Openai/696d4fbf-cd9c-8002-851c-19bcf98e97fa

This conversation was exported from ChatGPT

gpt-5-2

User: You are somewhat newly disabled and cannot bear any pressure at all on your feet and ankles.

You are somewhat newly disabled and cannot bear any pressure at all on your feet and ankles. You still have full strength in your core, hips and upper legs, and are trying to find a way to rig your snowboard to ride, so you are standing on your knees the same way you would on your feet. a way that would cup your feet behind you, almost touching your behind. You have already looked into the adaptive gear available, and they don't interest you because you spend enough time sitting in your wheelchair.

I want you to provide me with several different ideas and details for a different options.

Assistant: Got it.

Got it. You want a kneeling ride setup (no load on feet/ankles), with feet tucked behind you (almost to your butt), while still using your core/hips/quads to control the board. That’s absolutely a thing you can engineer, but it has to be done with a lot of attention to safety because your knees/ACL/MCL/hip flexors will be taking forces they were never meant to take on a snowboard.

Below are several solid design directions (from simplest to most “real build”), including how to keep your feet tucked, how to mount you to the board, and what you’ll need to stay stable and steer.

Non-negotiable constraints (so the ideas actually work)

If you build any of these, these points matter:

1. Your knees need a platform, not just pads. - Snowboard forces are torque-heavy; pads alone twist your knees. - You want a rigid “knee base” that spreads load from knee down the shin.
2. You need a “shin-to-board” connection, not “knee-to-board.” - Steering will come from hip + core rotation coupled into the board. - Best control happens when the tibia/shin is locked relative to board.
3. You need a bailout plan. - At minimum: quick-release buckles. - Ideally: “you can eject in 1 second without pulling a strap through a loop.”
4. Boots should be along for the ride, not bearing weight. - Since you can’t pressure feet/ankles, your feet should be in a cradle/cup behind you.

Option 1: “Knee-binding conversion” using snowboard bindings + shin cuffs

Best overall starting point because it uses snowboard parts that can handle the forces.

Concept

You mount two kneeling platforms where bindings normally go. Your shins go forward, your knees sit on a supported platform, and your feet tuck into a cup behind you.

Parts

• 2 snowboard bindings (for baseplates + mounting hardware)
• 2 motocross knee/shin guards OR hard-shell shin guards
• Dense kneeling pads (EVA foam / closed-cell foam)
• Aluminum or HDPE plate as a knee platform
• 2 quick-release ratchet straps per leg

Build details

• Remove highbacks (or keep them and repurpose).
• Bolt a flat kneeling plate to the binding baseplate.
• Add a wedge so your shin angle is comfortable (think 10–20 degrees).
• Strap your shin guard tightly to your shin, then strap the shin guard to the kneeling plate.
• Add a rear heel/foot cradle: - A U-shaped cup behind your calf that holds boots tucked back. - The cradle should have padding and a top strap so your boots don’t bounce.

How you steer

• Rotate hips and drive shins into the fixed shin cuff straps to tip board edge-to-edge.

Pros / Cons

• ✅ Strong, durable, uses snowboard mounting pattern
• ✅ Highly controllable
• ❌ Still hard on knees if the platform is too small or soft
• ❌ You must build the right knee platform geometry

Option 2: “One-piece kneeling sled deck” (your own rigid kneeling chassis)

This is the cleanest mechanical solution if you’re handy.

Concept

Instead of modifying bindings, you create a single rigid kneeling deck that spans both mounting zones (like a bridge). It mounts using standard binding inserts, and your knees land on a single strong surface.

Parts

• 1/4" aluminum plate or layered birch plywood sealed with epoxy
• 2–4 insert mount points (binding insert pattern)
• Thick closed-cell foam pads for knees
• 2 shin cups / shin clamps (can be hockey shin guards)
• Rear foot cup (foam + strap)

Build details

• The kneeling deck should extend from just behind the front inserts to just behind the rear inserts.
• Add raised ridges on both sides of each knee to prevent lateral slip.
• Add a center spine under deck (aluminum angle or wood rib) to prevent flex.
• Use two shin clamps at each shin (one near mid-shin, one near ankle area)
• Feet tuck back into a padded boot cup.

