Dynafit Radical 4.25? Heel Spring Shock Absorber

Post by WildSnow.com blogger | December 26, 2013      

Update 12-26-2013
Ok, we’ve put the new Dynafit “heel spring” feature to the test. One of our WildSnower aggressive skiers did about 13,000 vertical up/down over holiday on the new system. Once broken in, the mechanism moves quite easily. We still think it probably functions when needed — if needed. We noticed that while uphill skiing it also moves slightly fore/aft with each step, especially with higher heel-lifter deployed (perhaps depending on shape of boot sole lugs as well as accumulated ice and snow). This causes us to wonder about excessive wear due to the plastic/steel/aluminum interfaces of the device rubbing during thousands of cycles. What is more, while this might be splitting hairs it’s still a fact that if the system is moving during each step, it is absorbing energy you’d otherwise use for moving uphill. More consumer miles will answer the wear question fairly soon I’m sure, as some of you are really piling on the vertical these days. Also, to answer one commenter’s question about play developing in the system: I compared the new/used Radical to a well used Radical that doesn’t have the “heel spring.” The binding with the heel spring has ever so slightly more play when evaluated by wriggling with my hand, but the difference is negligible.

My opinion about this “inline” change to the Radical is the same as before: If you’ve been successful with previous tech bindings, it’s not a concern. If you’ve had trouble staying in Dynafit Radical bindings during aggressive downhill skiing, the mechanism (as detailed below) might help make the binding more elastic and thus more retentive.

More, see bottom of this post for heel gap adjustment info.

Original blog post
Talk about inline iterations of a backcountry skiing product. It’s still called “Dynafit Radical.” Yet with anti-rotation issues and more being dealt with over the past few years, the “inline” manufacturing versions keep marching on. Latest offspring of family Radical, they’ve added a nifty little feature that gives the heel unit about six millimeters of fore-aft elasticity. This on top of the normal tech binding movement allowed by the heel pins sliding in and out of your boot heel fitting.

We’re not really sure if this mod is wunderbar or a solution without a problem (perhaps pandering to TUV certification?). Whatever the case, it’s impressive what those European technicians stuck in such a small package. On my digital scale, older version 372 grams, latest 374. We don’t like weight creep. Nonetheless, check out what you get for those two grams:

Latest of the Radicals. Changes are totally hidden.

Latest of the Radicals. Changes are totally hidden. Two more grams. Click all images to enlarge.

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

Guts exposed. 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.

Looking from the top of the backcountry skiing Dynafit Radical.

Looking from the top of the backcountry skiing Dynafit Radical. New elasticity feature is somewhat hidden but evidenced by the tiny aluminum lug the fore-aft adjustment screw threads into.

I felt like a Swiss watch repairman while taking this apart.

I felt like a Swiss watch repairman while taking this apart. Once I found the parts that took flight to the workshop floor, I made this mock-up of how things fit together. The spring fits in a socket where the arrow points, and presses against the small aluminum lug the screw is threaded into.

Somewhat expanded view. How I'm going to get this all together again is a mystery. Perhaps I should send it back on warranty?

Somewhat expanded view. How I'm going to get this all together again is a mystery. Perhaps I should send it back on warranty? (Just kidding.)

In all, impressive. One has to wonder how the parts will hold up if they’re really worked hard. What saves the situation is that most (if not all) of the fore/aft movement of tech binding heels (while ski flexes) is absorbed by the heel pins moving in and out of the boot heel fitting. So perhaps this is sort of a last resort feature to help when you flex a ski like you’re Hercules bending a longbow. In that case your boot heel can bottom out against the heel unit and do who-knows-what to you or the machinery. A bit of built in elasticity at a price of two grams seems reasonable.

My final take? Perhaps this is mostly an attempt to receive TUV certification to existing DIN/ISO standards for ski touring bindings. But the change appears to have some benefit in the real world. For those of you who ask “do I need to upgrade?” Answer: if you’ve been happy with tech bindings over past seasons, no worry. But if you’re an aggressive, larger skier I’d consider this type of elasticity to be a beneficial feature you might want to seek out as more and more tech binding models offer it. Also, durability of this change is an unknown.

Oh, and the most asked question: “How do I tell if this ski touring binding is the latest?” Answer: Radical heel with elasticity mechanism will have a thin stainless steel plate installed underneath, and a small hint of the parts will be visible from the top. Also, the new version has a small nib of plastic protruding below the boot-length adjustment screw as illustrated in the following photos.

New version Radical to left; you can see a small hint of the additional machinery from the top.

New version Radical to left; you can see a small hint of the additional machinery from the top.

New Radical version to right has a small plastic bit protruding under the boot-length adjustment screw. Previous version at left doesn't have this. It's probably a reinforcement.

New Radical version to right has a small plastic bit protruding under the boot-length adjustment screw. Previous version at left doesn't have this. It's probably a reinforcement. (Note this little bit of plastic may have been a mold change before the spring addition. I'm checking on that, so be careful with your ID. Best is to just look for the parts as shown in photo above.

One other thing. Apparently the Radical models with this change require a slightly different process for adjusting to boot length. Use the little white gauge as pictured below to set the 5.30 mm heel gap. Only difference is you need to double-check your heel gap by taking boot out of binding heel, snapping back down again, then pushing heel unit firmly towards boot heel before checking the gap again. Idea is to take up any lingering slack in the elasticity system so you don’t end up with too wide a heel gap. We’re not sure why the gauge was changed from a solid plastic “shim” to the compressible device, but it works, so whatever. (Two nickles and an American quarter coin measure about 5.30 mm.)

