I've just finished installing my new traveller cars from Garhauer. I believe that the original lines were 5/16 ,does anyone know what the recommended size is for the new cars?
Use 5/16, if you run them all the way back to cam cleats on the aft end of the coach roof, you'll need a tad over 27 feet each side -- of course, measure yours, mileage may vary.
They'll take 3/8, for the "better hand" but what happens is the line starts to fuzz up and expand, and they get caught in the sheaves. Because of the superior mechanical advantage, the thicker line is totally unnecessary.