Bi-radius sidecut

Bi-radius or dual radius sidecuts have been around for a while on a number of skis you probably didnt know had it, and are included in our Pioneer freeride skis. Its about thinking how you drive the skis and where your weight pressures on the skis at different speeds. Dual/Bi radius sidecut splits the turn radius/sidecut of the ski into two portions, rather than a single arc shape going the full length of the sidecut, in front of the boot to the shovel, and behind the boot to the tail.

So at slow speeds, and in tight terrain, you want to be able to move and turn the ski around quickly(i.e. pivot) and so you will design the front sidecut portion to have a shorter turn radius, meaning when you pressure the front of your boot hard, engaging the shovel it makes the turn initiation easier and quicker across fall-line.

At faster speeds, once the terrain opens up, the opposite applies, you want to make wider, longer arc turns, and so by designing a longer turn radius in the tail portion, when you are more centred in your stance, you engage the rear portion of the edge more, making naturaly longer turns, going faster as you spend longer pointing the skis down the fall line.

It works to create a more versatile turning ski that you're not fighting against either in tight terrain to manhandle it into making short radius turn or on open terrain your not fighting the natural radius of the ski when you're trying to make longer arcing turns, which is where you get instability at speed.

SofaKingSickCan anyone explain "bi-radius sidecut" to me? i've had a little interest in a couple ON3P skis lately but after trying and hating a few modern skis with less traditional sidecuts, i'm a little gun-shy.

what is bi-radius sidecut and how does it make the ski behave? i straight up hate 5 point skis and don't really even like taper that much

thanks all

Which "modern skis with less traditional sidecuts" are you referring to? Cause, from my understanding, the bi-radius design on most skis only applies to the area between the widest points at the tip and tail, not the tapered sections past those widest points. I.e., bi-radius is not the same as a "5-point" shape like a Soul 7, JJ, etc. The "5-point" design refers to the tapered shape at the ends, not the radius created by the sidecut of the ski.

I'll let the guys who really know what they're talking about break down the specifics since I'm sure I'd mess it up or miss something, but from my experience, I've never noticed any weird feeling in dual-radius skis like the Moment Commanders, ON3P Woodsman 108, or Faction Dictators (or "triple-radius" skis like the Volkl Mantra 102).

To me, they all just felt pretty normal with nothing weird going on in terms of carving, slarving, or general performance on edge. And of course, the radius is only one part of the equation, and since I didn't notice anything weird going on with the radius, things like weight, flex pattern, rocker profile, mount point, and shape stood out more to me on those skis.

*edit: see Fauna's explanation

**This post was edited on Feb 25th 2020 at 11:53:54am

FaunaSkisSo at slow speeds, and in tight terrain, you want to be able to move and turn the ski around quickly(i.e. pivot) and so you will design the front sidecut portion to have a shorter turn radius, meaning when you pressure the front of your boot hard, engaging the shovel it makes the turn initiation easier and quicker across fall-line.

At faster speeds, once the terrain opens up, the opposite applies, you want to make wider, longer arc turns, and so by designing a longer turn radius in the tail portion, when you are more centred in your stance, you engage the rear portion of the edge more, making naturaly longer turns, going faster as you spend longer pointing the skis down the fall line.

great answer. thank you, much appreciated. this middle bit about HOW the different sidecuts are engaged is most of what i was missing

patagonialukeWhich "modern skis with less traditional sidecuts" are you referring to? Cause, from my understanding, the bi-radius design on most skis only applies to the area between the widest points at the tip and tail, not the tapered sections past those widest points. I.e., bi-radius is not the same as a "5-point" shape like a Soul 7, JJ, etc. The "5-point" design refers to the tapered shape at the ends, not the radius created by the sidecut of the ski.

I'll let the guys who really know what they're talking about break down the specifics since I'm sure I'd mess it up or miss something, but from my experience, I've never noticed any weird feeling in dual-radius skis like the Moment Commanders, ON3P Woodsman 108, or Faction Dictators (or "triple-radius" skis like the Volkl Mantra 102).

To me, they all just felt pretty normal with nothing weird going on in terms of carving, slarving, or general performance on edge. And of course, the radius is only one part of the equation, and since I didn't notice anything weird going on with the radius, things like weight, flex pattern, rocker profile, mount point, and shape stood out more to me on those skis.

*edit: see Fauna's explanation

**This post was edited on Feb 25th 2020 at 11:53:54am

right, i knew the bi-radius sidecut wasn't too similar to 5point etc etc, my point was just that i'm spooked about newer geometry specs that i don't fully understand because it blew me away how much i hated 5point/big taper so now i'm hesitant to try other ""non-traditional"" setups until i know exactly what they're about (and i don't get to demo very often)

5 point etc skis feel like they just want to make lame little pivot turns and traverse rather than doing fall line skiing. basically i like stiff, long sidecut skis with predictable and traditional shapes that want to bite into meaty turns and leave the smearing and surfy parts up to me

but the woodsman caught my eye and i like the idea of something that tries to be nimble in the trees but also be able to point it, and you basically nailed the answer i was looking for when you said they feel normal and not like something weird is going on. when i envisioned them in my head i imagined the possibility of some weird hooky feeling coming up sometimes depending on turn size and shape

so i might try them some time. big thanks for the great answers guys!

SofaKingSickright, i knew the bi-radius sidecut wasn't too similar to 5point etc etc, my point was just that i'm spooked about newer geometry specs that i don't fully understand because it blew me away how much i hated 5point/big taper so now i'm hesitant to try other ""non-traditional"" setups until i know exactly what they're about (and i don't get to demo very often)

5 point etc skis feel like they just want to make lame little pivot turns and traverse rather than doing fall line skiing. basically i like stiff, long sidecut skis with predictable and traditional shapes that want to bite into meaty turns and leave the smearing and surfy parts up to me

but the woodsman caught my eye and i like the idea of something that tries to be nimble in the trees but also be able to point it, and you basically nailed the answer i was looking for when you said they feel normal and not like something weird.

Your experience of 5 point cut skis is exactly what I felt when I tried others on the market and the ability to hold a long fall line carve is what I set out to be able to do on a 5 point cut freeride ski, so I could retain the benefits you get from the taper in soft snow but still rip long turns, which birthed the Pioneer.



I did this by having an (effective) GS cut camber section underfoot, which is stiff and where most of the mass of the ski is. (I say effective as they do have a dual radius). I then paired that with lighter, tapered, rockered, softer end sections to give them the soft snow performance I didn’t want to lose.

I feel I achieved that and, not wanting to speak too much for Luke and his coming Blister review but, I think Luke would come with me on that.

that's sick, i hope you're right! i'll def check the review, those guys are good

FaunaSkisYour experience of 5 point cut skis is exactly what I felt when I tried others on the market and the ability to hold a long fall line carve is what I set out to be able to do on a 5 point cut freeride ski, so I could retain the benefits you get from the taper in soft snow but still rip long turns, which birthed the Pioneer.



I did this by having an (effective) GS cut camber section underfoot, which is stiff and where most of the mass of the ski is. (I say effective as they do have a dual radius). I then paired that with lighter, tapered, rockered, softer end sections to give them the soft snow performance I didn’t want to lose.

I feel I achieved that and, not wanting to speak too much for Luke and his coming Blister review but, I think Luke would come with me on that.

Yep, I'd agree. The Pioneer does not feel hooky or like it has a tight radius on firm snow, but is super easy to slash around in soft conditions.