Roll Bar Question with pics

It looks like the previous owner didn't bolt down the roll bar it has just been welded. I'm not sure this thing will save me if I roll my car but it's better than nothing I guess. Do you guys think I should bolt it to the frame while I have all the carpet out or is the weld good enough?

Looks to me like it's only welded to the body, which will tear easily if you actually need the bar. If you can bolt it to the frame, it would provide more protection in a rollover.

But I'm not convinced it would be enough more to worry about unless you also build a more elaborate roll cage.

The ideal scenario is to put matching plates on the bottom of the underside. As ideal as it can get for this type of roll bar, that is.

Yes, I have one, so I can say that.

Agree with Paul, at least put a plate underneath the body tub. Will make it stronger.

Marv

Plate, bolted and welded................belt and suspenders don't you know.

Right....the hard part is the welding and it's done.

Those welds look like c**p.
I guess that's a TR6.
That car has a frame close under the back "seat" (bench) but not close enough to bolt to.
FIA racing rules are not eligible here but they normally require plates 120 cm² both over and under the body metal. But the mounting points for that bar are not anywhere near good enough to provide any type of roll over protection worth naming. The bar is basically for looks only.

If you're concerned about rollover protection, the minimum bar should be mounted to the floor/frame between the front seats and rear bench, have rear bracing that goes through the body to the chassis under the gas tank, and have a diagonal bracing.

This one would be good enough being a street bar with a diagonal
https://www.paeco.com/Rollbars%20and%20Cages.htm

Not that a minimum bar would be enough, but if you were unlucky enough that the car rolls over, like for example you accidentally fell off a mountain road, it would definitely save your head.

For other types of accidents it wouldn't be enough. But we don't usually drive that fast, do we?
example: https://autoholics.com/2011/11/07/Hemi--Cuda-Fatal-Accident-in-Delaware--580200

Even if you built a NASCAR spec cage for your TR, it still wouldn't save you in the type of hit that Cuda took.

As to whether or not to strengthen your mounting points, it's certainly a doable task. From a pragmatic standpoint, do you ever drive in a manner that would require rollover protection? If the answer is "Yes" and protection is a worry of yours, then you probably want to pull out what's there and cage it. If the answer is "No" that you drive these cars with the same alacrity that most of us drive our TR's, I'd say you are good to go.

If you do bolt plates up underneath, be sure to make them bigger than the existing plates. Same size plates will act like a shear and rip through the sheet metal.

What you should be concerned about isn't the 'Cuda style accident, but more like the "casual" rollover

Are they proud of this feat?

I don't think they were in that car when it ended up like that. I don't see any wet areas on there jeans!

I don't know where the frame rails are underneath, but bolting the bar to a set of plates under the sheet metal and then welding the plates to the frame using a crossmember is how I would do it.

As can be seen here, the chassis doesn't come completely to the rear bench. But like you said, plates raised and welded to the crossmember and the bar bolted to them might do the trick.

But please, welding only to heavy metal, not to sheet metal. the HAZ will be brittle and crack immediately under stress if it isn't broken already.