Detuning skis

A snowHead

Based on some conversations on here, when I got my skis sharpened recently I didn't get the tips and tails detuned. The following week, one of the instructors on my course gave an evening talk on gear including skis and their servicing. He was clear that detuning the tips and tails is a good idea (and I think said he did detuned his own skis). When he checked over my skis he thought the tips and tails were a bit sharp so detuned them with a gummy stone. The skis feel good.

What are the pros and cons of detuning the tips and tails?

A snowHead

Too sharp at the tips - too much bite at the start of the turn, too sharp at the tails - too pingy out of the turn. Don't see any cons to detuning

Well, the person's real but it's just a made up name, see?

@sugarmoma666, modern skis don’t need it done.

In fact, you are taking away some of the advantages to a “shaped” ski... definite con.

Used to be helpful for less skilled users to reduce incidence of catching edges. Which shaped skis don’t do, no idea why, must investigate.

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Anyway, snowHeads is much more fun if you do.

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Just to be totally clear on this point before I go out to the garage and service my skis. (2 year old volkl's). I should sharpen the edges the whole length and not de-tune any of it..?

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@sugarmoma666, @FrequentFaller, it’s a dated idea. Not sure why he’s suggesting it.

I refer to the expert https://thepisteoffice.com/index.php/tuning-guide/6-detuning.html

After all it is free · Last edited by After all it is free on Fri 19-01-18 9:51; edited 1 time in total

I would always gummi the very tips for generally serviced skis as the edge bevel will be consistent (off a machine) all the way up. I mean a single run with a gummi which you should do anyway to deburr the edge. Very sharp shovel edges can be a personal preference, i quite like mine sharp all the way to the end but then I know what that feels like. Even with ski shape changes theres no harm in having the first 5cm ever so slightly detuned, it makes engaging into the start of the turn less instant, alternatively if you are doing it by hand increase the base edge bevel 0.5deg for the top 5-10cm of the ski - does the same thing. Fwiw i've prepared skis FT for 7 years and teach as well.

@under a new name, I know that's the view here generally and I'd previously accepted it as gospel. Now I've been given a different view and I'm interested to understand if there are benefits to detuning that outweigh the disbenefits.

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@sugarmoma666, can’t think of any.

snowHeads are a friendly bunch.

Also, if you are on recent skis, they are probs early rise or rocker so effectively detuned anyway.

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@sugarmoma666, ask anyone in the mountains, instructor, coach or ski tech and they’ll tell you to define slightly at the tip and tail. Or sharpen that area yourself, you’ll see how it feels! Keep a gummy on you though...

I think it depends a lot on the specific ski model we are talking about. If the ski has rockered tips and tails (which most do these days), then I don't see much point in de-tuning those tips and tails. For aggressive skis with no early rise and a flat tail (I'm thinking Kastle MX) then a little tip/tail detuning makes a lot more sense.

Pros: Makes the ski less grabby and easier to release
Cons: Reduces effective edge contact length

Personally I keep mine sharp along the full length, but this has got me thinking that I should consider detuning my dedicated hard piste skis as they don't have any tip or tail rocker at all (Movement Le Fer).

You know it makes sense.

Otherwise you'll just go on seeing the one name:

@moseyp, only if they are retired.

You do not need to detune modem skis.

A snowHead

A snowHead

@uktrailmonster, i didn’t even like detuning my 201 7Ss in the early 90s.

I don’t detune my 201 SGs.

My friends and family who run one of the most highly regarded ski shops in Chamonix would regard me as though I had 3 heads if I asked them to “detune” my skis.

Well, the person's real but it's just a made up name, see?

And if you hand sharpen your skis you will probably find that the ends are not quite as sharp as the main length.

Bottom line, if your skis are hooking up too early for you then either detune slightly or get some slalom lessons and learn to really get the tips biting early.

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The detuning of modern shaped skis comes from shops who've got base grinders that undercut the base edge angle at the tips so the skis are less forgiving in that area. On top of that is the large hanging burr produced by excess side edge removal when sharpening which makes it harder to completely remove.

Detuning, or plain old 'blunting' as it should really be called is a quick idiot proof hack fix to this problem as opposed tackling the actual cause of the issue, ie machine set-up/user error etc.

If you understand the geometry/function of the base'n'side edges (which most shop rats & instructors don't) then if your skis are hooking up too early then (after first checking the base edge angle is correct & that the hanging burr has been properly removed)
just add a touch more base edge angle (to say 1.25 to 1.5 degrees) at the contact points to allow for a more progressive edge engagement but still giving full length sharpness etc. For a hand tuner this an easy job but most shops rats are too busy stoking an auto-load machine to have the time, even if they new how.

Anyway, snowHeads is much more fun if you do.

