Suggestion. My understanding is that these bars do not have a very thick wall material. The correct way to attach solidly to thin walled tubing is as follows:

Assuming that you wish to drill completely through the tube with a 5/16 inch drill to suit a 5/16 inch bolt you then need to have a piece of tubing which will fit neat over the bolt then measure the outside diameter of that tubing and drill a hole to enlarge one only of the previously drilled 5/16 inch holes, this will then allow the bolt with tubular sleeve over it to fit inside the tube of the sports bar  Simply mark and cut the small tube to lengthe which will be equal to the outside diameter of the bar less the wall thickness on one end  

Simply place bolt in through the side which is drilled 5/16 then insert the small length of tubing in through the larger hole and onto the bolt then attach item to the protruding bolt  

With the use of the anti crush tube the attached item will never come loose

This procedure is used when attaching tow bars to vehicles

Should you not have a large enough drill bit for the larger hole to accommodate the crush tube you can use a small round file to enlarge the hole 

I hope I have explained it clearly enough. Cheers Allen

When we bought our new Navara 4x4 ute last year we had a Nissan canopy fitted to it before delivery. The shiny ''chrome roll bar'' was removed. They asked us would we like to keep it & sell it on Fleabay, we said yes. The tubing wasn't much thicker gauge metal than a beer can. Sports, nudge bars are probably made of the same rubbish. I wouldn't be drilling holes in it as that would make it weaker than it already is. Clamping's probably the way to go.

Sports bars are only bling, there mounting points aren't capable of carrying any weight.

Agree that sports bars appear to be just bling - fashion before function. Although have seen a few with a rear bar for carrying pipes, ladders, kayaks etc.

I was planning to put a small shelf across the top of the tonneau. A piece of angle iron running length ways between the two bars on each side so I have something to put a shelf on. It's the angles of the bars that will probably halt this project.