New Skis Concave

[Noodler]

Originally posted here, but I've changed it a bit.


Got off the gondola and descended down a flat traverse. Immediately the skis force themselves into a wedge. I thought maybe there's ice on the boots. Stop, clean them off. Skis just as bad. They don't want to turn, have a chaotic mind of their own. The snow is graupel coming down an inch and a half , over compressed wet snow with a glaze and endless random small bumps. So it's also sticky. I stop again and go over all base edges with a diamond stone.I've carried it for a week for this situation and never used it. Maybe it's a hanging burr.

No, the skis are just as bad. Basically unskiable, dangerous. Especially since I'm tired after 7 straight days plus travel. Often with grippy bases you can throw them forcefully feom edge to edge, minimizing any low angles at transition. That doesn't work here partly because of the snow too. Dangerous because I really don't know what the ski will do. Even a quick hockey stop could be a big problem.

It's raining at the bottom, but I go all the way down to the bottom, walk across the street and pay a different ahop to rent a pair of 168 Stockli Ax. At least they worked.

Probably the worst tuned ski I've ever demoed, and there've been some bad ones. Maybe it was a combo of convex, concave with some edge high spots. Don't know. This situation is difficult to get across in English, never mind in bad French. General tuning knowledge is even lower in France/Switzerland I've found.

It's also occurrd to me since maybe the bindings were off center or skewed to the center line. Because of the instant wedge behavior. In addition to the base issues.

That's quite the ski tune disaster story. Sometimes a really bad tune can be a good thing though. Take for instance my purchase of the 2017 Stockli SR95 skis. The reason I was able to get them dirt cheap was because the previous owner just couldn't get along with them. When I got them I found them to be horribly hooky with a total mind of their own. When I put them on the bench I found little to no base bevel at the tips and tails. Underfoot they were fine, but this shows just how important a consistent base bevel is for proper ski operation. Crappy inconsistent side edge angles aren't anywhere near as impactful as a poor base setup.

 

[CalG]

I still routinely flatten bases with a steel scraper. (a very sharp one!)
I think your post is pretty much true.
A dedicated powder ski can be just fine even if it is convex.

You don't flatten concave bases with a cabinet scraper! ;-)

 

[Jacques]

You don't flatten concave bases with a cabinet scraper! ;-)

That is true to some extent. However given a good long base bevel first, you can make a slightly concave situation better. Just takes some skill and time.
I have done it more than thrice!
There has been reference to convex bases here as well. IDK, maybe just me.
If the base is way concave, then not even a stone grind will fix that.

 

[Jacques]

That's quite the ski tune disaster story. Sometimes a really bad tune can be a good thing though. Take for instance my purchase of the 2017 Stockli SR95 skis. The reason I was able to get them dirt cheap was because the previous owner just couldn't get along with them. When I got them I found them to be horribly hooky with a total mind of their own. When I put them on the bench I found little to no base bevel at the tips and tails. Underfoot they were fine, but this shows just how important a consistent base bevel is for proper ski operation. Crappy inconsistent side edge angles aren't anywhere near as impactful as a poor base setup.

^ Truth! Consistent base bevel. However that can change with base shape as we all well know.
When the ski has some "boat" shape at the tips for example.
Wham! Automatic progressive tune!

 

[Jacques]

Jacques...do you burr your scraper when you flatten?

Yes. The coarse file makes it leave structure in the ski base.
Anyway, the scrapers I use always have a rough edge after I file them.

 

[Noodler]

^ Truth! Consistent base bevel. However that can change with base shape as we all well know.
When the ski has some "boat" shape at the tips for example.
Wham! Automatic progressive tune!

I assume that your statement is due to setting a base bevel using a guide that is using the base as "reference". So a ski with a more convex base at the tip and tail will end up with more base bevel on the edges in those regions. If so, you really have to be careful in these situations to ensure that:

1. That's what you really want (progressive base bevels) AND
2. That the convex shape is consistent from side to side (and centered) or else you'll end up with an asymmetric base edge bevel with different angles between the each of the ski's edges.

 

[Jacques]

I assume that your statement is due to setting a base bevel using a guide that is using the base as "reference". So a ski with a more convex base at the tip and tail will end up with more base bevel on the edges in those regions. If so, you really have to be careful in these situations to ensure that:

1. That's what you really want (progressive base bevels) AND
2. That the convex shape is consistent from side to side (and centered) or else you'll end up with an asymmetric base edge bevel with different angles between the each of the ski's edges.

Thanks for that. Agree 100%
BTW, I recommend that the skis be rotated on a regular basis to keep base wear as even as possible.
Beyond that, ski half the time switch, and keep hockey stops going each way and right and left turns even! ;-)
When slipping a race track use both sides of skis even!!!!

 

[ski otter 2]

Originally posted here, but I've changed it a bit.


Got off the gondola and descended down a flat traverse. Immediately the skis force themselves into a wedge. I thought maybe there's ice on the boots. Stop, clean them off. Skis just as bad. They don't want to turn, have a chaotic mind of their own. The snow is graupel coming down an inch and a half , over compressed wet snow with a glaze and endless random small bumps. So it's also sticky. I stop again and go over all base edges with a diamond stone.I've carried it for a week for this situation and never used it. Maybe it's a hanging burr.

