Maruelli Antitwist Add-On for Dynafit Speed


Post by WildSnow.com blogger | July 21, 2014      
Maruelli Antitwist aftermarket mount plate and spindle (integrated) for Dynafit Speed ski touring binding.

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. Spindle shown mounted on longer adjustment rails; optional shorter rails are shown as well.

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.

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.

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.

Underside, showing how the length adjustment screws thread to trapped aircraft nuts–simple and elegant.

Fore-aft adjustment is similar; Speed to left, Maruelli to right.

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.

Original Speed Radical to left, compared to Maruelli shorter base rail to right.

Anti Twist on Speed Radical is ingenious but sometimes not 100 percent effective.

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.

Another view of OEM anti-twist.

We like that the Maruelli unit can be mounted without the adjustment rails (with care, though the screw seats do allow 8 mm of fore-aft) for an 18 gram weight savings over stock as well as a heel drop of  3.28 mm, resulting in a nice ramp angle.

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.

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.

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.

Longer rails can miss any pre-existing screw holes.

Maruelli with short rails (left) allows 21 mm of fore/aft boot length adjustment. Dynafit Speed to right yields 24 mm.

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 with adjustment rails, Maruelli unfortunately adds 3.3 mm to your heel height.

Mounted without rails, Maruelli DROPS your heel 3.5 mm, in our opinion making for the perfect ramp angle. Due to the screws being located in slots, even mounted this way you still have  6 mm fore/aft adjustment.

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.

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.

Comments

23 Responses to “Maruelli Antitwist Add-On for Dynafit Speed”

  1. Lou Dawson July 21st, 2014 10:47 am

    All please note, in original version of this review I got some of the hole overlap info wrong, correct info is that the short adjustment rail of the Maruelli matches up perfectly to Dynafit Speed Radical screw holes. The long rails can easily be located to miss existing screw holes if necessary, and when mounted without rails the unit can usually be located to miss holes if necessary. In all, any configuration of the Antitwist can be retrofitted in most cases without problems due to screw hole overlap.

    Also, we should mention that the Maruelli Antitwist for Dynafit Speed only works with the Speed model binding, it does not work with Dynafit Radical FT/ST, etc.

    Lou

  2. tyler beck July 21st, 2014 1:29 pm

    Lou,
    Would you expect the Speed Turn (almost identical to Speed Radical) heel to work with these?

  3. Lou Dawson July 21st, 2014 2:31 pm

    Probably, as yes it’s the same heel housing as Speed Radical only without the flip lifters. Or is it?

    The classic TLT and the Comfort/Vertical have two extra flats/lobes on the spindle so the housing can be rotated to the two climbing lift positions and would stay there (provided the lateral release spring was under compression, above around RV 5 or 6.)

    Sounds like it’s time to dissect the Speed Turn. I’ll try to make that happen.

    Thanks for asking.

    Lou

  4. kevin July 22nd, 2014 9:41 am

    Pretty cool but not cheap. Wish dynafit would come up with a better solution.

  5. Lou Dawson 2 July 22nd, 2014 10:37 am

    Any healthy sporting goods industry will have multiple players and lots of parts/add-on options. It all may not be cheap, but the bounty is huge in terms of what we get for the money. I’ve always felt the Dynafit Speed was the sweet spot in the Dynafit binding line, but in my opinion the anti-rotation could be better. It’s possible that the Speed for 2014/2015 will have OEM improved anti-rotation, but Maruelli’s solution has multiple benefits so it’ll still be viable no matter what, and is the ticket for the tens of thousands of Speed models out in the wild.

    I’d like to see Maruelli make a model of his Antitwist that worked with the Radical FT/ST heel units, that would be very cool as well as it would allow folks who own the FT/ST to configure a stripped down version of their bindings, without brakes.

    Lou

  6. lederhosen42 July 22nd, 2014 11:27 am

    Hey Lou; any opinion on using the longer adjustment rails to attach a dynafit toepiece onto? Perhaps use and additional center rail for the old school 5 screw design toepiece? I’ve always desired the ability to use one set of dynafit bindings for a quiver of skis and fore/aft adjustability to change the boot center mount for tweaking performance without having to redrill. For the heelpiece, I’ve found that the adjustment range of +/- 2cms ish (vertical st) is sufficient for tweaking and have simply ordered multiple sets (not a bad price) to mount for different skis and re/re the heelpiece proper onto different skis to keep the quiver alive.

