[GarbanzoBeanSnafu]

OK,

I have a Shimano Ultegra 11-23 and an 12-25 cassette, 10 speed. I want an 11-25 combo. How do I do it? Has anyone successfully done this?

I haven't taken them both apart yet (dont wanna mix the parts till I'm sure) Here are the specs. The parenthesis are on the carrier.
: 11-23: 11;12;13;14;15;(16;17;19;21;23)
: 12-25: 12;13;14;15;16;(17;19;21;23;25)


Do I simply exchange out the 11;12 and 12;13? I think that would "feel" the most right. Or do I exchange the whole 11-15 right up to the carrier? Is a 2-tooth jump too much in the middle of the cassette?

 

[WheresWaldo]

I have done the same conversion by just swapping the carriers. It is fairly straightforward, but you lose the 16T. I don't seem to mind the 2T jump from 15T-17T but others do. You will need to decide for yourself.

 

[GarbanzoBeanSnafu]

So, I assume, the carriers/gears are manufactured standard across the board as far as spacing goes. I was unsure about that aspect, given that shimano touts that their gears "work in tandem to shift from one gear to the next". (well, duh!)

I'll try it out tomorrow!

 

[Drone 5200]

Do I simply exchange out the 11;12 and 12;13? I think that would "feel" the most right. Or do I exchange the whole 11-15 right up to the carrier? Is a 2-tooth jump too much in the middle of the cassette?

NO. I've done it with D/A 10 spd 11-23 and 12-27. The 12-27 is same as 12-25 except for the last two low end cogs on the carrier. Here's what you do:

Use the 11, 12, 13, 14, and 15 from the 11-23 and mate that with the 17, 19, 21, 23, and 25 from the 12-25. Dial in the shifting just right and there's an ever so slight rough spot when going between the 15 and 17, but not a big deal.

I like having the high and low end. FWIW, this combo is the same as a 9 spd 12-25 with the 11T thrown on the high end. Perfect for use with a compact 50/34.

Enjoy!

 

[GarbanzoBeanSnafu]

I like having the high and low end. FWIW, this combo is the same as a 9 spd 12-25 with the 11T thrown on the high end. Perfect for use with a compact 50/34.

Enjoy!

I can't wait to try it out. I think it will be perfect for my 50/34, as well. Thanks!

 

[SenorBlanco]

I have a Shimano Ultegra 11-23 and an 12-25 cassette, 10 speed. I want an 11-25 combo. How do I do it? Has anyone successfully done this?

My 2005 Spec Roubaix came with a DuraAce 11-25 cassette, which at the time I didn't realize wasn't offered by Shimano to the public. I've been struggling with the long, steep climbs here in Colorado, so I just bought a 12-27 cassette.

I'm thinking I may try to piece together my two cassettes to do a 11-27 as I do use the 11 quite often. If I understand correctly, I should be able to do the same thing and just use the carrier with the 21-24-27 from the Ultegra cassette and pair it with the 11-12-13-14-15-17-19 from the DA.

I probably should just go to a compact cransket and then use the 11-25 or a 11-23 cassette, but I thought this would be a compromise to see if I can "train myself into a standard crankset" on these long, steep climbs around here.

 

[SenorBlanco]

My 2005 Spec Roubaix came with a DuraAce 11-25 cassette, which at the time I didn't realize wasn't offered by Shimano to the public.

I've been bamboozled! I took the specs listed on Specialized's site for granted, never actually looking at the cassette to ensure it was 11-25. In fact it was 12-25, so my conversion was quite easy. Swap the 12-25 for the 12-27 and wonder where I can get an 11t cog....

 

[MarvinK]

SRAM will be doing an 11-26 for their Force/Rival groups this year--supposed to be fully compatible with Shimano. Probably cant buy it for another month, though. :|

Looks like it will be more expensive and lighter than Ultegra--cheaper & heavier than Dura Ace.