Concave bases?

[Jacques]

Atomic skis during some of the Beta models era were commonly concave. As long as near the edge was flat for like 10-15mm it was ok I believe. @Atomicman would know.

Scott had a boat hull base shaped tip and a pronounced concave tunnel in the very end of the tail. I think the Crusade model had that in roughly 2009.

Yes. Atomic skis are good example of a ski that might come with a slight concave tip contact area.
Everyone raved about how well they would hook-up a carve......barely tip that puppy and woosh........if they knew how do do that.
@James, you always come up with some good trivial info on skis. Be a good boy now!

 

[Eleeski]

Excellent feedback guys! I'm not sure where the experiment will head now. So many fun ideas to try.

@ScotsSkier What is the base bevel you used? I went out on your racers today. They carve and edge wonderfully.

I'm trying to get that feel out of my quick responsive Goodes (I have a second old scratched worn pair to experiment with). Should I lift the bindings some? The new Goodes carve OK but are a long way from the Head SLs. Or the Slants. But if it's a trade off between carving and quickness - well, that's why I have a quiver of skis.

The Heads are heavy and difficult in the bumps, especially if it's soft. Can I get the quickness of the Goodes in the Heads with lighter bindings? (I have a new pair of lightweight bindings I could use - but they aren't lifted).

It sounds like a full concave grind might not work that well - especially with the accuracy of a handheld grinder I was planning to use. I don't have experience with the "sharp flexible scraper". Where should I get one? I use a box knife blade currently. It wouldn't be able to even do a small concave tip.

Most of my skis seem to have edges slightly below the ptex. Am I running the convex experiment already? What is a good scraper? Or does a good base grind do that better?

The Tahoe Snow Labs grinds resurrected the skis I gave them. Maybe I'm just not good at tuning.

I did like my old Atomic race skis in the hardpack. Old red Beta race skis that were quite light and edged well. Maybe the concave tip is the answer. Weight certainly wasn't.

Or should I try grooves next to the edges? Won't work on Ray's old skis as he filed too much edge off them! No wonder they were so sharp!

Regarding my skills, "I am the best skier on the mountain!" I can have fun down anything. I'm great in hero bumps, good in tough bumps, am willing to go in to enjoy ice bumps and measure the resort by the bumps. I can make it through a race course - slowly but not the worst time in my couple Masters races. Steeps and little cliffs are OK - especially if the snow is soft. More so if it's powder. My serious weakness is the smooth sheet of boilerplate (Red Dog!). My hip is in excellent shape (titanium rocks!) so I can angulate tolerably well on the right ski and in the right conditions - as far as my skills allow. I am old and weak so the lightweight equipment is very helpful. I barely notice boot changes (not really sacrilege as I reject any boot that doesn't fall within my acceptable range). Cuffs and canting hasn't had an effect in the past experiments. I'm skiing Full Tilt Mary Janes (women's boots - nice and soft for bumps!)(Olympic Bootworks did the fit, new liner and orthotics)(I have fit my own boots successfully in the past). I build and design waterskis that I have used effectively in high level competition - so I have a reasonable feel for what is on and under my feet. And I'm not afraid to ruin equipment with an experiment.

Eric

 

[Eleeski]

Would you consider putting gougea immediately next to the edges? Like so -u---u-

Since the experimental skis already had a lot of rock damage next to the edges, I'm trying this. Fairly easy to dremel the ptex a bit next to the edge. Only did one ski (I'm lazy and I might be able to feel a difference). Stopped a ways back of the back binding.

OK, @cantunamunch is trying to kill me. Do not repeat the experiment to groove the skis next to the edges! Actually wasn't heinous in the ice bumps (it was because ice bumps are heinous but the ski made them better) but everywhere else it sucked. The ski was slow and draggy. It resisted turning and was extremely grabby. I couldn't carve at all. If I got the ski tipped enough it was just as prone to slip as the other ski. FAIL!

However, perhaps just grooving the front edge might work. It did hook up nicely when I worked it right. The tip is loaded more lightly than underfoot so that might not force many of the problems but still lead the ski into a carve. I'll Ptex in the groove in stages.

Interesting experiment. The snow was horrible, firm to icy everywhere. Evaluating a ski was the right entertainment for the conditions. But we are headed home so the rest of the experiment will have to wait.

Eric

 

[Atomicman]

Atomic skis during some of the Beta models era were commonly concave. As long as near the edge was flat for like 10-15mm it was ok I believe. @Atomicman would know.

