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Base bevel experience with a Liberty Origin 96 all mountain ski

post #1 of 9
Thread Starter 

I had a really fun and interesting learning experience over the last couple of weeks and I am so stoked by it I want to share it. I have been reading a lot of tuning posts (and watching some of Jacques vid's) and learning a lot. It all makes sense to me, but I like the expression "the proof is in the pudding".


I demo'd some Liberty skis a couple of weeks ago from Sport Thoma. Skied Sunday River in ME. Very hard pack / icy conditions. Had a Liberty Helix (105mm) and a Liberty Origin (96mm) ski to demo. The Helix had very good grip on the ice. The Origin had outstanding grip, almost the best I have ever experienced. Definitely made a mental note to find out about the tune spec's. I bought the Origin 96mm ski in 182 cm for my son. Blister did an off the charts review on the ski and I agree totally with it.  My son skied his brand new pair of Origins the very next day and complained they did not have anywhere near the grip the demo pair had. The demo's held like a pit bull and hooked up really quickly. The ski has a huge amount of rocker in the tip and you could feel the demo ski's grip was mostly underfoot, which made sense. Talked to Sport Thoma and found out the demo skis were tuned to a 0.5 base bevel and a 2 deg side angle. I suspected the base bevel was the big difference. I usually ski a .7-1.0 bevel.


As an aside, the Helix lost its grip to a degree by the end of the day, the Origin did not. I attribute that mostly to me skiing on the Helix most of the day and I am 245lbs. I can wear out an edge slarving them on boiler plate and hard pack. The Origins carved much better so not as much slarving, plus my son is a lot lighter than me and he mainly used them.


So I checked on Liberty's website and they claim the factory tune is a 1 deg base / 2 side tune.(the new pair had the factory tune) I measured them with a true bar and feeler gauge and they were at  1 / 2. I did file and diamond stone sharpen the side angle to 3 degrees to see if that helped. I skied my son's Origins the next weekend (this past one)  and still the same, middle of the road grip. Again, I was thinking the 0.5 base bevel really made a difference on the demo version. My friend demo'd a ski from the same shop this weekend, an Armada Invectus ski, (95mm) and I skied it. It had the same tenacious grip on the icy conditions. Aha I thought, it must be tuned the same way as the Liberty demo skis. So in the parking lot at the end of the day I measured the base bevel and sure enough it was 0.5 degrees. I skied them for a couple of hours and the grip stayed excellent. On the first run I almost bit it, as the ski hooked up when I wasn't ready. They also felt just a bit hooky in the tips. I liked the grip a lot, but would have detuned the tips slightly if they were my skis.


So, back to the shop at the end of the day and I gave them my son's Liberty Origin 96 skis to put a 0.5 base and 3 deg side angle tune on. They charged a reasonable $50 for the grind and bevel job, and they were surprised the factory tune wasn't better. (I guess they don't tune their new skis very often). Picked them up the next day and decided I had to take a run on them just to see how they felt. I was at Attatash on Sunday and it was little bit firmer than SR. The skis were awsome again. They were turned back into the pit bull, maybe even better than the demo skis. Hard to say since I only took 1 run on them, but that was enough to know what the tune did to them. Actually one or two turns is all it took to feel the difference the base bevel change made. On this ski, they didn't feel hooky since the tip is so rockered. 


I was a bit surprised the base bevel made such a difference in the holding power of the skis. The Armada demo skis had outstanding holding power, so I do think the 0.5 base was mostly the reason. I didn't think the base bevel affect the holding power so much, but maybe they hook up so much quicker that there is minimal sliding before the ski hooks up. Once a ski starts sliding, it is much harder to get it to stop sliding and hook up. Whatever the reason, I really like the way they ski and I will request a 0.5 on my next grind on all my skis. Since I am so big, I like all the holding power I can get, especially on icy blacks and double blacks. I would also add I didn't really do a "controlled experiment" on the side edge angle, as some skis were 2 deg and some 3 deg, but Liberty Origins had a 1/3 on Saturday and a 0.5/3 on Sunday. What a difference there was between them. 


Anyone else try different base bevels and care to share the results?

