Surly Track Cog
Surly's track cog threads onto a track hub and, with a lockring behind it, makes a fixed drivetrain: no freewheel, no coasting, the cranks turning whenever the wheel does. It is a different thing entirely from a single-speed cog on a freehub, even though both leave you with one gear.
What it does
Because it is fixed, the cog is loaded in both directions - driving forwards and resisting when you slow with your legs. That reverse load is why a lockring exists and why it is reverse-threaded: backpedalling tightens the lockring against the cog rather than unwinding it.
Surly offer this one in both 3/32 inch and 1/8 inch. The 1/8in is the traditional track chain width, heavier and more forgiving of chain line; 3/32in suits a lighter derailleur-type chain and a conversion where you already have one. Match the cog to the chain and the chainring, not to the bike's intended use.
Steel, because a fixed drivetrain is hard on cogs. The teeth take drive and braking load every revolution, and an alloy cog in that application is a consumable measured in months.
Fit and compatibility
For a threaded track hub, used with a lockring. It will not fit a splined freehub body - that takes the splined single-speed cog instead.
Buying it from ProWheelBuilder
We are an independent wheel builder in Georgia, not Surly. We buy this like you do; the difference is we go through a lot of it.
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. Tools and accessories sit outside ProWheelBuilder's one-year wheel warranty, which applies to the wheels we lace. Cover for this item is the manufacturer's.
Full terms are on our Policies & Warranty page.
Surly track cog questions
Do I need a lockring as well?
Yes, and it is not optional on a fixed wheel. The lockring is reverse-threaded so that backpedalling tightens it rather than undoing the cog.
3/32 or 1/8?
Match the chain. 1/8in is the traditional track width; 3/32in is derailleur width and is common on conversions where the chain is already there.
Can I use it on my geared bike's rear wheel?
No - that has a splined freehub body, which takes the splined single-speed cog. A track cog threads onto a track hub.
Is ProWheelBuilder the manufacturer of the Surly Track 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.
