Cycling shorts for a Tri

You can, but you're going to feel like you're wearing a diaper when you get out of the water.  It'll slow you down.

My recommendation: Wear the tri shorts

Ever tried to swim with the bike shorts? Ever try to run with them?
I tried on bike shorts for one ride and cannot imagine how people can ride in them for any length of time

I'm sure I can find the answer to this somewhere but for someone starting out riding and having already been prefessionaly fit.  When I wear the "not as padded" Tri shorts after about 15 minutes "things" start to go numb.  Like I had to make an adjustment to feel comfortable and I lost osme sensation.  This scared the crap out out of me.  I jumped off the bike and with in a few seconds it was back.

If I keep doing this to myself are there any long term affects?

I'm not sure what kind of padding your cycling shorts have but mine don't absorb any significant amounts of water.  It's not like they have sown in a 50 cent sponge into the shorts.  I have not worn my cycling shorts for a tri since I have only completed a tri-a-tri so I did the entire race in my jammers.  I have done bike-run bricks with the cycling shorts and there was no noticable time difference in the run.  You can feel the padding so it is something to get used to.  The worst part is having to tell everyone you see that you haven't crapped your pants.

I'm going to use them on my next sprint.

Edited by Mrdaner 2009-07-22 9:22 AM

Although I will say that looking back, I would have purchased tri shorts instead of my cycling shorts.  Right now I am saving every nickel for a bike so I will stick witht he cycling shorts for now.

I just got used to cycling in my tri shorts. I now wear tri shorts 100% of the time (even on centuries) with out any discomfort.

I just did my first bike with tri shorts last night after biking in just regular shorts always before and I loved them.  My rear was so much less sore last night and there was none of the typical numbness I'd grown used to. 

Yes, you can, but as some others said, not recommended.  I have both tri shorts and bike shorts, and frankly don't really notice much difference, even on long (100+) mile rides.

And if you are going numb in 15 minutes, then something is wrong, and I'd strongly suspect your position on the bike (i.e., your fit), 'professional' or otherwise.

Agreed, if you are going number I would suspect your saddle position is not right.  I prefer cycling shorts for just riding, but when training on the tri bike and racing tris I will always were tri shorts.

my friend wore her cycling shorts for the last tri, and it was the run that got to her. A huge section of her upper thigh was chaffed raw during the run. Granted, she had cheap bike shorts, so maybe with quality ones you'll be fine.

Another friend of mine runs in his cycling shorts and he's fine, but he also has 0% body fat so there's less to rub, I suppose.

I have done three 70.3 races and all of them in bike shorts.  If you don't want chaffing while on the run, apply body glide liberally to the back of your thighs and other sensitive areas before the start of the race.  I've had no issues with water soaking into the shorts.  All those fluids pretty much dries up after 30 minutes on the bike.   I've done them in both ocean and fresh water swims.  All of my swims were wetsuit swims so I doubt whether anyone can tell/feel the difference between bike shorts and tri shorts during the swim when they have wetsuits on.

I guessed the bottom line is wear whatever it is that you are comfortable in.  If you are comfortable in wearing the bike shorts then do so.  Why fix what ain't broken ?