@spyderjon, so based on what you've said if you've had your skis sharpened by a shop rat where the machine hasn't been set-up correctly or there's been some user error in doing it then short of getting a hand tuner to fix it for you it sounds like 'detuning' is the quick idiot proof fix.

So rather than the blanket statement of 'You do not need to detune modern skis' it really becomes 'you should not need to detune modern skis but sometimes it's a quick and easy fix to a poor sharpening job'. Or am I missing something?

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@sugarmoma666, I posted this on another thread about the same thing, basically these are sections on detuning taken from the Swix, Holmenkol, Tognar and Toko guides. Each explains it better than I have

4.edge finishing
Edges on the front and back of the ski / board, that do not influence gliding properties (the part of the edges, that has no contact to the trails during straight position of the ski) should be rounded.
New cut edges and extremly sharp edges at the back and front end of the ski / board reduce the turning properties and may easily result in driving mistakes. Therefore, the edges at the front and back areaare lightly defused at a length of 5 to 15 cm (edge grinding rubber). The edge grip is preserved and the ski / board keeps its turning properies.

DETUNING The edges should be rounded off with a file from the point where the edge contacts the snow, up around the ends. Polish away the factory grinding or hand-file striations with a stone. Depending upon skiing style and ski manufacturers’ recommendations, you might want to slightly detune (dull) the edges back from the contact point about 15 centimeters. Use the Swix Soft Gummy Stone (T0992) or Diamond Stone (TAA200). Swix Fibertex T266N also works for this. Rub the stone back and forth along the edge point to reduce the sharpness. This is a good stone to carry with you - if the ski is hooking at the ends of the turns more than you want, detune the edge more and/or further back from the ends.

Dulling, on the other hand, is more like performing a lobotomy. It's usually done on new skis or boards with a file and/or deburring stone to intentionally dull (or radically bevel) base edges at the very tip and tail where skis and boards lift up out of the snow. Edges here curve dramatically in toward each other, and should be addressed so they don't unexpectedly engage in bump troughs, ruts, crusty snow or other funky condition to revector your planned line of travel downhill off in some new, wild and unanticipated direction.Yikes! Detuning refers to the subtle "massaging" of an edge's sharpness or base bevel near tips and tails to intentionally adjust performance of a ski or board. On old traditional skis, detuning behind the contact points made a skis less grabby and "hooky" for easier control...but detuning a shaped ski can make the ski more "nervous" due to shortening the effective running surface, plus the skis won't initiate turns as desired due to the decreased radius and running surface. So for shaped skis find the contact point of the tip and tail (you can do this by placing the ski on a flat surface and marking the sidewall at the points that the ski contacts the flat surface) and detune from contact point forward on the tip and contact point backward on the tail.

5. Rounding/dulling of edges in front and back: • Some prefer to dull or detune the edges in the front and back sections of the skis or snowboard. If you feel that the tip cuts out to the inside at the start of a turn too quickly, then you can round the edge on both sides of the tip. Use the diamond stone TAA200 and dull the edge in the “shovel” area from the point of snow contact and forward. Do the same procedure at the tail section of the ski or board, approx. 2 inches. If you want to take advantage of the entire turning curve on the skis/ snowboard or want to optimise use of the front section, then there is no need to dull the tip and tail sections. Depending on skill level, technique and application, some prefer this alternative.

Then you can post your own questions or snow reports...

@moseyp, sorry, but I’m with @spyderjon, and my chums who do this for a living.

After all it is free

@under a new name, I wasn't responding to you, my post was addressed to the OP

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@moseyp,

snowHeads are a friendly bunch.

@under a new name, my point is just that I'm not looking to argue it here, simply wanted the OP to get some confirmation as per the original post

@uktrailmonster, contrary to my not looking to argue it - but I'm a little interested - what makes you think that tuning companies like Swix, Holmenkol etc could be wrong?!

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@moseyp, my suspicion is that they just haven’t thought about updating them.

Really, truly, honestly, it’s an outdated idea.

I'm going to sharpen my edges for the 1st time this weekend.....so the above is very timely!

I bought a Kunzmann variable edge sharpener and the shop recommended that I set this to 88 degrees (is this 2 degree edge then ?). The skis are dynastar power track 84's and so based on the above was simply going to run the tool down the edge and use the gummy stone to clean them up (as per lots of youtube).

The edges have light rust and are not that bad at all so my thoughts were a light sharpen would improve them.

Does this sound like a high risk idea.....will I ruin my skis eeek

You know it makes sense.

@gravityslide, you’ll be fine; just don’t take too much off. A couple of passes with a diamond file and then deburr with gummi. Don’t grind them away with a rasp file!