The gauge for heel gap is now a compressible little device as pictured.

The gauge for heel gap is a compressible little device as pictured. It's a bit confusing to use. Don't over-think it, just line up the parts as indicated in photo and you've set your heel gap to plus-minus 5.3 mm.

Shop for Dynafit Radical ski touring binding.


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91 Responses to “Dynafit Radical 4.25? Heel Spring Shock Absorber”

  1. jbo December 11th, 2013 9:36 am

    Just to clarify, this affects the Radical ST and FT series but not the Speed Radical.

  2. Harry December 11th, 2013 9:48 am

    While I don’t know if it works, I do think that this addresses a real issue that I have seen with tech bindings.

    Just as the “power towers” were designed to help with the boot to shooting out of the front of the binding, I am hopeful that this feature helps to eliminate the force that causes boots to shoot out the front.

    The fore aft elasticity is the most exciting feature of the Vipec as well in my opinion.

    My real world experience with this issue is limited, I don’t ski my Dynafits in the resort, and as my bc skiing is lower energy than my in bounds skiing (lower speeds, softer snow). I cannot say that I have had any of my tech bindings pre-release after they were properly adjusted.

    I have seen plenty of my friends skis being launched like javelins through the air, and all under the same circumstance, often multiple times on the same run, and no amount of adjustment would fix it.

    The specific case is backseat skiing on icy moguls/drops on soft skis, leading me to believe it was the pins reaching the end of their travel under compression. Even locking the toes didn’t solve the problem, it instead resulted in the toe piece departing from the ski. It leads me to think it wasn’t a RV related issue, and the gap was not set too tight.

    Obviously skiing glare ice on Chute or Lift Line at MRG is not the situation these bindings are designed for, but it is nice to know that running improvements to the binding could be making it more versatile.

    A few mm of travel can make a huge difference in that case. If it makes people more comfortable skiing it inbounds, or if it makes skiers more confident skiing without locking out the toe then I think it is a good thing.

  3. Lou Dawson December 11th, 2013 10:05 am

    Thanks JBO, I’ll clarify in the edit. Lou

  4. Sam S December 11th, 2013 10:12 am

    2g difference? If you feel like you are 2g overweight, hawk a loogie to cancel it out.

  5. Pablo December 11th, 2013 10:16 am

    But….with this new feature… do we need to leave some gap between the boot hell and the heel piece of the binding?
    Can we stuck the pins all the way into the boot heel??

    I know this mod will fix some problems when the ski is over cambered, but it’s better for situations in wich the ski is reverse cambered?

  6. TJO December 11th, 2013 10:22 am

    So is this the current version that is in stores now or one to be coming out?

  7. Lou Dawson December 11th, 2013 10:26 am

    It’ll be a mix of this and old stock as things progress. Hence my effort to help with fingerprinting. Dynafit says ID the binding by the stainless steel plate underneath. But that’s not going to work well if it’s mounted on a ski, hence my other ID methods in photos above. Lou

  8. Greg Louie December 11th, 2013 11:02 am

    Thanks for pointing this out, Lou. When these first started showing up this fall, I thought the stainless plate was just to keep the screws from falling out!

  9. Lou Dawson December 11th, 2013 11:12 am

    I drank some Dynafit Koolaid (or was it weisbeer?), which resulted in me holding off on documenting it, nice to get it done! In my opinion they should have called this binding another model, like ST+ and FT+. But whatever, it’s not easy running a business making and selling this kind of product. Lou

  10. Dave Field December 11th, 2013 11:38 am

    Correct me if I’m wrong but it looks like the spring provides elasticity for pressure applied directed to the heel post only from the boot, therefore only aft elasticty, not for-aft elasticity.

  11. Lou Dawson December 11th, 2013 12:01 pm

    Dave, it’s just a matter of terminology. I wrote it that way because once the spring compresses, the elasticity would move forward and backwards, but yes, the spring at first would only provide aft elasticity. Same as Beast, come to think of it.

  12. Dave Field December 11th, 2013 12:14 pm

    Thanks Lou. Just trying to wrap my head around the failure mode this modification is looking to address and the forces involved, as opposed to nit picking.

  13. Lou Dawson December 11th, 2013 12:19 pm

    Dave, it probably will help when a very aggressive and large skier bends their ski and bottoms out the heel of the boot against the binding heel unit. That said, it’s not much travel… I’ve got some other tests up my sleeve to see if it’s real-world or just something to impress the non-skiing grandfathers at TUV.

  14. Rob December 11th, 2013 3:40 pm

    I’d noticed this change recently and commented on it in your Radical brake removal post. I hadn’t figured out that it was for heel elasticity but rather a better fix than the plastic thread that used to go through the heel post.

    It is a pain in the ass to reassemble. involves much swearing and crawling around on hand and knees to find components when they fly in opposite directions.

  15. Charlie December 11th, 2013 3:48 pm

    Interesting; I wasn’t ever under the impression that heel elasticity was a concern with Tech bindings. I think you’re right, Lou, regarding the TUV certification.

    That change represents a lot of engineering and development work. Hopefully any added stress-risers have been adequately managed.

    What’s the spring rate? (How many pounds/newtons of force are required to move the heel through its full travel?)

  16. Lou Dawson December 11th, 2013 3:57 pm

    Charlie, I had to press the spring about halfway to assemble after tearing apart, it took quite a bit of force but I could do it by hand while pressing with a a screwdriver blade, so it’s not particularly beefy. Stiff for how small it is… Lou

  17. Billy Balz December 11th, 2013 5:20 pm


    Does this counteract the rationale for buying vipec vs dynafit? Is there a better “inbounds” solution between the two now? Power tower toes vs lateral travel toes, with heels now being equal?

