Rado Camparo, Amigo — Dynafit Radical ST 2 x 1


Post by WildSnow.com blogger | April 4, 2016      
Radical 2.0 at bottom of photo,  upgraded in numerous ways yet Radical 1 is still viable.

Radical 2.0 at bottom of photo, Radical 1.x at top has been upgraded in numerous ways and is still a viable option that’s lighter and more affordable than Radical 2.0.

First, terminology. Both our vivisection victims are the ST version. Good for comparison, though FT version weights do vary. Further, we’ve lost count of the “in line” variations of the Radical 1 so we tend to call it Radical 1.x not as a joke, simply to make it clear you should pay attention to what version you’re sporting. In truth, I tend to regret not keeping a spreadsheet recording every “in line” change to Radical 1.x, as it would have been fun to number each version and made me look smart. On the other hand, doing so might have been like people who catalog every different shift knob variation used in the 1953 through 1986 Chevrolet Corvette. Smart, or just weird?

Examples of Radical 1 inline changes: Absolute first retail version of Radical 1 had an AFD that failed, which was fixed — yet there are still bindings with the AFD weakness out in the wild, we know so from personal experience and reports. Next came a problem with a clever but dysfunctional “anti rotation” system consisting of a brass pin inside the rear binding housing. This was not user friendly and weakened the housing to the point of easily failing. The legendary pin of brass was fixed with an external anti rotation system. Then a spring was added to help the rear housing move fore/aft as the ski flexed. Next, fragility of the heel unit instigated what we count as at least three different heel unit upgrades. I’ve probably forgotten something, but you get the point.

So, Radical 1.x binding we compare here with 2.0 has all the upgrades, thus weight and such are accurate if not slightly over stated. As always, we have no alternative but to recommend anyone using Radical 1.x sports a binding with all the upgrades. How could we say otherwise in good conscience? In that case, we feel the Radical 1 is equivalent or exceeds functionality and reliability of the Vertical series bindings it replaced (Vertical is our all-time favorite Dynafit full function binding, meaning the option of ski brakes and such).

Onward, first, weights (1.x weights are with all known upgrades, both with <>100 mm brakes, no screws):

Radical 2.0 toe, 224 grams
Radical 2.0 heel, 402 grams
Radical 2.0 total, 626 grams

Radical 1.x toe, 182 grams (with crampon mount at 10 grams)
Radical 1.x heel, 378 grams
Radical 1.x total, 560 grams (66 grams – 2.33 ounces, less than Radical 2.0)

Toe height is virtually the same for both bindings.

Toe height is virtually the same for both bindings. Radical 2.0 is about 1 mm taller at the toe. Heel height is virtually the same, 50.4 mm to center of heel pins from top of ski. Thus, you get a hair less ramp from Rad 2 — a good trend for most of us. More here about ski touring binding ramp delta angles.

Let's get the toe unit comparison out of the way first. Well known difference, Radical 2 toe rotates.

Let’s get the toe unit comparison out of the way first. Well known difference, Radical 2 toe rotates, Radical 1 toe does not. Why ? Most provable reason is that boot toe tech fittings vary. Some boot fittings provide a smooth ball-and-socket action yielding elasticity and return-to-center. Others stick and jam. The rotating toe lets the heel unit provide lateral elasticity no matter how your toe fittings perform (and they’ll release eventually no matter what). Reason #2 is a theory that without rotating toe, the toe “wings” open while the binding heel does its elastic rotation duty, but don’t close completely, and eventually pre-release. Problem is we have zero-zilch-nada lab or field data showing the latter is real. Anecdotal evidence is favorable. But the conversation often goes something like this: “Hey Lou, I ski those things like a god, unlocked, and never prerelease,” then “Sounds good, mister, what DIN have you got them on ?,” “Oh, I just bottom everything out even though I weigh 72 kilo…” Lots that tells us…

Rad 2 to left, showing rotation. It's  blocked after a certain point but quite noticeable. This is a radical concept. To the best of my knowledge there has never in history been a ski binding that had 100% lateral release function at the heel and did not have problems with pre-release. Reason, the basically "moronic" mechanics of ski bindings have a lot of trouble differentiating between heel thrust forces used to turn a ski, as opposed to lateral heel forces that can injure you. Original tech binding design, while not perfect in this regard, did contribute some of its lateral release tension at the toe. Rad 2 does not do so. Difference between Rad 2 and early

