Upgraded Index Ascender vs. Old nForce Ascender
Black Diamond has confirmed that the Index is sporting a whole host of updates, most notably a redesigned trigger-finger release for hassle-free operation, a molded grip, and a lightened frame. Check out this side-by-side comparison, with the new, sleeker Index on the left and the old nForce on the right.
First off, this device just looks cool. Half the fun in big wall climbing is collecting cool gear. This rates up there with a portaledge or a Pro Traxion hauling device for "top gear to wow your non-climbing friends." The trigger gives you two options for taking the ascender off the rope you can use your thumb as with with most other ascenders or use your index finger like you are pulling the trigger on a gun. This trigger makes it very easy to slide the ascender down the rope if you need to down jug. Usually down jugging is a jerky affair because the ascenders get caught up, but not with these. Also, if you are hauling with the "pulley and ascender" method, it makes it easy to get the bag off the hauler. The trigger does take a little while to get used to if you are used to standard ascenders, but fairly soon we found it easy to use.
The handle is very comfortable to hang on. The over-sized clip-in hole is very handy for clipping the ascenders and connecting to your harness. According to Black Diamond, one of the biggest advantages of this ascender is its performance on icy ropes. They say, "Giving you the best grip for jugging icy, muddy ropes, the nForce ascender generates more clamping force than conventional designs." We tried the nForce on icy ropes and found it works great, but not necessarily any better than the Petzl ascender.
Our main dislike is that this device does not slide up the rope as smoothly as we would like. When compared the Petzl or an old Jumar, we find that it has a little more resistance (not a big deal) and jams up more often before we get full extension when pushing up the top ascender (bigger deal). This could be because the clamping action on the device is more aggressive or because the bottom of the ascender seems to rub into the rope. It was not a big deal when we were jugging ropes while fresh. But when were tired (which is most of the time if we are trying to clean a pitch fast) it was hard to keep the device from locking up every fifth stroke or so.
This is not the lightest ascender. It is also not the heaviest, but if you are used to a lighter ascender, you will definitely feel it when two of these are clipped on the side of your harness.
This is the same price as the Petzl and less than other ascenders. We have not seen a pair of ascenders for less than $70 that we would recommend and have seen lot of them more expensive.
These excel on big walls and for ascending icy ropes in the mountains.