Heidenau K 37 3.50-18 Rear Enduro Motorcycle Tyre (TT, Diagonal)

The Heidenau K 37 3.50-18 is a rear enduro motorcycle tyre built for classic and dual-sport machines running 18-inch spoked rims. It fits Jawa, MZ, Simson, IZH and Ural models, along with other road-and-trail motorcycles in this size. The tyre uses a diagonal (bias-ply) casing and carries the TT marking, so it runs with an inner tube.

Key ratings are straightforward. The load index is 62, which equals 265 kg per tyre. The speed index is P, allowing up to 150 km/h. One tyre weighs 5.48 kg and is manufactured in Germany.

The K 37 tread pattern is designed for mixed surfaces. Its blocky layout bites into gravel and dirt, so the bike holds a line on forest tracks. On tarmac, meanwhile, steering stays predictable enough for everyday riding.

The 3.50-18 marking is an imperial size. It means roughly 3.50 inches of width, or about 89 mm, on an 18-inch rim. The dash between the numbers signals diagonal construction rather than radial. As a rough metric equivalent, riders often compare it to 90/90-18 or 100/90-18, depending on profile.

Benefits and Advantages

• Enduro tread pattern – the block layout delivers grip on gravel, dirt and mixed surfaces.
• Diagonal construction – the cross-ply casing resists impacts from rocks and roots.
• German manufacturing – Heidenau tyres are produced in Saxony, so quality stays consistent.
• Load index 62 – a single tyre carries up to 265 kg, which suits riding with luggage.
• Speed index P – permitted road speed reaches 150 km/h.
• TT tube-type build – used with an inner tube, so a trail puncture is fixed by swapping the tube.
• 18-inch 3.50-18 size – fits classic spoked wheels without modification.
• Known 5.48 kg weight – an exact per-tyre figure makes wheel balancing easier.

Who Is This Tyre For?

This tyre suits motorcycles with a rear 18-inch rim sized for 3.50-18. Riders frequently choose it for classic and Eastern European machines. Specifically, that includes Jawa, MZ, Simson, IZH and Ural models.

Beyond those brands, it works on enduro and dual-purpose motorcycles with spoked wheels. The K 37 appeals to riders covering mixed routes. Above all, that means gravel roads, forest tracks and dirt, with tarmac sections in between.

In addition, the tyre handles daily commuting and longer trips. The K 37 profile is produced in both front and rear fitments. In this 3.50-18 size, however, it is intended for the rear wheel. Therefore, follow the rotation direction marked on the sidewall during fitting.

Package Contents

• 1 x Heidenau K 37 3.50-18 rear tyre
• Inner tube not included
• Rim not included

Technical Specifications

Why Choose the Heidenau K 37 3.50-18?

Heidenau is a German tyre manufacturer based in Saxony. The company specialises in tyres for motorcycles, scooters and mopeds. As a result, the K 37 profile has a long service history on classic and enduro machines.

Unlike radial road tyres, the K 37 uses a diagonal cross-ply casing. That construction absorbs point impacts off-road more comfortably. Furthermore, it holds its shape under heavier loads up to 265 kg.

The K 37 is neither a pure road tyre nor a motocross tyre. Instead, it is a dual-purpose enduro tyre for road and trail use. One set therefore covers both a tarmac stretch and a gravel section.

Frequently Asked Questions

Can the Heidenau K 37 3.50-18 be run tubeless?

• No, it carries the TT tube-type marking.
• It is fitted with an inner tube only, even on a tubeless-style rim.

Does this tyre fit a Jawa, MZ or Simson?

• Yes, provided the rear rim is 18 inches and sized for 3.50-18.
• These classic spoked wheels accept the tyre without modification.

Is it suitable for an IZH or Ural?

• Yes, IZH and Ural motorcycles with a rear 18-inch spoked rim are common fitments.
• Check the rim size stamped on your wheel before ordering.

Is this a front or rear tyre?

• In the 3.50-18 size, the K 37 is a rear tyre.
• Follow the rotation direction marked on the sidewall.

What is the metric equivalent of 3.50-18?

• The approximate equivalent is 90/90-18 or 100/90-18.
• The exact match depends on the profile you compare it against.

How much load and speed does it allow?

• Load index 62 means 265 kg per tyre.
• Speed index P allows up to 150 km/h.

What surfaces does the tread handle?

• The block pattern grips gravel, dirt and forest tracks.
• On tarmac, handling remains predictable for daily riding.

Is a tube included?

• No, the listing covers one tyre only.
• An inner tube must be ordered separately.

The Heidenau K 37 3.50-18 pairs a German-made bias-ply casing with an enduro block tread. It carries 265 kg, runs to 150 km/h and weighs 5.48 kg. For a Jawa, MZ, Simson, IZH or Ural on 18-inch spoked wheels, it is a straightforward road-and-trail choice.