Dynafit Binding Comparison — Rotation and Radical 2.0


Post by WildSnow.com blogger | September 22, 2017      
The objects at hand. Dynafit Radical 2.0 and Rotation ski touring bindings are nearly identical, a few key differences.

The objects at hand. Dynafit Radical 2.0 and Rotation ski touring bindings are nearly identical, a few key differences.

Building on the venerable Radical series, Radical 2.0 offers a completely reworked heel unit that in our opinion is nearly impossible to blow up, as well as a rotating toe that’s said to make the binding less prone to pre-release. Testing last winter proved that “Rad2”, while fiddly in some ways due to the rotating toe (and not tourable unlocked), is a durable and effective ski touring binding.

Enter the Dynafit Rotation ski touring binding. An upgrade overall similar to Rad2; heel unit identical, important changes in toe unit.

Rotation has an improved toe unit that’s easier to use; it’s otherwise virtually the same binding. In all, a solid addition to the large variety of “free touring” tech bindings that boast integrated brakes, heel units that adjust to ski flex via a spring loaded track, and overall beef.

Below, I do a bit of comparo as to the differences between Rad2 and Rotation, and segue into describing how both bindings deliver their promise of a strong ride. Please know this is not a review, that’ll come later this winter after we abuse the retail version Rotation.

Before we begin, a few previous posts covering this same subject matter.
Dynafit Radical 2.0 Review
Radical 2.0 Brake Removal
Comparison of Radical 2 with ver 1

And the numbers…
Radical ST 2.0, heel unit, 110 mm brake, 416 gr – 14.7 oz
Radical ST 2.0, toe unit, 230 gr – 8.1 oz (steel wings)
Radical ST 2.0 single binding, total, 646 gr – 23 ounces

ST Rotation 10, heel unit, 110 mm brake, 416 gr – 14.7 oz
ST Rotation 10, toe unit, 208 gr – 7.3 oz (aluminum wings trim 22 grams, nice to see “negative weight creep”)
ST Rotation 10 single binding, total, 624 grams – 22 ounces

Delta and stack height are identical. See this post for numbers.

First, let's get down to brass tacks.

First, let’s get down to brass tacks. Both bindings have a toe that rotates a few degrees. Difference is the Rotation (bottom of image) has a small ball bearing detent that keeps the binding centered while you’re doing things such as clipping in for downhill skiing or locking for touring. Radical 2.0 is a challenge in this regard, as the freely moving toe rotation creates various points of confusion while you’re messing with the binding.

In more detail: Granted, when you prepare either binding for clipping your boot toe, the toe lock lever does secure it from rotating. But as soon as you clip your boot the binding toe can rotate, thus causing your boot heel to possibly shift out of alignment with the binding heel unit pins, as well as possibly rotating the toe off center and making it impossible to lock into touring mode. Latter situation appears to be the norm for inexperienced users — we’ve watched scores of such skiers struggle with the Rad2 binding in this way. We are optimistic the detent of the Rotation binding will eliminate or at least greatly mitigate these issues. Arrow in photo points to the detent.

Rotation underside shown at both left and right, with binding rotated (left) and straight ahead, held by the ball bearing detent.

Rotation underside shown at both left and right, with binding rotated (left) and straight ahead (right), held by the ball bearing detent.

With both bindings, the question: Why the rotating toe? According to Dynafit, this mechanical system allows the boot to absorb shock (essentially, a partial release) without the binding toe pins riding part way out of the boot toe sockets. In the case of tech bindings without rotating toe, every time the boot moves in lateral or rolling shock absorption, the toe pins ride some distance out of the boot toe sockets. Idea is that once the pins are partially out, the system is more prone to accidental release. Pop. Makes sense and can be easily simulated on the bench by moving the boot heel partially through the lateral release cycle and evaluating how much force it takes to knock the boot toe out of the binding toe — comparatively done in the case of both rotating and non-rotating toes.

The burning questions are, of course, is the rotating toe unit truly beneficial in real life use, and are there any tradeoffs other than the added weight? (Engineers will tell you, any time you change part of a machine there are _always_ consequences).

