Surly Splined Single Speed Cog
Surly's splined single-speed cog slides onto a standard splined freehub body, the same one a cassette uses. That is the point of it: you can take an ordinary geared rear wheel, strip the cassette, and run it as a single speed with spacers either side to put the cog in the right place.
What it does
It is a freewheeling arrangement rather than a fixed one - the freehub still does the freewheeling, so you can coast. That makes it the usual choice for single-speed mountain bikes, commuters and winter bikes, as distinct from a track setup where the cog is fixed to the hub and the drivetrain is direct.
Steel, in 13 to 20 tooth, all 3/32 inch - the chain width a derailleur drivetrain uses. That matters when you are converting a geared bike, because you are very likely to be reusing the chain you already have.
Tooth count is how you set the gear, and on a single speed it is the only adjustment you get. Think about the climbs on your regular ride rather than the flat bits; there is no bail-out gear.
Fit and compatibility
For a standard splined freehub body. Needs spacers to set the chain line - get that wrong and the chain will not run straight or stay on. Tell us the hub and we will advise.
Buying it from ProWheelBuilder
ProWheelBuilder builds wheels in Georgia and is not the manufacturer - Surly makes this. It is on our bench most days, which is where the notes above come from.
Warranty
Manufacturer's warranty. Surly warrants this product against defects in materials and workmanship. The duration, conditions and claim process are set by Surly and can change without notice, so ask us and we will confirm the current terms before you buy.
ProWheelBuilder. Our own one-year warranty is a wheel warranty - it covers wheels we build, not tools or accessories. This item is covered by its manufacturer, as set out above.
Full terms are on our Policies & Warranty page.
Surly splined single speed cog questions
Will this fit my existing rear wheel?
If it has a standard splined freehub body, yes - that is the whole idea. You will need spacers to position the cog on the correct chain line.
3/32 or 1/8?
This one is 3/32in, which is derailleur chain width. If you are running a 1/8in track chain you want the track cog instead.
Is it fixed or freewheeling?
Freewheeling - the freehub still does that job, so you can coast. A fixed setup needs a track hub and a track cog.
Is ProWheelBuilder the manufacturer of the Surly Splined Single Speed Cog?
No. Surly designs and manufactures it. ProWheelBuilder is an independent wheel builder in Georgia that stocks it and uses it on the wheels we build.
Not sure? Text or leave a voicemail on 470-253-0929 or email info@prowheelbuilder.com — you will be talking to the people who build the wheels.
