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How to Shorten the Silvretta Pure Backcountry Skiing Binding

By Lou

Silvretta Pure is an excellent binding for average to smaller size, less aggressive skiers. Thus, it’s frequently looked at for folks with smaller feet. The size small Pure goes down to a fairly tiny boot, and the Pure Kidz model goes small as well. But what if you need a shorter binding and have a longer version of the Pure that’s already in your possession? They’re easy to shorten. Here’s how.

1. Figure out how much you’ll shorten. Adjust binding length to middle of length range, then place your shorty boot in the binding with the boot toe inserted in the toe wings. Measure the distance from boot heel to binding heel unit, and that’s how much you’ll cut. (When doing this, measure back from the boot heel to the point where the heel touches the binding when being inserted.)

2. Look at the front end of the binding and memorize how recessed the ends of the rails are, so you can replicate later (not critical, just get it close).

3. Carefully drive out the roll pins holding the rails. The roll pins are re-usable if you’re careful. If you mess one up, roll pins are available at hardware stores, but it might be hard to match exact size. Best tool for this would be exact size punch that won’t end up inside the hollow pin. We don’t have that size punch so we began with a small punch on the edge of the pin, and once it started moving we used the butt end of the largest drill bit possible. (Whack the bit with a brass hammer or something equally forgiving, as hitting a drill bit with a hardened steel hammer can be a disaster.)

Punching out the roll pin.

4. Cut the rails. If you happen to have a Pure with aluminum rails, just mark with care and whack them off with a hacksaw. In the case of carbon fiber you’ll need more. Mark with care, then using your hacksaw cut a shallow cut all the way around the rail — before you cut all the way through. Then finish your cut. The idea here is to prevent a “run,” meaning a strand of carbon fiber ends up getting pulled back from the cut as you finish it.

4. Drill the rails — step one. Using the chunks you cut from the rails as a sample, pick a drill bit that’s as close to the hole size as possible, but no larger. In other words, the bit should be easy to push into the existing holes. Insert the rails back in the binding toe unit to the point where they have the proper inset from the front (see step two).

Set the heel and toe down on a flat surface as if mounted on a ski, so the hole locations will be perfectly aligned. Using the existing holes in the toe units as a guide, lightly drill on the rails to mark them. DO ONLY THE TOP FIRST. Remove rails from toe unit, swap drill bits to a smaller (sharp) size, and drill a pilot hole using the mark your larger drill just made. ONLY DRILL HALF WAY. Swap back to your larger bit, and drill out the pilot hole, again only half way through the rail.

If the bit you are using is slightly small compared to the original holes, lightly ream the hole by slightly angling the drill and moving it in a circular motion for a split second. The idea here is to make a hole that you can re-insert the roll pin in under a small amount of compression, but a hole that’s not too big.

Marking drill position, remove rails from binding toe unit to finish drilling.

5. Drill the rails — step two. Now you’ve got a hole on one side of the rails that the roll pin will press-fit in. Insert the rails in the binding toe yet again, and line up the holes you drilled with those in the binding. Insert a roll pin to index the rail position; insert it very lightly so it’s easy to remove in a moment. Flip the binding over, repeat step 4 (remember to remove the rails from the binding while drilling, otherwise you run the risk of accidentally enlarging the holes in the binding), then run your bit all the way through the rail. The idea is you now have a hole that’s perfectly aligned with the existing holes in the binding.

If you do mess up, know that you could easily shorten the bindings a bit more and re-drill the holes. The main thing is to remove the rails when doing any drilling other than marking, so you don’t run the risk of enlarging the roll pin holes in the binding toe unit. Also, note that the holes in the rails and in the binding toe unit must be nearly equal in diameter, otherwise the roll pin will not engage both parts equally and you’ll get wear from movement in that area as the binding is used. Epoxy helps with this issue.

6. Put ‘em back together. Mix up some 1-hour epoxy and smear a small amount inside the sockets where you’ll be inserting the rails. Insert the rails, smear a small amount of epoxy in the roll pin holes, then tap in the roll pins. The idea here is the epoxy makes up for small variations from factory spec. (To reverse, heat up the binding with a heat gun to soften the epoxy.) If the roll pins are shorter than the full distance of the hole, finish by tapping with a punch so they’re inset equally on both ends.

7. Mount using our WildSnow instructions and template, which are not dependent on length of binding.

That’s it, now you’ve got shorty bindings!

If you’re looking to buy Pure bindings, try this link.

Posted by Lou on December 12, 2007 | Filed Under Gear Mods

Comments

13 Responses to “How to Shorten the Silvretta Pure Backcountry Skiing Binding”

Josh Hartung December 12th, 2007 3:21 pm

Hey Lou…

nice tutorial on how to do this job right! Just wanted to mention that another good way to prevent a “run” when cutting carbon fiber is to wrap the place where you want to cut with masking tape (pref. 3M blue) and cut through it like you do when cutting a rope.

Happy Holidays!

Josh
Lou December 12th, 2007 4:47 pm

Thanks Josh, good tip!
RobinB December 12th, 2007 10:08 pm

A similar procedure is rumoured to work with the NAXO bindings as well
Dave Waag December 13th, 2007 9:58 am

Lou – thanks for the how to. I’ll let you know how it goes.
Cheers
Dave
Vince Lambert December 22nd, 2007 1:19 pm

Awesome instructions! Could not find a ski center to mount the pures, and I needed to shorten them also. Came out perfect with a set of ‘06 bindings!!!! Thanks so much.
Lewis December 31st, 2007 11:35 am

Anyone have any experience with the Silvretta Kidz? They don’t even show them on Garmont’s site. Are they still available? Will they work w/ my daughter’s 234mm soled size 19.5 alpine boots? Anyone know how to create a waxless pattern in the bases of some beater junior alpine skis?
Thx,
=L=
Dave Waag January 5th, 2008 11:37 am

Lou – it worked great. Thanks for the beta
Cheers
Dave
Lou January 5th, 2008 11:45 am

Thanks for checking in Dave, glad it worked!
Gray February 6th, 2008 10:11 pm

Lou,

Is it possible to do this mod with Fritschi Bindings?

Thanks.
Lou February 6th, 2008 10:19 pm

Gray, it would be complex but could be done.
roger March 13th, 2008 10:53 pm

hey lou, know anyone who would do the shortening…I am a hack with tools.
Lou March 14th, 2008 7:08 am

Roger, I don’t know of anyone offhand.
Roland September 26th, 2009 4:19 pm

Works great. Thanks a bunch
I used a 1/8″ Dasco Pro Pin Punch to remove the pins. It fits perfect and removes the pins cleanly.
7/64″ Split Point Titanium drill bit to prep the pin holes and a 1/8″ to finish.