Detuning Contact Points

[Muggydude]

First off I did search- and there are various posts about this in lots of different threads, but just wanted to consolidate some info here and ask up front to get some consensus. Still September so bare with me...

Just finished tuning the last of 10 pairs of skis for myself and family. Think I got that all down pretty good, edges seem nice and I did a lot of research on edge tuning. Set everything at 1/2.

Before I start waxing, I am going to detune the contacts points as per a lot of people's recommendations. Pretty much all of the skis are all mountain to powder skis, narrowest is 100 underfoot. I did do my ON3P Jeronimos a while ago- but I think I way overdid it with a file and the edges are pretty rounded at the contact points on to the tips. (though I'm not going to worry about it much because I do some park and use them primarily for that and messing around/easy days).

So first off, what should I use to detune it? I have a chrome file, diamond stones (100, 200, 400, 600), and a pocket stone. I also have a soft grey gummi but that isn't going to do much at all (Maybe get a blue extra hard one perhaps?). And then how much is the real question? Just how rounded off/dull should they be? Still be able to shave off some fingernail with the edge, or not be able to anymore? If anyone has a good camera even and could take a pic that would be appreciated.

Thanks for any help. Only two more months...

[Kevo]

Here's a video that's pretty good. I generally detune from contact point up toward tip or tail, but not too far toward the center of the ski from the contact point. I've seen a couple different ways to detune, including a hard gummy-


As for how to know it is detuned enough- pull the back (flat part) of your fingernail perpendicular across the edge where you are detuning. If it is still getting scraped by the edge, the edge is too sharp.

[SiSt]

Go easy on anything that is part of the sidecut (stone, gummi, rock), detune heavily (a file at 45 degrees) on everything which is not sidecut (tapered parts). Adjust after testing with heavier detuning if the skis are still grabby.

[Cabinfever]

Agree w SiSt, easy to take more edge off but a real pain to resharpen. I keep a 70mm stone in my pocket to adjust on the hill if need be.

[PlayItLeo]

Haven't you already asked and had this answered before? Just take a gummi to the hill and detune till your skis feel good TO YOU, there's no set formula for how much to detune. IMO, a soft gummi does the job on the contact points pretty well, especially if you don't know how much you want to detune, because it's taking small bites with each stroke - hard to fuck up your tune that way. If you want to heavily detune taper or rev sidecut, SiSt has it right.

edit: sorry to be cunty, but it is a Monday after all.

[Lindahl]

If by detune, you mean round the edges... Do NOT detune starting at the contact points, start at the taper points. Lots of skis these days are designed to engage beyond the contact points - you want a sharp edge there. Blizzard skis are a great example of this. Despite lots of rocker, you should have very little of that ski detuned (just a few cm at the tip, if at all).

If by detune you mean make the edges engage less aggressively, then just use a gummi stone at a 45 degree angle to the edge and experiment how much works for you. If its too much, just polish it sharp again.

[glademaster]

I recommend doing only a mild de-tune of the tapered sections of your skis. If you're experiencing hookiness or grabbiness, start by increasing the base edge bevel in the tapered sections of the ski before you go ruining the edge by running a file over it at 45 degrees. A 2 or in some cases 3 degree base edge bevel can be applied to the tapered sections of a modern ski to give it the loose, drifty feeling you want.

Bump that base edge bevel up, then give the taper 10-12 passes on each edge with a gummi and ski them before you do anything drastic or irreversible to the edges.

[LC]

I recommend doing only a mild de-tune of the tapered sections of your skis.

Nah, just go aggressive on the tapered sections. Completely round them; the edge there has no use in a turn at all. Then detune from the widest part towards the middle of the ski however you like it to be.

[Ggreenie]

I've always been a bit confused about the obsession with 'detuning' skis. I LOVE the feeling of having super sharp, grippy edges... Why would you not want that?... I do not detune at all.

[XXX-er]

I don't de-tune unless the ski actualy needs it, the last ski I detuned were some old verdicts that were evil handling, 10cms off the tails with a piece of emery paper made all the difference

[auvgeek]

I recommend doing only a mild de-tune of the tapered sections of your skis. If you're experiencing hookiness or grabbiness, start by increasing the base edge bevel in the tapered sections of the ski before you go ruining the edge by running a file over it at 45 degrees. A 2 or in some cases 3 degree base edge bevel can be applied to the tapered sections of a modern ski to give it the loose, drifty feeling you want.

Bump that base edge bevel up, then give the taper 10-12 passes on each edge with a gummi and ski them before you do anything drastic or irreversible to the edges.

