For some projects, the choice between a chain drive and a belt drive will be pretty clear-cut. On others, you’ll work through the pros and cons of both and no obvious winner emerges.
Let’s go through some of the factors in the chain drive vs. belt drive discussion.
System speed and ratio
Belt drives are more effective for high speed applications and systems with a low velocity ratio. Not only do they transmit power better at higher speeds, the fact that they are friction drives means they will slip in the event of an overspeed. That may sound like a mark against them, but belt slippage could protect the rest of the system from more serious damage by “disconnecting” the downstream components from the runaway component.
Chain drives are better for low speed, high torque and higher velocity ratio systems. The flexibility system designers have in setting the sprocket ratios allow them to take advantage of chain drives’ high torque production, increasing the efficiency and output of the system.
Arrangement of components in the system
The amount of space you have available may influence your choice of a chain drive or belt drive. Because they are friction drives, the belt needs to be wider to transmit higher power levels. For a given amount of power you need to transmit from Component A to Component B, you may not have enough clearance for a belt.
Belt drives also work better for longer distances between the shafts. This ties in to the speed discussion above. You’re more likely to have a larger distance between shafts in a high-speed application, while keeping close together two components in a high torque situation.
Belts also give you a bit of leeway in terms of the shafts staying parallel to each other. If you need to have some tolerance in shaft alignment, belts will permit that. Chains, on the other hand, will only work between rigorously consistent parallel shafts.
Costs, maintenance and lifespan
Chain drives cost more than belt drives for a given length and set of specs. Chain drives also require more maintenance and lubrication.
However, chain drives are more efficient than belt drives. Anything with the word “friction” in it, like “friction drives,” is going to have some losses. Chains also have a longer lifespan and durability under a wider range of conditions than belts.
These factors, then, somewhat balance out over the course of a component’s hypothetical lifespan. However, making the wrong choice between a belt drive and chain drive can exacerbate the downsides and run up the operational costs.
Deciding between belt and chain drives
As you list out the pros and cons, you’re ultimately answering a few basic questions. How much power are you transmitting? At what speeds? Over what distance? For what purpose?
The answers to those questions will answer the one we came here to talk about: Do we need a belt drive or a chain drive? And if you want to talk some more about these options, drop us a line.