Why are bobsleigh runners checked for temperature?
Officials' detail · The sled and officials · 3 of 4Warm runners glide faster, so they are checked before each heat. A reference runner of standard steel hangs in the open air from 45 minutes before the race, and a sled's runners may be no more than 4 °C warmer. If the reference is colder than -14 °C, the runners may be no warmer than -10 °C. Failing a second check disqualifies.
How it works
- Reference runner: standard steel, hung outside 45 minutes before the race at +18 to +22 °C.
- Limit: sled runners no more than 4 °C above the reference.
- Cold days: if the reference is below -14 °C, runners may be at most -10 °C.
- Where measured: on the side of the runner by the middle bracket.
- First check: in the parc fermé or start area, by start number.
- Over the limit: a second check right before the start; failing again disqualifies.
- No cooling: runners may not be touched with snow or ice to cool them.
- Display board: shows the reference, air and ice temperatures, updated regularly.
The glossary has the runner temperature, the parc fermé, the runners, the DQB, the start and the sled.
Tricky cases
A crew's runners are 5 °C warmer than the reference. What happens?
A second check right before the start; if still over, disqualification.
Can a crew rub snow on warm runners?
No. Cooling runners with snow or ice is not allowed.
On a freezing day the reference is -16 °C. What is the limit?
Runners may be at most -10 °C.
How is the sled moved to the check?
Carried, or pushed on its side on the bumpers.
Why the rule exists
Heating runners would melt the ice under them and cut friction. Comparing them with a runner left in the same air takes the weather out of the check.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Normal days | 4 °C above the reference | IBSF 10.11 |
| Very cold days | At most -10 °C | IBSF 10.11 |
| Hot days | Jury may order sleds onto snow before the start | IBSF 10.12 |
From the rule book
IBSF, International Rules Bobsleigh (September 2026), articles 10.11 and 10.12. Checked 14 October 2026. Official document: the IBSF International Rules, issued each season.