TLT5 Modder Madness Continues! Have Milling Machine — Will Make

Post by blogger | December 21, 2011      

Chris Marrone

To add to the TLT5P mod-madness: My mod has been to significantly alter the cuff cant of this backcountry skiing boot and in the process build and install cuff rivets that rotate, stainless steel on stainless steel. When I took a brand new pair of these boots and ground out the cuff rivets, I was surprised to see that the boss that was molded into the lower shell was quite small and I suspected that if the rivet got sloppy at all that the cuffs would loosen up significantly, as has happened with many users.

Dynafit TLT 5 cuff cant rivet constructed on milling machine.

Dynafit TLT 5 cuff cant rivet constructed on milling machine.

Because there is no cuff cant and the boot and liner are such a slim and precise fit and do not allow for much lateral adjustability inside the liner, I needed to modify my cuffs to tilt them out about one inch. So, with the help of a machinist friend I made custom removable stainless rivets. One piece of the rivet is glued and pinned into the cuff so that it never rotates on the carbon fiber and the inside rotates against a large taper on the underside of the screw head. This piece has an OD of .85″ and an ID of .5″. I also pressed in a .0625″ diameter pin at 90 degrees to the cord of the OD and milled a slot in the cuff so that when glued in place this piece will never rotate.

For the inside of the boot I made a threaded piece where the center line of the thread is not concentric with the outside diameter. Then I turned this piece up on the inside of the boot and down on the outside of the boot (you can see this .5” difference in the close up photo) so that the cuff is truly canted. This was then glued into the inside of the shell. To keep all this tight in both longitudinal and rotational direction I also machined a bushing that rotates around the outside of the screw and on the inside of the outer cuff piece and sets the distance from the inside of the cuff to the outer side of the shell. This took some trial and error and the ability to machine small pieces in a lathe and milling machine.

I made a prototype with UHMW polyethylene first to see if I was on the right track and they might have even worked fine but I was afraid of breakage in cold temps. I also had to tilt the rear spoiler that locks the outer cuff to the inner cuff and re-bore for a slightly larger diameter; hence the stainless bolts in the rear that you can see in the photos. I put lots of miles on these last year and they’ve held up well. IMO, a typical cant cuff on one side doesn’t have enough adjustment and also only distorts the cuff and doesn’t truly cant it. I’ve never skied on a ski so flat in my life. When I wear these out, I’m definitely cutting the rivets out of them to use in another pair!

I like the idea of locking out the flex, but I don’t want to add rivets in the shell where they might cause some stress relief cracks. Your idea with the 16d nail is clever but I think it might just destroy the top of the mushroom head rivet (it’s very thin where it hits the nail) if used frequently. I’m thinking I might remove the one main central rivet and make an oval spacer to lock out the flex and then install a new rivet right through the center of it to permanently lock out the flex. I’m not sure that Dynafit got it right for the North American market to add flex to this boot. Doing so had to add considerably to the cost and complexity by adding three more molded pieces they didn’t need and also made the boot more susceptible to leakage.

The only other mod I’m going to make is to replace the power strap with one from the Maestrale boot; it is wider and stretches a bit. I seem to wear out the Velcro on the stock strap and it doesn’t have enough Velcro surface area to last very long.

This boot performs great in almost every way and fits my narrow long feet very well. If they improve the cuff rivets, offer an alternative forward flex piece, and also offer some alternative lasts for higher volume feet and to add warmth, they may just dominate the market in light AT boots.

Dynafit TLT 5 backcountry skiing and ski mountaineering boots, fitting.

Extreme cant for an extreme boot!

(Wildsnow guest blogger Chris Marrone lives at the foot of Mount Shasta in California. He says he’s an “engineering/building contractor with a bad ski habit! He’s also managed the Sierra Club Foundation property and hut on Mt. Shasta as a volunteer for the last 20 odd years. You can go to his website to see the roof reconstruction that his outfit donated in ’04. It’s under the “public works” tab, “Shasta Alpine Lodge.”


