Whats the difference between and corvette and an SUV. They both have tires and an engine.

Seriously though here is a basic list of differences between two bikes I own. A Trek Madone (race bike) and my Surly Long Haul Trucker (touring)

Both have tires and a saddle that I sit on.
Trek has 23mm tires pumped to 100psi. Can only fit a maximum of 27mm tires and that would be pushing it.
LHT has 35mm tires pumped to 65psi. can fit up to 45mm tires if needed. This means I can haul more stuff with the wider tires.

Trek has 3inches of drop from the saddle to the bars. Allows me to be lower to reduce wind resistance.
LHT has 2inches of reverse drop from saddle to bars. Nice upright ride, don't have to "look up" to look ahead.

Trek has a 50/34 double crank and a 12/25 cassette. Fine for pretty much anything as long as the hills aren't too steep or long. Would not be good gearing at all if I had 50lbs of gear.
LHT has a 48/36/26 triple with a 12/32 cassette. A really nice low gear with that 26/32 combo. I can climb anything and keep my heart rate below 150 if needed. Even with extra baggage.

Trek weighs 16lbs. Can haul a small saddle bag with a repair kit. lol. Anything else and I would be breaking the rules.
LHT weighs 30lbs but can haul probably 100lbs more.

Trek has no eyelets for racks or anything.
LHT has a bazillion eyelets for more racks than you'll ever need.

Trek is a simple pleasure to ride.
LHT is a simple pleasure to ride.