Otherwise you'll just go on seeing the one name:

@gravityslide, I'd definitely read everything on the piste office guide first. When I first started doing mine way back in 2015 I used this as my goto for information, I've subsequently been on his tuning course which is the next level but as a starter I found this really really useful Tuning Guide. Particularly follow the information about base tuning i.e. don't go mad with the stones/files.

A snowHead

Yup, a light touch is all that's needed, a fine file is handy if you have really blunt edges but for touch ups diamond stones are great. I've only used a rougher cut file when changing edge angles, I do everything to 87 degrees, even my powder skis, It comes in handy for when you are on hardpack pistes between the off piste sessions.

A snowHead

Thanks all for the thoughts and advice. Is highlighted how much there is for me to learn about skis and how they're serviced.

On the specifics of detuning, I can see there are very strong views here, that don't all align. From what Spyderjon has written it may come down to how the rest of the servicing was done.

disclaimer

The instructor providing the strong advice to detune was Darren Turner, who knows a bit about skiing and skis, hence not being inclined to dismiss the idea outright.

Well, the person's real but it's just a made up name, see?

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I'm re sharpening 3 pairs of skis! snowHead

Anyway, snowHeads is much more fun if you do.

My Bent Chetlers have plastic edges on the rockered tips and tails, no need for anything there Toofy Grin

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Apologies for the thread resurrection.

Last season I had my skis serviced by a reputable local shop, with a good reputation and knowledgeable staff/owners and a long standing ski tech etc etc.

My skis are Head i-Speed, full piste skis, which are pretty full on, heavy, stiff things. My technique is quite good and a have been skiing regularly since the 1980's. I know how skis work but I don't know much about ski tuning.... I have always been very happy with the standard 'factory' settings in these skis, so I asked for the same when they were done on this occasion.

Anyway, I set off on the first run, for a gentle loosener and found that the skis wouldn't switch off. This was my third ski week of the year, not my first, so I was used to how my skis handled. The skis were perfectly stable, perfectly predictable and even handed - they did exactly the same in both edges. However, it was not possible to skid a turn at all. Perfect railed carved turns with unbelievable edge hold every time!

This was quite thrilling for the first few turns but it soon became apparent that I might need to moderate my speed a little with a skidded turn or two. No luck - hold tight! Try again, softer edges - nope. Time for a hockey stop and regroup - forget it!

I checked the edges for burrs and found none. Swapped feet but they were the same in both edges, so I carried on. I had to give everyone a wide berth and plan carefully where to reduce speed with extra-turny turns. Fortunately, the area was quiet that week. By the second day, they started to ease a bit and by midweek they were ok again.

I took them back to the shop this week and explained to the owner what had happened. He said that people with (ahem) proper technique could find this happens and that he would de-tune the tips and tails this time. Is he right?

To be clear, the skis worked impeccably. They were just too hardcore for a piste with other people on it! I can imagine that they would have been sensational on an iced run with gates on it....

Then you can post your own questions or snow reports...

@Klamm Franzer, was this around the middle of February? My first day in Ellmau was a similar experience, and I think was likely done in the same place by the same tech. An overnight service in a local shop returned them to normal.

I'm wondering whether something was wrong in the setup, or there was an uncharacteristic mistake, or whether an apprentice was left to do some of the backlog

After all it is free

Horses for courses, every turn is a combination of slide/skid and carve so depends on the skiers, the conditions, the ski etc etc etc, I don't thing you'll find a definitive answer to this.
I always pass the whole length of the ski with a gummy stone to see off any burrs and give the tips and tail on the rockered section a heavier pass. Its just what I like but might not suit the next guy along.

Once upon a time pre shaped carving skis there was some benefit to a bit of de tuning. With a modern ski especially if they aren’t race skis the softness alone would prevent any grabbing. One very specific situation where you might get some advantage, might, is if you found yourself sideslipping a narrow very steep icy gully the chance of tips or tails catching might be reduced. Lots of mights in there. The truth is outside level 3+ coaches few people are true carving, and there’s way more significant things for most of us to focus on.

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@ousekjarr, I suspect so. There is another Snowhead of this parish who also had the same experience, so that's three of us. We both got skis serviced in mid Jan.

@andy n netty, @jbob, This was a very different experience to normal, including when the skis were brand new. I have had decent shop tunes before but this was off the charts. I haven't raced since carving skis arrived but this would be exactly how I would want a pair of race skis to behave. It completely changed their performance.

I don't know enough about how the standard ski service is carried out to know if what they did was different, or whether for example they forgot to do the base edge?? I have asked for 1 degree on the base and 2 degrees on the edges this time. Standard Head angles are 1,1 and I have not noticed a difference like this when skiing on Atomic X9's where the standard edge are 1,3.

Help!!

Detuning skis

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