My “rotational” take: I’ve always felt that a unique feature of most tech bindings was that the boot toe fittings “ball and socket” joint provided a modicum of spring loaded resistance and shock absorption. In the case of a rotating toe, this front spring action in partially eliminated as the toe rotates (the springs only engage during the latter part of the release cycle, when the boot finally pops out of the toe unit). My take, could be a wash; could be an improvement.

Anecdotal accounts from binding testers indicate both Radical 2.0 and Rotation clearly have no more problems with accidental release than the original Radicals, perhaps less. Getting a firm read on that is tough without some sort of organized field study, and I’ve not heard any plans for the NTSB to be doing crash dummy testing with ski bindings (they’re busy figuring out how to test self driving cars). Mainly, I’ve spoken with strong and aggressive skiers who are very happy with the binding. So fine. Let’s leave the great rotation debate to the comments, or to the future after more consumer testing and WildSnow bench racing.

(If you chime in with glowing accolades for your Rad2 or Rotation in terms of release-retention performance, we’d be delighted to hear it. But please share what release values you’re skiing the binding with, as pegging the settings and thus essentially eliminating any sort of practical binding release probably makes any performance contribution from the rotating toe a non issue.)

Sidebar. I should mention that an ongoing problem with tech binding ski setups is boot toe fittings that don’t smoothly release from the toe pins, due to manufacturing defects or wear and tear. I’ve been told by insiders that getting the boot-binding tech interface right takes it to the limits of metallurgy and manufacturing. The rotating toe mitigates this challenge. Once the boot is partially through a lateral release cycle as allowed by the rotating toe, the system would have to be highly compromised for a release not to occur. Considering that, even with the rotating toes, all boot-binding combinations should be bench tested for releasability before being skied.

I stripped down the Radical 2 toe to show how the rotation works. I liked the colors better for photos, and didn't want to worry about the detent rolling accross my studio floor into a crack.

I stripped down the Radical 2 toe to show how the rotation works. I liked the Rad 2 colors better for photos, and didn’t want the Rotation detent ball bearing rolling across my studio floor into a crack.

After the toe unit is demounted, turntable easily comes out.

After the toe unit is demounted, turntable easily comes out. The design is nicely minimalist for something with moving parts.

Crampon mount is integral.

Crampon mount is integral.

Underside of turntable reveals T-nuts. Like I said, simple.

Underside of turntable reveals T-nuts. Like I said, simple.

Let's get down to an interesting difference.

Let’s get down to an interesting difference. Radical 2 (left) has steel wing arms, testing magnet attached. Rotation (right) arms are aluminum. Result is Rotation toe weighs 22 grams less, clearly the main reason Rotation bests Radical 2 in the weight contest.

It could be argued that the importan improvement to these bindings, over earlier  Radicals, is how the heel unit is  'bayonet mounted' on the base plate. Both are the same this way, and I've covered in previous blog post.

It could be argued that the most important improvement to these bindings, over earlier Radicals, is how the heel unit is ‘bayonet mounted’ on the base plate. Both the Rotation and Rad2 are the same this way. I covered this feature in a previous blog post, but it’s worth more exposition.

Rear binding housing (at top of photo), has obvious flanges corresponding to slots and flanges in the base.

Rear binding housing (at top of photo), has obvious flanges corresponding to slots and flanges in the base. Rad2 and Rotation are identical in this. Idea here is total resistance to the housing getting pulled up off the base spindle –a rare but nonetheless real event with many earlier tech bindings. I like this design, it’s smart and doesn’t seem to add weight. Deal maker? Probably not unless you tend to pull bindings apart. In that case, would your name be Igor per chance? Send photos.

While we're on the subject of heel units.

While we’re on the subject of heel units, both Rad2 and Rotation use oversize lateral retention spring and cap shown on left in photo. Spring to right is the common size nearly all previous Dynafit bindings used. Sizing this up is probably a good thing for a free touring binding, though not necessary for the average “moderate” user.

I like this. Rotation (top) has a thicker slightly higher trigger.

I like this. Rotation (top) has a thicker slightly higher trigger (~ 1 mm) than the Rad2 (bottom). Combined with the rotation detent, this should make a noticeable difference while clipping in, though it might create a bit of a hair trigger for boots with thick soles. Easy to tune by carving small amounts of material off your boot sole. We’ve been dealing with this sort of issue for years. Also, specific to removing sole material, see this post.