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18 Responses to “TLT5 Modder Madness Continues! Have Milling Machine — Will Make”

  1. Carl December 21st, 2011 9:12 am

    Looks great! I haven’t developed slop in my boots yet, how many days until this starts to happen? I only have about 20 days on them so far. Also, I agree that they need to make stiffer tongue inserts. That would be an easy way to stiffen up the boots, and an easy product to create.

  2. Michael Pike December 21st, 2011 9:36 am

    Aside from being so inventive, Chris is also very generous. He took time off work to meet me at the 5th Season, so I could try those boots on ( before the mod), as they didn’t have my size in stock.

  3. Tim December 21st, 2011 10:00 am

    Nice mod! I’d love to see pics of the rivet taken apart if you have them from the production process

  4. Tyler December 21st, 2011 10:26 am

    Wow! Good work. Speaking of additional lasts … the construction of the shell in the forefoot does not seem like it would work well with shell width mods for those of us with wider feet. I think that is a critically important change that could be made to the design of the boot. As it is, I just canr wear a boot comfortably with out width mods.

  5. Jonathan Shefftz December 21st, 2011 10:53 am

    ” IMO, a typical cant cuff on one side doesn’t have enough adjustment and also only distorts the cuff and doesn’t truly cant it.”
    — So very true. (But also, lateral cuff angle adjustment is just one of many steps in stance alignment.)

    “The only other mod I’m going to make is to replace the power strap with one from the Maestrale boot; it is wider and stretches a bit.”
    — This is the only mod I’ve made to my TLT5. I used a Booster Strap last year, but then swapped that with someone for his Scarpa stretchy strap. Unfortunately the Scarpa strap is not sold as an aftermarket option. Also, the TLT5 cuff is so slim compared to pretty much any Scarpa boot that I had to cut off lots of excess strap, and then also resew some of the rough velcro in place of the fuzzy velcro (so as to maintain adequate rough-on-fuzzy overlap). This entails hours of tedious work with an Exacto knife and Speed Sticher Sewing Awl, but I’ve been happy with the results, i.e., performance of the Booster Strap with nearly the same weight as the stock velcro.

    “they may just dominate the market in light AT boots”
    — Sure seems like they already do? (I’ve never seen such lack of boot diversity in all the backcountry skiers I know!)

  6. Jon Barlow December 21st, 2011 4:35 pm

    I have a wide E foot with a high instep and arch. I am told not to even try the TLT5.
    Wish they would make a wide version of this boot. I don’t think there’s anything else like it on the market for wide feet.
    Come on Dynafit!

  7. Chris Marrone December 21st, 2011 4:42 pm

    I’m not sure what kind of life the standard rivets have; I took mine apart when they were new. But, certainly there are people out there who have developed some pretty good sloppiness in one season.

    Thanks! I hope your fit worded out for you.

    No pictures of before or during assembly, I wasn’t thinking I would blog about it at the time and never got around to it until almost a year later.

    I just got Maestrale straps a week ago from Scarpa through our local retailer, The Fifth Season, and they only took a couple of days to get. I haven’t put them on yet, but they look like they will need to be shortened. I just liked the stretch factor to soften up the abruptness of the front of the cuff and the wider velcro for durability. Yes, if Dynafit makes a few changes they’ll have a great boot.

  8. Philip Maynard December 21st, 2011 5:50 pm

    Jon Barlow-

    Try Scarpa’s new offerings. If the Rush and Maestrale are too heavy, there’s always the Alien:

  9. Lou December 21st, 2011 8:05 pm

    We’ve gotta get going on the Alien! Looks like fun!

  10. Plinko December 21st, 2011 8:14 pm

    Tyler said, “… the construction of the shell in the forefoot does not seem like it would work well with shell width mods for those of us with wider feet. I think that is a critically important change that could be made to the design of the boot. As it is, I just can’t wear a boot comfortably with out width mods.”

