Setting Up Your Drivetrain for Quiet, Smooth Zwifting

August 10, 2023

LAST UPDATED August 10, 2023

Cycling is full of small but golden joys. Rounding a corner to encounter an amazing valley view… descending on perfect asphalt… working together in a chain gang to tick off the flat miles quickly.

One of my simple joys is pedaling along on a smooth, empty road atop a clean, quiet bike. Every cyclist knows that a quiet bike is an efficient bike, so that feeling of noiselessly propelling myself forward brings satisfaction on several levels.

The feeling carries over to indoor riding, too. A quiet, smooth drivetrain simply brings more pleasure to the Zwifting experience. Conversely, a noisy chain, skipping gears, or even a whiny trainer can really put a damper on a Zwift session.

If you’re annoyed by the noise of your riding on Zwift, never fear. Here are the tips you need to make your next Zwift session smooth and quiet.

Fixing Foundational Issues

There are some “big” drivetrain issues that no amount of adjustment or lubrication can fix. These problems should be addressed first, since your setup is fundamentally broken until these are fixed.

Wrong Cassette (Direct Drive Trainers Only)

While not necessarily a requirement, the number of cogs (“speeds”) on the cassette on your trainer should match the number of cogs on the cassette on your back wheel. It just keeps things simpler.

In some cases, you may be able to get away with a slightly smaller cassette on your trainer than on your back wheel (say, a 10-speed cassette on your trainer and an 11-speed on your back wheel). But this isn’t ideal, and will require some shifting adjustments whenever you swap your bike on and off the trainer.

In most cases, if the number of cogs on your trainer cassette doesn’t match your back wheel, you’ll have big problems! For example, a 10-speed trainer cassette on an 8-speed bike will be a huge mess, since the 8-speed chain is too wide for the 10-speed cassette.

Save yourself the hassle and just buy a cassette with the same number of cogs as your back wheel. Amazon has plenty, and so does your local bike shop. (Note: you’ll need a chain whip and lockring tool to remove/install your cassette.)

Worn Out Parts

Your bike chain is considered a “consumable” as it wears out and “stretches” with use. If you ride too long with a stretched chain your cassette will get prematurely worn as well. Here’s a video from Park Tool describing how to measure chain wear (your local bike shop can help you here if you don’t have a tool, but they’re quite affordable and easy to use):

If your chain is fairly stretched, it has probably already worn the teeth on your back wheel’s cassette. This means your bike may feel smooth outdoors, but when you put your bike on a trainer with a new cassette, the chain won’t mesh up with the cogs as evenly, and it will be noisy or even skip some teeth.

To quiet things down and avoid damaging (quickly wearing) your smart trainer’s cassette, replace your chain. You may also need to replace the cassette on your rear wheel, if its teeth are worn. Again, your local shop can give you expert guidance.

Indexing Your Gears

The most common drivetrain noises Zwifters encounter are caused by incorrectly indexed rear gears. That is, the rear derailleur is not adjusted to place your chain in the correct location for each of the cogs (speeds) on your rear cassette.

Ideally, your smart trainer will be set up so you can swap between trainer and outdoor use without needing to adjust your shifting one bit. But sometimes, your trainer’s cassette may not be located in exactly the same place (left to right) as your back wheel’s cassette.

Trainers typically ship with a spacer ring or two which can be installed on the inside of the cassette to “bump it out” a bit. This is a good option to try, because again, if you can get that cassette in the right location, you may just be able to swap between indoors and out without adjusting your rear derailleur at all. (Note: you’ll need a chain whip and lockring tool to remove/install your cassette.)

Sometimes, though, no matter what sort of cassette spacers you try, you just can’t get it to line up quite right. In that case, it’s time to index your gears so your bike shifts smoothly on the trainer. This really isn’t a hard job – here’s a GCN vid that walks you through how it’s done:

Chain Lubrication

Keeping your chain clean and well-lubed help quiet your drivetrain, but it will also save you money since it’ll help your chain and cassette last longer.

If you’re using an oil-based chain lube (as opposed to wax-based), you’ll want to clean your chain regularly, too. For a full, deep cleaning, picking up a chain cleaning tool such as this one from Park Tools makes the job much easier, and you’ll need a degreaser as well (I like Orange Degreaser). You can also use a product like Muc-Off Drivetrain Cleaner for a spray-on, wipe-off clean.

Here’s a video from Trek showing how to clean your chain using a chain cleaning tool (or toothbrush) and degreaser:

Not sure which lube to use? There are many chain lubes on the market, and every rider you ask will have a different opinion of what’s best. Here are a few popular products that work well:

I’ve actually been hot-dipping my Zwift and road bike chains in wax for the last few years (and really should write a separate post about this sometime). Chain waxing means my drivetrain is always clean to the touch, lasts longer, and doesn’t attract dirt. I use Molten Speed Wax products, but there are other good ones on the market.

A Note About Sound Absorption

It’s possible that your drivetrain/trainer sounds especially loud because you’re in a noisy room. If you’re on a tile floor, for example, the sound will just bounce off the floor and around the room.

If you’re in a noisy room, you may consider installing foam gym tiles on the floor. They’re quite affordable, feel nice underfoot, give your trainer a bit of side to side movement, save your floor from scratches, and of course, absorb sound and vibrations. (Your downstairs neighbors will thank you!)

There are other steps you can take to quiet your room further, including sound absorption tiles on walls or ceiling, carpet on the floor, etc. Those are outside the scope of this post.

Extra Credit: Quieting Your Smart Trainer

While your drivetrain may be lubed and adjusted perfectly, it’s possible that your trainer itself is noisy. (Wheel-on trainers, for example, are inherently noisy… not much you can do to fix them. Modern direct-drive trainers, though, are very quiet compared to what was on the market several years back.)

If your trainer too loud for your taste, here are two suggestions: