Ah – fair dos! In terms of what to wear under it… for an Oly, I’d go for a two-piece tri suit so you can stop for a toilet break if necessary. If your bladder is strong, go for a one-piece and hope you don’t need to pee during the run or bike.
The problem with an Oly (and indeed a sprint) is that you won’t be able to get changed – there’s usually a “no public toplessness / nudity” rule in place, and organisers often won’t bother with a tent, so you’re stuck wearing one set of kit through the whole thing.
If you don’t have tri kit and don’t want to spend, then I’d suggest lycra running shorts and probably a cycling jersey. Road bike is only 40k so just over an hour, shouldn’t be too much chafage going on, and the jersey will be useful with pockets and such for gels. As darcy says, bib shorts are great for the bike but will probably have too much padding for running – and the thicker padding will also retain a lot of water from the swim (more chafage!)
I suppose a better question would be – what kit do you have now that you’re comfy running or cycling in?