Heel units are overall mostly identical (Rad2 comes in both gold accent and all black), only obvious difference is the badging.

Heel units are structurally identical as far as we can tell (It’s my understanding that Rad2 has been sold in both gold accent and all black), only consistent difference in appearance is probably the badging.

Clones. Baseplates even have the same part number stamped on the bottom. Rotation to left, Rad2 on right.

Clones. Baseplates even have the same part number stamped on the bottom. Rotation to left, Rad2 on right. (Pictured Rotation has 120 mm brake, Rad 2 is 110).

Me likey, boot length adjustment screw accepts both 8 mm socket  or T20 torx (same as mount screws).

Me likey, boot length adjustment screw on both bindings accepts both 8 mm socket or T20 torx (same as mount screws). We waited years for this.

Back to the bottom, of the base plate.

Back to the bottom, of the base plate. Both bindings have a fairly beefy spring that compensates for ski flex pushing the binding heel unit against your boot heel. Many tech bindings take care of this by having a gap between boot heel and binding. While that solution is elegant in simplicity, it can be problematic in terms of friction and lack of range. Our understanding is that in order to receive TUV certification to ISO/DIN standard 13992, the bindings need to have this spring feature. Yes Virginia, both Rad2 and Rotation are “DIN” certified. How important is that? You can inform yourself here, and with more DIN/ISO info here.

Super strong top plate is 'keyed' into the lower housing, both 2 and Rotation are identical in this regard.

Super strong top plate is ‘keyed’ into the lower housing, both 2 and Rotation are identical in this regard.

Conclusion: Both bindings are virtually the same. While clearly a good idea in terms of shock absorption performance, the toe rotation can be problematic. You can’t tour with either model’s toe unlocked, and clipping your toe in can be tedious. Rotation model significantly mitigates the tedium due to the toe rotation detent — this is the only major difference between the two grabbers. Nice the alu wing arms of the Rotation save 22 grams per binding. We like the rotation’s slightly taller toe “trigger,” this will go unnoticed by most people but saves tuning work for the outliers with boots that don’t interface quite right. As mentioned above, while this is not a review, I’m comfortable giving Rotation a 98% of two thumbs up base on this bench race. We’ll see if the last 2 points can be added after we test the retail version binding this winter.

Shop for Rotation and Rad2 at Cripple Creek.

Dynafit Radical 2 and Rotation ski touring bindings, comparison.

Dynafit Radical 2 and Rotation ski touring bindings, comparison.


Comments

28 Responses to “Dynafit Binding Comparison — Rotation and Radical 2.0”

  1. See September 22nd, 2017 4:11 pm

    I wonder if the detent in the Rotation toe has an effect on the spring tension in the heel piece relative to the Radical for a given release value. It seems like an increase in resistance to rotation at the toe would require a slight reduction in resistance to rotation at the heel for a given setting. Maybe the difference is insignificant, but are the lateral rv numbers printed in the same place on the housings?

  2. Lou Dawson 2 September 22nd, 2017 4:20 pm

    See, that’s a good question. I think it’s probably insignificant. The DIN/ISO standard allows quite a bit of variation in actual torque compared to the numbers printed on the binding, added torque from the detent is quite easy (you can move it with a few fingers) and probably falls within that deviation.

    Incidentally, the detent does add a tiny bit of “return to center” force that while minimal, might take the place of having the binding pins riding in and out of the boot toe sockets.

    First thing that occured to me when I saw the Rad2 and now Rotation was that adding some spring tension to the toe rotation could be quite beneficial to the binding’s retention characteristics, though might actually be no different than supplying it at the heel.

    Overall, Dynafit has really thrown us some food for thought, and perhaps testing.

    Lou

  3. Todd September 22nd, 2017 4:54 pm

    T20 BSL adjustment is new, right? Pretty sure my Rad 2.0 STs have Pozi BSL adjustment.

    If you mount multiple bindings with inserts and end up with one or two under the rotating part of the baseplate, and you’re not particularly good at mounting bindings (like me), you get a similar effect as the ball-bearing detent: the baseplate doesn’t want to turn smoothly. Way easier to step in that way! I ended up with B&D shims under the toe pieces, though, which solved that problem.

