Custom Cassette (for touring)?
 

Greetings fellow tourers, I have been thinking about making a custom (13-36 or 34 ,10 speed) cassette to replace my standard Shimano HG500, 11-34 cassette. I am using a standard trekking crankset (48-36-26), and a Shimano Deore XT rear deraileur, which I am told will accommodate up to a 36-tooth cog with my existing crankset. My current configuration gives me a range of 19.2 to 112 gear inches with 700x35 tires. My goal would be to get closer to 18 by 96 gear inches. I use this bike predominantly for loaded touring. I am getting too old to swing the higher ratios, and I really appreciate the ultra-low ratios when I am pushing a load up grades greater than about 7%. Ideally, I would like to;

Delete the 11-tooth cog
Replace the 13-tooth cog with a 13-tooth cog that can accommodate the locking ring
Add a 36-tooth cog

This would yield a range of 18.6 to 95.1 gear inches without any changes to the front end. Alternatly, I would also consider;

Delete the 11-tooth cog
Replace the 13-tooth cog with a 13-tooth cog that can accommodate the locking ring
Add a 28-tooth cog

This would yield a range of 19.2 to 95.1 gear inches without any changes to the front end.

The biggest problem seems to be locating a 13-tooth cog that will accommodate the locking ring AND be compatable with a 10-speed chain. Shimano used to make a HG50, 13-36 8 speed that was HG compatible. Would that work? I have a 36-tooth cog from a previous cassette, and I presume I could locate a 28 tooth 10 speed cog without too much difficulty.

Any advice, experience or suggestion you have would be much appreciated.



Thank-You and please stay safe.

Why not just use a 12-36 cassette? Here’s a comparison of the 11-34 to a 12-36 change.

I’d also suggest looking more seriously at a change in the front end. If you changed the outer ring to a 44 tooth with the 12-36, you’d get into the range you want on the high end. A 42 tooth outer ring, 22 tooth inner ring, and a 12-36 cassette would give you the high you want and a low around the right ratio.

Frankly, I’d go about changing the chainrings because finding individual cogs for a cassette is more difficult. I know it makes no sense but that’s just the way it is.

You may want to try MICHE and XT cassettes. ex: Miche 15-16-17-18 and XT 19-21-23+27-30-34.

Miche has variants in 12..18 first cog (and matching cassette) so you can adapt to your taste. I prefer 15 to minimize gaps.

The problem with this is the enormous gap between 15-13 (and 12). 13%-15% steps. I prefer corncob (15-16--17-etc.) which yields 5% steps. Sure I lose gear-inches about 87, but I rarely felt the need for > 90 anyways.

The 12-36 option is very appealing, but I can't find one by Shimano in a 10 speed.

Next time your drivetrain is due for a total replacement, you could go with a SRAM GX 2x11 speed drivetrain. The cassette goes up to 42t. The crankset is 24/36.

You would lose a bit of top speed compared to the triple but your low end would be good enough for even the steepest hills.

This SRAM groupset is quite a few years old now and can be found for pretty cheap. It would be a lot easier than trying to piece together a custom cassette. If you use drop bars, there is a Microshift bar end shifter that works with this rear derailleur. You can use any random front bar end shifter since front shifting is friction. I got an old Shimano front shifter from my local bicycle recycler.

It doesn’t have to be Shimano. SRAM, Microshift, SunRace, etc. are equivalent in all ways.

I’ve never understood the desire for close ratio gearing for high gears. When going down a hill where the 15-13 step would have any utility, I feel that the jump isn’t all that noticeable.

I would start with just swapping out the existing 26 up front to a 24 granny gear. That would lower your lowest gears. Then not worry about trying to lower the higher gears.

If you do that, you might find that if you are using your 24T front with the smallest couple of sprockets in back that the rear derailleur can't take up all that chain. But those couple of gears are quite cross chained and it is best to avoid those gears with the smallest front and smallest in back anyway.

you may want to consider putting a mtb triple on the bike, a 42/32/22 or 44/32/22 or the other more recent variations. I find them to be very user friendly with a loaded up bike.
your comment about "I use this bike predominantly for loaded touring. I am getting too old to swing the higher ratios, and I really appreciate the ultra-low ratios when I am pushing a load up grades greater than about 7%." seems to indicate that you may very much enjoy lower ratio chainrings overall.

but only you know what you want, or how much lower you would want your gearing.
look at some gearing charts , this may help you compare what you have and possibiliities

A custom wear item on a touring bike, no thanks! Stick with the many cassettes already out there. If something does happen I would rather be able to replace with a commonly available part rather than waiting on some specialty parts to build some custom cassette. Now if I was a sponsored racer yeah custom all day every day and my team mechanics can figure out the parts. If I was a casual cyclist or was mostly riding around my area then yeah custom fine but for touring I want known reliable quantities.

It really depends on the type of touring. It is rare to blow out a cassette, unless one is putting on thousands of miles and also changes the chain and notices it skipping.

Nonetheless, if a 13T cassette is not available, one can simply buy what is available and put it on.

Very clear, very concise, some of the best advice on this board.

That is why my derailleur touring bikes use eight speed chains and a Sram 11/32 eight speed cassette. Last time I bought a chain and cassette was in the early months of covid. I paid about $12 for the chain, $25 for the cassette, plus a few bucks for sales tax. You want expendables to be easy to source and easy to swap out and cheap enough that you do not even think about replacing them.

For simplicity, my rando bike and folding bike use the same cassettes and chains, so I keep several spares on the shelf. I do not even want to think about replacing expendables, just do it when they are due.