Mountain bikes are great fun, but they require significant maintenance, especially if they are used frequently. The wheels and tires of mountain bikes receive more wear and tear than any other bike component and therefore experience the most issues. A very common MTB problem is tire wobble, and many wonder what can cause this frustrating issue.
Mountain bike tires can wobble if the rim, wheel, or spokes are damaged or if the tire is not seated correctly in the rim. Other causes may be a twisted inner tube, damaged tire beads, a rim that is out of true, or even incompatibility between the tire and the rim.
If your mountain bike tire is wobbling and you are unsure why it can be infuriating. Fixing this issue is critical, as it can make the bike dangerous and uncomfortable and can cause damage to the bike itself. There are several causes for mountain bike tire wobble, and they are all addressable.
What Can Cause A MTB Tire To Wobble?
Mountain bike tire wobble is a very common issue, and there are several causes for it, but they are all difficult to identify.
Everyone who has installed a new tire onto a mountain bike knows that it can be very difficult. There are many factors that go into seating a tire properly, and if any of these factors are not what they should be, the tire will wobble significantly.
Tire wobble can cause serious safety and maintenance issues for mountain bikes, which means that this problem must be rectified quickly.
Let’s identify the most common causes for mountain bike wheel wobble and what can be done to fix them.
A Bent Or Out-Of-True Rim
A common cause for tire wobble is a damaged rim or a rim that is out of true.
If the rim of the wheel is damaged, the tire may not be able to seat properly in the rim. This will cause the tire to wobble significantly as it rotates. This may have occurred if the bike had a recent accident or a hard knock that may have caused damage.
A wheel that is out of true has warped dimensions. This means that as it rotates, it will wobble, and these dimensions may cause the tire to become unseated or misaligned. If the wheel is out of true, it is sure to wobble when in motion.
The only way to fix these issues is to repair the wheel, return it to true, and reseat the tire. If the wheel is damaged beyond reasonable repair, it will need to be replaced entirely.
An Improperly Seated Tire
The most common cause for a wobbly mountain bike tire is when the tire is not seated correctly.
Some tires, especially tubeless tires, are only compatible with specific rims. New tires can be especially difficult to fit well, as they are very stiff and struggle to pop into place.
If the tire and rim are not compatible, the tire will not seat properly. If the tire is too stiff, it will not seat easily.
To check if this is the issue, simply examine the wheel. If the tire is evenly seated all the way around on both sides of the rim, the problem lies elsewhere, but if the tire is incorrectly seated at certain sections of the rim, this is the cause of the wobble.
To rectify this issue, you can use tire pry bars to wrestle the tire onto the rip properly, or you can take the wheel off and use some soapy water to lubricate the rim and re-install the tire.
If the tire does not fit, overinflate it slightly until the soapy water allows it to pop into place correctly.
If the tire and rim are not compatible, you will need to buy a compatible set to rectify the wobble.
A Twisted Tire Tube
Mountain bike tires that use inner tubes are usually easier to seat in the rim, but if the tube inside the tire is not functioning correctly, or if it is twisted inside the tire, it will cause serious wobble.
This is a common issue among inexperienced riders.
If your tires use inner tubes, remove the wheel, deflate the tube, remove the tube, and re-install it correctly.
Be sure to slightly inflate the inner tube before inserting it into the tire, as this will prevent the tube from twisting during installation.
When you are sure that the tube is seated well and not twisted, inflate it correctly and properly seat the tire.
If the wobble has been corrected, this was the cause.
Damaged Wheel Spokes
Sometimes a tire can wobble due to an issue, damage, or defect in the wheel. The most common instance of this is damaged wheel spokes.
If the wheel spokes are damaged or broken, the wheel itself will not be as strong as it should be, and it will become unbalanced. This will cause the wheel to wobble in rotation, especially with weight on the wheel.
Inspect the wobbly wheel to look for any damage to the rim, spokes, or any other component. If the spokes or other components are damaged, this is likely the cause of the wobble.
Repair any damage that you can, and check if it reduces the wobble. If not, you may need to take the wheel to a repair shop to be fixed or replace the wheel entirely.
Damaged Or Unseated Tire Beads
Damaged or unseated tire beads are another common issue that causes tire wobble.
If the beads of the tire are not seated correctly, this could be that they are too high or too low in the rim, or the beads could be misaligned, then the tire will wobble.
If the beads are damaged, causing the tire to become unseated or unstable, it will wobble significantly.
Damaged tire beads are, unfortunately, irreparable, and if this is the cause of the wobble, the tire must be replaced.
However, if the beads are simply not seated well, the wobble can be rectified by looking up some techniques for properly seating these tire beads and taking steps to install the tire correctly.
Conclusion
A wobbly tire on a mountain bike can be frustrating and even dangerous. It is important to take steps to rectify this issue. Find the root cause of the wobble before taking any steps, and you will be far more likely to resolve it.
Some wobble issues can be solved, while others require replacement tires, replacement rims, or both. If you have real trouble with the wobble, take your bike to a repair shop to be assessed, and take advice from professionals.