  7. Lou Dawson 2 July 22nd, 2014 11:46 am

    Leder, I just fiddled around with your idea and I’m certain it would work with a Radical toe and just 2 rails, and probably with old style using 3 rails though the outside edges of the binding are not supported the way they are when sitting on ski, so heavy use by larger skiers might cause metal fatigue problems. Very cool idea.

  8. lederhosen42 July 22nd, 2014 12:09 pm

    Also, just kinda popped a visual into mind’s eye…I don’t have any new radical series dynafit bindings to experiment on…but I have to wonder if a home ghetto version of the anti twist post could be constructed simply using an ‘L’ shaped piece of bent aluminum j.b. welded or expoxy’d onto the ski top sheet and bent to the exact shape for the correct angle/contact position? Was thinking in terms of extreme stress, catastrophic failure of the bond between top sheet and ‘post’ could prevent binding heelpiece cracking/failure in case of an out of performance envelope situation occurs. Or, the aluminum post could simply be tweaked in terms of shape and thickness much like a cotterpin, to ensure it snaps before the heelpiece breaks….just a few thinking out of the box ideas.

  9. Lou Dawson 2 July 22nd, 2014 12:39 pm

    Leder, the anti-twist post can easily be cobbled, problem is that when the binding heel is adjusted fore/aft it will not work correctly with the fixed position post. If the post is adjustable fore/aft in some way, then yes it would work.

    Lo and behold, someone at Dynafit/Salewa was reading this post, and this sort of device just arrived in the mail. Great minds think alike! I’ll work with it tomorrow.

    BTW, I just checked closer on the Speed Turn as to if it’ll fit on the Maruelli unit. I’m waiting for a sample for 100% verification but I’m 99% sure it’ll fit just like the Speed Radical. As someone mentioned above, Speed Turn is pretty much a Speed Radical with a different top plate on the heel. But as also mentioned above, it might have a different internal post/spindle. We shall see.

    This is fun.

    Lou

  10. Pascal July 23rd, 2014 2:21 am

    Hello Lou.
    Thank you for showing us so much of the mechanical design geniuses of our good old Europe, without you I wouldn’t have even noticed. Well done!
    You indicate you’d be mounting the binding on the Maruelli piece without rails. It maybe tempting, after a quick glance, it seems to me the hole pattern of the Maruelli base plate without rails is shorter in the length as in the original Dynafit one. Don’t you think there there is a risk of ripping the bindings from the ski with such a lowered Maruelli spindle post?
    Lederhosen’s idea mounting the toe piece on rails seems good and expensive 😉
    I remember of a post concerning B&D shim plates, which in my opinion let the forces be better transmitted to the ski.
    It’d be interesting to see if the speed turn can also be tuned with the Maruelli. solution.
    So many thanks for this post and mod on !

  11. Lou Dawson July 23rd, 2014 9:01 pm

    Pascal, good to be cautious about strength of binding mount but if done well on a ski with strong binding mount area I’m not worried. Lou

  12. Stefano July 25th, 2014 9:44 am

    Hi Lou,

    Thanks for the nice review. Yes the Speed Turn (as the old TLT) can be upgraded with my Antitwsit base and rails. You need just to put on a Click-Clack system if you already have this, or buy a new top plate+lever of the Radical. Has no sense without the heel lever system on.

    Speed and Speed turn has the same shaft. TLT has his thin one.

    You can also use that to transform a radical with stopper in a Speed with lightest base and no stopper (just cutting the plastic nose)

    Thanks
    Ciao
    Stefano

  13. Stefano September 1st, 2014 12:58 am

    Hi Lou,

    Thanks again for the work on my antitwist.

    I’m glad to inform you that Skimo.Co http://skimo.co/ will have in stock all our antitwist, and Safe Loop, from midle/end of september.

    Thanks
    Ciao
    Stefano

  14. Lou Dawson 2 September 1st, 2014 5:26 am

    Thanks Stefano. Good to hear you are opening up dealers.

  15. Stokes December 28th, 2014 12:57 pm

    Stefano, could you clarify what you mean with “you can also use that to transform a radical with stopper in a speed with lightest base and no stopper”?

    I dream of a 12 din speed, with about 6mm less ramp than the current radical ft which I have. Will you be making a version of this compatible with the rad ft or were you suggesting above that this already works with the ft?

