HED Goes Deep with the Jet 180 - Slowtwitch

You may find Lionel Sanders and other HED-riding athletes aboard a radically deep rear wheel at the IRONMAN World Championships in Kona in a couple of weeks.

You'll only find the Jet 180 used as a rear wheel in Kona.

There is no good evidence I have seen showing that a disc on the rear is dangerous in Kona.

(Indeed, discs are legal in most other IRONMAN races.) However, a front wheel too deep is problematic in windy conditions, and Kona doesn't have a depth restriction on front wheels.

Most Kona veterans would probably say that a disc on the rear in that race is way less dangerous than, say, a 120mm wheel on the front.