  18. Mason December 11th, 2013 6:34 pm

    Lou, quite often when in tour mode, and traveling across an abrupt compression such as a gully or creekbed, it feels like the heel piece catches on the boot heel as I lift up the ski while it’s flexed. Gap is adjusted correctly. This makes me think I am bottoming out in ski mode as well, probably all the time. I’m only 165 lbs and ski normally stiff skis. Can you explain or demonstrate why you think only heavy people or people with soft skis will bottom out?

  19. Mason December 11th, 2013 6:36 pm

    edit: it feels like the heel piece catches on the boot heel as I lift up while the ski is flexed

  20. Ed December 11th, 2013 7:06 pm

    Re: Harry above . . .
    “I have seen plenty of my friends skis being launched like javelins through the air, and all under the same circumstance, often multiple times on the same run, and no amount of adjustment would fix it.”
    This weekend on a pair of brand new G3 Zenoxide 105’s skiing hard on ice I too blew outa the Radical toe on one ski, not once but twice,
    The second one was 5.9 From The Russian Judge – almost a rib breaker. NEVER had this back country but stiff skiis driven hard seems to have exceeded some limit for the Radical ST toe piece. Am a little sketchy about using the Radicals now, esp after a friends rotation problems with brand new heel units, again Radicals. Never had these issues with the old Dynafits we’ve used for years.
    Anyone else blowing outa the toes?
    BTW the G3 carbon Zens are otherworldly . . . G3 nailed these! Like being on rails on hard stuff (remember Kastle Red Sleds?)

  21. Lou Dawson December 11th, 2013 8:27 pm

    Billy, I have no idea. Consumer testing will be the deciding factor. Both Vipec as well as the latest Radical are just barely out there. BTW, I can say it now, we’ve got an official press visit scheduled with Fritschi in January to get the lowdown deep details of Vipec. And we’ll be hitting up the Dynafit Press Event as well. Ultimate blog fodder! Who knows, there might be even more crazy stuff on tap for 2014/2015! The tech interface is not going away, that’s for sure!

  22. Shawn December 11th, 2013 8:32 pm

    Yep…took my worst digger in 20 years blowing out of the toe. Guess I can’t really call it a digger tho as it was in resort on ice. Testing out the new skis and letting them rip…chattered on some ice doing about 70k…felt something “not right” and looked down to see my boot out of the toe. Followed quickly by a body slam to the ice and a 300m otter slide under the lift. Stood up dazed and confused and my elbow is still not better. Have also lost both afd plates from the brakes and now you have to replace the whole heelpiece instead of just the brake. Found one and glued it in place so snow wouldn’t collect in the gap. Couldn’t find the other one. Was having issues with the spring in the toe unit last spring too. Love the tech binding but have had a few too many issues with the radical for my liking. Looking forward to the new offerings from diamir and g3.

  23. Lou Dawson December 11th, 2013 8:33 pm

    Mason, because you are bottoming out with the heel unit rotated to a totally different position than downhill mode. I’ve tested this by suspending skis across saw horses in shop and weighting/bouncing. The normal tech gap does a pretty good job of allowing enough travel, though once in a while the boot heel will touch the heel unit, and that seems to be absorbed by flex of the heel unit and other parts of the system. The bigger the skier and more flexible the ski, the more likely it is for this to go beyond something the system can handle. WHAT LEADS ME TO BELIEVE THE CURRENT SYSTEM WORKS is the thousands of skiers it works for. Gad, I’d hope that would be proof! But yes, skiers to get launched out… do you? If so, then you should look at improved systems. If not, it’s a non issue for you. Lou

  24. Lou Dawson December 11th, 2013 8:35 pm

    Shawn, I have to say that if I skied that fast in those conditions, I’d have locked my toes… or were yours locked? Not sure any currently retailed tech binding other than Beast is designed for those kinds of forces…

    Sorry to hear you got hurt. Likewise, some of the worst diggers I’ve ever taken have been while testing touring bindings. Thus, I don’t do very aggressive testing any more, I leave that up to you guys (grin).


  25. Tay December 12th, 2013 1:08 am

    Skied the radical speed superlite mounted to a pair of Wailer 99’s all last season with no issues of prelease, though I decreased the boot/binding gap for 4.5mm to 3.5mm so that may have something to do with it. Sometimes the simplest solutions (bindings) are the best….and lightest.

  26. Pablo December 12th, 2013 2:44 am

    I’ve just talked with Dynafit Spain today about this new iteration of radicals.
    My question was about the heel gap:
    It’s necesary to mantain the heell gap of the “old” versions of Radicals?

    They told me that the gauge provided to adjust the gap just have changed.

    I can’t compare them both (the old and the new) by now.
    Maybe you can Lou!
    If yes I think a photo could be useful… 😉


  27. KMS December 12th, 2013 8:01 am

    Well, I can see the benefit from this after bending both spindels a couple of weeks ago. I was trying to do a fronflip and underrotated, causing the tail of ski to catch pretty violently and seriously flexing the skis. The binding heels crashed in my boots and the spindels bent. Maybe this elasticity would have saved my spindel, maybe not…

    But my guess is that even though Dynafit is marketing the Radical 12s as freeride/freetouring-bindings, they weren’t meant to withstand the forces applied by 225ibs of human mass flying through air 10-15 feet, and land with tails straight down..? 😉

    Solution: Inserts/Marker Duke for the stupid stunt days! 🙂

  28. Lou Dawson December 12th, 2013 8:17 am

    Pablo, I’m planning on documenting the heel gap. It’s not a big deal, the bindings come with a gauge for setting it. More soon. Busy with some other gear at the moment.

