You can run them in your radio no problem. Low 11s is where mine is at after a full charge too.

I would recommend against using them in a truck though. Not enough voltage. That's why everyone goes from 4 aa's to humppacks. Humppacks have 5 batteries in there, which make up for the fact that rechargeables are 1.2v verus the 1.5 from an alkaline. If you wanna use nimh batteries in your truck, use 5 not 4 (pretty much making your own humppack at this point).

Transmitters are much more tolerant in the low voltage department than receivers. Even the cheaps will throw a low battery warning low before it actually shuts itself off. You don't get this luxury with a receiver unles you have a strong throttle return spring to center a powerless, stuck at wot servo.