ブチルインナーチューブ: 浸透性が耐用年数を決める理由

The tube's job is to hold pressure over weeks, not hours. That makes air permeability the defining property, and it is why butyl remains the standard tube material.

Why butyl

Butyl rubber has very low gas permeability compared with natural rubber, so pressure loss between top-ups is much slower. It also has good heat and ozone resistance at the temperatures a tube sees inside a tyre.

Specification fields

• •Size range the tube covers, and whether it is designed for radial or bias application.
• •Gauge or wall thickness — thicker gauges resist punctures but add weight and heat.
• •Valve type and stem length — mismatched valves are among the most common reasons a delivered tube cannot be fitted.
• •Butyl content — higher content generally means lower permeability and higher cost.

What causes premature tube failure

• •Incorrect size, causing folding and chafing inside the tyre.
• •Valve stem damaged during fitting.
• •Contamination or trapped moisture inside the tyre at fitting.
• •Running at low pressure, which generates heat and flexes the tube far more than designed.

On delivery, check the valve specification against your rim, and confirm the size marking matches the tyre rather than the box. ## Need the documents or today's price? Send us the grade, quantity and destination port — we return a quotation with COA and MSDS attached. Email manager@fipolymer.com or use the inquiry form on this site.