HIM - Bike shorts or Tri Shorts?

whole race tri shorts.

Definitely tri shorts the whole race.
Practice a long distance beforehand in them so you know if you need to "lube up" in any surprise places.

 

Tri shorts.

Before my HIM back in 2007, I made sure to ride with my tri shorts for a good month ahead of time... to break my rear in.

I was fine race day. It wouldn't have been worth changing into bike shorts. There wasn't a changing tent so I would have had to go to a port-o-john (aka: 10 minute transition).

x4 tri shorts

for my upcoming HIM in T1 i'm putting riding shorts over my tri shorts (it's what i've been doing in training)  for doubled up padding and then in T2 i'm sliding them off and running in my tri shorts.

Definitely TRI Shorts or TRI Suit for the whole HIM. One less thing to worry about and manage during the race. Like everything else"nothing new on race day". Do a few long rides in what you are going to wear on race day. By doing some long rides well before race day in my planned race outfit, I found I needed to switch saddles to be comfortable in my Tri Suit for the 56 mile ride. I switched saddles and did a couple of more long rides to be sure I was good to go. I did a short swim before one of the rides to make sure there was no issue starting out in a wet tri suit. Also did a few bricks in my TRI suit to be sure I was OK on the run as well.

I really like the Oomph Tri shorts.  I used a model with the "distance" pad and it was super comfortable for the HIM ride and run (dried really quickly after the swim, too).  I think they are more comfortable than any bike shorts I own.  Got mine at on ebay for half price...and bought 2 more.  Thanks Kathy G!

TRI shorts for me. I use 2XU. Done 2 HIM's with them and i was persoanlly fine

Thanks for all of the advice and the overwhelming concensus. I was thinking Tri Shorts but just wanted to be sure. I will definitely do a few longer rides in them now that I know I will be racing in them as well. Thanks everyone.

I don't even own a pair of bike shorts. All rides in tri shorts and my one HIM in tri shorts. I don't think I'm going to own a pair of bike shorts either.