I have been using NE white Safety Blue (1/2" or 13mm) for 4 years with my Petzl paired ascenders (toothed cam) for SRT climbs, about 85 ft in my case. I usually do this climb 2X, back to back for a cardio and strength workout.
I have not experienced any problems running 13+mm line thru the ascenders.

In all my gear catalogs, 11mm line is the recommended diamater for SRT and mechanical ascenders.

What exactly is the advantage here? Is it a safety issue - the 11mm is a better "fit" and therefore less likey to jump the channel?

Don't think there is any safety issue running 13mm rope through a Petzl Ascension ascender, since it's rated for 8-13mm.

I've heard that the 24-strand kernmantle arborist ropes (typically 11mm) run though the ascenders more easily because of the smoother rope surface compared to a 16-strand 13mm rope. Makes sense.

I think the advantage to using 11mm or thinner rope is less rope weight to handle.
-moss

The only cam jumping I have hear of are Panteen foot cams without a carabiner lock down (just clip it in the hole Sam for jump free climbing) and an ascender with a broken locking lever (common problem with a CMI Ultra Asceder) that creates an alarming surprise when the ascender jumps out of your top rope system in the classic Texas rig.

11mm ropes seem a bit quicker with hardware or is it just my natural biological chemical reactions to percieved faster leg work while pumping on a a pretty colored rope? Geeze! Possibly a head shrink could give me an answer to this question.

For me, I switch to SRT methods when I'm ascending higher heights. Maybe SRT is for 80' and taller? With that in mind, for me SRT means I have to carry MORE rope to get into those taller trees. Thinner diameter ropes weigh less and take up much less space in a backpack. Check the spec's and you might be surprised how easy it is to shed a couple pounds just by switching ropes.

love
nick

You guys - thanks for good fdbk here. Peter, you are a nut. Funny but true how much the psych aspect influences everything!

I have recently been paying attention to rope weights and characteristics, and yes, it is surprising the differences in weight vs. diameter.

And I think I partially answered my own question recently when I experienced a different climbing line, Safety Pro - 11mm is typically a choice for mechanical ascenders and SRT because friction hitches become less dependable as ropes get smoother and narrower. (Duh, I know, but for years I never used anything BUT 14 strand 1/2", so what did I know?) It makes sense to use a mechanical ascender because who the hell wants to mess about with a "will-it-slip-or-will-it-grip-or-will-it-bind"? situation if you've got a 150' upward trek ahead of you?

Recently I have had the distinct pleasure to purchase and work with 12 strand Safety Pro. It's awesome!! An 11mm tail tied with a simple Blake's is as effective on 1/2" Safety Pro as a VT with 8 or 10mm eye-to-eye is on 14 strand. It slides beautifully and then it locks fast. The thick (by comparison) weave of 12 strand is a perfect match for any garden variety friction hitch. I bet 1/2" 14 strand tail works great on it too.

And, it's light. And, it doesn't stretch too much.

If I follow my heart and eventually open up a rec climbing outdoor "gym" where people can come and experience the pleasure and thrill of tree climbing, it'll be Safety Pro all the way for novice climbers.

So in addition to the points that you all make - better belay, lighter, more compact, prettier(I love aesthetics, can't help it) I have found that one of the reasons why SRT is mentioned in the same breath as 11mm line isn't because the mech ascenders like the narrow line - it's because the narrow line prefers the mech ascenders - you don't want to be constantly re-setting a hitch on smooth narrow lifeline.

And lastly, I'd rather grip the handle of my Petzl texas _style_ rig than a narrow 11mm line. If I grip the line directly I way prefer 1/2' line for my 44 yr old paws.