4 Reasons Your Rear Bike Wheel Wobbles Side To Side.?

After some time of continuous use, your bicycle may develop some issues that affect riding efficiency. One of the scary ones is when the rear bike wheel wobbles side to side. So, what causes these wobbles?

The two main causes for side to side wobbles in a bike wheel are loose bearings and the wheel not being true. At the same time, damaged hubs and cones could also make your bike’s wheel rock sideways. 

By the time you realize that your bike wheel has some lateral movement, it may have lingered for a while without your knowledge.

Rear bike wheel wobbles side to side - A rider observing his mountain bike on the green hill

4 Reasons Why Rear Bike Wheel Wobbles Side To Side?

Before we get any remedy for wobbly wheels, it is prudent to look at possible wobble causes.

1. Loose Bearings

One possible reason why your bike wheel moves from side to side is loose bearings. Bikes that have free ball bearings use cone nuts to hold the balls in place.

Unfortunately, if the cones unscrew, they create some play in the hub components. As a result, your bicycle wheel will develop lateral movements that cause the bike to wobble.

Also, bearings can get loose if the cups are damaged. With time, they could stretch inwards, creating extra room for the bearing. Consequently, the wheel will develop side wobbles since the balls will be loose.

2. Damaged Hubs

If the bike hub is damaged, then the wheel will most likely wobble laterally. If the cups are broken, they may get out of line and will eventually hurt the hub.

Also, some bikes that use cone and cup mechanisms have unremovable cups that come joined to the hubs. In such a case, if these cups get pitted, you will need to get a new hub.

3. Broken Axle

The other possible reason as to why the rear bike wheel wobbles side to side is a broken axle.

Though this scenario isn’t common, a wheel axle can snap inside the hub. All the same, since the chainstays and the seat stay exert some pressure on the hub, the wheel may carry on but with a lateral wobble.

Definitely, if you don’t replace the axle in time, the broken ends on the inside may cause more damage to the hub, and you may have to replace it too.

4. Uncentered Tire

At times, the rim could be true, but the tire seems to wobble sideways. Actually, it could be a result of a misaligned bead.

In such a case, the rim runs true, but the tire doesn’t. When this happens, you shouldn’t worry at all.

Deflating the tire and re-seating the bead on the rim will solve this problem without special skills or tools.

How Do You Fix A Side To Side Wheel Wobble?

The appropriate method for fixing a wobbly wheel will depend on the cause of the wobble. As we had earlier noted, there are several reasons why the bike wheel could be rocking sideways.

1. Tighten The Loose Hub

With the traditional cone and cup bearings, a loose hub could be the reason why your rear bike wheel wobbles side to side.

Fixing the problem is a simple DIY task.

All you need is a pair of thin wrenches such as the Park Tool Shop Cone Wrench Set (14 Piece) (view on amazon) to help you tighten the loose hub. Notably, the set includes one of 13mm to 24mm and has 26mm and 28mm wrenches.

Once you have the correct tools, unscrew the lock nuts to allow easy access to the cones. Use the open-ended wrenches to tighten the cones snuggly. Notably, an extra one-sixteenth of an inch turn of the cone nuts than it’s necessary would bind the wheel.

Once the cones are in their correct positions, it’s time to screw back the locknuts. Use one wrench to hold the cone in place and another one to turn the outer nut.

How Do You Fix A Side To Side Wheel Wobble

2. True The Wheel

If your bike hub isn’t loose and the wheel has a side to side wobble, the next suspect is unevenly tensioned spokes.

The spokes of any wheel help to keep the wheel straight without wobbling. Unfortunately, if the spokes don’t pull at the same force, the wheel will be untrue.

All the same, using a quality spoke wrench such as the Goabroa Spoke Wrench, which is made of 9H hard steel, will make adjust spoke tension easy. Actually, this tool is ideal for most common spoke cap sizes.

Put the wheel on a truing stand and spin it to locate the wobble. Note to which side each spoke is pulling and locate the ones causing the sway.

