Tyre Bead

The bead is the inner edge of the tyre, reinforced with a steel wire or aramid bundle, that sits against the rim flange. It holds the tyre on the rim and, on tubeless tyres, forms the airtight seal.

When fitting a tyre, use tyre mounting lubricant and push the opposite side of the bead into the rim well, which makes it far easier to lever over the edge. Inflate until the bead pops into place and check that the moulded line on the sidewall sits evenly all the way round. Never exceed the maximum seating pressure stated on the tyre.

Off-road riders use rim locks to stop the bead and tube slipping at low pressure. A damaged or kinked bead wire means the tyre must be replaced.