Hybrid Bicycles - skinniest tire acceptable on Trek 7.4 FX?

I'm going to be doing a sprint triathlon next month using my 7.4 FX
It came stock with 700x32c tires (Bontrager Nebula rims)
How skinny of slicks can I put on these rims? (it's Easter Sunday so all my LBS are closed)
I see on the triathlon forums people recommend going with 23 or 25 mm slicks. Just want to make sure I am safe going as low as 23mm?
--Thanks

Look on your rim for a sticker that says 622 x some_number (unless you've taken the stickers off). That number is the rim width.

Then go to this page and go to the colorful chart at the very bottom to see what tire sizes will work.
http://sheldonbrown.com/tire-sizing.html#width

Man I love BF!
Thanks a million for the super fast reply + info
My sticker said 622 x 15
According to that chart I can safely go as low 23. Sweet!

Time to order some slicks now. Any recommendations?
The current 32mm tires are the skinniest I've ridden on. I've always ridden MTBs

Lots out there; you're looking for raw speed? You're not likely to want to change rims/go to tubulars etc., so probably Continental GP 4000s (would be my choice; I use the 25s as an everyday tire) or Michelin Pro3 (or 4?) a very good bet ... whatever you can get your hands on. Any 'race level' clincher from the big names (Conti, Michelin, Vittoria etc etc) will do you fine.

Yes, I think I'll aim for raw speed but maybe with some control and puncture resistance.
I'm not a daredevil so the idea of leaning into a corner doing 30 is too fast for me right now.

Also yes, I'll stay with clinchers.
I'll check out those Contis you mentioned and Michelins as well.

Thanks for the advice

Go for 25mm tires. That's what everyone in the Road Cycling forum is going after these days. If you are looking for speed, you won't want really heavy, durable road tires. With less weight at the rims, you will be able to accelerate faster. You'll have more flats, though. People in the Road forum really like Continental GP400s. You might check out some tire threads on that forum. The folded tires weigh less, but cost more.

Excellent --- thanks a1penguin. You have *perfect timing... I was just about to place an order for 2x23mm Vittorias.
I'll check out the road cycling forum.

Gee, 2nd rec for Cont GP400s (badger1 too)... hum!
Thanks guys

Oh wait, badger1 recommended the GP 4000 whereas a1penguin recommended GP400
Typo on one of these or are there really a 400 and a 4000?

Probably just a typo ... a1penguin meant GP 4000s, I'm sure. I also agree with a1penguin re. the 25s; you've probably no real reason to go to 23s at this point. One other point: don't be tempted to use ultra high pressures (i.e. pump 'em up to the max!) ... use proper pressure for your weight (just search "Psimet's tire pressure chart" on BF for a 'calculator'). Fewer flats, better grip, and (yes) lower rolling resistance.

Cool - thanks for the clarification. Makes sense, as I was seeing a lot of glowing reviews for the GP 4000s.

I'll heed both of your advice on the 25 vs 23mm choice, and tks for the pressure chart/info. I'm not one of the typical light bike jockeys out there... =)

Yep, I made a typo. GP4000s. I'm going to try those after my Ultragatorskins wear out. 25mm for me! But check out the Road Forum and decide what will work best for you.

Thanks a1penguin. Appreciate the correction and recommendation. Good stuff