HYROX · Gym-to-race load converter
Your gym sled is lying to you.
HYROX is raced on high-pile event carpet — one of the grabbiest surfaces a sled ever meets. A 152 kg sled on rubber gym flooring pushes like roughly 103 kg on race carpet. The Sled Truth Calculator converts your training load into race-day drag, then prescribes the exact plates that make your gym sled tell the truth.
Your current push, translated to race carpet
— kg effective
Full blueprint · locked
The fix is behind the start line.
You've seen the gap. The full blueprint closes it: the exact plates to load on your sled for your surface, your target total, your race-readiness verdict, and the complete drag table.
Locked: plate prescription · target load · readiness verdict · drag table
Full performance blueprint · unlocked
—
Target gym total
— kg
Change vs today
— kg
Load this on your sled
Rounded to real 2.5 kg increments. If the prescription exceeds your sled or plate stock, get as close as you can and log the shortfall — the gap is information, not failure.
The drag table
| Setup | Total mass | μ effective | Drag (kgf) |
|---|---|---|---|
| Gym — today | — | — | — |
| Gym — prescribed | — | — | — |
| Race day | — | — | — |
Re-run this after every surface change. Friction is a moving target.
Sports science, shown working
How this works — the friction math
A sled moving at steady speed resists you with kinetic friction: the drag force equals the friction coefficient of the sled-surface pairing times the total loaded mass times gravity. Because drag scales linearly with both μ and mass, two setups feel identical when their μ × mass products match. That gives an exact conversion:
drag ≈ μ × mass × g → gym target = race mass × (μrace ÷ μgym)
| Surface | μ kinetic |
|---|---|
| HYROX-style event carpet (high pile) — race baseline | 0.62 |
| Thin commercial carpet | 0.50 |
| Rubber gym flooring | 0.42 |
| Concrete or asphalt | 0.38 |
| Artificial turf / sled track | 0.32 |
| Hardwood / court | 0.30 |
| Base | Modifier |
|---|---|
| Bare steel skids | × 1.00 |
| Powder-coated / painted steel | × 0.95 |
| Plastic (HDPE/UHMW) skids | × 0.85 |
| Division | Total |
|---|---|
| Women Open / Women Doubles | 102 kg |
| Men Open / Men Doubles / Mixed Doubles | 152 kg |
| Women Pro | 152 kg |
| Men Pro | 202 kg |
Honest limits: coefficients are representative mid-range values drawn from published sled and material friction estimates — your exact floor varies with pile height, wear, dust, humidity, skid finish, and push speed. Breakaway (static) friction runs higher than the moving values used here, and wheeled resistance sleds (Tank-style) are not friction-dominant, so this tool does not model them. Treat the output as a calibrated starting point, then confirm by feel and split times.