Dynafit Vulcan & Mercury Boot Mods

[VI]

Summer time is modding time.

For a variety of reasons, I took the tools to my Vulcan's and the wife's Mercury's. After a season in them, I had a lot of love, but also some hate, as some of the typical issues I'd heard about began to present themselves. With a background as a mechanic, it seemed to me, however, that the design choices causing the typical reliability complaints were all solvable, or, at least, could be compensated for.

The goals of the project were as follows:
-Replace all rivets with removable fasteners, using a common drive.
-Reduce friction at wear points and in moving parts, as much as possible.
-Do the above with minimal or no modifications to the factory shell/cuff/buckles, such that I could still use a factory part/rivet/fastener if I wanted or needed to down the road.

I'm posting as there seems to be some love on the forums for the Vulcan's and Mercury's, so I'd like to know if there is interest in a write-up of the mods (please read the note at the end of the post on tools required first). If so, I'll find the time in the next few weeks to do a write-up, along with part numbers and whatnot. I may have enough parts left over for a couple more pairs of boots (these parts usually come in packs of 100) and could send em out for the cost of postage.

I've attached photos of the result:
- All buckles, bands and tongue can be swapped or snugged up with a flathead screwdriver (or something that resembles one in the backcountry), secured by t-nut/washer/bushing/screw combinations modified to match the boot's existing fastener specs. Could press a factory rivet back in if needed, or pop on a warranty part off the shelf without having to modify it. No more slack rivets in the backcountry that need to be repressed by a shop.
- Toe/instep buckles and bands can be rotated without friction and hence are easy to rotate out of the way with a brush of the hand for foot entry and swapping of the power insert. Faff factor is down.
- Cuffs can be removed with a 4mm hex key (B&D UCP mod). Could press a factory cuff rivet back in if needed. Friction-free rotation, and reduced wear in the cuff pivot.
- Cuff buckle operates noticeably smoother and takes noticeably less force to close. I suspect the likelihood of the slide-rail binding-up in the spring-loaded pivot during switch to ski mode and contributing to the classic fracture of the buckle is down as well.
- No more carbon/plastic dust from the rear of the cuff and reduced wear on the cuff buckle hole+plug.

Note:
- The rivet replacement mods (as I've done them) require the ability to cut and/or grind screws, t-nut barrels and shoulders to certain dimensions, as well as the ability to drill out rivets. A good measuring tool (i.e. caliper) will be a big help.
- The cuff rivet replacement on the Vulcan only requires the ability to drill out rivets. On the Mercury, it requires a Dremel to grind away a recessed shoulder on the inside of the cuffs.
- The basic friction reduction mods for the buckles themselves require no special tools, just the right types of lube, but the ability to polish metal/resin/plastic surfaces (either by hand or with a rotary tool) and take the edges off some sharp corners will get best results.

We've got about 20 days since the mods on em now - so far, so good.

[riff]

Sweet as, Vitamin!
I’m trying to keep my very tired vilcans alive for another year, i might look at the UCP if I can arrive at a suitable fix for the little cracks in the cuff. Field swapping buckles etc sure seems like a great option.


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[riff]

Some other points to consider bolting are the rivets that hold the plastic wings onto the front of the carbon- i tore those out last year and spent a bit wondering why the boots suddenly felt so soft....the top buckle pulls inside plastic wing, it takes huge force in deep forward flex.


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[riff]

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[swissiphic]

Thanks for posting mods. Fully intend on skiing mine into the ground and hoping they last another 20 seasons or so. The mods will be useful once things start to wear after a decade. The boots fit like the shells were molded to my anatomy so it'll be hard to part with the magic slippers after their eventual demise. After experimenting with the progressive forward flex mod last season and finding game changing positive results all around, my only regret is not stocking up on more backup Vulcans in time....they were all sold out of my size when funds allowed purchase. Long live the mighty Vulcans.

[VI]

Some other points to consider bolting are the rivets that hold the plastic wings onto the front of the carbon- i tore those out last year and spent a bit wondering why the boots suddenly felt so soft....the top buckle pulls inside plastic wing, it takes huge force in deep forward flex.


