Maruelli Antitwist aftermarket mount plate and spindle (integrated) for Dynafit Speed ski touring binding. The OEM binding housing rides on an aftermarket spindle that’s mono-block machined with the base. Main feature is the rotation locker (pin sticking up to right on binding base) but the unit also appears to be quite durable, albeit slightly heavier unless mounted without the adjustment rails.
Maruelli Antitwist aftermarket mount plate and spindle (integrated) for Dynafit Speed ski touring binding. Unit to left is mounted on longer adjustment rails that give you boot length range similar to Dynafit rental-demo binding, and an even longer version may be available. Unit to right is on shorter rails that yield about the same boot length adjustment as the OEM Speed baseplate. The Maruelli Antitwist can also be mounted without the adjustment rails resulting in a weight savings over stock of 18 grams per binding, as well as less boot ramp angle. The configurations with adjustment rails are slightly heavier than stock and add a bit of ramp. (See complete metrics at bottom of post)
Dynafit Speed heel unit installed on Maruelli Antitwist. The small vertical post blocks any chance of twisting in the most common accidental direction.
Maruelli fasteners are socket head screws that we suspect will stand up to high torque and repeated use. This ‘rail’ system for length adjustment is used by other brands as well but frequently with weak phillips or pozi screw head fasteners.
Design and innovation are in the Italian soul. Funny thing, their favorite ski touring binding was invented by an Austrian. Solution to that nationalistic dilemma? Mod the heck out of it.
To that end, Italian metal manufacturing expert Stefano Maruelli is getting crazy with Dynafit mods. He’s published a print catalog chockablock with everything from his silly appearing (yet effective) Natural Walking Plate, all the way to a fascinating variations on the basic tech binding. This plethora of after-market “arte italiana” includes a snowboard toe unit as well as a variety of race rigs. For now, let’s just concentrate on this cool little jingus he’s cooked up (yum, taste that aluminum!) for the Dynafit Speed binding model: The Maruelli Antitwist for Dynafit Speed ski binding (we’re not using trademark or copyright symbols here, but please know that in no way is Maruelli associated with Dynafit, he’s simply making aftermarket add-ons).
Underside, showing how the length adjustment screws thread to trapped aircraft nuts–simple and elegant.
Fore-aft adjustment is similar; Speed to left provides 24 mm movement, Maruelli to right has a bit less at 22 mm (though you can use longer Maruelli base rails for maximal adjustment).
Original Speed Radical to left, compared to Maruelli shorter base rail to right.
Anti Twist on Speed Radical is ingenious but in my experience sometimes not 100 percent effective. The notches circled in red on the heel unit housing engage with the notches on base unit as the binding is weighted and flexed.
Another view of OEM anti-twist.
We like that the Maruelli unit can be mounted without the adjustment rails (with care) for an 18 gram weight savings over stock as well as a heel drop of 3.28 mm, resulting in a nice ramp angle for backcountry skiing. I’d probably mount them that way.
Question will be how easy is it to retrofit the Maruelli system on a ski that’s already been drilled for OEM Dynafit Speed? No easy answer, but one way or another it is certainly possible. The longer rails easily allow a mount without overlapping original holes. If you use the shorter rails, you can fit perfectly to original jig-drilled holes of previously mounted Dynafit Speed Radical. If mounting without the rails (lightest configuration, and lower ramp angle), you can probably find a spot without overlap, again depending on where the original mount was located.
Maruelli base unit shown below OEM Speed base where you’d probably mount if you were working with skis that had holes from previous mount.
Due to clever offsetting of holes in Maruelli adjustment rails, they match same pattern as Dynafit Speed for easy retrofit.
Longer rails can miss any pre-existing screw holes.
Maruelli with short rails (left) allows 22 mm of fore/aft boot length adjustment. Dynafit Speed to right yields 24 mm. Virtually the same. Maruelli longer versions of rails yield huge boot length adjustment! Because the longer rails still form a solid boot/ski connection and the socket head screws can be worked multiple times, this could be an ideal setup for rental or demo skis used for backcountry skiing.
Mounted with adjustment rails, Maruelli unfortunately adds 3.3 mm to your heel height.
Mounted without rails, Maruelli DROPS your heel 3.3 mm, in our opinion making for the perfect ramp angle. Mounted in this stripped down configuration you still have 6 mm of fore/aft boot length adjustment, so the mount is not as tricky as bindings with fixed screw positions.
Obligatory workshop view. Too many skis, too many parts, so little time.
Metrics, all for single binding:
OEM Dynafit Speed base/spindle, no mounting screws, 1.9 oz, 54 gr. (This is the part you swap out for all options below.)
Maruelli Antitwist base with no adjustment track, 1.3 oz, 36 grams, allows 6 mm of fore/aft boot length adjustment. (Our favorite configuration — saves 18 grams per binding and also drops your heel 3.3 mm to better ramp angle. Can probably be mounted between existing standard holes.)
Maruelli Antitwist base, short rails version, uses Dynafit Speed Radical mount pattern, 3.5 mm additional heel rise over OEM, 22 mm of fore/aft boot length adjustment: 2.5 oz, 70 gr. (16 gr. penalty over OEM)
Maruelli Antitwist base, long adjustable version is similar to demo bindings and matches screw hole pattern for Dynafit rental binding, 3.5 mm more heel rise than OEM, 58! mm of fore/aft boot adjustment: 2.9 oz, 84 gr.
More info about boot length adjustment ranges for Dynafit bindings.
As of fall 2014 Maruelli aftermarket parts are available here.
Also, check out Dynafit’s twist blocker for Speed Radical.
WildSnow.com publisher emeritus and founder Lou (Louis Dawson) has a 50+ years career in climbing, backcountry skiing and ski mountaineering. He was the first person in history to ski down all 54 Colorado 14,000-foot peaks, has authored numerous books about about backcountry skiing, and has skied from the summit of Denali in Alaska, North America’s highest mountain.
