Question: Do those of you who keep bikes in your car have any worries about them getting damaged from the heat?

We have the front fork-lock set-up in our car and I used to keep my old bike in there all the time, but I've been reluctant to leave my new bike in the car in the summer because I'm worried that the heat will mess it up. It's a mountain bike so I guess the tires would be alright, but I haven't wanted to take the chance. Any thoughts?