UK rules or ITU rules?

Are you age group or pro?

If ITU Age Group, no. Aero bars are not allowed.

Duathlon says

"This event is a draft illegal event and shall be ran in accordance with the BTF Rule Book."

Trying to read the rule book now. I had always assumed that elite and age group rules were the same.

It's the "Scottish Student Triathlon (SST) Duathlon Championships 2019 - Race Info"

Rule book says that aerobars for draft legal must have a solid factory bridge. So no, those won't work, you can't buy a set and join them yourself

Draft legal. No aero bars see page
17 of BTF rule book you linked above. there is a picture
Draft illegal . In section (iii) again on page 17 states rules.

If it's a non drafting race you can have them along as all ends of bars are plugged like normal handle bar ends for safety reasons. And don't go past the front wheel.

Hope that helps. If you need more help get back to me and I'll ask further up the chain. I'm a newly trained official. Might see you around Scottish events

It's not bars per se that tend to be illegal. It's having holes in the ends of them.

Thank you. Unfortunately my racing days are over but my son will be having a go in his first duathlon. I think this will probably be his only one as despite being previously done a bit of cyclocross he has been a runner only for the last 5-7 years.

At one time, the rule was that the extensions could not protrude beyond the brake hoods, but that may well be obsolete now.

---

29 years and counting

Will depend on the category... For age groupers, no aerobars are allowed in DL... For the Elite/U23/jr/youth DL, shorty bars can be used as long as they are bridged at the end and don't extend beyond that leading edge of the brake hoods... You can quickly check the length by using a hardcover book or a piece of wood touching the leading edge of the hoods to ensure that the bars don't extend too far (this is the method that the officials will use to do the bar length checks...).