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Backcountry skiing homebrew install tricks and tips -- part 2 -- heel unit

By Louis Dawson

Okay, you've got both skis mounted with your Dynafit toe units, the screws are snug but not heavily tightened (and not yet glued), and the heel center marks line up perfectly with those on your skis. The hard part is over. Now the heel units.

Step 1 Snap a backcountry skiing boot in the binding, and again drop the heel onto the ski. Grab a Dynafit heel unit, flip it upside down, and make sure the for/aft adjustment system is located at the midpoint of its range (Sounds more complicated than it is).

Mark the location of the front screws after you set the gap between boot and binding. If you forget this step, you may have to drill another set of holes in your skis!

Place the heel unit on the ski, and slide the metal prongs into the corresponding slots on the boot heel. Take the small plastic feeler gauge spacer provided with the Dynafit bindings, and slip it between the binding and the boot heel. With earlier TLT bindings don't jam the spacer down over the plastic bump on the binding, but rather let it set on top of it. Eyeball the heel unit so it's centered on the ski. On the top edge of the ski, make a mark that corresponds to the for/aft location of the front screws. This simply shows the front/back location of the screws.

For position of the heel unit, you can also use the heel line on the paper template. Mounting to this line works fine for most mounts of bindings with larger adjustment range such as ST, FT and Comfort models. But be more careful when mounting bindings that have less adjustment range. Our advice is before you drill the heel, simply dummy it up by placing boot in toe then setting heel unit on ski with pins (prongs) inserted in boot heel, and verify you have useable adjustment range.

(Important: The thickness of the heel spacer feeler gauge and corresponding clearance setting for the Tourlite/TLT/Speed/Race binding is 4 mm , while that for the Comfort and Vertical models is 6 mm, or 5.5 mm for Vertical models starting in 2009. Note the spacer/feeler has come in different colors over the years. If you don't have a spacer, make one using above dimensions.)


Step 2 Lift the boot heel up out of the way. Using that trusty framing square trick, scribe a Sharpie mark across both skis, corresponding to the for/aft screw mark you just made.

Step 3 Grab the paper heel template you downloaded and printed several copies of in previous instructions, cut it down so it's slightly narrower than your ski, and cut the ends so the center-line on the template goes to the edge of the paper.

Step 4 Place the paper template on the ski (remember to orient it via the arrow on the template). Center the template left/right using the tip/tail line you drew in the center of your backcountry skis, and line up the forward screw line with that on your ski. Tape template to ski.

Step 5 Drop the boot heel down onto the ski and slide the heel unit back into place. Look down thorough the screw holes in the heel unit, and make sure they seem to line up with those in the template.

If it looks good, remove the heel unit, lift the boot heel, check the location of the template to make sure it didn't move, then center punch the screw holes.

Remove the paper template, then using a ruler make sure the center punch marks are equidistant from the ski edges. When satisfied, center punch all holes more aggressively.

Step 6 Drill the holes per drilling instructions in part one of this guide. To figure out which screw to place first, use the same process as the toe: Drop the boot heel onto the ski, place the heel unit into position, and eyeball which screw hole lines up the best. Get the boot out of the way, and place that screw first. If you need room for your screwdriver, rotate the upper part of the heel unit out of the way.

Line up the other screw holes with the holes in the base plate, hold the unit tightly to the ski so it doesn't move, and drop the boot-heel gently down. If it lines up close to the center of the heel unit pins (within a millimeter or so), run screw number two in the other hole that lines up best. With two screws holding the heel unit, and the release tension set super low, you can now do the final alignment test. Gently drop the boot down, and make sure the wedge shaped metal drops between the prongs with little or no sideways nudge (a millimeter or so of misalignment is okay, you'll fix this in step 9). Then -- with a sharp press down -- snap the boot into the heel piece (it should go down easily with the low release tension setting). Look and feel good? If so run the remaining two screws, checking alignment each time.

Step 7 Remove all four heel unit screws, place some epoxy in the holes, and run the screws back in. When placing the epoxy, wipe all excess off the top skin. If any oozes under the for/aft adjustment unit of the heel, it will harden and prevent fine-tuning. One-hour epoxy is best, but use 5-minute if you're in a hurry. Continue to check alignment as you do the final torque on the screws.

Step 8 Re-check heel clearance with the small red shim, and adjust as necessary using the small screw on the rear of the base place.

Step 9 THIS IS SUPER IMPORTANT, remember how you didn't epoxy or heavily tighten the toe unit screws? Now take all the toe unit screws out, place some epoxy in the holes, and run them back in. Again, tighten the forward most screw but leave the others only snug. Place boot in binding, then drop heel down. Nudge boot left or right 'till the metal fitting on the boot is nicely centered on the heel unit pins. Remove boot, and tighten toe unit screws that line up the best, re-check boot heel alignment, and continue to tighten toe unit screws. The idea is to gradually tighten the toe unit screws while making sure the heel of the boot is aligned with the backcountry skiing dynafit binding heel.

Step 10 Adjust lateral and vertical release according to directions in the Dynafit binding pamphlet or use the chart located on this page. Or subtract one number from your settings on your alpine bindings, and start with that. If you ski out of the bindings, gradually crank up. Last time I checked the Dynafit binding on a DIN setting checker, the sideways release was pretty close to the indicated number, but the vertical release was higher than the number indicated. In other words, be careful and tweak your settings gradually.

Enjoy these backcountry skiing engineering marvels, but remember, while the Dynafit binding is incredibly functional, it's not an alpine resort binding. Ski these backcountry bindings more conservatively than you would your alpine gear, and use good technique on the uphill so you won't torque out during kick-turns and such. Remember that during touring you need to lock the binding by pulling up on the front lever (see directions). Also, if you're in doubt about your hand skills, but want to try this project anyway, do a dummy mount on a pair of dumpster skis. After a practice session, you'll have no problems doing the real thing.






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