    KMS, one of the most important skills in life is knowing what gear to use for what (grin). For example, one doesn’t use a road bike for hucking cliffs, they make other types of bicycles for that.


  29. KMS December 12th, 2013 8:37 am

    Well, some of us need to learn through failure 😉
    On the other hand I found out that it takes quite a bit of force to bend the spindels, so this particular brakage actually improved my confidence in the Radicals. They may not be meant to be used for hucking cliffs, but they won’t break on quite sizeable stuff unless you land in a really weird position.

  30. Dave Field December 12th, 2013 9:57 am

    FWIW my personal experience is that Dynafit and other tech bindings are best used for non-resort skiing and non-aggro soft snow conditions. Once you get into hard icy conditions or super aggressive skiing, the issues of unintended release or smooth release (when needed to prevent injury) come into play. I’m sure the heel elasticity will help, however it seems that traditional alpine type bindings still have a more consistent release function in challenging conditions. I know many people who have skied tech bindings in-bounds at resorts and in difficult snow smoothly without incident for years, however I also know several who have discovered that its really easy to get hurt through unintended release (or non-release, tib-fib type injuries). Of course, no binding can do everything for you and you pay the consequences of your binding choice and skiing foibles. It will be interesting to see if any tech binding gets full TUV certification or proves its release characteristics to be as reliable as current alpine bindings.

  31. Scott December 12th, 2013 12:38 pm

    Hi Lou –

    I thought you might be interested in this situation. I have two pairs of TLT speed Radicals and 3 out of the 4 heel pieces have cracks in the front of the rear plastic housing (bottom edge, below heel retention pins). Both pairs are only two years old and have been only skied backcountry. Maybe 30 days each. One pair owned by my wife and neither never abused. Dynafit is going to replace them under warrantee, but I was quite surprised to discover the problem. I am happy to send you pictures if you like.

  32. Paul December 12th, 2013 7:48 pm

    Don’t like the weight creep of 2 grams!!!. You guys need to get over yourselves.

  33. Lou Dawson December 12th, 2013 9:04 pm

    Sorry, didn’t mean to panic you. I hope you get over the shock of seeing me write about 2 grams. It is just, so, shattering!

  34. Lou Dawson December 12th, 2013 9:06 pm

    Scott, that sounds like something to watch out for. I think a picture might be appropriate. What year did you acquire the bindings? Send photo to the email address in contact link in menu above. Thanks, Lou

  35. Steve December 12th, 2013 10:52 pm


    I heard Dynafit was going to change brake/heel assembly so that you could swap out brakes without having to buy an entire heel piece, which is pretty $$$. Any word on this potential change?

  36. travis December 12th, 2013 11:16 pm

    Scott- sounds similar to the breakage associated with the anti-rotate pin system. Any chance the bindings you’ve broken had the pins?

  37. Hallvard December 13th, 2013 3:09 am

    “one doesn’t use a road bike for hucking cliffs”

    Well, not everybody, but theese guys do 🙂


  38. Lou Dawson December 13th, 2013 6:36 am

    Love that video, thanks!

    Yeah, it’s a post-modern world with no rules. Still, I get so tired of our sport treating each piece of gear like it’s supposed to do everything. That’s simply not a very smart approach. It’s a good way to be disappointed, if not injured or even killed. Instead, each item of gear should be carefully designed for a given range of abuse, and consumers/users should have some feeling for what that range is. For example, I’m certain you could find some pretty nice wheel sets for that Colnago, but some of those wheels wouldn’t hold up to trials riding as depicted in the vid. I’d imagine the trials riders are pretty careful about that, as a wheel collapse in some of their stunts could be fatal.

    I guess what I’m saying is let’s get a grip, and be aware of our gear instead of just blundering along, thinking everything can do, everything.


  39. Lou Dawson December 13th, 2013 6:40 am

    Steve, regarding swap brakes, they were one of the coolest but most problematic features of the binding up to last season, when they started selling the trapped brake. I wouldn’t be surprised if they go back to a user removable brake. It did seem insane to make customers have to buy a whole heel unit just to use their bindings on a wider or narrower ski.

    The history of the removable brake is a saga. The first ones came off accidentally due to the clip/prongs that wrapped around the heel post being thin and weak, so they came up with that little after-thought retainer clip — which also comes off accidentally on occasion. What I’d suspect is they’ll redesign this entire system.

    So we shall see, that’s all I can say for now.

  40. Forest December 13th, 2013 5:33 pm

    I am SO glad I bought Onyx!! To hell with the last 2 grams!

  41. Adam Olson December 15th, 2013 11:05 am

    It is very obvious to me, that Dyna Fit has an issue accommodating large skiers and hard conditions. (Are they just lying to themselves?) The worst, hardest and most hazardous ski conditions occur OUTSIDE the resort. Breakable crust, ice hard spring corn or wind buffed cornices. And once you are there your gear HAS to perform. You have no other choice.
    “Ohh, this snow is too stiff for my bindings or these bumps are too big……. maybe I should repel or boot down this slope”. WTF! Are you kidding me!
    In the ski area you can ALWAYS find and escape to better snow……always. Lets just be honest here. So to say these “tech” bindings aren’t meant to ski hard in the areas seems like a bit of misinformation. And having just dropped $650 on a pair, I am slightly disappointed. They should just say they are for light skiers, not for certain conditions…….
    The sweet spot of this bindings is for skiers who are 180# all decked out, or less. If you are bigger that this you WILL have issues.