This was true. Except that it was ONLY in the tip and tail and they were flat a godd 10-155mm or more in from each edge. Center of ski was flat! Had no negative effect on the skiing characteristics. In fact Atomic made the claim they were more stable when running straight. As long as 10-15mm from each edge was flat the ski skied fine. They all came form the factory with a 1/3 tune/

 

[LiquidFeet]

I had the Atomic R11 beta. I had to use a credit card, held in a curve, to scrape the wax off all the way tip to tail. Someone on Epic said they came this way from the factory. They were definitely concave at the waist.

 

[James]

I had the Atomic R11 beta. I had to use a credit card, held in a curve, to scrape the wax off all the way tip to tail. Someone on Epic said they came this way from the factory. They were definitely concave at the waist.

Yeah I'm not buying not under foot was it concave. Mine was. I had the Atomic 9.34 slalom ski for a brief period. (188/34 meters! -shaped) Brand new, but a year old, I took it to a shop to have it flattened. They spent an enormous amount of time on it and charged $60 which in 2000/1 was a lot. I skied it one day then sold it. It was already a year old and being passed by more radical shaped slalom skis. I remember nothing good about that ski.

 

[LiquidFeet]

That was my beginner ski years ago. It was not the right ski for me, as I could not bend it easily. By the end of my time on that ski I was quite the heel-pusher and pivot&bracer. I do have one memory of bending the ski while making aggressive short carved turns around shadows from a non-functional lift. That run was sweet; I had no idea how I accomplished it, the ski surprised me, and I couldn't repeat the experience. Funny how single runs can have such an impact.

 

[cantunamunch]

Since the experimental skis already had a lot of rock damage next to the edges, I'm trying this. Fairly easy to dremel the ptex a bit next to the edge. Only did one ski (I'm lazy and I might be able to feel a difference). Stopped a ways back of the back binding.

OK, @cantunamunch is trying to kill me. Do not repeat the experiment to groove the skis next to the edges! Actually wasn't heinous in the ice bumps (it was because ice bumps are heinous but the ski made them better) but everywhere else it sucked. The ski was slow and draggy. It resisted turning and was extremely grabby. I couldn't carve at all. If I got the ski tipped enough it was just as prone to slip as the other ski. FAIL!

Eric

I even bet it was hard to get on the true edge as opposed to the immediately available false one. Good on you for trying!

FWIW the ICE edges were only done in the middle 40-50cm of the ski.

In case you're wondering where the idea comes from, it is a variant of the hollow grinds currently used on ice skates.
https://wissota.com/support/skate-sharpening-101/choose-your-radius/

 

[newfydog]

I had some of the Atomic Metrons with a factory concave base. It ran the length but was strongest at the shovel (figures, that is where is is widest) When I had them ground, the ski became pretty boring.

 

[Atomicman]

Yeah I'm not buying not under foot was it concave. Mine was. I had the Atomic 9.34 slalom ski for a brief period. (188/34 meters! -shaped) Brand new, but a year old, I took it to a shop to have it flattened. They spent an enormous amount of time on it and charged $60 which in 2000/1 was a lot. I skied it one day then sold it. It was already a year old and being passed by more radical shaped slalom skis. I remember nothing good about that ski.

Trust me, your pair were an anomaly. You have no idea how many pair of Atomic race & non-race skis we have owned over the years both my boys were racing. In fact when they become J3's (2nd year) they were both sponsored by Atomic. We had a t one time over 26 pairs of skis and some of those rotated out from year to year as rules change. None were concave under foot. Only in the tip and tail.

 

[Atomicman]

I had some of the Atomic Metrons with a factory concave base. It ran the length but was strongest at the shovel (figures, that is where is is widest) When I had them ground, the ski became pretty boring.

Also had 5 pair of Metrons B5...Flat underfoot.

 

[Eleeski]

I even bet it was hard to get on the true edge as opposed to the immediately available false one. Good on you for trying!

FWIW the ICE edges were only done in the middle 40-50cm of the ski.

In case you're wondering where the idea comes from, it is a variant of the hollow grinds currently used on ice skates.
https://wissota.com/support/skate-sharpening-101/choose-your-radius/

I definitely felt the "true edge, false edge". I'm really curious if the false edge feeling might help get into the true edge if it is just at the tip. I didn't even test with the tails grooved because I know that when I'm on the tails I want to be able to slide them around to save me back into balance - I can't carve from my tails. Since I don't think my "true" edge improved with the grooves (and the handling downsides were pretty severe) I'm thinking that the stock edges underfoot might be close to optimal. There is a lot of factory testing to support that?

Interesting feedback on the Atomic concave. I don't know if I still have my old ones around to measure (but I am kind of diseased with hoarders syndrome). It does seem like the concave worked (for some) especially for racing. If I can just figure out how to get a smooth consistent grind to try the concave...

Or get it to snow so I don't have to worry about firm snow edging!

Eric