cheapnewb24 wrote on 07/01/16 at 14:43:28:Why do dirt bikes use chains?
I read in other threads that dirt roads were hard on belt drives.
Dirt roads, and dirt race tracks, are pretty hard on chains too. Ask a motocross or enduro racer how long his chains and sprockets last.
Chains are used on dirt bikes for reasons that aren't really related to their longevity.
Sprockets are smaller and lighter than pulleys. That's especially important at the rear wheel where the less unsprung weight the better. A sprocket instead of a pulley on the output shaft contributes to designing a skinnier engine, which is a plus on an off road bike.
Dirt bikes have a lot of suspension travel. A chain can be run looser than a belt to accommodate that travel.
Chain and sprocket final drive makes gearing changes simple. That's mostly important to racers, but it comes in handy for tinkerers too.
If you happen to break a chain on a long off road ride or enduro type race it's pretty easy to repair it with stuff that doesn't take up much room - couple of master links, a three or four inch section of chain, a chain breaker will fit in a jacket pocket. The only way to fix a broken belt is to replace it. A new belt isn't as easy to carry.
Chains and sprockets are considered to be normal maintenance items on any motorcycle that is ridden hard or for long distances in the dirt. I've got no idea how a belt would stand up to that kind of riding. Iv'e never seen one on a real dirt bike.
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