Rad 2 to left, showing rotation. It’s blocked after a certain point but quite flexible. This is a radical concept. To the best of my knowledge there has never in history been a ski binding that had 100% lateral release function at the heel and did not have problems with pre-release when set at “normal” release values. Reason, the basically “moronic” mechanics of ski bindings have a lot of trouble differentiating between heel thrust forces used to turn a ski, as opposed to lateral heel forces that can injure you. Original tech binding design, while not perfect in this regard, did contribute some of its lateral release tension at the toe. Rad 2 does not do so. Difference between Rad 2 and the early problematic bindings is that it’s using the tech binding toe wings as well as Dynafit Power Towers, thus blocking at least one mode of lateral pre release. In the end, this could be genius. We figure another season of consumer testing will give us a better read, but this season did go well both in-house and from what I’m hearing with my ear to the railroad track. Have you been using Radical 2.0 at “normal” release settings? Comments would be appreciated.

Next, just to get it out of the way, here is what you want to look for if you're buying Radical 1 or have your own and want to be sure about reliability.

Next, just to get it out of the way, here are a few things you want to look for if you’re buying Radical 1 or have your own and want to be sure about reliability. While there is some question about the need to go to the latest version (with steel plate as indicated) it’s clear that everyone should have basic Radical 1 heel upgrade features detailed in this blog post.

Let us have fun.

NOW, let us have fun. Removing housing from Radical 2 center spindle is not child’s play. I’m impressed by how Dynafit keyholed the housing down on the spindle so no matter how low you set your release values, it can not pull up off the spindle (rare, but happens with trad tech bindings). Shall we let the exact procedure remain magical? Ask in the comments, or brag how you figured it out.

Center spindle of Radical 2 is interestingly made of strong ostensibly carbon infused plastic.

Center spindle of Radical 2 is interestingly made of strong ostensibly carbon infused plastic. I’ve always been a fan of modern plastics, but I have to admit surprise at this departure from aluminum. Thing is, skiers have been breaking tech binding center spindles for years, the alu ones. So why not make a bigger one out of high-tech plastic? Jury definitely out on that! At least plastic is somewhat self lubricating.

Radical 1 has skinny aluminum spindle the heel unit rides on.

Radical 1 has skinny aluminum spindle the heel unit rides on. Note the vestigial notches inside the bore shown above spindle, those are for the failed “brass pin” anti rotation system of the first Radical, somewhat surprising they’re still there.

Rad 2 at left has larger lateral (side) release adjustment screw. What's inside there?

Rad 2 at left has larger lateral (side) release adjustment screw. What’s inside there?

Radical 2 has a large single spring that's quite powerful.

Radical 2 has a large single spring that’s quite powerful. Reason, the rotating toe contributes zero resistance to lateral release so the heel has to be correspondingly stronger. I have no easy way of accurately measuring the difference, but crude experiments indicate that if you set both the Radical 2 and Radical 1 heels to the same lateral release value (e.g., 7), the Radical 2 has around 15% higher tension. Along with that being of rhetorical interest, if you choose to run a 2.0 heel with a 1.* toe you’ll need to dial DOWN your lateral setting accordingly if you want anything close to chart recommended values.

Zee springs. We like the single big beefy guy.

Zee springs. We like the single big beefy guy. He makes sense.

Now we get to durability issues.

Now we get to durability issues. You never know what will crop up in consumer “testing,” but one thing Radical 2 will not do is break apart like a rejected wedding cake. Re heel unit, the top plate is physically keyed into the lower housing with “teeth” that basic laws of physics say can not fail. Amen Newton!

Matter can not occupy the same space as other matter, at the same time.  Interesting how long it took engineers to figure that out.

Matter can not occupy the same space as other matter, at the same time. Interesting how long it took engineers to figure that out (I thought they learned that in school), but the solution does appear BOMBER.

Features that prevent heel unit rotation while in tour mode are important with Radical series bindings.

