Heidenau Inner Tube 18 K – 34G SV Valve

Heidenau 18K fits the 240/40, 250/40, 260/40, 280/35 size range for 18-inch rims — the lowest-profile tube in the 18-inch line.

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

Material and durability

Heidenau 18K 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 18K comes with a straight, long-stem 34G SV valve — the extra length helps when the standard stem doesn't reach through a wide rim, and no bend angle is needed here.

Application

Heidenau 18K suits motorcycles with low-profile tyres on an 18-inch rim 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 18K, 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.