Why is my tube deformed when I inflate it?

When a tube is inflated without being installed over a rim and under a tyre, it may become deformed or uneven in shape. This usually happens when the tube is over-inflated. To avoid this, always inflate your tube very slightly (around 5 PSI) if you’re not installing it directly onto a rim and under a tyre.

What should I do if my tube is deformed?

If your tube feels uneven or lumpy after being installed, it’s likely because it was over-inflated before installation. However, once installed over a rim and under a tyre, the pressure from the tyre will usually help shape the tube properly.

If the tube still feels lumpy or has an uneven texture after installation, it could be a sign of damage caused by over-inflation. In such cases, the tube may need to be replaced. This is not a manufacturing defect—it’s caused by improper inflation.

Can I still use the tube if it's deformed?

If there are no visible bumps or damage, and the tube is properly installed with the tyre, it should be fine to ride. However you should continue to monitor its performance and if you observe possible damage, such as a bump, that’s a sign that the tube is permanently compromised, and it should be replaced for safety.

Example

Deformed tube Why is my tube deformed when I inflate it?

Example of a deformed inner tube

Here you can see the tube has been over-inflated outside of it’s intended environment (ie without the tyre and rim surrounding it). As a result a deformity has been created and is a high chance of exploding.