    If you are an XL skier, I mean like 6’4″ and 240# decked out, and have had a good experience, I would like to hear about it please.

    About the bike references, there is this sport called cyclocross and they mostly use road bikes equipped with road wheels to race off trail, in horrible conditions and I do not hear any wheel companies complaining that they are riding in the wrong spot. Maybe rethink that analogy a bit.

  42. Lou Dawson December 15th, 2013 11:17 am

    Adam, good points. I’ve said numerous times that tech bindings are not for everyone. I don’t know where this assumption comes from that they work well for everything and everybody. That attitude reminds me of the days of televangelism, when telemarking was THE answer. There is NO ski binding that works well for everything. Again, just like there is no one bicycle that works well for everything. Sure, you can do a mountain bike race on a road bike, or do a road race on a time trials bicycle, or…. But that doesn’t mean it’s supposed to work great. I actually do know big guys who ski tech bindings, but I think skier weight is a big factor in how happy you’ll be with a given tech binding. But…. Dynafit Beast might be a binding that’ll work fine for larger skiers. Lou

  43. Jay in Boulder December 15th, 2013 12:28 pm

    I recently picked up a pair of used skis with Silvretta Pure Freeride bindings (circa 2007). noticed there was a lot of talk about these a few years ago. Do you or anyone on the blog know how I could get a copy of the original users manual. Maybe available online? Thx. Jay

  44. Bob December 15th, 2013 1:36 pm

    One point I thought was interesting that hasn’t been mentioned is Dynafit’s lack of advertising of this feature. The carbon plate is still at the forefront of the features list, but no mention of improved elasticity etc. I wonder why?

  45. Lou Dawson December 15th, 2013 3:33 pm

    Jay, the user manual is a valuable collectors item for your antique bindings. It’ll thus probably be pretty hard to find. Lou

  46. Lou Dawson December 15th, 2013 3:36 pm

    Bob, it’s just a timing issue as far as I know. Apparently it wasn’t known for sure when the bindings would begin to be sold with this inline change (I hesitate to call it a feature until it is consumer tested). Thus, PR communication was difficult. Of course, WildSnow.com is always here to help. Lou

  47. Bob December 15th, 2013 3:50 pm

    So if one were to purchase radicals today on the web, would he receive bindings with this new “feature”? To me, if a new mechanism has been physically designed into a binding with supposed performance benefits, I would qualify that as a feature of the binding. Of course, plenty of features don’t work to well – for instance the Radical carbon plates, as you have documented well.

  48. Lou Dawson December 15th, 2013 4:57 pm

    And the original anti-rotation “feature” that instead weakened the binding causing widespread breakage.

    And, I doubt with mail order you could depend on getting this inline change. What you’d get would be unknown. Though I’d imagine it’ll got to 100% certainty at some point…

    Brick and mortar dealers exist for a reason (grin).


  49. Billy Balz December 15th, 2013 6:25 pm

    Re: Adam Olson’s rant, I have been on speed radicals for a couple weeks now in the east. They have been awesome on hardpack and 14″ of fresh powder with decent ground underneath…however, I took them into some boulder drop pillows (no base so I lost about 8 oz. of petex) in the trees today and though I was skiing conservatively they released a couple times when I bottomed out while shaving off rock. This would not have happened on my jesters. Still don’t know if it was the toe releasing or the heel…the snow was fresh and we have no base in Maine, so I was hitting roots/rock pretty hard. I’m 5-11″/190lbs and was not wearing a pack. RV was set at 9 and toes were not locked out. This was definitely pre-release. That said, I love these bindings and the weight differential. I’m wondering if the new VIPECS or new dynafits will help with this problem. Lou, you alluded to “who knows what’s in store for 2014/15….you da man, so I’m guessing you know. Maybe it makes sense to wait for a year before buying more speeds/vipecs, etc….i.e wait for these guys to enahnce tech binding elasticity and adjustable release settings for BOTH toes and heels???? Please dish Learned One!

  50. Lou Dawson December 15th, 2013 7:40 pm

    Obewhanskinobi speaking: Give it about 8 weeks or less, and we’ll have much much more information filtering in from the great cloud of unknowing on the 4th astral plane. For example, we’ll be visiting Fritschi in person in a few weeks. If I can’t get answers then, I’ll move to Bimini and take up sailing as my hobby. And change my name.

  51. Greg Louie December 15th, 2013 8:50 pm

    @ Adam Olson: The 6’4″ 240 lb. guys have long known that traditional tech bindings have their limitations. The Beast 16 is an attempt on Dynafit’s part to remedy that.

    As for the cyclocross analogy, the guys riding Zipp 303’s and 404’s to race cyclocross are the same 140 lb. wimps that have no problem charging on a Speed Radical, though most of them go through a pair of carbon wheels or two each season.

  52. Gunnar December 16th, 2013 3:48 am

    Having ridden Radical FT’s for some time now I think they can be ridden hard in most conditions (6’1, 180lbs) as long as you don’g get in the backseat. It’s pretty much only when I get my weight way to far back combined with trying to force the skis around that i’ve had them release on me.
    A good friend of mine who rides fast, hard and with excellent technique (former world cup racer) has no problem at all with radical ft, even when dropping and charging through crud.
    So i’m thinking that the combination of charging the tail of the ski, getting pressure on the heel piece, together with upwards pressure on the toe-piece would be the reason for most pre-releases. Any thoughts on that? Or am i totally wrong?

