Do these roll-over hoops (the ones behind driver and passenger seats) provide structural support in event of a roll-over? Or is it for aesthetics like the Mazda MX-5?

 

If the top of your head is well below the top of the hoop, they’ll provide some minimal protection, but they by no means meet the requirements of any sanctioning body for rollover protection. Better to keep your car shiny side up and rubber side down.

 

Ah sorry I should be more clear, I am asking because I am thinking about taking the car onto a track. The track requires that the roll-over bars are structural (for example the newer Boxsters) and not cosmetic (for example the MX-5/Fiat 124).

 

Pretending for a minute that they are structurally sound, as @Unhingd mentioned they have extend above your head for them to be viable protection in a rollover. Check out the broomstick test to understand:

 

Thanks for sharing that. The track told me to contact Jaguar dealership to find out if these structures are attached to the chassis of the car or not.

 

Just to note, even broomstick fail rollover bar is better than nothing if you roll over. Especially old Miatas bad for failing the test, as you have to be able to close the top.

 

Seems to me all you need to pass the broomstick test is to adjust the seat to it's lowest possible setting, scrunch way down in the seat and wear a low profile helmet!

 

I will agree that it's better than nothing. However in the spirit of the requirement and what it's protecting, it doesn't meet it since the head is still the highest point (i.e. first point of possible impact in a rollover).


That only works if you are short enough. Some people are just too tall that you cannot lower seats enough.

 

One of the HPDE groups in my area has a list of vehicles with convertible roll bars that are functional and those that are not. Jaguar roll bars of this era are supposedly functional, i.e. they do not require a roll cage. There are no references so take it as you wish.

https://autointerests.com/vehicle-requirements

 

The headrests are bolted to unibody of vehicle. I dont think this would pass for integral roll-over hoops

 

So for the rest of us convertible owners who do not race, will the rollover bars protect my unprotected head in case of rollover?
Assuming my head is lower the the bars (haven't measured yet)...

 

Based on what was posted by Rummy? Not likely. My old organization keeps a list of approved convertibles and they do get manufacturer statements for them for rollover protection:

https://docs.google.com/document/d/e...k9i3xSAVtI/pub

EDIT: It's also not only the rear portion behind the driver. The windshield frame usually needs some structural safety as well which is how some of the other cars get by.

 

When purchasing the car my salesman told me that there was substantial effort into reinforcing the windshield for rollover protection..

Salesman talk?

What he said.

 

So with flimsy cloth top down, the windshield + rollover bar should provide adequate protection in a rollover...?

 

Yes, but clarifying "proper roll bar or roll hoops".

 

Windshield + factory rollover hoops = rollover protection...?

 

Since the factory hoops are just bolted on, they would not pass for any track organizations which enforce rollover protection. There are track organizations who do not enforce rollover protection. However, be careful with some of those organizations that run more loose events as they may also not provide track services (i.e. like car tows or onsite first aid). For example, if you run out of gas on a track and have to get towed off, if the organizer didn't pay for tow service as part of the event then you as the driver have to pay for that tow.

 

Given the regulations In the US I would tend to think convertibles would be required that those roll bars would be an actual safety Item and not for looks.
I also have a hard time believing Jaguar would go to the added expense of adding these and attaching them to the unibody if they were not somewhat functional.

Just because an item is bolted don't make it a weak connection. I am quite sure their engineers did ton's of Finite element analysis (FEA)
on these cars. Also before you can conclude these are not functional you need to look at how they actually attach to the unibody
(additional mating features) and how that stress is distributed under all conditions(crash types). These along with the strength of the windscreen frame were more then likely considered.
That"s just my opinion based on 40 years working in the engineering field.

 

Possibly explains the complaints from people about the thickness of the A pillars ....

 

Well, having been in the racing/competition field for 20+ years, I can tell you that the majority of convertibles do not have structurally integrated rollover protection from the manufacturer. I'm a former Chief Instructor for NASA and I've had my fair share of telling drivers their cars don't meet the requirements (and that is coming from the manufacturers). Take a look at the list I posted above as those are known cars that have full rollover protection off the showroom floor.

But yes, I did mention in post #12 about the windshield frame. To your point, it does take a lot more testing than looking at a photo. While it's been a while since I've been in a F-Type vert, I don't recall the head rest hoops being of the proper crash bar diameter or material.