Light stuff in the roof box is a definite! The trailer doesn't want to be too light,but should have a max limit plate on it,so keep it below that. There should be info for the nose weight too. The focus estate has stiffer suspension at the rear than the hatchback and ease of loading plays a part,so best for things that are hard to lift. Delicate stuff is better in the car too,and anything valuable. Kids go in the back seats with the dog,wife in the passenger seat with map and bag of sweets,you sit behind the wheel with your earplugs.
If you are not sure about loading your trailer, take it to a public weigh bridge when loaded, to check you have not overloaded it.
Also check the nose weight, is not above your cars capacity, at a guess I would say 75kg max for the Focus, but your car handbook will confirm the figure.
You can check the nose weight using bathroom scales, decent nose weight checker costs around £25 the Milenco model seems to be about the best.
My concept of nose weight is that if I can't lift it, its too heavy. My car's nose weight is 80kg. We loaded the trailer in a balanced manner, the tent across the axel, the poles (roughly the same weight) went across the axel as well. Then we put weight at front, equal weight at the back and so on until it was full. Result was I could lift the nose. Check your tyre pressures are correct, remember its not the tyres which carry the weight its the air pressure in them, and also check the tyre temps for the first hundred miles, they should be less than or around the same temp as your car tyres at least. If they are too hot then you probably are under-inflated... And don't forget 50mph single carriage ways, 60mph dual/motorway.
As to where to put the weight, put it in the trailer as much as you dare. If your car feels like its being mauled to death or you can't accelerate then think about moving it back into the car, but don't put much more than 60-80kg in a roof box (check your car's roof bar specifications)
Thanks for the advice astronomypete I have checked load weight for roof basically have a max of 50kg in the box. Looking at putting the tent in the trailer but can't get secure cover for the 102 only the tarp type. Was thinking of fitting some ply to the top and locking it down to make it a little more secure.
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