OneUp Components releases range-extending 42t cog

by Marc Basiliere 17

Add-on sprocket extends Shimano & SRAM cassettes

My, what a big cog you have.
My, what a big cog you have.

Part of what makes SRAM’s XX1 and X01 1×11 drivetrains work for everyday use is the massive 10-42t cassette’s 420% gearing spread. By going from teeny-tiny to massive, the cassettes provide 96% of the range provided by the first two ‘rings in a Shimano triple- at a fraction of the complexity, weight, and clatter.  Of course, SRAM 11s cassettes are notoriously expensive: the least-expensive option retails for £300/$400 without the required shifter, derailleur, mech, or freehub.

The clouds parted and angels sang.
The clouds parted and angels sang.

OneUp Components has a solution.  Making use of a rider’s existing 10s clutch-type mech, shifters, and cassette, their 42T Sprocket kit sits behind widely available SRAM or Shimano 11-36t cassettes after a mid-block 17t cog and spacer are removed.  Crank down the B-tension screw, add a narrow/wide chainring, and shorten the chain and the result is – at least in theory – a 382% gearing range and 367g weight savings at under £100 total.  The range is still shy of XX1/X01’s 420%, but a nice bump over most 1×10 setups’ 327% range.  Given the price and ability to re-use a modern drivetrain and maintain a standard freehub, it’s hard to complain too loudly.

Put a big cog on,  pull a small cog out.
Put a big cog on,
pull a small cog out.

The jump from 36t to the 42t cog is the same as seen on SRAM 11s cassettes- noticeable but not unbearable.  Once the 17t cog is removed, the mid-stack step from 15t to 19t might also be felt- but the system is all about finding an acceptable compromise.  OneUp has tested and approved their system for use with XTR, XT, X9, X7, and X5 11-36t cassettes.  Only a couple of Roval (Specialized) wheels are known not to work- see the company’s compatibility page for more details.

Don't care for the green? Black is also available.
Don’t care for green?
Black is also available.

OneUp’s 42t Sprocket sells for $100 (£61), including shipping anywhere in the world.  For the time being, purchasers can exchange their e-mail address for a 15% discount ($85/£52 shipped).  For anyone intrigued by single-ring drivetrains but not quite ready to muscle a 11-36 spread ’round the hills, OneUp is presenting what looks to be a promising alternative.  Kits ordered now are expected to begin shipping in January.

Who wants ratios?

Cassette11-36OneUp 11-42XX1 10-4211-3611-3611-3611-3611-36

Comments (17)

  1. Could this also work on 9 speed too? Can’t remember if they have a cog you could remove?

  2. How do you get the discount? I put in my email address in the checkout and it still came to $100.

  3. Mikey, you need a clutch rear mech really, which don’t come in 9spd.

  4. Leku – You need to email them and you get a auto-reply with a voucher code

  5. I’d be tempted to get a 16t sprocket to replace the 15 and 17 to make that jump smoother. Old Dura Ace CS7900 spares would work and they’re about £4.

    Despite the fact that 22/36 on a 29er hurt quite a bit on a big Peak ride at the weekend I’m still tempted by this. I’m bound to not be able to put up with it. I’m probably an idiot then 😉

  6. Any news on when the fabled works components version might appear yet?.

  7. mmm no code yet. Anyone else luckier?

  8. Has anyone fitted one yet, as I can only assume it will make a mess of the freehub body.

  9. Why Squeaky? Looks quite wide where it meets the freehub.

  10. Would you need a long cage mech to take up all that slack in the chain? Or could you get away with a medium cage? The one in the image does look like a medium.

  11. fabled works components – is that a company or shimano?

  12. Any thoughts on whether rather than removing a cog, you could tack it onto the end of a regular 10 speed 11-36 and run it on the XD driver? Effectively giving you an 11-42, 11 speed replacement cassette for less than half the price of an X01. It going to be a different interface/spacing right…

  13. a much cheaper alternative already exists, see
    cy turner @ cotic alerted me to this & i’m planning to put it on my (1 x 10) hardtail early next year.
    couple of answers to questions posed above:
    yes, this will work fine with a medium cage derailleur — the cog range is 31t & from memory a medium cage will handle about 36t or so. my hardtail has a short cage x0 & even that might well work — sram say it can handle a 30t cog range & they’re almost certainly being conservative. @ the worst the chain might be a bit rattley on the smallest cog.
    however, no, i don’t think you can get away without losing a cog (presumably the 17t on an 11-36 cassette), coz the stack of cogs would be too long for the freehub.

  14. @kelvin – I *think* you could use a SRAM clutch mech with 9-speed cogs and chain?

  15. While it’s a lot of money for one sprocket, I reckon this might make more sense than the leoni/ General Lee one as you keep the known durability metal of most of your SRAM/Shimano sprockets, and as it’s bottom gear, it might even last 2 sprockets. But why only green or black? Surely at least plain silver. Tempted to get one though…

  16. I’ve had success with a non clutch 9 speed mech and a wide/narrow chain ring. Works great with no dropping and no chain guides

Comments are closed.