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Too much friction on rappel?


Original Post
Erica J · · Washington DC · Joined Oct 2016 · Points: 0

When rappelling down after cleaning in anchors, I set up my ATC on an extension, teeth/friction side down, then Auto block clipped to belay loop. My rope is 9.8mm. The rappel is work to get down due to friction it seems.

To reduce friction enough to make the rappel smooth, is it best to just not use the friction side of the ATC, do something other than an auto block? Something else?

Ben Williams · · van · Joined Sep 2015 · Points: 35

What are you doing for your auto block? 

FrankPS · · Atascadero, CA · Joined Nov 2009 · Points: 275
Erica J wrote: When rappelling down after cleaning in anchors, I set up my ATC on an extension, teeth/friction side down, then Auto block clipped to belay loop. My rope is 9.8mm. The rappel is work to get down due to friction it seems.

To reduce friction enough to make the rappel smooth, is it best to just not use the friction side of the ATC, do something other than an auto block? Something else?

You should be able to use the high friction mode without too much, uh, friction! What diameter autoblock and how many wraps? Possibly the next size thicker autoblock so it doesn't bite so hard into the climbing rope.

Erica J · · Washington DC · Joined Oct 2016 · Points: 0
Ben Williams wrote: What are you doing for your auto block? 

Using a 6.8mm Sterling Hollow block loop cord,wrapped 3x

Everett · · Nevada · Joined Jul 2016 · Points: 25
Erica J wrote: When rappelling down after cleaning in anchors, I set up my ATC on an extension, teeth/friction side down, then Auto block clipped to belay loop. My rope is 9.8mm. The rappel is work to get down due to friction it seems.

To reduce friction enough to make the rappel smooth, is it best to just not use the friction side of the ATC, do something other than an auto block? Something else?

The extension adds a lot of friction due to the sharper rope path, but I wouldn't change that.


You can definitely tune the ATC friction and the number of wraps, as long as you settle on something that keeps you safe.
Prof Snax · · GA · Joined Aug 2013 · Points: 15

Next time keep the hitches on your auto block a little looser, using your break hand to "guide" the prusik down the rope as you abseil, without it cinching tight. This will give you a smoother ride.
The auto block will still do its job if/when you need it to.

Bill Lawry · · New Mexico · Joined Apr 2006 · Points: 1,630

Some times it isn't easy to balance competing demands regarding the "right" amount of friction.  A couple additional thoughts below …

Going to a smaller diameter rope would help with reducing the friction during a rap.  Of course, this has to be balanced against feeling comfortable with having enough friction for lead belays assuming the same rope is used.  And a smaller diameter rope may not be an option if you have a heavier partner.  I feel like other options should be considered first (below).

The slots on the ATC Guide seem to me to add more friction than the slots of a regular ATC; friction from the guide slots is in addition to the use of the jaws on the break strands or not.  If you like to belay with the ATC Guide (which I could understand) another option is  to carry a different device for raps.  Perhaps try carrying a regular ATC?  They are pretty light and relatively inexpensive.

I suspect the hollow block is not the issue.  From what I have seen/heard of it, it really is pretty sweet for the purpose it was designed.  Though I'll confess I have only ever held one in my hands (i.e., have never actually used one on rappel).  Still, consider whether you could see yourself going without one.  Perhaps with an attentive fireman's belay for the times that someone else raps first?  (The person giving the fireman's needs to be very attentive.)

The last option I'll mention is the type of biner used with the rap device - though am not hopeful about this.  Anyway, it can matter (i.e., provide more or less friction depending on the biner thickness and shape).  Though I have only ever wanted to add friction in which case I usually double up the locker with a same-style locker.  Likely, it'd probably be trial and error to find the 'right' thickness and shape of biner - assuming there is one that offers you sufficiently less friction.

Erica J · · Washington DC · Joined Oct 2016 · Points: 0

Thanks for the feedback. I'll look into adjusting my autoblock first, if that doesn't help I'll flip out my ATC for the smooth side possibly (only use the ATC for rappels, have grigri for belay)

T G · · Boulder, CO · Joined Jun 2015 · Points: 51

You can also try flipping your rap device and using a more rounded carabiner like the older style Petzl Attache in guide mode. I find that the I-beam shaped carabiners that are everywhere now often add too much friction in guide mode – regardless of rope diameter – due to the sharp angle that the rope needs to bend around the carabiner.

Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 680

I usually flip my ATC over so the brake side is on the smooth side versus teeth side.  It feeds smoother and is less jerky.  

