Drivetrain Sprocket

[Chris is me]

For WCDs, your options are 18T or 22T for #25 chain, or 12T for #35 chain.

The bigger the sprocket, the less chain "stretch" (pin wear) you have to deal with, and the easier it is to keep in tension. The tradeoff is more weight and less clearance.

It is honestly not that hard to keep 25 chain aligned and tensioned if you plan ahead and don't build sloppy drivetrains. The challenges are often overstated. I would generally recommend starting with 25 and switching to 35 chain if you have any problems with the 25 chain - the weight penalty is pretty big.

This year, especially if you had larger pneumatic wheels, the rough driving over defenses led to more chain and sprocket damage than normal, making 35 chain a safer choice, particularly for big wheels which place more load on a sprocket and chain (all other things equal). For 6" wheels, you are probably okay with 22T #35 chain. This the size my team ran and we never had issues apart from having to tension it repeatedly. For 4" wheels, or 6" wheels on a flat field game, 18T #25 chain can work just fine too with a bit more clearance.

Originally Posted by lark95

We have always used #35 chain for drive train and tend to use 22 tooth sprockets on the wheels. This gives plenty of teeth while still being small enough to fit on a 4 inch wheel. Our size of choice for general wheeled drive trains. Last year being the exception as we had treads.

This does not work for west coast drivetrains - a 22 tooth 35 chain sprocket is bigger than 2 inches in diameter and will not fit within the profile of the tube. If there is a belly pan placed below the tube (as is common on most WCDs) the chain will not have clearance.