Getting Heavy Rover/Mobile Base into space

[locustgate]

So I've recently built 2 heavy rovers, 1 is meant to be a mobile base and the other is for mining Kethane. I'm just right now trying to test both of them on different environments, on kerbin. However anytime I put either on a rocket, it immediately goes flying towards the direction of the wheels, and it ends how you would expect a giant vehicle with a rocket strapped to it.

[Pecan]

When you build your rocket under the rover make sure you have a probe-core that faces 'up' and ensure you 'control from here' on that part when you launch so your navball is pointing in the direction you want to go. As long as you balance the Centre of Mass, point in the right direction and have enough thrust and deltaV you will go to space today.

[Specialist290]

As Pecan already touched upon: When building your launcher, make sure that your rocket's thrust goes through the Center of Mass of the combined vehicle. Otherwise, it's prone to turn cartwheels.

[locustgate]

When you build your rocket under the rover make sure you have a probe-core that faces 'up' and ensure you 'control from here' on that part when you launch so your navball is pointing in the direction you want to go. As long as you balance the Centre of Mass, point in the right direction and have enough thrust and deltaV you will go to space today.

Decreased from near instantaneous to it occurring about 3 secs after launch.

[Boomerang]

What Pecan said. Also, if you're trying to mount the rover with the long axis of it parallel to the long axis of the rocket, you're going to have one hell of a time trying to balance/correct for that much asymmetric mass. So build the rocket beneath the rover in the orientation that it sits on the ground in. Decoupler underneath the chassis, presumably a skycrane on top.

[Pecan]

Add a reaction wheel to help stop the thing falling over, struts to keep it all stable and not wobbling around. Do you have too much thrust? Over about 2.5 TWR can cause all sorts of unpleasantness up to tearing the thing in half. You have cuploas on both those? That's a very heavy part so make sure that's at the bottom of the rover at launch or all its mass will be right at the end - which makes all my rockets flip as soon as they move from vertical.