  16. Lou Dawson 2 December 28th, 2014 3:58 pm

    Stokes, sheesh, get a Radical FT, cut off the brakes and ditch the connector plate, shim up the toe, done “Speed FT.”

  17. Stefano December 28th, 2014 11:02 pm

    Hi Stokes,

    As told Lou, the transformation is very easy and give you a lighter fully working bindings.

    To arrive at 12Din you can just put a 2mm thickness waser between the big rear springset and the plastic tap,

    but remember that you do that ad your own risk,

    and it has no effect on the vertical release that rest max.10.

    For sure is still better than other false “12” on the market.

    Thansks
    Ciao
    Stefano

  18. Stokes December 29th, 2014 11:11 am

    Lou Dawson 2 December 28th, 2014 3:58 pm
    Stokes, sheesh, get a Radical FT, cut off the brakes and ditch the connector plate, shim up the toe, done “Speed FT.”

    I already made a toe shim, lost the connector plate and have been thinking of getting the saw out but a lighter, neater and less ghetto version is still appealing.

  19. Lou Dawson 2 December 29th, 2014 1:32 pm

    Stokes, sure, less ghetto ver is a reasonable idea… if you can wait till next season or perhaps later this season there are some other options coming up from various brands, looking really good and some at RV 12. Have to say I like the Dynafit Speed in latest incarnation, as well as my little mod with the Maruelli heel post. But I only need to ski at RV 6 or 7…

    P.S., I was about to go out into the shop and try some mods, but then, thinking about above I realised my time might be better spent on preparing some reviews of the secret peeks I’m getting at some of the new stuff.

    Lou

  20. Mic August 26th, 2015 6:39 pm

    I’ve been following these mods for some time, as I’ve had rotation problems since day one. (It’s been uggested my style is too narrow and parallel, and that because I’m on a DIN of around 7, perhaps I’m knocking it a bit with my stride)

    The plasticky ‘rotation locks’ Dynafit have sent me many times keep breaking in the same spot after a couple of trips. A little bit exasperated and looking into these aluminium solutions.

    Correct me if I’m wrong, but if I strip the brakes from my Radical ST, I could pop it onto this Maruelli spindle?
    And the base plate has identical screw pattern to the original ST one?

    I know there is the other Maruelli wire frame job for the ST, but this seems more elegant. Besides I finally realized brakes do nothing to stop you losing skis in deep snow!

  21. Mic August 26th, 2015 7:13 pm

    OK before I get told to RTFF…. I think I’ve answered my own question with a bit more homework.
    The ST and the Speed share the same heel screw pattern…. and the 23mm Maruelli rails will fit this perfectly.

  22. Mic August 26th, 2015 9:45 pm

    Final brain fart. This one might actually be worthy of discussion. What if one removed the ST brake but kept the base plate. The metal bracket that normally holds the brake in has a hole where the brake ‘hinges’… just next to the heel post. Perhaps this could be used to screw in a anti-rotation stop like the Maruelli one?
    Has anyone tried this that could recommend dimensions?
    I guess it would need to be soft enough to allow the ‘wing’ on the ST heel piece to slide over it….

  23. Stefano August 26th, 2015 10:44 pm

    Thanks Mic to report your experience, is what I spent my life on, to prevent with my antitwist solutions.

    Your idea for the solutions is not wrong, but require a soo big and strong (more than 2mm) inox plate and the distruction of the stopper: YOU’VE TO DRILL AND DESTROY 2 VERY STRONG PINS… not easy w/o Widia drilling tool that cost like my adapters… But up to you.

    If you’re in the US/canada you can find my adapters at http://www.skimo.co

    Or I can send them directly to you elsewhere world wide.

    Thanks
    Ciao
    Stefano

    Maruelli ose
    http://www.n-w-b.com

    Widia link added by Lou:
    https://www.widia.com/en/products/24019771/24064245.html

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Welcome to Louis (Lou) Dawson's backcountry skiing information & opinion website. Lou's passion for the past 50 years has been alpinism, climbing, mountaineering and skiing -- along with all manner of outdoor recreation. He has authored numerous books and articles about ski touring and is well known as the first person to ski down all 54 of Colorado's 14,000-foot peaks, otherwise known as the Fourteeners! Books and free ski touring news and information here.

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