Buck Rio · · MN · Joined Jul 2015 · Points: 0

Your profile pic appears to be that of a slim woman, and as such you may not generate as much force as me, a 200 pound guy. So a toothed friction device like the Petzl Reverso or BD atc-xp may be overkill for you....the weight of the rope at the start of a rappel is enough to cause you to have to feed rope through instead of just leaning back and enjoying the ride.

The extension and third hand are OK, you may just want to use the smooth side for rappel.  The Trango Pyramid works well for me. You can flip the device round for more friction if you need it.

Al Pine · · The 'yack, NY · Joined Apr 2017 · Points: 0

I use an ATC guide with a 9.8 rope and weigh around 150. As other folks suggested, I flip the device so that teeth are up and keep my backup loose enough to feed rope smoothly without locking up. Way smoother... Be safe, have fun.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490

Sport routes don´t rap, lower  
Dump the extension and the autobloc as well, there´s a belayer below doing nothing  
Use the lower friction side of the ATC XP, it´s then the same friction as a regular ATC.
Add another biner in the device BUT DON´T CLIP IT INTO YOUR BELAY LOOP.
Eat more burgers and drink beer  

Serge Smirnov · · Seattle, WA · Joined Oct 2015 · Points: 262

Some less likely possibilities:

 - If the carabiner is worn (has noticeable grooves from the rope), replacing it will reduce friction.

 - If the rappel is long (20+ meters), the rope's weight sometimes means choosing between too much friction at the beginning and not enough at the end.  Rappelling off the belay loop allows one to adjust the rope's angle, but then the friction hitch has to be above the belay device - not recommended unless you're willing to learn and practice getting it unstuck in that position (also not recommended if the rappel requires a free hand, e.g. for pushing off the side of a corner/chimney).

John Wilder · · Las Vegas, NV · Joined Feb 2004 · Points: 1,535
Serge Smirnov wrote: Some less likely possibilities:

 - If the carabiner is worn (has noticeable grooves from the rope), replacing it will reduce friction.

 - If the rappel is long (20+ meters), the rope's weight sometimes means choosing between too much friction at the beginning and not enough at the end.  Rappelling off the belay loop allows one to adjust the rope's angle, but then the friction hitch has to be above the belay device - not recommended unless you're willing to learn and practice getting it unstuck in that position (also not recommended if the rappel requires a free hand, e.g. for pushing off the side of a corner/chimney).

The friction hitch goes on your leg loop if your device is on your belay loop.

mbk · · Unknown Hometown · Joined Jul 2013 · Points: 0

Keep in mind that if you rappel with the ATC-Guide in "regular friction mode" you won't be able to do the sneaky rappel-to-ascend transition.

Christopher Smith · · Unknown Hometown · Joined Jan 2017 · Points: 0

I will second flipping the ATC to where brake side is smooth side when extending.  Works great for me and still properly brakes when needed.

SeƱor Arroz · · LA, CA · Joined Jan 2016 · Points: 10

I flip my ATC guide around if I'm ever using it to rappel. I find the teeth create too much friction. Might also try moving your autoblock from the belay loop down to your leg loop and see if that angle change eases it a bit.

FrankPS · · Atascadero, CA · Joined Nov 2009 · Points: 275

Erica,

Do you have a more experienced partner that can look at your set up and help you figure out the problem?

Nathan Doyle · · Sierra Foothills · Joined Feb 2016 · Points: 26

I believe I'm using the same setup as you.

I'm 210lbs and use my weight and a bit of leg strength to walk down and this with some force (talking less than vertical here.) Recently my brother, and my brother is probably 40lbs lighter than me, was having a hell of time doing the same.

3 wraps seems to be nice and safe. However, and now that I think about it, I hold two hands on the backup to allow it to feed more smoothly, that is, I'm almost pulling it down to slide it along, which inturn creates slack that feeds through the ATC.

Hmmm, I might flip my ATC too and see how that feels.   

Larry S · · Easton, PA · Joined May 2010 · Points: 840

Different ropes feed different too, regardless of diameter. My buddy's old petzl 10.1 and a petzl 9.8 I used recently were both very very fast ropes to rap on, so much so that I always use gloves rapping those ropes. My mammut 9.5 is slow by comparison. 35m of my mammut hanging underneigth is enough for a solid fireman's belay, and I need to pick up the brake side to get moving in the beginning.  

Keep one hand on the autoblock and get it nice and loose. 3 wraps should be fine, I would not do less. Use the other hand below the autoblock to lift up the rope and it should feed no prob. As you get nearer the bottom, you should have an easier time, and just be braking.

It is perfectly safe to turn the atc around and reduce the friction a bit.

Guideline #1: Don't be a jerk.

General Climbing
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