[TaxSheemaSter]

In the US, tiles are rated for coefficient of friction, moisture content and hardness. The coefficient of friction will determine how slippery they'll be, moisture content is for freeze/thaw issues, and hardness is a PEI rating which has to do with some commercial building codes. I put tile in my garage, and it was the first tile setting I had ever done. Four years later, I'm still very happy with it. It's a great floor option for a garage.

As others have indicated, cracking is an issue with the way the tile is installed, not (generally) with the strength of the tile itself. Usually, your tile will be stronger than the concrete it's sitting on. But like concrete, it's very strong in compression, but weak in tension -- which means that any void will create a potential area for cracking. So you 'double-butter' both the floor and the tile to get the kind of coverage Givadogahome is talking about.

Here's a video showing my hitting my tile with a four-pound sledge hammer. You can see it makes the camera jump.

Tile Strength - YouTube

My concrete pad was poured in 1925 and had suffered a lot of earthquake-related heaving in its lifespan. I did not make much of an attempt to flatten it out, but I was careful to bridge the more severe elevation changes. I'm very happy with it. Here's a picture, although the site will apparently not let me post pictures.



There's more information about the garage at The 12-Gauge Garage