Agree with this. Create a white-trash spoon! Also: don't touch the sidecut until you ski them. I've only ever used a soft gray gummi to detune, but that's just me. I guess I like my skis sharp because I don't seem detune except the tapered part and sometimes right where the taper ends (depending on ski shape). I've made new skis too dull by being impatient and taking 5 passes with a gummi stone instead of one at a time.

There was only one exception to this for me, and it was a pair of prototype Kusalas that splat rushed out the door to get us without a factory tune on them. One pair got tuned by a maggot shop in Utah and skied great; the other pair got tuned by the shop at home that I only use in a pinch and were basically unskiable without SERIOUS detuning. Not sure what happened there, but I've never had it happen on a pair of skis that came with a factory tune.

[Lindahl]

^^^ Probably no base bevel, or even negative base bevel (edge high). Easy to do if you forget to do any base edge work on a new ski or assume it was done at the 'factory'.

[Muggydude]

Alright- so it's ok to lightly round the edges from taper on towards the tips- and then some light gummy at 45 degree angle from taper to the contact point and maybe a bit past? Then if they are still hooky detune that area more.

I guess specifically I'm referring to my new Praxis GPOs and some BCs as well- just seems like most people say they need to detune them a decent amount because they are pretty hooky from the factory, and in general most referred to contact point detuning and not taper in the posts I read.

[adrenalated]

As this thread shows, detuning is a matter of personal preference.

My personal preference is NOT a sharp ski. I like a ski that has a predictable edge that will hold when needed, but also break free and slide effortlessly, and I absolutely cannot stand a ski that tries to turn before I tell it to.

Praxis come from the factory really, really sharp. So people like that. I don't. My methodology is pretty close to what SiSt describes. When I get a pair of Praxis, I:
-retune the edges to 1/2. Factory tune is 1/1.
-detune the ENTIRE ski, including sidecut underfoot, with a soft gummy stone. Just enough to knock the sharp edge down a little.
-detune moderately with a diamond stone from the rocker contact point to the taper point
-detune heavily with a file at a 45 from taper point to tip/tail
-all of this is feathered into the adjacent areas, it's not like I just stop with the stone at one point and start in with the file. I smooth them together.

Other brands of skis don't come as sharp and I don't do as much. ON3P, for instance, does a lot of detuning at the factory and I've only needed to smooth a little bit with a gummi on their skis.

That's just what works for me an my style. YMMV.

[AlpiNord]

One person's sharp and 'hooky', may be another's burr. There is a difference between a burred edge, typically found after sharpening with a file vs a honed edge with a stone or diamond, possibly followed by soft subtle detuning with a gummi. Also remember, soft snow makes the edge less relevant. You might be best served to make sure your edges aren't burred but consistently smooth and sharp. Get some miles on them before detuning a little at a time if you feel the need.

Beyone the contact points (not on the bench, but in a turn) by all means dull the daylights out of the tips and tails. I'm confident that had I REALLY dulled my tips, the wind shield wiper affect and stresses on my knee caused by catching a buried log while in the back seat would have been considerable reduced, if not eliminated. I used a flapper wheel on an angle grinder for a quick and effective job.

[creaky fossil]

Just get into deconstructing skis. Remove that friggin' metal. Completely. True bros don't need edges because they're always doing everything right, right place on the ski, right angle, right pressure, in the right sequence. Hence, edges are redundant. Remove them. You're good enough. You're posting on TGR.

[ill-advised strategy]

As this thread shows, detuning is a matter of personal preference.

My personal preference is NOT a sharp ski. I like a ski that has a predictable edge that will hold when needed, but also break free and slide effortlessly, and I absolutely cannot stand a ski that tries to turn before I tell it to.

Praxis come from the factory really, really sharp. So people like that. I don't. My methodology is pretty close to what SiSt describes. When I get a pair of Praxis, I:
-retune the edges to 1/2. Factory tune is 1/1.
-detune the ENTIRE ski, including sidecut underfoot, with a soft gummy stone. Just enough to knock the sharp edge down a little.
-detune moderately with a diamond stone from the rocker contact point to the taper point
-detune heavily with a file at a 45 from taper point to tip/tail
-all of this is feathered into the adjacent areas, it's not like I just stop with the stone at one point and start in with the file. I smooth them together.

Other brands of skis don't come as sharp and I don't do as much. ON3P, for instance, does a lot of detuning at the factory and I've only needed to smooth a little bit with a gummi on their skis.

That's just what works for me an my style. YMMV.

I'm the same way. I started skiing a 1.5 degree base bevel many years ago and found that to be a great help. It's there when you lay it over and every bit as sharp (as long as you adjust the side to match the base) but buttery on a flat ski.