If you don’t have a truing stand, you can go for Park Tool TS-8 Home Mechanic Wheel Truing Stand (view on Amazon) It accepts wheels from 16” to 29,” and you can use it freestanding or bolted to a bench. In addition, the stand is made of heavy steel to avoid flexing.

At times, the overly tight spoke will cause a wobble, just like loose ones. Therefore, if the wheel wobbles to the right, the spokes on the left could be loose, or the ones on the right are too tight.

First, locate the loose spokes and tighten them using a wrench. Remember to go slow, turning the nipples half a turn each time.

Once you tighten the loose spindles, go ahead and slightly loosen the adjacent ones pulling to the other side.

Repeat the procedure till the wheel is true.

Notably, truing a bicycle’s wheel isn’t as easy as it sounds. Therefore, it is advisable to seek help from a local bike store if you aren’t sure how to handle the gig.

3. Reseat The Tire Bead

As we had earlier noted, there are times when the rim runs true, but the tire doesn’t. Mostly, this problem is a result of a tire bead that isn’t correctly seated on the rim.

All you have to do is deflate the tire and reseat the tire bead to rectify this error. If you spin the wheel, the line on each side of the sidewalls should appear to have the same distance from the rim. In case the lines seem to be rising and dipping, then the tire is defective.

However, if the tire has no defects, reseating the bead should make it run true without a side-to-side wobble.

Rear bike wheel wobbles side to side - a Mechanic removing the inner tube

Is A Wobbly Rear Bike Wheel Dangerous?

A wobbly wheel can be dangerous, but the level of danger depends on the reason behind the wobble. There are times when a wheel that wobbles could be a hazard while others are not.

Actually, riding a bike with a wobbly wheel may not pose an immediate danger to you as the rider, but it could eventually make the wheel fail. Actually, one problem leads to another, and finally, the wheel will collapse.

Technically the magnitudes of rear-wheel wobble matter a lot. The greater the wobble, the more likely you are to get broken spokes.

Therefore, a wobbly rear bike wheel may not pose any danger to the rider, but it could lead to more damage to the bike components.

Notably, most riders admitted to having ridden bikes with wobbly tires at one time or another to get them home.

What Does A Loose Wheel Feel Like?

A loose wheel will feel as though the steering of your bike is shaking. In addition, you are likely to feel the whole bike shake or vibrate.

When a bike’s wheel is loose, the bearings have some play which is not supposed to be the case. In such a case, the wheel will wobble side by side in quick succession, transmitting the wobbles through the frame.

For beginners, it is easy to confuse the shaking due to a loose wheel for effects of faulty steering components.

However, conducting a quick check on both the wheel and the steering will clear the doubts.

Is A Wobbly Rear Wheel Easy To Fix?

The ease of fixing a wobbly rear wheel will depend on the cause of the wobble. If the wheel wobbles side to side because of a loose hub, it is easy to fix.

All you need is a set pair of thin wrenches to help you tighten the cones and locknuts against the bearings.

On the other hand, if the wobble results from broken/missing spokes, fixing it can be quite demanding. Also, if the wheel is untrue because of loose and overly tight spindles, the principle used in fixing it is easy, but the actual task isn’t.

Therefore, if you are sure of how to fix a wheel that needs the replacement of spokes and trueing, it is advisable to seek the services of a professional bike mechanic.

Rear bike wheel wobbles side to side - A man repairing a bike wheel

Also Read: Can You Ride A Bike With A Broken Spoke?

Final Word

When the rear bike wheel wobbles side to side, the first suspect is a loose hub. If the ball bearings are in good condition, tightening the cones to a snug should stabilize the wheel.

Consequently, don’t forget to screw back the lock nuts to keep the cones in place.

On the other hand, if the wheel wobbles due to uneven tension, trueing it would solve the problem.

If you aren’t sure of what to do, visit your nearest bike shop for help.