No, the skis are just as bad. Basically unskiable, dangerous. Especially since I'm tired after 7 straight days plus travel. Often with grippy bases you can throw them forcefully feom edge to edge, minimizing any low angles at transition. That doesn't work here partly because of the snow too. Dangerous because I really don't know what the ski will do. Even a quick hockey stop could be a big problem.

It's raining at the bottom, but I go all the way down to the bottom, walk across the street and pay a different ahop to rent a pair of 168 Stockli Ax. At least they worked.

Probably the worst tuned ski I've ever demoed, and there've been some bad ones. Maybe it was a combo of convex, concave with some edge high spots. Don't know. This situation is difficult to get across in English, never mind in bad French. General tuning knowledge is even lower in France/Switzerland I've found.

It's also occurrd to me since maybe the bindings were off center or skewed to the center line. Because of the instant wedge behavior. In addition to the base issues.

I can relate: for example, on Stockli SR 88s at most recent SIA - yikes, including some of the steps you took to correct em on your own not working one wit;
and the new Mantra V-Werks I've just gotten - ugh. These things skied so wonderfully at SIA, in the same length. I've still not figured out completely what's wrong, after five times working on them and five times testing them for one run (still obviously a mess, noticeable immediately). Before this, I can't remember a ski that didn't get fixed the first or second time around, at most - unless they turned out to be badly warped or otherwise defective.

Some year's back I got a pair of Fatypus D-Senders 106 that were badly rail high and felt like one was riding on train tracks, but they were at least predictably skiable, and fixed up properly - what a great ski - with elbow grease, a few base files and ski vision tools for bases, a good burred metal scrapper, and a touch up viewing of @Jacques' great "how to" video on u tube on edge flattening with a scraper, just the ticket! (just one of many great ones by him).

 

[ski otter 2]

Please define "fat".

Not race skis, and the like. Otherwise, not going to "bite." I left that vague on purpose. You decide. I know I will.

 

[ski otter 2]

That's quite the ski tune disaster story. Sometimes a really bad tune can be a good thing though. Take for instance my purchase of the 2017 Stockli SR95 skis. The reason I was able to get them dirt cheap was because the previous owner just couldn't get along with them. When I got them I found them to be horribly hooky with a total mind of their own. When I put them on the bench I found little to no base bevel at the tips and tails. Underfoot they were fine, but this shows just how important a consistent base bevel is for proper ski operation. Crappy inconsistent side edge angles aren't anywhere near as impactful as a poor base setup.

Thanks for this. It's a mistake that's common, and I gotta keep reminding myself not to take for granted those base bevels. Usually, with hookiness in a new ski, I'll just go to routinely increasing base bevel at the tips and tails past (or around) the contact points, in small increments, as if it's a built in design defect or something, that increasing base bevels in that way will usually cure. But the other side of that coin is that the base bevels might just need to be correctly set in the first place, maybe without increasing the base bevel from the contact points forward, etc.: just to make sure they are set right and consistently, and not at a greater bevel underfoot than at the tip and tail, for instance, as you described, I think.

 

[Jacques]

I can relate: for example, on Stockli SR 88s at most recent SIA - yikes, including some of the steps you took to correct em on your own not working one wit;
and the new Mantra V-Werks I've just gotten - ugh. These things skied so wonderfully at SIA, in the same length. I've still not figured out completely what's wrong, after five times working on them and five times testing them for one run (still obviously a mess, noticeable immediately). Before this, I can't remember a ski that didn't get fixed the first or second time around, at most - unless they turned out to be badly warped or otherwise defective.

Some year's back I got a pair of Fatypus D-Senders 106 that were badly rail high and felt like one was riding on train tracks, but they were at least predictably skiable, and fixed up properly - what a great ski - with elbow grease, a few base files and ski vision tools for bases, a good burred metal scrapper, and a touch up viewing of @Jacques' great "how to" video on u tube on edge flattening with a scraper, just the ticket! (just one of many great ones by him).

Thanks man. My videos on ski tuning & waxing are basic. I did them to help others that want to learn a few things.
Not everyone has a shop close by. Some handy people just like to work on things.
I'm glad it has helped you out!

 

[ski otter 2]

Many of your videos have helped my tuning, etc. - overall, best I've watched. Lots of your experience learned over time is in those videos, often thinking outside the box. Some of it was new to me, some of it I'd used at some point in the past but forgotten. So thanks very much.

 

[Flo]

How much is too much? I contacted the manufacturer and they told me to skis them and that they should be fine.

 

[GregK]

@Flo I’d definitely be getting those ground flatter as they will feel heavy and hard to pivot being that edge high.
Had many skis worse that than that were easily solved with passes on a stone grinder and then reset the base and side edge bevels by hand.

 

[James]

How much is too much? I contacted the manufacturer and they told me to skis them and that they should be fine.

What are you using for a true bar there?

Shaft of a roto brush?

 

[Flo]

What are you using for a true bar there?
View attachment 158075
Shaft of a roto brush?

I did not have a true bar in hand (just ordered one to double check) but I looked with different “bars” and new wax scrappers.