Edelrid Ohm Product News

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The Edelrid Ohm

Balancing the weight difference between belayer and climber.

Edelrid Ohm 1 The EDELRID Ohm is an innovative, new solution for the problems experienced by climbing partners with a significant difference in weight. That is to say the risk for a heavier lead climber if their partner has difficulty controlling their falls and the risk for a lighter belayer if their partner's falls pull them off the ground, hurling them against the wall. The OHM is an assisted-braking resistor that you install at the first bolt in the safety chain. In the event of a fall, the OHM increases rope friction so that a lighter belayer can hold a heavier partner without being suddenly pulled off the ground and thrown against the wall. The OHM still enables smooth paying out and taking in rope when climbing and belaying and has no negative affect on handling. The OHM was developed for use at both climbing walls and outdoor sport climbing venues.


If there is a significant difference in weight between lead climber and belayer this frequently causes problems. This applies in particular to climbing couples, where the woman is often significantly lighter than her partner.

In the event of a fall, a lighter belayer can be suddenly pulled off the ground and hurled against the wall. In addition, when a belayer is pulled high off the ground, this significantly increases the distance that the climber falls. If the climber is still near the ground, belayer and climber might collide. In the worst-case scenario, the climber might hit the ground.

Using a weight bag to reduce the difference in weight is not possible all the time (nobody wants to carry a weight bag to the crag). In addition, weight bags restrict a belayer's freedom of movement. And even when using a weight bag, the belayer still has to supply the full braking force (with the associated risk of friction burns as the rope runs through belay device).


The development of the Ohm was supported by the Institute of Mechanical Handling and Logistics at the University of Stuttgart. It is an assisted-braking resistor that is attached at the first bolt with a quickdraw and the rope runs through it. In the event of a fall, the rope is pulled into the device's braking mechanism. This then brakes the fall. The device does not stop the rope abruptly; instead it progressively brakes the speed it runs through, so that the belayer can still dynamically arrest the fall. The Ohm increases the amount of friction in the safety chain, independent of the belay device used. As a result, the belayer needs to apply significantly less hand braking force to the braking rope to arrest the fall and they wont be hurled against the wall in an uncontrolled manner.

The Ohm is designed not to affect rope handling when belaying a lead climber. It nei-ther increases rope drag for the lead climber, nor has a negative affect when paying out rope. The device's assisted braking mechanism is only activated in the event of a fall.

Edelrid Ohm 3 The OHM benefits both climber and belayer: The belayer wont be pulled against the wall in an uncontrolled manner. The climber can climb right to their limits, without having to worry that their belayer might not be able to hold them should they fall and with no fear of a hard landing.

The German and Swiss Alpine Clubs (DAV¹, SAC²) recommend that a climber should not weigh more than 1.33 times their belayer, i.e. maximum one third more (for exam-ple: belayer 60 kg/climber maximum weight 80 kg). In the event of a big fall, in particular at the climbing wall, such large differences in weight require extreme care and attention on the part of the belayer.

Including the Ohm into the safety chain increases this factor significantly. With this device, it is now possible for climbers in the lower weight ranges to belay a lead climber, who is up to 100% heavier than the belayer. The Ohm is suitable for ropes with a diameter between 8.6 and 11 mm and is particularly beneficial for belayers with a body weighing upwards of 40 kg.

Edelrid Ohm 4

For more information EDELRID

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5 Mar, 2016
If it works as described with no increased drag or friction during normal climbing then it sounds like it could be quite useful.
6 Mar, 2016
Agreed, seems to be a pretty decent product. I know a few climbing couples who would be very happy to use this. They really should get Robbie Phillips to do a version in English though, I had to pause the vid a few times to read the subtitles as well as the side-by-side video sub-captions.
6 Mar, 2016
Roll on payday I need one of these! I'm 100kg and most of my partners are around the 60 to 70 and I don't like leading too much when they are anchored solid to a boulder at the base. This could help out massively.
6 Mar, 2016
An interesting product that looks like it could be quite useful for some people. It would be interesting to know whether it puts additional stresses into the rope and what the impact is on rope wear and tear over a period of prolonged use. I'd imagine it could be an issue, but possibly one you'd happily put up with.
9 Mar, 2016
ditto, when are these available and any idea on price? Have a very light belayer/girlfriend who would think this is the best thing since ground anchors
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Product News at UKC presents climbing, walking and mountaineering equipment posts that will be of interest to our readers. Please feel free to comment about the post and products on the associated thread.
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