OneUp Components releases range-extending 42t cog

December 3, 2013

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?

Chainring 32 32 32 24-32 26-38 24-36 26-39 24-32-42
Cassette 11-36 OneUp 11-42 XX1 10-42 11-36 11-36 11-36 11-36 11-36
Max 2.91 2.91 3.20 2.91 3.45 3.27 3.55 3.82
Min 0.89 0.76 0.76 0.67 0.72 0.67 0.72 0.67
Range 327% 382% 420% 436% 478% 491% 491% 573%
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