My v-brake lever (just one) is stiff. What's wrong? After tuning my brakes a lot (I was learning how) I noticed suddenly my back brake got really stiff. Does't really matter if the cable is loose or not, the lever itself feels really hard to pull when comparing to the front brake. What could cause this? The cable (since I don't mind cycling when it's raining, maybe it's rusty? but I got the bike for like 3 months) or the lever itself?
Sounds like the cable is not routed properly. Unhook the outer going into the brake level and slide it way from the brake lever - the lever should be free. If not, pull the cable and see that its moving freely all the way to the the brakes.