Features that prevent heel unit rotation while in tour mode are important with Radical series bindings. Both bindings integrate brake retraction holder with the anti-rotation. Radical 2.0 to left does it with a clever system of small catches, Radical 1.x to right holds brake by rotating over a metal plate, and the anti rotation stops are attached to the same plate. WE like the 100% positive nature of the 1.x configuration, but the 2.0 system has a nice positive snap when you contract the brake as well as what feels like beefy anti-rotation.

Following photos detail a sometimes perplexing features we’ve seen added to Dynafit’s (and a few other brand’s) bindings over the last few years. Yes, Virginia, a binding needs to compensate for ski flex. Most tech bindings do so by simply allowing heel pins to slide in-out of boot heel fitting. Worked for 25 years, change needed? Read on.

Underside view of Radical 2 showing ski flex compensation spring.

Underside view of Radical 2 showing ski flex compensation spring.

Guts exposed. A thin stainless steel plate sits between the spindle base (shown) and the ski top skin.

Underside of Radical 1.x showing ski flex compensation spring. A thin stainless steel plate (not shown) sits under the spindle base (shown) on top of the ski allowing the spindle base to slide forward and back about 6 millimeters. Look closely and you can see the spring that enables this function. Because the Radical 1.x is still set to a 5.5 mm heel gap, we are not sure this spring actually does anything for average skiers other than add weight, but it certainly contributes if a ski is strongly flexed and your boot heel gets to the point of banging against the binding heel unit. You can test this to some degree at home by placing a boot in a ski and flexing the ski.

Illustration of small gap used for spring-loaded tech binding.

Pictured here is a Dynafit Radical 2.0 heel unit (all black, later versions have green and gold components), with ‘kiss gap’ adjusted to what we think works best, a very small gap that just allows a sliver of light to come through. THIS IS A BIG DIFFERENCE BETWEEN Radical 2 & 1, as all versions of Radical 1.x need a 5.5 mm gap at the heel, including the versions with a flex compensation spring. In my opinion the reason Radical 1 still requires the 5.5 mm gap is the Radical 1 spring system is clearly not as robust as that of the Radical 2.0, which uses the “kiss gap.” More here covering the Dynafit heel gap setting.

Takeaway points about tech binding ski flex compensation springs. 1.)Adjust heel gap correctly. 2.)These are not “forward pressure” springs, they remain passive until activated by the ski flex, and somewhat during lateral release rotation of the heel unit.

There you go folks. I’ll continue dissecting the bindings and adding commentary if more questions come up. Comments on!

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Comments

20 Responses to “Rado Camparo, Amigo — Dynafit Radical ST 2 x 1”

  1. Maciej April 4th, 2016 10:43 am

    My Vertical FT’s died this year after a few hundred days of use, and I got a set of Radical FT 2.0’s as replacements. Since there’s more elasticity in the system, I was able to dial back the release tension from RV10 to RV 9. I’ve had a couple of releases since, but they were smooth, predictable and happened when needed (hitting unexpected features in whiteout, sloppy landing on a big drop etc.). At least in my experience, the added elasticity in the new system does provide a smoother ride and better feel for when I’m approaching the limits of retention. I loved my old Verticals, but they gave no warning and then blew off if pushed to release.

    I’m guessing that Dynafit was able to go to a reinforced plastic heel post because the heel piece moves with the boot. Most of the breakages on traditional Dynafit heels occur from boots repeatedly banging on the heel unit, but this stress has been largely removed with the new design (the heel unit on my old Dynafits didn’t break, but the rear adjustement spring blew out of the back of the base plate, likely from me “bottoming out” the bindings a lot). Considering the minimal weight gain in the heel, this seems to be a worthwhile upgrade.

    As for the toe, I’ve now skied it in everything from cold smoke to ice to crust to corn. While there are more crannies for slush to pack into, I’ve had no more issues than with a 1.0 style toe. Popping the bindings open and shut a couple of times clears any packed-in stuff, same as always.

    As with other Radial Series bindings, the flip risers are awesome, but I find the alignment towers on the toepiece to make clipping in more rather than less difficult, but it’s a minor quibble.

