Rope Drag Discussion

[rendog]

rope drag can be a real pain in the ass...


the link above will outline the factors in causing rope drag and ways to eliminate it, including single rope, double ropes, and twin rope systems.

This is a pretty good article, and I personally couldn't find any fault with it.




discuss and......



GO

[Guest]

even if the line is straight up and down, or you extend your runners to make the rope fall in a plumb line, you WILL have rope drag. doesn't matter how good a leader you are, if the rope snakes at all you will have drag above and beyond the inherent drag of the rope's weight..

since the drag all comes from the friction between the rope and the biner (plus the weight of the rope paid out -- since drag the equivalent to the force required to pull the rope up, the weight and friction both play a factor), the weave of the sheath most definately would have an effect on the amount of drag produced (again, on a route that snakes too much to safely extend runners for a plumb line).

whether someone should buy a rope cause it is marketed as having a better sheath and thus less rope drag is another subject in itself. that was not my intent in starting that whole other thread.

this feels like physics class...

[Fred]

I have a theory that a tight weave such as the one on the Maxim Glider will also result in longer lasting ropes since it is less likely to fray on crystals. We've all seen picks on our ropes where the crystall has torn a strand from the sheath.

This is just a theory of course. Where the hell is 33 so he can tell us about the Maxim Glider?

[sb]

Adam, I have to disagree with you. If the leader does a good job of where they place pro and extending runners to avoid sharp bends in the rope, rope drag should never be an issue as a result of rope/biner friction. In my un-engineering but very opinionated opinion, rope/rock friction creates way more drag than anything short of a double Z through biners would create (which is why it feels like you are pulling 50+ lbs at the top of a Whitehorse slab route). Even on a route like Weeping Whisker done in 1 long pitch, rope drag is usually not encountered until after the bulge and up on the slab (where it can get pretty heavy). But this is due to rope/rock friction over the bulge. So what I am saying is that while yes there is some friction between rope/biner, with pro placed correctly (even with some slight bends), it should be negligible and not make the difference between send and whip. So when you buy your rope (sorry mod to cross contaminate subjects but I'm too lazy to go back to the rope buying thread), there are many other atributes which should be considered before rope/biner friction. If you decide on that rope anyway and you think the lower friction will help you climb harder, great...cause what matters anyway is what you THINK.

[Guest]

no, you are right shawn on one count... i was just thinking of a vertical or overhanging route... yes, on a slab route there will be friction from contact with the rock. tried, tested, and true.

but *besides* that, it comes from biner-rope contact. again, there would have to be *some* snake to the rope to feel that friction. if its a plumb line then there would be negligable friction from biner-rope contact.

will a rope's drag affect my decision of whether i buy it? maybe. will it make me climb harder? i doubt it.

[Fred]

If I'm not mistaking, the smaller diameter single ropes are mainly geared towards sport climbers and hard sends aren't they? So every little bit of weight and drag helps for sending that 5.14 doesn't it? I guess I'm just not visualizing using a 9.8 glider on "Weeping Whisker" but rather on "Prend Ton Trou 5.13a 60m one pitch" in Kamou. I think it has over 15 draws and it's a full rope length. So I've crunched some numbers for FUN! since it's what I do best.

You've just reached the top of "Prend Ton Trou" which means at this point you are essentially hauling the entire rope. Lets look at three different ropes:

1. Shawn's Mammut Flash Duo 10.5mm weighing in at 69g/m
2. Brent's Maxim Glider 9.8mm weighing in at 65g/m
3. The lightest single rope on the market Mammut Revelation 9.2mm at 54g/m

Total Weights:
1. Flash Duo 9.13 lbs
2. Maxim Glider 8.6 lbs
3. Mammut Revelation 7.14 lbs

Now lets consider a conservative 5 lbs normalized rope drag for all the ropes with the Maxim Glider having 20% less sheath friction than the Flash Duo and the Revelation having 30% less friction than the flash duo. Now stay with me people. Alot of factors are involved in reducing friction. The texture of the sheath, the weight (friction force= coefficient of frictin x weight or normal force), and the surface area. So as the ropes get smaller they have less weight (lower friction) and less area (lower friction because of smaller diameter). So assuming a 20% and 30% reduction on friction is probably conservative. So throw on a smooth sheath onto a much smaller rope and voila. Slippery as KY in the morning.

So back to friction:
1. Flash Duo 9.13 lbs + 5 lbs = 14.13 lbs
2. Maxim Glider 8.6 lbs + 0.8(5 lbs) = 12.6 lbs
3. Mammut Revalation 7.14 lbs + 0.7(5 lbs) = 10.64 lbs

Thus, reaching the top of the 60m climb your total weight added to your body weight for sending this hard route will be:
1. Mammut Flash Duo = 14.13 lbs
2. Maxim Glider = 12.6 lbs (2 lbs less)
3. Mammut Revelation = 10.64 lbs (3.5 lbs less)


If you want to convince yourself that 3.5 lbs makes a difference try sending the hardest problem at the gym with no weight on you. Then send it with 14.13lbs strapped on you and then send it with 10.64lbs.

Hence why I've been skiing so much to lose a measily 5lbs. Also, why you don't see sport climbers sending routes with Gri Gri's and daisy chains and useless crap on their belts. So when people laugh at bare chested boulderers wearing nothing but thin shorts I'd say you'd better consider it as an efficiency thing rather than a fasion statement. But yes of course it's all about looking cool too.