I have a 9 speed rear cassette that I am looking to replace some or all of. I would love to have a 9 speed cassette with a 10 tooth or even 9 tooth top gear, but the combination doesn't seem to be available with existing cassettes, so I am contemplating a mix and match affair.

I know each sprocket is indexed and has particular profiles to smooth the down and upshifts depending where around the cassette the shift happens, so this might make the idea a bit crap.

Alternately can someone point to an existing 9 speed cassette that is 10-28 or 9-28?

  • Interesting, I would need the opposite direction for off-road riding. What goes beyond my understanding is why there are no 12-34 or oven 13- 8-speed cassettes. All 12- ones are legacy ranges only to 25 or so from the olden days. If one wants to go to 32 or 34 one has to start at 11. And changing the cranks is a) more expensive, b) less convenient to be done for the day according to the route.
    – Vladimir F
    May 16 '20 at 13:10
  • @VladimirF: Yes its strange. On the other hand keeping sprockets and chainrings small makes sense from a weight perspective.
    – Michael
    May 16 '20 at 15:30
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    @VladimirF I've never needed the lowest gearing I have even in the steepest climb, traction loss tends to happen well before then. The higher speed is just useful on faster flowing sections, road transfers or even full on road cycling with it. I know it bastardises its purpose but one less tooth might be the difference of not getting a dedicated road racer bike to take up space in the hall..!
    – J Collins
    May 17 '20 at 7:50
  • @JCollins I can understand that, you are clearly speaking about a mountain bike while I about a gravel bike with road bike gearing.
    – Vladimir F
    May 17 '20 at 8:33

As far as I’m aware there are no 10 teeth sprockets for normal Shimano hyperglide freehub bodies because the freehub diameter is just too large. That’s why SRAM created the XD Driver standard and Shimano created the Micro Spline standard.

Can’t you install a larger chainring and use a 11–30 cassette?

  • 1
    The larger front chain ring seems to be the way it is going to go. Annoying as it reduces ground clearance, but the compromise might just be necessary.
    – J Collins
    May 16 '20 at 16:55

The vast majority of 9 speed bikes have the 8/9/10 speed freehub design, which doesn't go lower than 11. (Technically the iteration of the HG freehub that goes to 11 is called Hyperglide C, I think.)

Stock Shimano Capreo 9spd cassettes for folding and other small-wheeled bikes are 9-26. You need a Capreo hub. If you really want to build one into a bigger-than-20" wheel you can, but personally I don't think there's much of a conceivable good reason to. People have hacked Capreo cassettes to have bigger large cogs and even sold them commercially. I don't know if there are any hidden tricks to doing so. If you did this on a big wheel you'd be even more at risk for exceeding the torque the hub mechanism is designed to sustain. No idea whether anything would come of that.

The Miche system is difficult to make practical use of in my opinion, although there's plenty to like about the idea. It's also expensive for having both a weight and shifting performance trade-off.

  • Torque handling is important I tend to rant pretty hard on the drivetrain when I need to get moving. Does the Capreo use the same thread to interface with with the wheel centre as the hyperglide? What did you think of the Microshift or Box suggestions? Coming from motor racing I can see where a competition cyclist could want a custom set of ratios for every event, to cover off every terrain type he might come across.
    – J Collins
    May 17 '20 at 7:54
  • @JCollins Nope, Capreo freehubs use a different lockring that's similar in concept but smaller. It has external notches rather than internal splines and takes a special tool. Personally I think that getting higher gears by tweaking your chainring sizes is much more viable, and it's also the standard approach. It's not clear what kind of bike this is for, and that could change the answer. May 18 '20 at 20:03

There are manufacturers that offer individual sprockets and spacers for cassettes with custom steps. The example image below shows those for making an 11-speed cassette, but I think 9-speed options should also exist.

Miche sprockets

These sprockets are plain, you won't have ramps and tooth profiles that optimize shifting in either direction. As a positive effect, you will be able to replace individual worn sprockets without throwing the whole cassette away.

To have the smallest sprocket with fewer than 11 teeth, you will have to use a freehub with SRAM XD, SRAM XDR or Shimano Microspline interfaces. The traditional Shimano Hyper Glide freehub body diameter is too big for that (maybe there are one off solutions with an overhanging tiny cog/lockring, but they are definitely not very popular). I am not sure that individual cogs for anything but Hyper Glide are offered though.

  • I'd be okay without the ramps, I think, not sure how much difference they make. The problem with the smaller diameter hub is they seem to be standardising on 10-12 speed with a narrow chain and sprocket, whereas I'm looking for 9 speed. I wonder are there chain ring spacers that could be used to keep the original 9 speed spacing.
    – J Collins
    May 16 '20 at 16:58
  • @JCollins Indeed, people rode multi-geared bicycles before invention of Hyper Glide just fine. Slower shifts do not make difference unless one is competing. 9-speed shifting systems are pretty much legacy now in the eyes of major industry players. In this area, innovation is driven by smaller players. For example, both Microshift and Box offer modern 9-speed wide range MTB solutions for Hyperglide hubs. In your case, your desired 9/28 range is equivalent to the 11/34 range of existing 9-speed Shimano MTB HG cassettes. This, and 20% larger front chainrings should do the trick, I think. May 16 '20 at 17:35

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