I want to cut off the top of my van and use it for some kind of weird convertible, touring vehicle.
I would, of course, leave the windshield in place. Are there any laws against this?
thanks,
hh
Yes, it would be illegal, as you would be driving an unsafe vehicle.
The roof is a structural part of the vehicle, and removing it would drastically weaken the remaining stucture, making the vehicle completely and utterly unsafe.
Regardless of whether or not there are applicable laws where you are, you first should consider the advisedness of such a course of action. For one thing, vehicles that are not designed from the ‘ground up’ as convertibles just don’t have the torsional rigidity that they need. The least of your worries would then be that you’ll have some uncomfortable and/or weird twisting going on at speed. A much more dire result would be catastrophic bending of the drive shaft (although that’s more likely for an all-wheel or rear-wheel drive van) or body. If the front and rear wheels get out of line with each other (as you sometimes see with abused cargo vans), it can result in an odd driving attitude where the driver is no longer quite facing the direction the vehicle is traveling in. Made worse, this can make the vehicle un-steerable.
I don’t know the law in Oklahoma specifically, but the roof is a major structural component of any modern vehicle. Just cutting it off without reinforcing the rest of the body may not be illegal where you are, but it’s very dangerous, so I’d advise someone not experienced in major modifications of this type against doing it, in the strongest possible way. 
At the very least, it will invalidate your insurance, so you’ll have to get a new policy.
Have you considered a less ambitious plan such as installing a huge sunroof rather than removing the entire van top? The “Car Talk” guys recently counseled somebody who wanted to do this with a station wagon:
That’s funny. The first thing I thought of when I saw this thread was my college neighbors that turned their spearmint green station wagon into a true convertible.
I saw an episode on, I think, The Discovery Channel (Don’t remember the series title, but the guys did surprise customizations of people’s cars. It wasn’t Pimp My Ride.) where the crew not only restored this man’s father’s T-Bird, but cut the roof off and made it into a roadster.
It was a LOT of work and they did have to reinforce things as I recall to maintain the structural rigidity. The result was beautiful, but like I said, it was a LOT of work, not by any means something the average person could di in his/her garage.
I agree with the posters above. Unless there was something really special about your vehicle, it would probably cheaper to buy a brand new (or at least used)convertible than to do the job properly.
I’d be leery of that - in a roll-over, the roof is meant to protect you. I know that all the convertibles I’ve seen that don’t have visible roll-over bars have hidden ones that pop up in the event of an accident. Removing that protection seems unsafe to me.
As mentioned above, after market shops chops roofs off of cars all the time. Usally cars that were never designed to be convertibles. But they also go to great lengths to increase the stiffness of frame due to the lack a structural integrety from the roof. A car that was designed to have a roof could buckle onto itself if they didn’t. No, it’s not illegal. Convertables have always been inheritly dangerous vehicles, roll bars or not.
Really? Can you name a few models?
I’ve never rolled my Miata, but I’m pretty sure there weren’t any magic hidden rollbars to save my ass if I had.
thank you all very much for your replies. I think that I shall defer the project indefinitely.
thanks,
hh
I don’t know about the Miata specifically, but this Google Search should get you a few results.
While a few convertible models have them, it’s definitely not all.
No, Miatas don’t have them, I think they’re exclusively in German cars. The idea was introduced in the Mercedes 300SL and 500SL, which came out in 1990. The roll bar pops up if sensors detect the car is rolling over. Other Mercedes convertibles have them, and I know some Porsches have similar systems as well. On the VW Beetle convertible:
From here.
Sounds like Overhaulin’
That was the episode called “Illegal Fowl”.
Just clicked on it and …That’s it! You nailed it in one!
Thanks.