    Glowing praise: my Rad 2.0 STs have never prereleased, and they release when they need to. I’m 135 lbs and run them at RV 8. They definitely feel more damp than Speed Rads or TLTs, although part of that might be the skis the various bindings are on and the conditions I take them out in.

    Hopefully the Rotations mean we’ll see the Radicals on closeout more frequently….

  4. Mr.Weenie September 22nd, 2017 5:00 pm

    Think there might be an error with the weights calculations?

  5. Lou Dawson 2 September 22nd, 2017 5:05 pm

    Can’t believe I messed that up, space case! Fixed now. Thanks for the help. Lou

  6. Lou Dawson 2 September 22nd, 2017 5:16 pm

    Todd, yeah, T20 adjustment is new.

    Good to hear you’re able to run RV 8, that speaks well to the binding. Still, isn’t that a bit high for 135 pounds, re “chart” settings? I didn’t look.

    Thanks, Lou

  7. David September 22nd, 2017 7:09 pm

    Waiting for your 2017 take on the Superlite 2.0!

  8. TMS HAWAII September 23rd, 2017 12:12 pm

    I’m 6’2″ and 220 lbs, I use the Radical FT and run the tension @ 10. I feel more comfortable running the FT at 10/12 than the ST at 10/10. Maybe it’s psychological, but I’m an engineer, so running anything continuously @ 10/10 of its design envelope gives me the willies.

    I’ve blown up several of the original FT (1.0) heel units, but so far the FT 2.0 have performed flawlessly for me.

  9. Lou Dawson 2 September 23rd, 2017 1:57 pm

    TMS, RV 10 at your size sounds about right? Good to hear it’s working. Helps people to get these real-life opinions. Lou

  10. Lou Dawson 2 September 23rd, 2017 2:56 pm

    test

  11. Torquil September 23rd, 2017 3:05 pm

    I see they didn’t bother changing the brake plate so its easier to get to the mounting screws, they are a pain when taking in and out of quiver killers, 2 minutes with a dremel on the plastic makes it a world easier. I was hoping dynafit would sort that out second time round!!

    Otherwise I found the rotating toe was easy to use once you get used to it but I’m sure the Rotation is great for new users.

    Anecdotal release experience: the first time I crashed and released, all I was thinking mid-crash was how surprisingly smooth the release was. 68kg set on 6

  12. Lou Dawson 2 September 23rd, 2017 3:15 pm

    Thanks Torquil. Lou

  13. swissiphic September 24th, 2017 10:11 am

    I don’t know…with all this incremental weight creep and complexity increase year after year…why doesn’t Dynafit just start from scratch, blank slate it and offer a laterally releasing toe with elasticity and a good solid wide pin spacing heel unit? One up the Vipec design.

    Time for a rethink, I think.

  14. Justin September 24th, 2017 12:37 pm

    I mentioned the Look bindings in an unrelated post, but this is much more related.

    I’m assuming these new look bindings are clones of the dynafits? or just rebadges?

    http://www.look-bindings.com/en-us/product/look-hm-12-d90

    Any insight into this? Has anyone seen this in a store?

  15. VT skier September 24th, 2017 7:58 pm

    Anyone have a problem with the Anti Friction Device , mounted on the ski brakes flying off? I lost one of these AFD’s but my Local Ski Shop replaced the whole heel plate/brake unit under warranty.
    AFDs on the Radical 2.0 seem to be flimsy. OTOH a very low friction AFD may be necessary to obtain the ISO/DIN standard 13992 certification.
    Mine are setup with a Release Value of 8 for lateral and forward release now. Came out of them once on chattering Eastern resort ice, but that may have been with a lateral setting of 7. Only one ski came off, I stayed upright on the other one .Haven’t come out yet with the 8/8 setting..
    I am 6’2″ 195 lbs.

  16. Lou2 September 24th, 2017 9:56 pm

    The Look is just a rebadge. Started a while ago. We covered in at least one blog post back then.

    https://www.wildsnow.com/15674/dynafit-oem-products-fischer-skiing/

    Lou

  17. Matus September 25th, 2017 1:13 am

    @swissiphic – My words. But this is probably the result of the hunt for ISO/DIN binding.

