Why are mountain bikes always sold with mud tires?

Simply,it's because you're buying a specialist bike where mud tyres would be an advantage,and using it for another purpose..if you want a bike for road use,they'd expect you to buy a road bike instead.I get your point,where MTB suspension would be good for soaking up bumps and road damage when commuting..I bought an MTB before because it was an inexpensive purchase,but the upright posture didn't suit Me..and I didn't like the tyre noise! Dunno if I'd have liked it any better (or kept it!) if it had the option of road tyres or I'd tried replacing them..I suppose you COULD get road tyres for an MTB..I've never looked for them,but I've only seen replacement mud tyres available..and you could try selling on the mud ones if you could get road ones,getting some of your money back..

You will actually find that a lot of the low end mountain bikes, are sold with an on/off road tire like the AlphaBye or some knock off of this. These tires have a strong center bead so that with higher pressure you just ride on the smoother center line of the tire, but if you run a lower pressure or on a softer surface you get a little more bite. The Higher end mountain bikes are expecting to be performance mountain bikes rather than commuters so they typically will stock a more specific off road tire. WalMart bikes always use a beefy tire because Walmart is selling what looks cool but doesn't work rather than functional pieces of equiptment. Also you will note that many of the race tires are starting to use a more minimalist tread like a Kenda Small Block 8, or a Continental Race King. THese look like they should be fast on the road, but you will find that they will just wear out fast if used that way. If you truly want a street tire on your mountain bike, your shop will probably just trade you tires at purchase, so you don't have to wear out a tire you don't want.

I assume it is because most of the back country bike trail is full of mud and make of rocks and gravel. This type of tire is a better choice for the rider and serve the original purpose of the design. The commonly used tires on street bike may not last long on a mountain bike if they are put to use under this type of bike trail. The manufacturer may not know that his buyers will never ride their bike on mud road instead on public street and concrete road only.

Get a racer bike instead. They don't come with mud tires. Or you can opt to set up your own mountain bike. My brother does that. he buys parts individually and set it up himself.

First of all dear, I think the reason why they sell mountain bike with mud tires on them is that they expect you to go on dirt roads. And the other reason is that you might want to ride in snow and it gives more traction. And the other reason can be just for the look, like usual. That is about it for my opinion.