    One final thing I found going to a fresh set of bindings was that the toe pins on my old Verticals were totally shot. I didn’t realize how bad the problem was until I clipped into the new ones and the slop and clicking I’d just gotten used to was gone. Dynafits are (IMHO) the best touring bindings out there, and their durability is a selling point, but nothing lasts forever. If your toe sockets are sloppy (even with a new set of boots) it’s likely time to get a fresh set of tech bindings.

  2. Lou Dawson 2 April 4th, 2016 10:54 am

    Mac, perfect comment, thanks. A couple of things:

    That fact that the toe pins on your old bindings were worn out is key. We have found that worn toe pins can cause all sorts of trouble with classic tech bindings. The rotating toe is indeed a way of getting more reliable elasticity, and once the toe pins wear it will continue to do so. On the other hand, a properly functioning classic tech binding does have quite nice elasticity — it’s just that it’s got to be evaluated on a case-by-case basis and carefully watched over the wear cycle of the binding.

    As for the boot alignment towers, they also function to possibly prevent a mode of pre-release so make them your friend (grin).

    Again, much thanks for chiming in! I also heard from a 180 pound x skiracer “freerider” who raves about the Radical 2, so that’s good testimony as to retention, though he’s skiing at more of what I’d call “race” settings in terms of release value.

    Lou

  3. XXX_er April 4th, 2016 11:03 am

    “Center spindle of Radical 2 is interestingly made of strong ostensibly carbon infused plastic. I’ve always been a fan of modern plastics, but I have to admit surprise at this departure from aluminum”

    the rad 2 redesign was looking pretty good until this ^^ plastic spindle

    goodbye Dynafit …hello G3

  4. Chris B April 4th, 2016 11:05 am

    Fascinating as always, Lou. Here is a question about the needed upgrades you mentioned for Radical 1.x’s. I have two pairs of Speed Radicals, one from the 13/14 season and another from the 14/15 season. Never had any problems but I don’t get out that often ’cause of the kids. (Not once this season as we just had our third boy Sept. 30.) Is there anything I need to or can do to prevent possible problems with those units in the future?

    Next year I will be do a lot of touring. My 13 year old wants to start up hilling and touring the BC and since he can ski anything I can these days he is totally ready.

  5. Lou Dawson 2 April 4th, 2016 11:20 am

    Chris, the process is you first ID what binding heel you actually have, then if you assume it qualifies for an upgrade you contact Dynafit customer service.

    The year you bought the bindings has little to do with what you actually have, though the earlier you bought them the more likely they are to need the basic upgrade.

    As for how often you use them, in my opinion based on numerous reports I’ve received it doesn’t mean much one way or the other.

    https://www.wildsnow.com/17797/dynafit-radical-rear-break-screws/

  6. Bobby April 4th, 2016 4:24 pm

    What is the exact procedure to remove the Radical 2 housing? No reason to brag about how bright I am.

  7. Lou Dawson 2 April 4th, 2016 4:56 pm

    Hi Bob, this Google query works:

    https://www.google.com/search?q=radical+brake+removal&oq=radical+brake+removal

    Or ask and ye shall receive this: https://www.wildsnow.com/15074/dynafit-tech-binding-take-apart/

    Same procedure as shown for brake removal insofar as taking the housing off. Trick is if you strip the spring cover threads you brick the binding. Don’t you have a shop that can do it?

    More, if you look at the menus at top of site, you’ll see one for “Ski Touring Bindings,” drill into the Dynafit options and you’ll find about 75,000 words about Dynafit bindings (grin).

    Lou

  8. Jim Milstein April 4th, 2016 5:36 pm

    “Matter can not occupy the same space as other matter, at the same time.”

    I suppose, Lou, you mean matter in its solid phase. Of course, this rule also depends on the meaning of space. Ordinary matter is almost entirely space. Even an ingot of solid osmium is very spacious. The world is full of wonders . . . and space.

  9. Lou Dawson 2 April 4th, 2016 5:48 pm

    Terms of art to some degree I suppose. But the atoms in a gas, likewise, can’t occupy the space of say, atoms of another gas that’s mixed with it… or do we throw all that out the window in the quantum world? Lou

  10. Jim Milstein April 4th, 2016 6:11 pm

    That’s why physicists passed the Law of Partial Pressure, Lou, though I heard that it’s coming up before the Supreme Court on a Second Amendment challenge. Stay tuned!

