TD3's Step In Questions

[barryj]

In thinking of purchasing TD3's, a couple of questions:

For the cant disks, with trying to get close to the same height/thickness of my current cant/lift system (Oxygen 01's rings) what the mm thickness of a 3 degree and a 6 degree disk?

Also, how much adjustability is there for applying Gilmour Bais?

[teach]

Thickness relates to angle but you need to know the length of the base of the angle as well... a 6 degree cant disk gives you around 0.1 mm lift per 1 mm of boot length, or about 10%. So for my M29 boots, I get a little over an inch of lift under heel relative to toe. A 3 degree disk gives you about half that. This assumes the slope of the disk is along the boot axis (maximizing lift).

I say "around" because there are several approximations involved. The full story is that you are asking for the length of one leg (the vertical one, lift) of a right triangle, given the angle measurement of the angle opposite it and the other leg length (horizontal leg, the boot sole length). The ratio of vertical to horizontal is the tangent of the angle. The approximation is that for small angles measured in radians (fractions of 2 pi, rather than fractions of 360), the tangent is nearly the angle itself. The other approximation is that pi is about 3. So 6 degrees = 6/360 = 1/60 is pi / 30 radians, or about 3/30 = 1/10 and this is also nearly the tangent of the angle. (Use the "tangent" key on a calculator to get a better approximation, then multiply by length over which the lift reaches.)

Lots of fore-aft adjusetment possible with TD -- see two ravens' post.

[teach]

I get more like 144mm length, and the measurement on the low side may be off because it's not meant to support the baseplate (it's just one of the three tabs, about 1-2 mm or so from the baseplate on a 6 degree disk). For a six degree disk, I get 21 mm on the high side and 4 mm on the low side, so make that 5-6 mm to the baseplate. That's 15-16 mm lift per 145 mm, so a little over 10%. A 3 degree disk has low side about 6mm as Ursle says, but that's 2-3 mm off from the baseplate, and the high side is 15 mm so actual rise is about 7 - 8 mm per 144 mm length.

You can flip toe/heel blocks to get more fore-aft adjustment (you lose the stops for the bails, though), and I just discovered that the baseplate isn't quite symmetrical, so if you need to you can reverse it as a last resort to get an extra few mm.

Edited March 9, 2013 by teach

[barryj]

Thanks for the info guys - that helps alot.

Considering I'm currently riding on 10 year+ plastic plate bindings, ( Oxygen 01's) and this might be like camparing apples to oranges, but whould you consider TD3 step in's a performance or convienience upgrade?

[Beckmann AG]

^

Performance, convenience, and quite possibly, safety. At least after you get them configured to your liking.

[teach]

The TD3 SIdewinders are going to be a lot closer in feel to those Oxygens than the regular TD3. Many people switch to SW from SnowPro or Burton and consider it "similar, but better and safer". For me they're easier to get into, also, and feel more precise compared to the SnowPros I sometimes use. The TD3 non-Sidewinders are definitely more locked-in feeling, which some prefer, but it's a major adjustment.