    Tyler, don’t give up hope! As I understand it, this is a done deal on the next generation TLT5, (just as the current version of the DY.N.A Evo) the forefoot hinge/bellows will be eliminated and will make the boot easier to mod for width (and even lighter overall). Personally, I chickened out of modding the forefoot for width and instead swapped for the next shell size up, and had great results.

  11. Terry E December 21st, 2011 8:56 pm

    Jon Barlow,

    I have very wide feet and a high instep as well. I just bought a pair of TLT5s, haven’t had them fitted yet, but they feel better than I expected. I intend to have them stretched out for extra width.

    Try a pair on. Depending on the skill of the bootfitters where you live, you might want to get the shells punched out a bit. There’s no other boot like it as far as I’m concerned, so I’m going to get these to fit!

  12. Bart December 21st, 2011 9:50 pm

    Looks good. Great post.

    I did the same thing to my Dyna’s to take out the slop. They were not skiing anything like the boot I fell in love with. After taking them apart I found that the hole in the carbon cuff had ovalized and the alloy rivet had stretched. I replaced them with a replaceable rivet from a BD efficiency series boot. I had to redrill the carbon hole to the new slightly larger diameter, cut off the lower shell plastic boss, cut some nurls on the inside of the BD rivet, grind a larger diameter recess in the outside of the carbon, and tighten the new rivet. The lower shells are very hard plastic and don’t allow the rivet to set as well as in a BD boot but it still works fine. I am now going to add a very thin plastic washer between the carbon and new rivet as I think I have just enough room. It seems dynafit should have done this originally and should consider it in the future.

    I have also had to replace all the alloy rivets to attach all the buckles because of the slop and have just finished a new rehab fix for tightening up the locking pin in the back. Love the boots and have a couple pair but would trade a little extra weight for longer life and better durability any day.

  13. Lou December 21st, 2011 9:54 pm

    My TLT 5 Ps need this sort of love. Gad, can I clone myself?

  14. Erik December 21st, 2011 10:15 pm

    Bart, do you know which BD kit you used? Looks like they have them with part numbers BD012025 and BD012029 from the 2011 fall spares catalog. Any thoughts on whether it was a good fix or just an ok fix?

    For those interested in specifics, I’ve had 1 year with probably around 130-150k vertical on my TLT5P. I’ve got about 0.100 vertical, 0.050 fore-aft inches of cuff motion on the inner right boot, maybe 0.070 vertical 0.50 fore-aft inches on the left. Even though the outside rivets have loosened, they haven’t developed nearly as much slop as the inners. They move maybe 0.0010-0.025 inches.

  15. Bart December 22nd, 2011 8:48 am

    Erik- I believe it was the BD012029 which is the one for the lighter weight boots and is thinner than the 025. But it is still to wide for the Dynafit boots and thus the need for a thin plastic washer. It is not a perfect fit but with some work will do the job. My second boot turned out much better as I new exactly what to do and how to keep the tolerances as small as possible.

    I can’t be sure it was a good fix until I get more time on them but they at least feel way better than they did. Mine had more play than yours and every one had loosened significantly. I did not measure the movement but I would guess near .5″ at least at each one. In ski mode the boot was becoming fairly useless with the miles of free swing between the nice fore-aft and medial-lateral stiffness.

  16. Kirk Turner December 23rd, 2012 1:06 pm

    Hey Bart or Lou any update? How as that mod held up? Its been about a year, anyone know if there is a consensus on what the best easiest, and economical option might be to fix tlt5p’s with significant cuff play?

  17. Lou Dawson December 23rd, 2012 7:37 pm

    Kirk, I’d imagine folks out there are starting to figure out that mod, myself, I’ve not done it yet. First person to make it can sell it. Get on it. Lou

  18. Herb Jones November 30th, 2013 9:22 am

    Do you have any plans to make/sell this mod? I need to tilt the cuff the other way to get flat and have been unable to find any other designs. Or, if you are agreeable, I may be able to have a set of rivets made locally {VT}. I so, would you have any more design details?
    Any help is greatly appreciated.
    Thanks, Herb Jones

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