Geeking out on ramp angle/delta.

[Shorty_J]

Bound to stir up some shit with those who don't care about these details, but whatever.

I've been thinking about how delta might affect my skiing, and wondering how (personal skiing style aside) certain ramp angles are better suited to different skis/mount positions. I have this feeling that a more neutral delta favours more centre-mounted skis and more forward mounts... since that mount position isn't as much about driving the tips as it is about a centred stance.

I have some old PX12 demo bindings that had a HUGE heel riser plate, and I removed it and shortened the screws and re-mounted... only to find a negative delta. Thinking that's not good.

So I can create a small shim with some plastic stock I have, and that creates about a zero ramp angle. Heel contact with the boot doesn't look great but it is held in there (binding probably designed for the positive delta it came with)... but it would be going on a relatively centre-mounted Praxis Powder.

Geek out... and... go!

[Snowy Spartan]

Take this shit to epic ski

[XXX-er]

I just took the red shims out of the FR+ on my JJ's becuz they felt different than the deadbolts that were on the ski for a couple of years, I felt I was too upright to get an edge in SO I just measured the difference between the front and rear of the sole and decided the delta needed changing, start with removing the front shim and I can add a little at the back if more is needed, with a short BSL removing a shim changes things pretty fast

Sure itsa little geeky but what else do we have ?

[Shorty_J]

Take this shit to epic ski

Ding ding... winner!

You been saving that one up since 2011?

[Shorty_J]

Sure itsa little geeky but what else do we have ?

Exactly. It's Friday night and I posted this. I clearly have nothing better to do.

[Dee Hubbs]

I ski P18s, and always have, and I have always liked the the flat (zero delta) ramp angle
On my touring set up I didn't like the ramp angle from my Dynafits. So this summer I set out to fix this.
So I put my alpine skis with P18s in the ski vise, made sure the skis were level, clicked in my boot without a liner and measured the angle of my boot board.
I recorded this angle, and have replicated the same boot board angle on my touring set up by shimming the toes of my dynafits.
I will now be skiing the same ramp angle on both my alpine and touring set up.
Is that geeky enough?

[Shorty_J]

I ski P18s, and always have, and I have always liked the the flat (zero delta) ramp angle
On my touring set up I didn't like the ramp angle from my Dynafits. So this summer I set out to fix this.
So I put my alpine skis with P18s in the ski vise, made sure the skis were level, clicked in my boot without a liner and measured the angle of my boot board.
I recorded this angle, and have replicated the same boot board angle on my touring set up by shimming the toes of my dynafits.
I will now be skiing the same ramp angle on both my alpine and touring set up.
Is that geeky enough?

Nice and geeky... thanks.

[Driver]

Bound to stir up some shit with those who don't care about these details, but whatever.

I've been thinking about how delta might affect my skiing, and wondering how (personal skiing style aside) certain ramp angles are better suited to different skis/mount positions. I have this feeling that a more neutral delta favours more centre-mounted skis and more forward mounts... since that mount position isn't as much about driving the tips as it is about a centred stance.

I have some old PX12 demo bindings that had a HUGE heel riser plate, and I removed it and shortened the screws and re-mounted... only to find a negative delta. Thinking that's not good.

So I can create a small shim with some plastic stock I have, and that creates about a zero ramp angle. Heel contact with the boot doesn't look great but it is held in there (binding probably designed for the positive delta it came with)... but it would be going on a relatively centre-mounted Praxis Powder.

Geek out... and... go!

I have been over obsessing on my ramp angles lately as well. Not enough snow in CA I guess. Agree that more delta could match better with a more aft ski mount. I believe the design of the boot itself - and how your foot is sitting in the boot - varies enough between boots to factor in. Not sure on that one, but seemed like a geeky thought to share.

Another thought - not all ramp angle is bad for all people. WC slalom skiers use positive angles, and tweak to match personal preference... I think I remember seeing some old plate bindings that had a 4mm height delta...

[auvgeek]

I ski P18s, and always have, and I have always liked the the flat (zero delta) ramp angle
On my touring set up I didn't like the ramp angle from my Dynafits. So this summer I set out to fix this.
So I put my alpine skis with P18s in the ski vise, made sure the skis were level, clicked in my boot without a liner and measured the angle of my boot board.
I recorded this angle, and have replicated the same boot board angle on my touring set up by shimming the toes of my dynafits.
I will now be skiing the same ramp angle on both my alpine and touring set up.
Is that geeky enough?

How thick did your shim end up being?

[vanisle]

Found going to a more forward mount and rockered ski ie. Hoji and Renegade that i preferred a flatter angle than my more traditionally mounted skis. Modified both 916s and Gaurdians with a thicker AFD and adjusted the toe height of the binders, much better now...

[Shorty_J]

Found going to a more forward mount and rockered ski ie. Hoji and Renegade that i preferred a flatter angle than my more traditionally mounted skis. Modified both 916s and Gaurdians with a thicker AFD and adjusted the toe height of the binders, much better now...

Thanks... This confirms my suspicion.

I had these PX demo bindings on spatulas and felt like I needed to move the bindings back to feel comfortable on them.

Powders are also fairly centre-mounted and I think being more neutral will benefit.

How neutral did you go with your shims... In mm difference between toe and heel?