  53. Lou Dawson December 16th, 2013 6:36 am

    Gunnar, I’d agree. With big guys, it’s when they get into sort of “non standard” leverage situations. Ditto with the pre-release mode involving the toe wings opening to the side. What’s funny is that most concerns with tech bindings over the years have been with durability since they look “small.” Turns out that when built well (and not defective) they’re plenty durable, but without the elasticity of a good quality alpine binding they do have modes of pre-release and other problems caused by how the elasticity works. That’s why no tech binding has ever receive TUV certification to DIN/ISO ski binding standards. I make fun of TUV and they deserve it to some degree, but the DIN standards were created for a reason, and tech bindings are certified to NO standard. It’s like the wild west of tele bindngs over the years.

    It should be said that the way tech bindings work is pure genius, what with the fore/aft elasticity being provided by the heel pins sliding in and out of the boot heel fittings. But the tech binding was developed to be a lightweight ski touring binding, NOT AN ALPINE BINDING for huge skis and boots, used at speed. Recent design iterations have attempted to address this to varying degrees, especially Beast, but in my view the jury is still out if the current configuration of tech boot fittings and binding pin sizes etc. can EVER be an alpine binding. Again, bring on Tech 2.0. Who will be first?

    Meanwhile, literally hundreds of thousands of ski tourers are very happy with current tech bindings. Lest we forget.

    Additional reading:


    And especially this:


    And if you want to get a laugh on what we do in our “spare time:”


  54. Lenka K. December 16th, 2013 1:54 pm

    Hi Lou,

    I absolutely second this. But my impression is that this is precisely what Dynafit has been forgetting lately: namely, that they have (HAD) a superior, lightweight product (Vertical ST) that makes (and would make) a VERY MANY people happy.

    Instead, in the race to increase marketshare, they’ve changed the proven design, somehow damaging the equilibrium in the system in the process so that now you need an “anti-rotation” patch on the brake (just got my first Radicals, as I couldn’t easily find a 110mm-Vertical-brake for my new skis, and this piece of metal slapped on the brake is just ridiculous. Not to mention the pain of turning the heel by force 270 degrees every time you want to go from walk to ski mode, plus the “clicking brake” on flats — I am NOT impressed).

    What’s more, every iteration now adds some extra weight and as I am told, an even heavier Radical version is in the pipeline.

    Luckily, there are now alternatives, although I doubt Vipec will even manage to match Radical ST weight. But if Plum finds a reasonable brake solution, that’s where my money will be going. In the meantime, I have several mounted pairs of Vertical STs that should get me through the next decade or so :).

    Lenka K.

  55. Buck December 16th, 2013 2:58 pm

    Billy Balz – “the snow was fresh and we have no base in Maine, so I was hitting roots/rock pretty hard. …… I’m wondering if the new VIPECS or new dynafits will help with this problem. ”

    I don’t think a change in binding will help with your line selection.
    Save your money, the solution costs nothing except a couple of brain cells.

  56. Billy Balz December 16th, 2013 5:10 pm

    Point well taken Buck! I wasn’t d oing anything crazy, just very, very carefully
    jump turning down a dicey early season tree line. I was interested in seeing the speeds’ release issues without jeopardizing my knees. I think I found one aspect of the limit of Tech binders which intrigues me to the possibilities of creating Tech Binders At low weight, with some alpine DIN release properties. People were knocking Lou for suggesting 1Kg skis could become a reality…and it seems we are moving in that direction…the engineering for bindings will be tougher. I’m riding that train! (with brain cells telling me to keep it cool during experimentation!)

  57. Mark December 16th, 2013 9:54 pm

    Binding User Manual: Another item which appears to be headed the way of the dodo. Some binding brands essentially force the owner to go to a certified shop as no information on mounting or adjustments can readily be found. True of Dynafit, Marker, etc.

  58. Greg Louie December 16th, 2013 10:42 pm

    Mark, your best bet for finding out anything relative to Dynafit bindings (written in English, at least) is probably wildsnow.com . . .

    A quick Google search will turn up tech manuals for most common alpine bindings – Marker’s is here:


  59. Greg Louie December 16th, 2013 10:47 pm

    Mark, I take it back. That’s basically just a catalog; you need a dealer logon to see the actual tech manual, though you can access other manuals (Salomon, for example) without dealer credentials.

  60. claus kampmann December 17th, 2013 11:23 am

    As I mentioned in an earlier post, when I received these new bindings mounted there was a huge amount of lateral play in both the heel pieces. After checking with dynafit, I removed the heel pieces: Un-mounted there was even more play (in ski position with stoppers held down). I deepened the ski screw holes, remounted the binding after putting some thick silicone grease on either side of the thin metal sheet and tightened the heck out of screws, trying not to rip out the threads. That has tightened up the bindings considerably. But it has probably also tightened up the front-rear elasticity!
    I don’t know if all the new bindings have this lateral play and need to be mounted extremely tight on ski to reduce it or if it is just mine.
    Any feedback?

  61. Lou Dawson December 17th, 2013 11:32 am

    Soon, mounting them today or tomorrow. Lou

  62. Ed December 17th, 2013 6:07 pm

    @ Lenka K above.
    I agree 100% – I’ve been doing a completely unscientific small shop market survey in interior BC and Vertical FT’s (in white!!) and Vertical ST’s (in good old mud) are all still available (Dec 2013). Stock up!
    These Vertical bindings were bomber and didn’t need fiddling with like the current crop – little screws and plastic bits and do-dads.
    On the Wapta NOTHING matters except IT WORKS. And keeps on workin’. In – 30 degC yet!
    The rando race types, a chopper ride away from a warm shop, do not figure into the use of the bindings in most of N. America I’d bet.
    Please, on your trips to Europe Lou, get the tech binding folks to recognize this.
    Safety first!
    For bombproof simplicity you’ll get faithful allegiance from the throngs . .

