Heidenau K37 SW 4.00-19 71P RF TT

Heidenau K37 SW 4.00-19 71P is a workhorse for heavy sidecar rigs. SW stands for Seitenwagen, "sidecar": the square profile and reinforced carcass are tuned for Urals, Dneprs and the like, so the tyre carries the weight and puts power and braking down cleanly. The tread is the same classic block pattern as the K37 — only the construction is beefier.

What K37 SW gives you

• Square profile for a sidecar: Unlike the standard K37, Heidenau K37 SW has a more "square" contour. With a sidecar that means stability and predictability — the tyre is not pulled off centre.
• Carries the load: The reinforced (RF) carcass of Heidenau K37 SW is rated for a loaded sidecar (load index 71 — around 345 kg per wheel for reference). It works under load rather than at its limit.
• Grip on dirt: The big blocks of K37 SW do not flinch at broken roads and light off-road — which is where sidecar rigs live.
• Even-tempered: The bias construction of K37 SW forgives bumps and stays calm over changing surfaces under a loaded machine.

Rubber and carcass

Heidenau K37 SW uses a bias-ply construction in tube-type (TT) form, with a reinforced carcass and a square profile. The block tread grips on dirt and clears itself, while the reinforced sidewall holds the sidecar's weight and the side loads through corners. It is the square contour and the carcass that set K37 SW apart from the standard version — the tread is one and the same.

Which machines usually take K37 SW 4.00-19

The 4.00-19 (TT, reinforced) is the standard for heavy sidecar rigs: Ural, Dnepr, K-750 and similar frames. Heidenau K37 SW goes on the front, rear or sidecar wheel depending on the build. A guide to the class of machine, not a guarantee: check the wheel and approvals against your documents.

In winter

When the cold sets in, there is a winter version with the same casing and profile but a Silica compound and an M+S marking: Heidenau K37 SW M+S SiO2 4.00-19. Below +7 °C it is worth switching to it — the summer K37 SW goes hard in the frost and grips less.

Who it suits

Heidenau K37 SW 4.00-19 is for when you need reliability under a serious load: a sidecar, the road, broken tarmac and moderate dirt. Choose your size and order K37 SW with delivery across Kazakhstan — the full range of Heidenau road-and-trail tyres is here.