Edited by bttocs - 3/21/16 at 4:50pm
post #2 of 9

Right on. My experience setting to a 0.5/3 completely matches yours. It's also why I'm taking my skis for a base grind every season - the base edge seems to get more beveled over time on its own. 

post #3 of 9

Nice story.  Shows you like a quick engaging ski that will start to hook up with little tipping.  I prefer a slower engaging ski that needs to be tipped more, thus I use a 1 degree base. 

On ice .5 may be your best bet.  For the most part I ski softer snow, or lets just say snow.  When it's super icy I have a harder time to get an edge.

The proof is in your pudding!

post #4 of 9
Very surprising that Sport Thoma does a 0.5 base bevel on any ski let alone a wide ski.
post #5 of 9
Interesting that you think an Invictus has tremendous holding power.     What size was it and how much do you weigh?
post #6 of 9
Thread Starter 
Originally Posted by cantunamunch
Interesting that you think an Invictus has tremendous holding power.     What size was it and how much do you weigh?


It was 186 cm long and it is not the wide Invictus (I think around 110mm) but a narrow one (95mm wide) with no metal. The holding power was very good, better than a lot of skis I have used except for race skis. I weigh 245 lbs.  I was surprised as well, shocked actually. I measured the base bevel at one or two points on the edge and it was under 0.7, I would put it at a 0.5 angle. Not sure about the side angle. The tips were a bit hooky on the ski, and it hooked up really quick. The edges were also very sharp, which helped.


Very surprising that Sport Thoma does a 0.5 base bevel on any ski let alone a wide ski.


I just measured it on my son's Liberty Origin 96 skis last night to confirm what I wrote above, and guess what, it measured about a 0.75   (I need to apologize to Sport Thoma, my true bar had a nick and effected my measurements, the bevel is 0.5) toaverage angle. I used the true bar, back lighting and a feeler gauge at 60 mm from the edge.It was running about 3/4 of a mm. Varied a little.  So all my observations on the Liberty ski were between a .75 and a 1.0 bevel. Also disappointed that Sport Thoma did not deliver what I asked for. That is not too surprising, since I have only found 1 out of about 6 shops that actually produce a tune to the spec's they claim. (SKIMD is the one). Another interesting thing is I measured a Kastle MX78 I skied over the weekend and it measured 0.5 deg base bevel. SKIMD did the grind and tune a few months ago on that ski.  I will add the edges on the Sport Thoma  tune were very sharp and the edges on the SkiMD tune were beat up and rolled over a bit from the last 3-4 days of skiing. The Kastle had average ice grip. So sharpness of the edge was a factor between the Kastle and the Invictus. The new Liberty skis had sharp edges on both tunes, so more of a second order effect if at all.


Lesson learned is always measure your bevel and don't trust what the shop tells you it is.  If you want to make accurate conclusions.  Now I have some idea why Atomicman invested in the expensive angle measurement tool he has. I do it the old fashion way, but I think i can pegg it to the nearest 0.25 degree

Edited by bttocs - 11/3/16 at 8:24pm
post #7 of 9

bttocs, Just one question, when you put the ski on edge, do you continue to roll your ankles to increase the edge angle ?


I know its hardtop do going slow like getting the lift and turning in that same spot everyone else dose. That one little test is how I know my tune is great. Okemo has a couple lifts that you turn as soon as your past the cone, the Solitude lift is one of them, from the left seat puts you right into that ice spot where everyone else turns.

post #8 of 9
Thread Starter 

Yes, I vary the edge angle a lot. It depends on a lot of variables such as speed, how tight a turn I want to make, and how good the snow grip is. I am a coach for a ski race team and we do a lot of carving drills and technique drills.

post #9 of 9
Thread Starter 

I just did a correction to my second post above. When I measured the base bevel on my skis as described above, my aluminum true bar has a very slight "divot" on the spot I put on the edge of the ski. I have it marked at 60mm from the end and I always place the mark over the ski's edge (the mark is on the side of the true bar, not the bottom). Over time, I have worn a very slight divot in the aluminum true bar and that is making a 0.25 degree differences in my measurements. I had to use two magnifying glasses to see the divot but it is there. I marked 60 mm from the opposite end of the bar and the base bevel measurement is 0.25 degree less than before. I apologize to Sport Thoma again and can now say they delivered what I asked for. 


I will probably spring for the more expensive true bar made from hardened steel which should stand up to use on steel edges without deforming at all. Live and learn.

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