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