sisärenkaalle

Sisärenkaalle is a Finnish term that literally translates to "for the inner ring." This phrase is most commonly encountered in the context of car tires, specifically referring to the inner tube of a tire. Historically, many tires were of the tube-type variety, meaning they required a separate inner tube to hold air. This inner tube would be placed inside the outer tire casing, which then mounted onto the wheel rim.

While modern tubeless tires are prevalent today, the concept of an inner tube still exists. In some specialized applications, such as heavy-duty vehicles, off-road vehicles, or older tire designs, inner tubes remain in use. The term "sisärenkaalle" would be used when discussing the purchase, replacement, or maintenance of such an inner tube. For example, a mechanic might tell a customer that they need a new "sisärenkaalle" for their tire.

The function of an inner tube is to provide a sealed air chamber within the tire. It is typically made of a flexible, airtight rubber material. When a tire is inflated, the inner tube expands and presses against the inside of the tire casing and the rim, creating a seal that holds the air pressure. A puncture to the inner tube would result in a loss of air, causing the tire to deflate.