    I am dreaming about Dynafit Superlight 2.0 + wider mount pattern and flat mode. Currently, the closest to this is Salomont MTN (however, 100g heavier).

  18. Pablo September 25th, 2017 4:14 am

    @Matus, Salomon’s MTN are not only 100g heavier, but also have BSL adjustable and this feature causes a nice weight increment. just to be fair on comparos.

  19. Lou Dawson 2 September 25th, 2017 3:01 pm

    VT, the sliding plate coming of the AFD was a known problem with previous Rad model before it was fixed.

    https://www.wildsnow.com/6908/dynafit-radical-broken/

    I had not heard of it being a problem with Rad2, but I’ll keep my eye out. Glad to hear your binding got fixed and that it’s working.

    Lou

  20. Lou Dawson 2 September 25th, 2017 3:04 pm

    Pablo and Matus, don’t forget that the Backland Light binding (and presumably something the same from Salomon) has no boot length adjustment but only weighs 236 grams per binding.

    https://www.wildsnow.com/15664/salomon-atomic-backland-tech-binding/

  21. Todd September 27th, 2017 1:20 pm

    8 is what I get from various online DIN calculators, although maybe I’m not as good at skiing as I think I am. Certainly 8 seemed appropriate for resort skiing last season.

  22. Rudi September 27th, 2017 2:45 pm

    speaking of Backland Light…! Does anyone know an etailer selling this thing currently? Telemark Pyrenees does not have it and even the atomic website does not show the light (non-adjustable) version.

  23. Andrei September 27th, 2017 4:46 pm

    The one time I demoed Rad 2s I had an issue that if I didn’t lock the toe all the way it would go (3 or 4 clicks) my heel would inadvertently release the brakes and a couple of times rotated the heel piece into ski mode while I was hiking.

    While I appreciate Dynafit’s desire to keep up with the new trend of toe flexibility, I’m going to go ahead and stick with my two sets of 1.0…

    I found that running about 10/11 for the side release and about 6 for vertical release helps to keep the release force about equal.

  24. Anne October 7th, 2017 1:00 pm

    I’m not the best at tech talk, but I did have an interesting mechanical breakdown with the 2.0 last season. Having skied various Dynafit models over the years without issue, I gave the 2.0 a try thinking the improved releasability would be valuable in my work teaching and guiding. I don’t consider myself a hard charger as I’m 5’1″ and mostly cruise mellow terrain. I was surprised when I was out guiding a client in mellow terrain with soft turns and the spring connection to the brake snapped. I managed to use a ski strap to compress the brake and to force my heel into the heel piece to not have to cut the day short. I had thought it would be a quick fix to simply replace the brake, but with the 2.0, it was necessary to replace the entire heel piece. In thinking about field repair options and spare parts for more remote expeditions, I’m not sure I’m sold on the 2.0.

  25. Lou Dawson 2 October 7th, 2017 4:19 pm

    I have to tell you, I’m so over these attempts to integrate brake with the binding. I’ve lost count of all the known or otherwise reported problems, like yours… I think they can eventually get it right, but I sure miss the removable and easily replaced brakes of the Comfort and Vertical model series. Lou

  26. Lou Dawson 2 October 7th, 2017 4:25 pm

    Rudi, there seems to have been some kind of delay in supply. Cripple Creek tells me they have them now. https://www.cripplecreekbc.com

  27. atfred October 7th, 2017 5:58 pm

    +1 on Comfort and Vertical.

  28. Scott Robbins October 17th, 2017 6:57 pm

    Do the Radical FT 2.0 Toe Plate Extensions (the plastic bit that goes around the the swiveling toe plate in the Radical 2.0 FT), fit the Rotation-10 toe plate? From the pictures it looks like it *almost* does, but not quite. Could someone check if they’re compatible (or close enough to make it work with a file)?

    If so, one could effectively make an “FT” version of the Rotation-10, by swapping out the Radical 2.0 FT’s rotating toe base plate. At least until Dynafit actually makes a proper “FT” version of the Rotation-10 that goes DIN-12.





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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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