Pros / Cons

• ✅ Best load distribution and knee protection
• ✅ Most stable
• ✅ Can mount stronger ejection releases
• ❌ Most fabrication work

Option 3: “Hard-shell knee bucket + shin lock” (maximum knee stability)

This is like a prosthetic-level solution.

Concept

You build knee “buckets” (hard cups) that capture the knee and upper shin and prevent twisting. It’s the most protective for your knees.

Parts

• Hard plastic buckets (formed Kydex or modified kneepads)
• Hinged shin clamp (snowmobile boot cuff, hockey shin, or custom)
• Padding + gel inserts
• Board mount plate (binding baseplate or custom deck)

Build details

• Knee bucket holds knee without letting it slide or rotate.
• Shin clamp locks tibia rotation relative to bucket.
• Straps connect bucket assembly to board.

Pros / Cons

• ✅ Knee twisting reduced dramatically
• ✅ Very secure
• ❌ Hard to DIY unless you’re good at forming materials
• ❌ Heat forming Kydex / plastics needs tools

Option 4: “Rear-calf cradle to tuck feet behind you” (attachable add-on to any system)

This solves your specific request: feet tucked behind you nearly to your butt.

Concept

A padded cradle behind each calf that keeps the boots pulled up, like kneeling in a gym stretch.

Parts

• Thick foam
• Semi-rigid plate (HDPE or aluminum)
• A “cap strap” over the boots

Build details

• Position the cradle behind the calf/heel area, not behind the ankles (protect ankles from pressure).
• Add a top strap that pulls boots upward and inward.
• Optional: a single shared “boot tray” for both feet.

Pro tip

You don’t want hard pressure on the Achilles. Make the cup load on the boot shell, not your body.

Option 5: “Kneeling + outriggers” for balance while learning

If you’re kneeling, balance is different. Outriggers can make this workable.

Concept

Add two small stabilizer arms with mini skis or UHMW pads so you don’t instantly slam.

Build details

• Hinged arms off a central kneeling deck.
• Pads should be slightly above snow when flat, and engage only when you tip too far.

Pros / Cons

• ✅ Makes early attempts possible
• ❌ Adds drag and complexity
• ❌ Not great in deep snow

Option 6: “Cable steering + kneeling lock” (turn by pulling handles)

This is how some sit-skis and MTB snowboard rigs steer, but you do it while kneeling.

Concept

You kneel solidly locked in, but steer with a handlebar/rope setup for additional control.

How it works

• A short handlebar on a post mounted on the board.
• Or a chest harness connected to lines to help turn (like kite control, but fixed).

Pros / Cons

• ✅ Gives you a second control input besides hips
• ✅ Helps prevent toe/heel edge washout
• ❌ Risky: handlebar can become a lever in a crash

Materials that work (don’t cheap out here)

• HDPE (cutting board plastic): great for kneeling deck surfaces
• UHMW tape/sheets: low friction underside or edges
• Closed-cell EVA foam: knee padding
• Gel knee pads: shock absorption
• Stainless bolts + nylock nuts: vibration proof
• Cam buckle straps or ratchets: with quick release

Avoid:

• soft couch foam (bottoms out)
• Velcro-only as primary retention
• weak wood without sealing (water wrecks it)

Biggest danger points (tell-it-like-it-is)

• Knee ligament injury is your #1 risk. Snowboard edge catches create twisting.
• Tibial torsion (shin twisting) is a real risk if your shin isn’t locked.
• Hip flexor strain is common with feet tucked hard behind.
• You need to be able to eject in a crash, or you’ll get levered.

If you attempt this at all, the safest first tests are:

• flat gentle slope
• soft snow
• low speed
• helmet + knee braces + padded shorts

If you want, I can design an actual build plan

If you tell me:

1. your board length and binding insert pattern (standard 4x4? channel system?),
2. your height/weight,
3. whether you want hard boots or soft boots,

…I can lay out a complete parts list + a step-by-step build for the best option (I’d recommend Option 2 + Option 4 combined).