Box Tech Tips: Changing a Rear Cog

June 12, 2018 by  

Box Tech Tips: Changing a Rear Cog

Changing your gear at the races is always a harrowing task. The pressure is on to get to practice, or before your next moto is called to staging. So, it really helps to know exactly what you’ll be facing when you pull the wheel off and start spinnin those wrenches.

In this week’s Box Tech Tip, Tyler Brown takes us through the process of changing a cog.

The process is somewhat the same on most brands of hubs–you’ll need to purchase a “chain whip tool,” which holds the cog in place as you use the next required tool–which Tyler refers to by it’s given name: a “bottom bracket tool.” Don’t let that fool you, it plays double duty here on the back wheel as well, to loosen/tighten the locknut that holds the cog on the hub.

A Chain whip and Bottom Bracket tool are essential parts of your BMX toolkit, so pick them up at any online vendor, like Amazon, Chain Reaction or similar.

You’ll probably invest $30-$40 on those tools, but NOT having them when you need them is one of those moments when you’d pay triple for them, so best to get them now.

OK, now that you have some of that primer, here’s the demo of the quick-and-easy process.

If you have a complete bike that is on the entry level, price-wise, your back hub may use a “clip ring” to hold the cog onto the hub, in which case, you can probably get away with a couple flathead screwdrivers to coax the ring out of its groove, then back on. Give it a look before buying those “essential” tools noted above, to ID which format your hub uses.

Still others don’t use a cog at all, but a “freewheel,” which threads on to the back hub, and requires different tools to remove. We’ll cover that in a future tech tips feature.


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