Dynafit Cuff Rivet Replacement

The Dynafit TLT5/6 and DyNA Evo are hugely popular in the backcountry skiing community. Despite their popularity, Dynafit has yet to address a glaring design flaw: the cuff rivets. (At least they changed the lower buckle on the TLT6 from the catastrophe that was on the TLT5 but still remains on the PDG!)

Back to the problems with the cuff rivets, yes plurality was intended. The issues at hand are that the rivets are a pressed rivet but the more fundamental flaw is that the rivets are not oriented to operate in parallel planes. If the rivets operated in parallel planes, the pressed rivets would be much less of an issue (except for those that need to cant their boots). Because the rivets are not parallel, each rotation of the upper cuff puts a force on the rivet that over time will loosen the press on the rivets. Once play develops in the rivet, the carbon cuff will begin to wear. This downward spiral can lead to the destruction of your very pricey boots. Another way to think about the issue is a straight line should be able to be drawn that goes right through the center of each rivet. The boot designers obviously had more pull than the engineering team.

1114151605_Mod

Angle formed between cuff rivets in non-parallel planes can easily be seen during a test fit of the metal components of the rivets.

Bill over at B&D has developed a replacement system to address this issue. It isn’t cheap and does require a fair amount of effort to install but well worth the investment over buying a new pair boots. Once the replacement rivets are installed, the system is much more rigid and the lower shell will now flex slightly with each rotation to absorb the energy that was formerly loosening the pressed rivets.

The B&D replacements will work on the TLT5, TLT6, and on the DyNA Evo. Due to thinner materials in the Evo, an additional washer is required. The standard spacer for the TLT5/6 is 0.030″. Bill provided additional 0.040″ washers in the kit for the Evo but I found that the 0.030 + the 0.040 didn’t allow for resistance free cuff rotation over the entire range. I instead used 2x of the 0.030 washers.

Here are a few pictures from the retrofitting process

1114151536

Start with a pilot hole, I used 1/8″ and it is not necessary to go completely through the rivet.

1114151537

Swap to a 3/8″ bit and drill until you expose some plastic material.

On the Evo this exposed material is not part of the lower shell but a bushing (installed on all models that also have a full rubber sole). On the TLT5/6 there is no bushing and this will be a small protrusion of the shell. You will be removing this protrusion at a later step but it is prudent to check your progress often!

1114151539

Pry off the rivet being careful not to damage the carbon cuff.

1114151534.jpg

(Many) drilled rivets and an old bushing from the DyNA Evo.

Repeat on the other side of the boot and then tap/press the remains of the rivet from the outside of the boot and retrieve it from the inside of the boot.

1021152133a

Old bushing on left and the individual components of the B&D replacement kit in assembled order. All rivet sets are shipped properly assembled. Keep at least one fully assembled for reference.

1021152132_crop

Slight gap between bushing and carbon cuff.

Bill will provide oversized bushings at your request. The standard bushings have an outer diameter of 0.500″ and the oversized are 0.560″. I measured my cuffs from 0.510-0.520″. That seemed like a lot of carbon to sand away so I wrapped some electrical tape around the bushing to fill the gaps. The tape should not see much wear but the great thing is it will now be simple to remove the rivets whenever you need to.

1119152212

Electrical tape placed on the bushing.

Two wraps of tape got me a nice snug fit. The amount of tape required will depend on how worn your cuffs are.

Some lubrication on the delrin/metal interfaces is highly recommended. The grease I used was Molykote EM-30L by Dow Corning. This is the same grease Dynafit uses when assembling their bindings. You can usually find this on eBay or Amazon for around $10.

1119152156.jpg

Don’t forget the lube!

Bill will sell you a spanner tool with the kit to hold the inner nut in place while you tighten down the screw. A dab of thread locker should keep the screw from backing out.

Advertisements
This entry was posted in Backcountry Skiing, Gear and tagged , , , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s