  63. Codey C December 17th, 2013 8:02 pm

    @Adam Olson I might not be as big as some, but I am 6’3″ 205# no gear, so I can get up there with a pack. I have been skiing on G3 Onyx bindings the last few seasons, with no release issues. This includes some front side riding (mostly Revelstoke, some in the Rockies). The caveat is that I am not a very aggressive skier, so that could be the difference.

  64. Stewart December 27th, 2013 9:13 am

    Typical Dynafit. Come up with some half baked idea, test it on an unsuspecting public, and work the bugs out over a few generations. I don’t know if the new options from Fritschi and G3 are going to be any better, but I’m ready for a binding actually engineered and tested to professional standards.

  65. Lou Dawson December 27th, 2013 9:23 am

    Ed and all, in my opinion we will soon have such a vast variety of tech bindings you will indeed be able to choose between simple versions that are just basic reliable, and more complex versions intended to address elasticity and easy-of-use issues. Now that the bugs are worked out, two of the best simpler options out there are the Dynafit Speed Radical and the Plum Guide, both used without brakes. But yeah, the Vertical ST and FT are a definite sweet spot. Get ’em while you can, as far as I know they quit making them. I’m guarding my pairs with lock and key, though Louie ran off with all our FTs already. Oh, and my regular Radical STs are also working fine, though I actually like the older rotating heel lifter of the Verticals rather than the flippers. The flippers are easy to flip, but I like being able to easily rotate the heel unit with my ski pole for different transition sequences. Lou

  66. Steve December 27th, 2013 2:12 pm


    Speaking of the rotating heel unit on the Radical ST, would you recommend a lithium grease to ease the turning mechanism? Or perhaps something less viscous? The heel unit on my Radical STs is causing some wear on the metal lever piece attached to the brakes. I doubt there’s much I can do to completely prevent that, but there must be some kind of lubricant that can help the situation.

  67. Ed December 27th, 2013 11:25 pm

    Not sure if this is as scientific an answer as some might have, but I’ve used white lithium grease from Canadian Tire on Verticals for years – a dab in each toe socket (prevents ice build-up and I suppose lubes the toe pins) and some on the brake “bar”. I don’t seem to see any issues with the grease on the little anti-rotation patch job (screw and plastic bit) on the newer Verticals with brakes either.
    The white lithium doesn’t affect plastic parts on car doors (years of trials on this) so it’s probably OK for boots/ plastic ski binding bits.
    We’ve used it down to -30 degC with no issues. That’s been our experience here.
    And have a great rip Lou – Luftansa is a great way to cross the pond (from you ticket on Friday’s blog post)!
    Happy New Year,

  68. Lou Dawson December 28th, 2013 6:41 am

    Agree on Lufthansa. We always go for them if possible, even if it involves a bit of extra cash. The free booze makes up for it (grin).

    As for grease for plastic, thanks for the tip, but don’t forget that G3 sells actual ski binding grease that’s specific to lower temps and use on plastic. As for external lubrication, rubbing alpine ski wax on those binding surfaces is also very effective and can be done whenever the skis are waxed, or even several times a day. It makes less of a mess when smudged on your clothing (grin).

    I carry a small chunk of “universal” alpine ski wax, and use it for everything from preventing snow buildup on top of skis, to waxing bases before a downhill run in cold temps when the snow is slow, to yes, rubbing on binding parts.


  69. Ryan Bressler December 30th, 2013 10:12 pm

    So, since you can buy radical baseplates a couple of places to get different size brakes can you upgrade old vertical bindings if needed? And while we’re on the subject do all vertical/radical st/ft bindings use essentially the same heel spindle making the rotating heels more or less interchangeable?

  70. Adam Olson December 31st, 2013 1:47 pm

    What are the dimensions of your aggressive skier? Height and weight, decked out or not?

    It is still my opinion that overall weight and leverage (height) are the root of pre-release problems, and NOT skier ability or skiing style. Kind of like a rider weight limit for that cool scooter everyone has.

    I have been out a few more days now on my new DynaFits, and after adusting up the “din” they seem to stay on my feet in hard conditions. But I am gun shy and have mostly healed from my last body slamming, double ejection on a blue slope. Time will tell………

  71. Jakub January 17th, 2014 3:36 pm

    Have any of you found if it is possible to remove the system that blocks the Radical from turning it anti-clockwise.
    I am used to old style that I can turn the bindings in all direction and the clockwise only rotation annoys me as hell.
    It takes so much more time and energy to switch to the skiing mode. I can’t see any reasonable explanation why they did that .

  72. Charlie January 17th, 2014 5:20 pm
  73. louis dawson January 18th, 2014 12:51 am

    Jakub, it is an ongoing evolution to prevent the heel from accidentally rotating. Yes not perfect. Lou

  74. louis dawson January 18th, 2014 12:56 am

    As for removal, easy. Just take the black plastic off the brake plate. Lou

  75. Paul January 18th, 2014 3:30 am

    a very good friend and frequent touring partner of mine has the Radical and was too lazy to install that anti-rotation thing when Dynafit tried to make up for their non-existend real world testing. Now I am getting used to hear him shouting obscenities at least three to four times per day of touring whenever the heel rotated by itself and my friend has accidentally entered skiing mode. This tends to always happen on the steepest and most exposed situations. Not so nice. If I were him I would have returned this piece of crap to the people of Dynafit and asked my money back!