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So I'm not alone! I had the cuff flaps begin to pull through the rivets as well... after only a week on the boot!!!
At 6'2" and 220lbs (plus clothing + gear), I realized that the stock Vulcan MS cinching power strap would loosen ever so slightly under flex, transferring the forces of flexing to the cuff buckle and flaps (and unevenly, to make things worse - putting most of the load on the top rivet instead of the equally among the three.) So after swapping in new cuffs I switched to a velcro power strap, and regularly check it throughout the day to make sure it has the tension - I've been shredding with no problems ever since. The feel is also much better, as the leg's connection to the cuff happens a bit higher above the leg.
That's not to say the stock cinch power strap is a bad design - I did some carpet flex testing with a couple friends, and at 195lbs, it seemed to hold when pulled tight and doubled back through the little keeper. So I guess at 220lbs + gear I'm just outside Dynafit's design spec... and in general means I will get less miles out of them than a lighter cat.
But like swissiphic, the shells have now got the magic fit for me and I plan on being able to run em til I can't run anymore.
So that has been my solution for the cuff flaps. With that said, the hardware I used the replace the tongue rivets is the same I would use on the cuff flaps - the t-nut barrels would just be cut shorter - so the option is there.
So I take it there is interest in a full write-up?
Cheers

[swissiphic]

At 6'2" and 220lbs (plus clothing + gear), I realized that the stock Vulcan MS cinching power strap would loosen ever so slightly under flex, transferring the forces of flexing to the cuff buckle and flaps (and unevenly, to make things worse - putting most of the load on the top rivet instead of the equally among the three.)

Experienced the same issue and i'm only 5'10" and 180lbs.

I think the gripping teeth are too few, poorly shaped and not long enough. Just a layman's guess.

Ghetto fix was to shoe goo on a piece of i think 60 grit emery cloth in the cam mechanism.

Totally bomber fix, durable, and resulted in zero micrometer of power strap backslip.

Really do prefer the quick release cam style powerstraps for daily ski touring utility vs. velcro...if they hold securely.

[VI]

Sweet as, Vitamin!
I’m trying to keep my very tired vilcans alive for another year, i might look at the UCP if I can arrive at a suitable fix for the little cracks in the cuff. Field swapping buckles etc sure seems like a great option.


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My original cuffs had cracking in the same spot, above the inside cuff pivot.
I have 2 theories.
1. Due to the stiff carbon cuff, the flexing of the boot happens in the shell, where the area around the cuff pivot buckles to allow the cuff to drop. The buckling changes the shape of the shell and hence through the cuff rivet tries to change the shape of the cuff with it, putting a bending force on the bottom of the cuff. Carbon doesn't like to bend.
2. Impact from ski edges (this would explain why I only saw it on the inside.)
In reality, both would work together... an initial micro fracture caused by either will quickly propagate by due to more of either given the nature of carbon.
Before this winter spools up, I am going to glue a small patch of 1/8" rubber sheet on to the cuffs around that area to protect from impact (leading edge between top of cuff pivot and bottom of cuff flap).
As for repair, you could definately try with a carbon fiber repair kit i.e. put filler in the crack, and bond a couple sheets to either side. No guarantee how long it will last, given the nature of the force (bending/buckling). A bike shop with experience in CF repair may be able to give a better opinion.
If you're thinking of finding new cuffs and installing with a UCP... know that the whole range is covered by 4 cuff sizes, which makes finding a donor boot easier.
22.5-24.5 ("245")
25.0-26.5 ("265")
27.0-28.5 ("285")
29.0-31.5 ("315")

[phattypowpow]

The Mercury is my favorite boot ever and I'm still rocking the 1st year model. I've purchased a number of other boots along the way but keep coming back to the Mercury + Intuition Pro Tour Liner. I did give the toe box a small lateral stretch but these things have been as indestructible for me as comfortable. I'm guessing I probably have around 500 days on the shells now.

My mods have all been subtractive. The more I took away, the better the boot skied somehow, and the easier my transitions became. (YMMV, I'm 6', 155):

- Removed power strap
- After trying it a few days, I never put the tongue back in.
- Cut off the front buckle. Never seemed to make much of a difference for me. I know others who have done the same.

So I've got a 1400g (with liner and custom footbeds) touring boots that skis great, walks great, and I can stay in all day long. Every so often, a manufacturer makes a product just for you, it seems. Two buckle flips (the top buckle also does the walk/ski mode) and I'm ready to go. Even with no power strap or tongue, these dogs drive my 186 120mm skis as well as skinnier/lighter skis.

[VI]

Totally bomber fix, durable, and resulted in zero micrometer of power strap backslip.

Sweet

[riff]

I’m in the same boat with my Vulcans; I mostly go without a power strap and removed the bottom buckle too. I’ve got some decent punches for forefoot width, and if i can resolve the cracks, maybe I could extract two more seasons. Thanks for the ideas for fixing the cracking Vitamin!


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