If you're exploring resoling options or shopping for climbing shoes, you might have come across Unparallel’s RH and RS rubber compounds. These are Unparallel’s go-to high-performance rubbers — known for their feel, stickiness, and reliability across a range of climbing styles.

Both rubbers are top-quality and used on Unparallel’s flagship shoes, but they serve different purposes. Here's what sets them apart, how they perform, and how to choose the right one based on how and where you climb.

Quick Comparison: RH vs RS Rubber

Unparallel RH 4mm: Reliable Grip with Edge Support

RH stands for "Real Honor", and it's the workhorse rubber of the Unparallel lineup. At 4mm thick, it offers solid edge stability without feeling overly stiff. It’s designed to balance grip, durability, and support, making it a great all-rounder for climbers who tackle varied terrain.

Key Features:

• More structured feel: Slightly firmer than RS, giving better edge hold on small footholds.

• Longer wear life: Great for resoles where durability matters.

• Good all-round performance: Suitable for sport, trad, and indoor climbing alike.

Best used for:

• All-purpose resoles

• Outdoor routes with small edges

• Climbers who prefer slightly stiffer shoes

• Anyone looking for durability without sacrificing too much grip

Unparallel RS 3.5mm: Soft, Sticky, and Sensitive

RS is Unparallel’s soft compound rubber, and it’s all about maximum friction and sensitivity. At 3.5mm, it’s thinner and more pliable than RH, which allows it to conform to the rock or gym holds more easily. That means better surface contact and more trust in marginal smears or slopey feet.

Key Features:

• High friction: Grips well on volumes, polished holds, and sandstone.

• Maximum sensitivity: You’ll feel exactly what’s under your feet.

• Faster wear: Being softer, it does wear faster — especially on rough rock.

Best used for:

• Indoor bouldering or competition climbing

• Steep overhangs and toe hooks

• Climbers who value stickiness and feel over edge rigidity

• Resoling shoes designed for performance and grip

How to Choose Between RH and RS

Both compounds have their place, and the right choice depends on your needs:

• Choose RH (4mm) if you:

  • Want a longer-lasting resole

  • Climb mainly outdoors on vertical or technical terrain

  • Need better edging and support

• Choose RS (3.5mm) if you:

  • Prioritize friction and foot sensitivity

  • Climb mostly indoors or on steep routes

  • Need max performance for smearing or comp-style bouldering

Many climbers actually run RH on edging shoes and RS on bouldering shoes — or choose based on the specific demands of the shoe model being resoled.

Final Thoughts

Unparallel’s RH and RS rubber offer high performance in different ways: RH gives you durability and edging precision, while RS maximizes friction and feel. If you're getting your shoes resoled, picking the right rubber can help them perform like new — or even better — for your style of climbing.