. (I don't get into bunch sprints these days.) I also really like having a 16-tooth cog, which is right in the "sweet spot" of the gear range. So I was thinking of buying a 12-28 cassette, and an 11-30, taking the 12-17 cogs from one, and adding the 19-30 cogs from the other. That would leave me with a 12-30 that I could use, and an 11-28 that I could sell to someone who likes that kind of thing.

Any thoughts about whether this would work? The only thing I've found from Shimano's site is that on the 12-28, the 17 cog is "17C," while on the 11-30, it's "17B." I suspect that refers to different ramping orientation. I'm not sure whether there'd be any noticeable impact on the shifting.
Depends on what cogs are on held together on the carrier. I did a 105 12-28 because I didn't want to have to buy Dura ace every time I needed a cassette.
Every now and then it would take an extra half a revolution or so to change from the 17 to the 19 as the ramps are slightly different, but as a whole you probably won't notice the difference very often
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pdlpsher1
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Location: CO

by pdlpsher1

Since the 12-17 cogs are steel, you might as well buy the Ultegra 12-25 cassette instead and save yourself some money. Then you can sell the 11-25 Ultegra/Dura-Ace hybrid cassette without losing too much money.

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LAN
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by LAN

I have done this and it works fine.

The 17C is "in sync" with a 16 cog, while the 17B is in "sync" with a 15 cog.

So if you use 12-17 form a 12-28 and the rest from a 11-30 it should work perfect.

Ritxis
Posts: 355
Joined: Fri Jun 01, 2012 3:00 pm
Location: San Sebastian

by Ritxis

mimesis wrote:
Wed Jul 03, 2019 9:32 pm
Dura Ace 9100 offers a 12-28 cassette, and an 11-30. I really like the idea of having a 30-tooth low gear, but I have no use whatsoever for an 11 tooth cog. (I don't get into bunch sprints these days.) I also really like having a 16-tooth cog, which is right in the "sweet spot" of the gear range. So I was thinking of buying a 12-28 cassette, and an 11-30, taking the 12-17 cogs from one, and adding the 19-30 cogs from the other. That would leave me with a 12-30 that I could use, and an 11-28 that I could sell to someone who likes that kind of thing.

Any thoughts about whether this would work? The only thing I've found from Shimano's site is that on the 12-28, the 17 cog is "17C," while on the 11-30, it's "17B." I suspect that refers to different ramping orientation. I'm not sure whether there'd be any noticeable impact on the shifting.
Cassette 11-30..............remove 11 cog and lock ring, add an 16 or 18 cog (your choice) can be from a cassette of 10 or 11........ 11 speed spacer and lock ring for 12 cog......you already have a cassette 12-30
Last edited by Ritxis on Thu Jul 04, 2019 3:59 pm, edited 1 time in total.

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LAN
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by LAN

This is not correct.

The 11-30 already have a 15 and 19 cog, it´s the 16 cog that is missing.

Also there is a difference between a 12 cog 1st position (12-25/12-28) and a 12 cog 2nd position (all other rations)

You can just buy a 16 cog and put it in, but you will not get usual Shimano level shifting performance between 15-16-17 cogs since the ramps are out of synch

by Weenie


Ritxis
Posts: 355
Joined: Fri Jun 01, 2012 3:00 pm
Location: San Sebastian

by Ritxis

LAN wrote:
Thu Jul 04, 2019 3:39 pm
This is not correct.

The 11-30 already have a 15 and 19 cog, it´s the 16 cog that is missing.

Also there is a difference between a 12 cog 1st position (12-25/12-28) and a 12 cog 2nd position (all other rations)

You can just buy a 16 cog and put it in, but you will not get usual Shimano level shifting performance between 15-16-17 cogs since the ramps are out of synch
Edit.....edited ......... things to see on the phone and not on the pc monitor.... :oops:

it is still using the cog of 12 of 11-30....you only eliminate 11 and the lock ring for 11......it is clear that some of the efficiency of a cassette is lost without modifying...but the result is satisfactory

on my bikes I have never used cassettes with 11 and 12......I modify them to my liking and uses and they work well for me

in my 2 current bikes I use a 13-30 and a 14-30 (winter bike)
1 cassette with 10 and 11 Shimano cassette cogs and a Miche cog of 30, and the other one even with a spider (24-27-30) from an XT 11 cassette......Very happy with the result

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