9 Things to Know About Belt Drive E-Bikes

Are you intrigued by the idea of a maintenance “free” e-bike with a belt drive? Is a belt drive best for an electric bike? It really comes down to your unique use case and personal budget.

In this article, we will cover whether a belt-drive electric bike is right for your next bike, answer belt-drive frequently asked questions, and review belt-drive maintenance tips. Let's dig into belt-drive electric bikes!

What is "Belt Drive" for Your E-Bike?

Simply put, you have a carbon fiber belt instead of a chain on your bike's drivetrain.

Belt drive technology is not new, as it has been used in the engines of cars, motorcycles, and bikes for many years. It hasn't been super popular for non-electric bikes because it adds weight, cost, and some drag to the bike's drivetrain. Also, you need a specially designed frame for the belt to slip on since the belt is one piece. This means it isn't easy to add after you own a bike unless it is designed for this to begin with. Finally, if you want gears, you’ll need an internally geared system because a belt does not work on a derailleur.

Belt-drive bikes have become more popular recently thanks to the increased interest in electric bikes and using electric bikes for transportation. Electric bikes really benefit from a belt drive system because the belts last much longer than chains with the high torque of mid-drive electric bikes. You often can get 1 belt to 2-3 chain replacements, or even more! You also have all the benefits of an internally geared hub! There isn't a derailleur hanging off your bike, a chain to keep clean and lubed, and you can shift your bike at a stop with the internally geared system. This is very handy if you have a heavier electric or cargo bike!

The most popular brand of belt drive systems is from Gates, and you’ll often hear belt drive and “Gates Carbon Drive” used interchangeably. Gates is a huge company that largely works in the automotive industry.

What is a Belt Drive Made Out Of?

The belt is made of carbon fiber, and the front and rear cogs are made of stainless steel. The belt is one piece and does not come apart, so you have to have a special bike frame that allows for an opening for the belt to slide through.

Why You May Want a Belt Drive E-Bike

I asked on Twitter why people chose a belt-drive electric bike. The main reasons:

1. A lot less week-to-week maintenance

2. Longer intervals between needing to be replaced

3. A cleaner drivetrain

4. How quiet it is

Why You May NOT Want a Belt Drive E-Bike

1. More expensive to get started

2. Requires an internally geared system

3. Special parts that not all shops keep in stock or know about

Most Common Belt Drive Service Problems

• Super dry areas can get dirt statically stuck to the belt. All you need to do is wash it off with plain water

• Some people try to use bike lube on the belt - Do not do this!

• The belt is over or under tension

• When removing the rear wheel, some do not loosen the tension enough, so the belt is under too much tension when you reinstall the wheel. If forced, you will manipulate the belt or walk it on like a chain. This can break the fibers in the belt. It may look fine at first, but it can cause premature failure.

Basic Maintenance for Belt Drive Electric Bikes

• If your belt is dusty or dirty - use water to gently wash it off

• In highly dusty areas, you can try a silicone spray that Gates recommends. Do not use bike lube!

• Every 200-500 miles, you want to check that the belt is properly tensioned. You should also check that your rear wheel is aligned correctly and tight and that the sliding dropouts, if you have them, are tight and haven’t slipped forward. Depending on the bike, the main reason your belt tension changes is the bike, not the belt. This could be your wheel pulling forward, the tensioner wearing down, or something else.

• If you have a tensioner, check it for wear and ensure that it is spinning freely. Then, lube any bushing or bearing within it.

• A quick note: If you happen to be riding a new GSD Gen 2 cargo bike, all of your work will be done on the non-drive side to access the belt. On the normal drive side, where the belt is, there is a full chainguard covering it. This is removable but unnecessary for normal maintenance, like checking the tension or lubing your tensioner.

How to Check Tension on a Belt Drive E-Bike

This can be done with a very fancy and expensive tool or the free Gates Carbon Drive phone app, which I recommend for home users.

Set yourself up in a quiet place, as it uses sound to check. Now, you are going to pluck your belt like a guitar string. You do this in 3 different places on the belt: pluck, rotate a bit, pluck again, rotate, etc. It then takes an average. 

Depending on your bike and gear system, you’ll be looking for different numbers. The most common range that I’m looking for is an internally geared hub with a mid-motor e-bike system; this range is 40-55Hz.

What to Know About Belt Drive Replacement Parts

I don’t believe this section will apply to most folks, but if you are looking to replace parts on your belt-drive bike or have replacement parts at home just in case, here are some things you need to know.

1. The belt is a fixed piece, and you’ll need to know how many teeth yours has and which type of belt it is, as there have been a few different ones over the years with a groove or “CenterTrack” in the middle and not.
   At the time of writing, the Gates CDX belt style is the most popular. For example, on the GSD Gen2 S00, this is the replacement belt: “Gates CDX 174T, 92551077, 11M-174T-12CT BLACK.” What you need to know is Gates CDX 174T.

2. Do not fold or kink the belt. Treat it like a garden hose as you try to keep it round or oval.

3. The sprockets need to match the belt type and your hub. CDX = CenterTrack. There are specific ones for Rohloff bikes.

4. Any bike shop can order these parts for you, or you can order them online as long as you know what you are looking for.

Belt Drive on a Bike Overview Video

Final Thoughts

I don't believe a belt drive is a "must-have" for many riders, but it may be worth the money for those who don't want to deal with service, put a lot of miles on their bike, or ride somewhere that really would benefit from not having a chain.

Do you own or plan to buy a belt-drive electric bike? Let us know in the comments!