~59 km up, ~59 km down. The master rule is heart rate, not pace — pace is only ever an estimate, HR is the discipline. Times assume you're acclimatised on the day.
◆ The one rule: ride/climb to these HR zones
EASY <136 — recovery, descents, the very bottom warm-up
STEADY 151–158 — brief only; the early tar if fresh. Never above this on the climb.
Above ~3,000 m your HR will drop on its own even as effort rises — that's hypoxia. Don't chase the number up; let it sit lower and slow down.
set your gun time → checkpoints auto-fill
~10½h
Ascent
~5h
Descent
~16–17h
Total + stops
5,118m
Net relief
⚠ THE CRUX — 4,350 → 5,666 m. Your own line reads as ~29% average grade over 4.5 km on semi-loose scree, at full altitude. That's the hardest thing on the route by a wide margin and the single biggest unknown in these times. Two things: (1) check that gradient on the ground — a hand-plotted line can read steeper than reality. (2) This is where HR means nothing and patience means everything. Tiny steps, rest-step technique, do not stop dead (you stiffen and chill). If you're going to turn around anywhere, it's here, and that's a good decision, not a failure.