Mountain Biking - Sorry, but a newbie in need

I've used the search function but maybe I just don't know how to word my question. I just got a Trek 4500 and I was wondering what all you could mount to the frame using the existing hex bolts (besides the obvious water bottle cage). Maybe a bike lock?

most bike locks mount to the vertical "seatpost" tube on your frame. Preferably get a u-bolt type lock, and some sort of cable as well to lock down your seat, suspension fork, etc.

If you have eyelets around your rear wheel mount, you can add a cargo rack.

Most lights and such mount to your seatpost and handlebars. A cycle computer mounts to your handlebars and one downtube on your fork (your choice which one).

Really the possiblities are rather diverse. I've seen guys fit laptops in the open portion of their frame using bungies while commuting before (don't try it...it just looks like an accident waiting to happen). Just gotta compare what you are installing carefully to your frame.

I'm not sure about locks. I have a Planet Bike U-lock. The mounting bracket does not attach to the bottle cage braze-ons, but wraps around a frame tube.

There are mini pumps with brackets that mount to the cage braze-ons. Usually the bracket is designed to mount under a water bottle cage.

There are also CO2 inflation systems that mount the same way.

I recently saw a water bottle cage made by ToPeak that was designed to carry a 2-liter bottle of convenience-store water.

Oh yeah, I've also seen a sound system with speakers that plug into the ends of the handlebars, and a special bracket for a walkman that attached to the cage braze ons.

Thanks. Are mounting points (for bottle cages) the same distance apart on most bikes? In other words, will just about any bottle cage that has mounting tabs with holes fit on most bikes? Sorry for the dumb ?'s but I have no local bike shop and pics on the web are not too clear.

There is a slight variance, but usually one tab has a round hole and the other is ovalized to compensate for the minimal differences.

L8R

Yea, there is usually a small difference but one mounting tab will be a slot allowing for varience.

Thanks. Now if I can find a pair of training wheels that will fit this thing, I can get started riding it.

you could mount one of thos mini bike pumps