Cheers4Gears

Hi,

I thought that buying a 12-34 cassette would be easy and inexpensive. Man, was I wrong! The only one I found costs several hundred dollars. Ouch! So I guess I'll need to build one myself. Hopefully someone can guide me through the process, if it's at all possible to do.

I'm thinking of getting an 11-34 cassette and modifying it from

Hence, I'd need to buy the smallest 4-cogs (12,14,16,18) and position them on the cassette. Is it realistic? Is it possible to get these cogs? If so, where?

Thanks in advance,
C4G

Bill Kapaun

I've mixed & matched cogs, but more for close spaced road gearing, rather than wide spaced mountain gearing.
Individual cogs tend to get relatively expensive.
I don't see a "good" match for any lower priced cassette to give you the exact gears you want.

Would a simple swap from the 11T to a 12T satisfy your needs?
Most any 7-9 speed 12T would work IF you are only changing the top cog.

shelbyfv

You would have to buy two cassettes and maybe still not get the exact gears you want. Also, mixing cogs may result in a loss of shifting precision if you are using indexed. Be easier to change your cadence. If you are able to make it work, let us know how.

Gonzo Bob

Getting a smaller large ring might be another way to get the gearing you want but you didn't mention what chain rings you are currently running

Al1943

You need a first position 9-speed 12 with built-in spacer and a single 16. I would expect the 16 to be hard to find. You might find a 10-speed 16. It should be OK if used with 9-speed spacers.
Not sure you can save any money.
I've assembled several 9-speed Shimano cassettes from mixed parts and they shift very well.

ThermionicScott 

I do like your proposed cassette, but the cost/benefit may not be there.

Cheers4Gears

Thanks for the replies! They might have led me to a solution. I'll explain, but first...

Apparently it wouldn't work. According to the online gear calculator that I used, those other, inner cogs are more important than the small 12T. I'm concerned about the overall gear spread and shifting between chainrings. Please read on...

It will be a 24/36/48 chainset with my abovementioned 12-14-16-18-20-23-26-30-34 cassette. It looks like this combination will work very well for loaded touring. The bottom gear has a 1.4 gain ratio (about 17.6 g.i.) and ratios for shifts between chainrings are evenly spaced, with 2-recovery shifts on the cassette for each chainring shift.


Ok, so here's the proposed solution: I'll get a standard 11-13-15-17-20-23-26-30-34 along with a standard 11-12-14-16-18-21-24-28-32. These two-cassettes should give me exactly what I need. Each one is available as a SRAM PG-950. They're not very expensive. Are these good quality cassettes? I could just break them apart and recombine, couldn't I?

Bill Kapaun

NOPE!
The problem is the end cog HAS to have a built in spacer.
The splines on the end of the Freehub body are beveled, so you need the built in spacer for adequate purchase.
That was why I suggested a 12T top cog only swap.
To mix cassettes you will need to get a 12-XX.

https://sheldonbrown.com/harris/k7.html#sprockets

Bezalel

The Shimano (9-speed) 12T cog can be used as an end cog or with an 11T end cog. I don't know about SRAM.

SkipG

From Sheldon Brown’s 9 speed cassette page, the cassette can be assembled from 3 cassettes:

cs-hg50-9 12-25t (12,14)
cs-hg50-9 11-32t (16,18)
cs-hg400-9 11-34t (20,23,26,30,34)

Cost of the cassettes run between $25 - $30 each.

—Skip

cs1

Not very cost effective is it?

SkipG

After posting, I found you can find the used Ultegra(?) cassette for about $60. Cost effective is in the eye of the beholder. I’m thing about replacing the cassette and crank in a 9 speed system. It’s less costly than upgrading to a 10 speed Deore drive train.

shelbyfv

After seven years, I expect many of the folks obsessing over not having a 16.5 tooth cog or whatever have moved on to 10 or 11speed. Now they have so many choices they'll have to worry about something else

Jeff Wills

Please note that you are replying to a post from 2012.

IRD sells a 9-speed 12-34 cassette: https://store.interlocracing.com/9elroca.html .