Heidenau Inner Tube 21 D – 34G Valve

Heidenau 21D fits the 3.00, 3.25, 80/100, 90/100, 90/90, MH90 size range for 21-inch rims — wider than the 21C.

The wall here is thinner than in the Cross class — 1.5–2.0mm: enough for everyday road riding.

Material and durability

Heidenau 21D is made from natural rubber: the material resists mechanical stress better than synthetic compounds and holds elasticity for longer. The trade-off: it loses pressure slightly faster than synthetic rubber, so check pressure with a gauge from time to time.

Valve and fitment

Heidenau 21D comes with a standard-length, straight 34G valve — a simple, reliable choice where no bend angle or extra stem length is needed.

Application

Heidenau 21D suits motorcycles with a 21-inch front wheel under normal road conditions. Natural rubber retains elasticity better at low temperatures in Kazakhstan's winter, but ages faster than some synthetic materials during prolonged use in summer heat.

Fitting recommendation

When fitting Heidenau 21D, check the length of the original valve and use a new rim tape of the correct size. Pinching the tube with tyre levers remains one of the most common causes of premature tube failure.