Quick Overview

An assisted-braking resistor. Edelrid's solution for climbing partners with a large weight difference.

An assisted-braking resistor. Edelrid's solution for climbing partners with a large weight difference.

In many climbing partnerships, there can be a great difference between the weight of two climbers. This is particularly common (though not always the case) in climbing couples, where the woman might weigh significantly less than the man.

In these situations, it's common for the lighter climber, when belaying, to get pulled upwards violently, or sucked into the first 'draw. Belaying someone heavier also demands more hand braking force.

As a result, you can get into a situation where the climber isn't confident that the belayer will catch his/her fall, or they're worried about their belayer getting injured. Conversely, the belayer is worried about his/her ability to catch the fall, and of injuring himself/herself in the event of flying into the wall/'draw.

For the lead climber, a big weight disparity is also problematic, because a light belayer can mean lead falls of a bigger distance. That, in turn, increases the possibility of groundfalls, or colliding with the belayer in the event of a fall.

Edelrid invented the Ohm to address these issues.


The lead climber clips the Edelrid Ohm to the first bolt of a sport climb. If the leader falls, the Ohm increases rope friction. This helps reduce the likelihood of a light belayer being jerked violently upward - into the first 'draw, or into the wall. This means, it'll also be easier for lighter belayers to hold on to the brake rope, in the event of a fall.

Commonly, it's recommended that belayers don't belay leaders with a weight difference of more than 30% (for instance, a 60kg belayer should belay someone no more than 80kg). The Edelrid Ohm makes it possible to belay a lead climber up to 100% heavier.

The Ohm still allows for a dynamic belay. It achieves this by progressively braking (as opposed to braking abruptly).

The device doesn't affect smoothness of paying out rope for the belayer, or clipping for the lead climber.

It's designed for use both on indoor climbing walls and outdoor sport routes.

  • Allows dynamic belay
  • Possible to belay climbers up to 100% heavier
  • Less chance of belayer being thrown into the wall
  • Belayer needs to apply significantly less hand braking force to the brake rope to arrest the fall
  • Lead climber can climb with less worry
  • Can decrease the distance of lead falls
  • Less chance of groundfall
  • Less chance of collision with belayer
  • Belayer can be mobile
  • No need to anchor belayer to the ground
  • No need to attach a weight bag to belayer
  • For ropes 8.6-11mm
  • Particularly beneficial for belayers with a body weighing upwards of 40kg
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