my lab is just to strong

Question
My lab ted is just over a year old and is a BIG lab he is both strong but also strong willed i started lead training at 6 months, i live in the county and he is fine on the lanes and comes when called and is perfect but the second i take him to town he goes deaf and pulls so hard and trys to trip me up he is perfect in every way bit this i have tired 4 different collars and harnesses and i just don't know what to do  

Answer
The problem is that the dog has not been trained to know that he has to behave in the town as well.  For instance, if you train a dog to sit in your kitchen for a treat, it won't necessarily know that sit means sit no matter where you say it, it just knows that sitting in the kitchen when you say the word gets him a treat.  When you first asked that same command in the living room or in your yard, it had to go through the process of learning that the command means the same thing in a different area.  

Part of socialization is that a dog gets exposure and learns commands all over, in different places and situations.  Town is DIFFERENT and very exciting compared to listening to you at home.  

If possible, I would take small steps and see if you can find a shop to sit outside of where folks come in and out of, that's different for your dog, and train him to behave with the distractions.  Then change that to training him, if possible, in a park with lots of children.  Take a trip to town for the sole purpose of training the dog for 15 minutes where all you do is sit him and let the people pass you by.  Bribe the dog with treats if necessary.  Start from scratch with your training but in a very distracting area so that the dog learns that when you say COME or HEAL or STOP, it doesn't matter WHERE you say it, he must obey.