Why Your Bike Rack is Wobbling (And What to Do About It)


As a rider, taking care of your bike is top priority, and you want to make sure it’s safe and secure when attached to your vehicle. But bike racks can wobble…sometimes a scary amount, it seems.

You might be wondering why your bike rack is wobbling and what to do about it. 

Bike racks can wobble for several reasons, depending on the style of rack you use. Wobble is especially pronounced if the rack is installed incorrectly or overloaded with too much weight. A slight movement is normal for certain racks, but there are a few easy ways to stabilize them to put your mind at ease. 

This article will look at different types of bicycle racks and why they wobble. We’ll talk about when a bit of wobble is ok and when it isn’t. But first, let’s talk about why your rack might wobble or shake. 

Why Your Bike Rack Wobbles

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My heart drops into my stomach every time I turn a corner, and the bike on my rack sways a little bit. I get a sick feeling thinking that my bike might come loose or fall off my car. If you’ve ever felt that way, you are not alone! 

There are a number of reasons your bike rack can wobble, but the number one reason is that it isn’t compatible with your bike or your vehicle.

Some racks just don’t fit certain vehicle models. Others, depending on how they hold the bike, may only work with hardtail bikes and not full-suspensions (an issue I ran into myself with my first bike rack…very frustrating!) So first, make sure the rack you are using is designed to be used with your specific vehicle and bike. If you have the wrong rack, it simply won’t work correctly. Check out our article on bike rack compatibility to learn more.

The next step is to make sure your rack is installed correctly. Poor installation can make the rack loose and wobbly. If you’ve checked both of these things and your rack still wobbles, let’s identify some other reasons based on what type of rack you are using: 

Roof Racks 

Roof racks are bike racks that install on the top of your car. They typically will clamp onto your car’s roof rails. These racks are generally very secure and stable, but there are a few reasons they may start to get wobbly: 

  • Rough terrain can make the bike wobble side to side, no matter how secure the rack is. 
  • The clamps or bolts that hold the bike or the rack are worn out and need to be replaced. 
  • The wind and weather are too strong to carry your bike on the car safely.
  • Your bike(s) is too heavy for the rack you are using.  

Trunk Racks

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Trunk racks generally hook onto the top of the trunk. Straps run through the trunk to keep the rack fitting snugly against the back of your car. Your bike hangs from clamps on the rack. Most trunk racks feature adjustments to help them integrate with most (but not all) car shapes and designs.  

Reasons why a trunk rack might wobble:

  • Trunk racks are pretty stable, so the main reason they might wobble is that they aren’t correctly adjusted for your car model. 
  • The straps that secure the rack are not tightened or evenly attached. 

Hitch Racks 

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Hitch racks are some of the most popular types of racks because they hold any type of bike. Hitch racks mount to your trailer hitch and hang off the back of your car.

The biggest downside to hitch racks though is that your car needs to have a trailer hitch installed first…something that can be done on most cars, but at an added expense, making hitch racks some of the most expensive options out there.

These are generally recommended for heavier bikes, such as mountain bikes or e-bikes.

Unfortunately, these racks are the most likely to wobble, potentially due to the following: 

  • There may be movement at the receiver and hitch connection (a little wobble is typical). Also, if there is a little space between the hitch connection and the receiver, there will be a little bit of wobble in the rack. 
  • The car’s momentum and making turns can cause wobble, similar to the feeling of pulling a trailer, although less pronounced.
  • Rough road surfaces can cause the rack to shake and wobble.  
  • Bikes that are not secured properly to the rack can wobble and make it feel like the rack itself is loose. 

Should Your Bike Rack Wobble (Is it Normal?)

Roof Rack

Roof racks are some of the most stable racks because they attach directly to the car’s rails. It is not normal for the rack to wobble, but you might feel some wind resistance when the bikes are attached to the rack. 

Trunk Rack 

A trunk rack fits snugly against the back of your car. It should not have any side-to-side movement and it should not bounce against the trunk of your car if installed properly. It would not be normal for a trunk rack to wobble. 

Hitch Rack 

Due to the method of attachment for a hitch rack, you might feel a little bit of movement or wobble in the rack. This is because the rack extends out behind your vehicle rather than sitting closely against it. A little wobble is ok. Too much wobble, however, could mean the rack is not attached correctly or safely. 

If you think your bike rack wobbles a bit more than it should, here are a few ways to keep them secure. 

How to Fix a Wobbly Bike Rack

How to Secure a Wobbly Roof Rack 

Roof racks shouldn’t be wobbly at all. However, if yours does, you’ll need to check that it is installed correctly and designed to be used on your specific vehicle.

You can do this by checking the owner’s manual or consulting the manufacturer’s website. Check to ensure all the bolts and clamps on the rack are tight, but also check that the roof rails are mounted securely to your car (it may not be an issue with the rack at all, but rather the roof rails.)

It’s also possible the bike itself may be causing the issue. It is normal for bikes to sway a little bit as you drive, but make sure they are mounted to the rack correctly before setting off.

If transporting multiple bikes, you can add additional support by securing the bikes together via a bike lock or ratchet strap. This will at least keep the bikes from swaying in opposite directions and causing added stress on your bike rack.

How to Secure a Wobbly Trunk Rack

A trunk rack fits tightly to your trunk, so it should not be wobbling at all. If it is, you’ll need to check that the rack is designed for your car and that you have installed and adjusted it correctly.

If the rack is rocking because the straps are uneven, uninstall the rack and adjust and the straps, ensuring they are tight enough to keep the rack firmly in place. 

Any motion, however slight, could cause damage to your car. You don’t want 50lbs of bikes crashing through your rear windshield!

If your bikes sway on your trunk mount, you can reduce the wobble using:

  • Ratchet Tie Downs or Rope. Use tie-downs to secure the bikes from the seat tube or the frame to the bike rack and to each other. Adding this extra level of protection may reduce sway.
  • Foam. Adding a little foam around the bikes where they attach to the rack will help protect the frame and reduce any movement from the bike being loose in the mount. 

How to Reduce Wobble on A Hitch-Mounted Rack? 

Hitch racks are the most likely to wobble, and a little bit is normal (although it might be annoying!) You can reduce wobble in a few different ways:

  • Hitch Tightener. It’s very common for there to be a little bit of space around the hitch mount when you slide it into the hitch receiver. So it comes as no surprise that there is a commercially made fix, a hitch tightener. You can see a video on how the hitch tightener works here.
  • Hitch Pin. Another way to reduce the wobble and the noise of your rack is to use a hitch pin. Not only does the hitch pin reduce wobble, but it can also lock your rack to your car to prevent theft. Here’s a video on how that works.
  • Hitch Clamp. A hitch clamp is a cheap and effective way to reduce the sway that comes with normal wear and tear of your hitch mount and rack. Check out hitch clamps here.
  • Bike Rack Support Strap. A bike rack support strap helps secure the bike, and is sometimes required by certain brands to be used with their hitch racks. These straps usually attach inside your trunk or hatchback lid and can be tied around the bike rack frame to add extra support. 

Rob Marlowe

With years of experience as a dedicated mountain biker and an unwavering passion for research, I have cultivated a deep expertise in all facets of cycling—from the intricacies of bike mechanics and gear optimization to the subtleties of riding techniques. My journey has been one of continuous learning, driven by countless hours delving into the science and art of biking. It's this wealth of knowledge and practical know-how that I aim to impart, offering a trusted resource for novices to gain their footing and for seasoned riders to refine their skills and push their limits.

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