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[mntlion]

other variables:

the bindings angle, is different then the boots angle.

changing the binding, keeps your boot (and ankle in the boot) at the same overall angles. you just are tilting the whole boot

changing the boot angle, on the inside, will change your lower foot angle, but keep the upper cuff at the same angle. If you add a heel lift, inside the boot, your shin is at the same angle, but your heel is higher, so the angle between your shin/foot is larger. This is "opening the ankle angle" in CSIA talk.

play with both, but they are different for some people.

yes I boot fit some geeks.

[GeezerSteve]

Dialing in the right RA can be very helpful for some people. There are no hard rules cuz RA preference varies with boot forward lean (FL), individual physiology and skiing style. I like a relatively upright boot, i.e., less FL, and a bit (5mm-10mm) of ramp delta (RD). (I have a long BSL boot, so 8mm of RD for me might yield the same RA as 5mm or 6mm of RD on a shorter boot.) But that's me and my boots. YMMV.

As ML, says, interior ramp angle varies from boot to boot.

Back in the day, more RA was nice on traditional camber (pre-rocker) skis cuz the RA helped you get the tips out of the snow, so 10 years ago I didn't mind the stock Dynafit 12-15mm RA on non-rocker tips in soft snow. But now that we have rocker tips the days of >10mm RA are long behind me -- although Dynafit didn't seem to notice and keeps putting lots of RA for most people in most of their bindings. No biggie. It's easy to shim Dyna toes.

[mntlion]

and the ramp angles are different based on boot/bindings size/length too.

10mm lift is more angle in a 260mm boot then a 360mm boot...

[Shorty_J]

Of course... Many variables.

But changing as few variables as possible, I think less delta favours a more central mount. Given the same boots, skis , physiology, etc.

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[vanisle]

Thanks... This confirms my suspicion.

I had these PX demo bindings on spatulas and felt like I needed to move the bindings back to feel comfortable on them.

Powders are also fairly centre-mounted and I think being more neutral will benefit.

How neutral did you go with your shims... In mm difference between toe and heel?

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Pretty sure both were around 5-6mm and im now at 2mm with a 298mm bootsole. Doesnt sound like much but the difference was significant. Went from feeling constantly backseat to nice and neutural. The solly are nice and easy to play with,just slide a piece of plastic between your boot and the afd, adjust the toe height and go for a rip to see how it feels...

[Shorty_J]

The solly are nice and easy to play with,just slide a piece of plastic between your boot and the afd, adjust the toe height and go for a rip to see how it feels...

I like this idea... might have to try that.

I have some thin plastic stock and debating on whether to put 1 layer or two... but your comment of going from 6mm down to 2mm being huge difference is great info to know while I consider this.

I suppose I can always put two thin sheets in and cut the screws to length, and if it's not cutting it, take one sheet out and cut the screws a bit shorter.

[LC]

Way too many variables. Just go by feel.

[Shorty_J]

Made some 1/8" shims and ended up with 0-1mm positive delta (tough to measure exactly with my short-armed calipers on 138mm wide skis).

Hopefully this should work well.

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[XXX-er]

I had a boot & ski that had previously been fine until I changed the binding and I couldn't get the ski initiation right so I measured the difference in mm boot sole to ski-top between front & rear of boot sole with a tape measure and then decided on how many mm I needed to add/subtract

so I started with removing the 3mm fr+ toe shim, I gotta wait for some actual snow to see if that is enough, if not I got some thin shimage for the back if need be

[Shorty_J]

I had a boot & ski that had previously been fine until I changed the binding and I couldn't get the ski initiation right so I measured the difference in mm boot sole to ski-top between front & rear of boot sole with a tape measure and then decided on how many mm I needed to add/subtract

so I started with removing the 3mm fr+ toe shim, I gotta wait for some actual snow to see if that is enough, if not I got some thin shimage for the back if need be

Don't forget longer screws (presuming you shortened the existing ones when you removed the shim).

[XXX-er]

yeah I checked 1st on the front screws so there was no problem with dimpling the ptex, for the heel piece I have a piece of PVC hose from princess auto to use as the rear shim and I will just use the same rear screws with some slowset & FG since we aren't talking > a couple of mm

[Shepherd Wong]

You have it backward. Generally the more upright the stance(created through ramp angles, forward lean and bootboards) make it easier to drive your hips forward and feel the front of the ski. The more forward leaning your gear is, the more your hips move back and you use your tails. This is how it generally works though but there are so many factors with body and technique that it's rarely so simple.

[Driver]

You have it backward. Generally the more upright the stance(created through ramp angles, forward lean and bootboards) make it easier to drive your hips forward and feel the front of the ski. The more forward leaning your gear is, the more your hips move back and you use your tails. This is how it generally works though but there are so many factors with body and technique that it's rarely so simple.

I was told by someone at Dynafit they create the angles because Euros like to ski more forward. To me it seems like there is a sweet spot of forward ramp and boot lean that puts you most forward. If it's too much, you'll be trying to compensate like you postulate. But if it's not enough you're probably not skiing as forward as you should be. Imagine a scenario where you are totally flat on the ramp with totally upright but stiff boots.

[rod9301]

Driver, upright and stiff boots will make very easy to pressure the front of the ski.
Any force that you apply to the front of the boot will be instantly transmitted to the bring of the ski.

Dynafit has it wrong. That big ramp angle causes you to stick yo butt out to remain centered on the skis.

Not a great position to make quick moves.
Most skiers today have an upright centered stance, from where you can move quickly forward or back, depending on needs.

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