  76. Gentle Sasquatch January 19th, 2014 1:19 pm

    Speaking of Lufthansa to cross the pond…are there extra lees for a ski bag? Seems that normal length limit is around 158 cm.

  77. Lou Dawson January 19th, 2014 2:39 pm

    Gentle, any reasonable length ski bag is considered luggage, weight limit 50 pounds with whatever fees they are charging at the moment. We pack our ski bags like luggage. This time we brought an extra bag for a total of 3 checked bags. The fees ad up to substantial percentage of the ticket price. A ridiculous game they play, but it’s the way it is. Lou

  78. Lou Dawson January 19th, 2014 2:41 pm

    Paul, let me get this straight. The guy doesn’t install the binding correctly and then blames problems on the binding? Something doesn’t compute. Nothing is perfect, but first step is to install/configure/use correctly. Lou

  79. Paul January 19th, 2014 3:05 pm

    that binding was bought and mounted when there was no anti-rotation device yet. Obviously the design of the binding was flawed in the first place. And the way Dynafit “fixed” that problem is far from ideal (see Lenkas post above). When I spend a bunch of money for a binding I expect its proper function to be extensively tested before and not me becoming the tester for the product.

  80. Lou Dawson January 20th, 2014 12:17 am

    Paul, the original internal “pin” anti rotation was indeed flawed in my opinion. Looking back, it seems it would have been better if all those bindings were recalled and fixed rather than the add-on part being supplied as a fix. As a result, it has indeed been a pain in the rear ever since as the associated issues haunt this website like some sort of cheap horror movie. On the other hand, the small black plastic anti-rotation stops that fit on the brake plate work for most people, your friend could at least try them, perhaps he wouldn’t have to curse so much. As for you, what binding do you use and how is it working for you? Lou

  81. Paul January 20th, 2014 1:52 am

    Hey Lou,
    I am going to install the anti-rotation on my friends skis as soon as I see him. Maybe that cures the symptoms of his beginning Tourette’s disorder 🙂
    I use several TLTspeeds (best value for the money), a LowTech Race and a ATK SL-R. I am very happy with all of them but I sure understand that there are people that want ski brakes.

  82. Judith March 3rd, 2014 9:49 am

    Hi Lou – I recently switched from Vertical ST to Radical ST bindings and yesterday inadvertently rotated one heal piece in the counterclockwise direction before remembering the mandated clockwise direction. I then checked the operation of both heal pieces and they seem identical in tension, spring, etc. Is there a chance that the counterclockwise move damaged something and / or would it be outwardly noticeable? Thanks for your advice with this…

  83. Lou Dawson March 3rd, 2014 11:09 am

    Judith, no, it the binding is a current model Radical ST, it has tiny black plastic things on the brake retraction plate that prevent rotation, the binding will skip over these if forced. Doing this once in a while doesn’t hurt anything, but will eventually cause undue wear. Lou

  84. Judith March 3rd, 2014 11:49 am

    Thanks, Lou. That’s what I was hoping to hear.

    And I think I see what you are referring to. Is it the somewhat triangular plastic piece on the left side of the binding that is attached with small screws on either side of the metal plate?

  85. Greg March 5th, 2014 9:13 am

    Hey all, I have some 2012-2013 Radical ST’s, and I’m looking to get a second pair of base plates with different size brakes, and swap my heel units between skis. The only base plate sets I can find are with this new spring. Anyone know of any reason why I couldn’t swap the older heel units onto the newer base plates?

  86. OMR April 10th, 2014 6:14 pm

    Apologies if you answered the heel play question (ie. a noticeable up/down movement with hand or boot), but here’s what I believe is the cause: the post is aluminum and the mounting bracket is plastic and over time the plastic will wear. The movement is small, maybe 1/4-1/2mm, but it messed with my head so I fixed it by removing the heel and remounting with a small shim fashioned from soda can, cut just a bit smaller than the footprint of the post. It took out the play. I figure when the plastic wears down again it’s time for new gear.

  87. Geoff December 31st, 2015 6:59 pm

    If I understand correctly, this post says that the heel gap for a Radical binding with “forward pressure” (heel elasticity) is 5.30 mm. However, the Wildsnow Dynafit binding FAQ page seems to say that there is no heel gap for a Radical binding with “forward pressure”. Which is correct?

  88. Louise February 6th, 2016 12:17 pm

    I am a victim of pre-release at a ski resort on a soft snow covered courdroy intermediate slope. Rather than a big guy, I am a 130 pound 70+ year old female skiing at a normal cruising speed. After 2 hours of varied cruiser and gully skiing my toe popped out on this groomed cruiser. I have been using Dynafit for 10 years and never come out, but I got a new ski with this new binding and have only skied the new skis a couple of times. Bam! It wrenched my knee on the non-released side.

  89. See February 6th, 2016 1:16 pm

    Sorry to hear about your fall. Did you check the release values? Shops often set them on the low side.

  90. Lou Dawson 2 February 6th, 2016 3:54 pm

    Geoff, super confusing I know. I just put them so the heel is close, small gap of 1 mm… I’ll check on the specifications. Problem is the heel gap speck is not on the consumer literature that comes in the box, or at least it isn’t here in the box I have… Ion is same, you just adjust with little to no gap. Main thing is to not over-tighten and close up the gap to the point where there is some pre-load, that’s why the term “forward pressure” is incredibly bogus. When the binding is at rest there is NO forward pressure. Lou

  91. Lou Dawson 2 February 6th, 2016 3:57 pm

    Louise, some shops crank them all the way down low and expect the user to adjust! What are your bindings set at for release values, and exactly what model? Lou

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