Springs need to be matched to the weight of your garage door, so that the lift of the spring matches the weight of of the garage door, and the door is balanced.  When the door is opened half way, and you let go of it, the door should not move (within reason).  When you close the door, it should not jump off the floor, and it should not be heavy to lift either.  That being said, to match the correct spring to your door, you can sometimes find the original manufactures tags that indicate the strength of the spring, or you can weigh your door (without springs attached).  The spring strength is equal to the door weight, for example a 150 pound door takes two 150 pound springs.

Note:  Our standard freight charges are not always accurate for spring orders (usually for orders for more than 2 springs - due to their weight).  After receiving an order, we may contact the customer to collect an additional shipping and handling fee.  You can E-mail us for a freight quote if you wish.