Fitting Roof Bars and weight worry question- 300tdi

So - I fitted the genuine roof bars to the Disco after giving them a spray tidy up.

I you are attempting this, I just can't see how you can do it well without taking the whole roof lining out ( I did read a post suggesting bending back the trim but that was asking for major lining damage). It doesnt take that much longer to get it out and after that access is great.

Plus you can clean it while it's on the dining room table...

First , with the bar upside down, INSIDE the car - check and DOUBLE CHECK you have the right holes...

I drilled a pilot hole up through the roof, through the support bracket.
Then drilling down up to a 10mm drill bit.

You now need to open the hole in the roof scin up to about 1" (bigger than a £2 coin)
This is a BIG hole and I used a die grinder with carbide cutter which did it in a few mins per hole. A metal cutting hole saw might also do a decent job, in which case suggest you don't open up the hole with 10mm drill bit as you'll need a guide. Just make sure the locating disc is truly dropping through the roof skin - you should be able to compress the foam down as you push.
Run in some undercoat onto the raw edge and then I slabbed on plenty of roofers mate tar gunk.
Drop the bars in and bolt up from the inside and swear a bit while you put the roof lining back in...

So here's my question:

I put in the 3 cross bars. They are held with plastic spring loaded pins.

I then bolted up my Thule Vision 650. This is 7.5ft long... Max load 70kg to the front and rear cross bar.

The Disco manual says 50kg max but those cross rails just don't look very solid to me and have a fair bit of give.

Has anyone actually broken these? Are they tougher than they look? Slightly concerned. Do people just ditch them and put proper heavy cross bars on?

Phil

Ratchet strap under the side bars and over your roof box. This will stop your roof box flying open leaving the motorway covered in the good ladys skimpys and give extra securing or under the top box and through what ever mounts bars or holes are under the box this will mean you are not relying on just the cross bars for securing. The heaviest thing I have ever straped to the roof bars was a large inflatable raft about the size of the roof but to be honnest its not even close to 50kgs.

oh - thats a good idea. The box is a 7.5ft long thule thing with loads of lock points so not worried about it flying open.

But strapping it so the main roof rails directly is going to hold it really solid though.

I'm also going to move it right over to one side against a roof rail - that way it will reduce the bounce it seems to have on the cross bars.

Will keep the skimpies in the car just in case....

please keep yer roof box locked

Thems make a nice pair of curtains or a cracking catapult for firing cannon balls