  11. Jim Milstein April 4th, 2016 6:54 pm

    The Law of Partial Pressure states that more than one gas may occupy, by force of arms if need be, the same volume of space and that each gas may behave as though it alone occupied that volume of space.

  12. Olivier April 5th, 2016 10:55 am

    Using the 2.0, I’m having the issue of the brake deploying while in touring mode. Anyone having similar problems?

  13. Lou Dawson 2 April 5th, 2016 11:30 am

    Dang brakes. No matter what the brand, on occasion the brakes will do this (unless they’re the old style of having the heel unit rotate over it to hold it), usually from ice or snow packing but sometimes they just lack the exact tolerances they need to pop over their little holder, or under their hook, or whatever. Plum has the best solution. Brake is simply stowed and deployed by the user, independent of binding heel operation. I wish all the other binding makers would get that.

    Not to get too negative, I should have mentioned in the review that the Radical 2.0 brake is full-on alpine binding style, with a powerful deployment spring and strong arms. It’s super nice, albeit weighs a ton.

    I’m pretty sure it’s easy to remove. I need a break from the keyboard, perhaps I’ll strip one off a binding and see how it goes.

    Lou

  14. Thom Mackris April 5th, 2016 12:19 pm

    Thanks Lou! Good work as always.

    Good on them for the strong brake. Placebo brakes are worse than no brakes. Get it right or just skip it. Agreed on Plum’s approach. Separate the functions for ease of design and reliability in the field.

    I agree with XXX-er on the composite post. Are they getting bored? Are they finally over the replacement process for all of the stripped screws?

    I fear they’re asking for trouble on this one and I’ll watch the public beta test this one 😉

    If anything, I would have expected a titanium part, although the price adder would have likely been prohibitive. Failing that, I’d stick with aluminum – Luddite that I might be 😉

    Cheers,
    Thom

  15. Lou Dawson 2 April 5th, 2016 12:34 pm

    Thom, I don’t get this mythology about aluminum necessarily being more durable than composite. Plenty of people have broken various aluminum binding parts over the years, including the Dynafit aluminum rear center spindle! This composite one might be incredibly strong… it’s about design and engineering as much as the exact material, don’t you think? Lou

  16. Lou Dawson 2 April 5th, 2016 1:06 pm

    RE the Radical 2.0 brakes. They can be removed, which removes the anti rotation catch (though it may be possible to actually reinstall the rotation catch after the brakes are gone!). Thing is, the heel unit has quite a bit of resistance to rotation while in touring mode even without the anti-rotation catch engaged. I think average weight folks could easily tour it without the brake and without the anti-rotation, at normal release settings, since the heel lateral release tension supplies the anti-rotation if the catch isn’t engaged. Lou

  17. Erroneous April 5th, 2016 1:24 pm

    @ Olivier – I had this problem until I figured out that the 2.0 has a different procedure than earlier versions for stowing the brakes. Don’t try to hold them down while you turn the heel piece. Just turn the the heel piece first until it clicks into the tour position, then either depress the brake by hand or step on it after clicking into the toes. And make sure there isn’t any major snow buildup underneath the brake before locking them down. Brakes have worked great for me using this approach.

  18. Lou Dawson 2 April 5th, 2016 2:33 pm

    Added comparative photos of anti-rotation features.

  19. rols April 5th, 2016 11:10 pm

    In changing the post, they have a done a lot more than just change to a GF composite. The high vertical forces that come stomping on the heel risers, big guys landing jumps etc are now transferred directly into the base via the large diameter thrust face, the new ‘post’ should see less bending moment than the old design. With the 1.? design, vertical forces applied to the edges of the heel unit translate to bending stress in the Aluminium post. It should be better, we’ll see I guess.

  20. Thom Mackris April 6th, 2016 12:46 am

    Hi Lou (and rols),

    I agree that composites can be very strong. I just have to wonder if this material change wasn’t a solution in search of a problem.

    rols’ comments are provocative and potentially instructive – about the force vectors and thrust face design. Maybe they’re on to something in this regard.

    I suppose that the use statistics will tell us what we need to know.

    Cheers,
    Thom





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