BootCamp

The challenge with a convertible automobile is that not only is the top no longer "integral" to the structure (structurally, the top is "missing entirely"), but you have additional "flex points" on each side - where the doors are. You can't just reinforce the corners. There has to be additional floor reinforcements extending beyond both ends of the door openings.

Think of it this way:
Take an empty Cool Whip container, remove the top, duct tape a tennis ball to the middle of the bottom of the bowl and make four 2" cuts down the sides of the bowl with a pair of scissors (like cutting a pie into quarters) and then replace the top, putting four small pieces of duct tape holding the "sides" (areas of the bowl between the cuts) to the lid. This will simulate the rigidity of a coupe or sedan. Now roll it down the stairs. Watch the shape of the bowl. The bowl basically retains it's shape / structural integrity, flexing a bit, but not much. The structure inherantly returns to it's original shape as it absorbs impacts from the steps.

Now remove the tape and remove the lid from the container. This will simulate the rigidity (or lack thereof) of a convertible. Now roll the bowl (with the cuts and the tennis ball taped to the middle of the bottom) down the stairs and watch as the bowl flexes, shakes and changes direction more drastically than when the until was sealed.
The best way to reinforce the structure now is to tape popsicle sticks on the bottom / underside of the bowl spanning the cuts (that simulate the doors). While this helps the rigidity and reduces the propensity of the bowl to twist/wring, the tennis ball is still exposed and prone to ejection as a result of the forces on the bowl as it rolls down the stairs.

That's the best way I can simulate the differences between a coupe or sedan, and a convertible - and how they have to add weight in reinforcing to the frame/body to minimize the flexing that occurs in a convertible during a crash/rollover.
Hope that helps.

DSkippy

Irregardless, Awsure,

Jeremiah and BootCamp make salient points, I'm sure don't disagree. BootCamps analogy speaks to a point I was going to make, and that's not only does the roof add structural rigidity, but so does the windshield and backglass. A lot of people don't understand how much structural stiffening is provided by the glass in an automobile. This is like the PickUp truck with the tailgate down to improve gas economy (dis-proven but not totally done well by myth busters..I believe them...but think they could have done a better job), after a while you'll see the beds (or at least on much older trucks) get rickety, in this example the tailgate is the metaphor for the roof.

I'm babbling. And now I'm making redundant observations. And now I'm looping.....and now I press the OK to submit this post..... must stop.

Jeremiah 29:11

awsure.....I knew better about that moot point spelling. I was so tired, I know better but I did not proof read it. In fact the whole last sentence was worded wrong, but now corrected.

Like I said 2 years ago, I am a road performance guy and not a drag strip guy. I do not like convertibles because of safety, don't handle as well, theft security, and are heavier. Material roofs require maintenance as well.

Give me a roof so I have better and tighter control of my car in the curves.

The old TransAm with the T-top roofs had a chassis that was never stiffened. You could actually feel the road handling change when you removed the roof panels.

I thought that was an economical design but a poor one.

mac

Irregardless, Awsure,

Jeremiah and BootCamp make salient points, I'm sure don't disagree. BootCamps analogy speaks to a point I was going to make, and that's not only does the roof add structural rigidity, but so does the windshield and backglass. A lot of people don't understand how much structural stiffening is provided by the glass in an automobile. This is like the PickUp truck with the tailgate down to improve gas economy (dis-proven but not totally done well by myth busters..I believe them...but think they could have done a better job), after a while you'll see the beds (or at least on much older trucks) get rickety, in this example the tailgate is the metaphor for the roof.

I'm babbling. And now I'm making redundant observations. And now I'm looping.....and now I press the OK to submit this post..... must stop.


Regardless not irregardless. Sorry, my own spelling, and sentence structure is rather poor, however that word always bugs me.

jh27n0b

Lets not forget that in a convertible the added frame weight is on the bottom of the car which helps to lower the center of gravity. This does help in handling and safety with the lower chance of rollover, it is just once she does rollover it is better to have the hard top. These older unibodies wether hard top or convertible, are pretty weak from the factory.

As a convertible owner, just my 2 cents worth.
Bob

Jeremiah 29:11

That is true but now you have 200lbs of extra mass which slows you down (.2 secs in the 1/4 mile) and the extra later force in a curve (oh yeah we have to worry about tire technology).

Bottom line: Give me the hard top.

awsure

I guess I want it all...hardtop cause I do not really care for the convertible look but I also want no B-Pillar. Can they construct a safe design to deliver both? Again, I will give back .2 seconds of 0-60 thrust.

DSkippy

Mac, that was me attempting to be clever I put the winky there to indicate I was using a "wrong word". What I could have, and maybe should have, used was a "(sic)" (said in context, a la meant to be the wrong word, a purposefully stated malapropism) in reference to Awsure's correction, thought he'd get a kick out of that one too.

And yes...that word bugs me as well...again that was the vein of humor so fecklessly was trying to tap....oh well.....

There are few more that pop up on threads that spin me up, I just grimace and keep reading.

Mikesan

I wouldn't expect any engine bigger than the 5.7 in any of the convertibles. Too much torque equals too much body flex. I'm thinking the 6.4 with a sunroof would be sweet. Not sure on the tranny yet but leaning towards the manual.

awsure

I tried to resist the bait but yes...that word also bugs me. As somewhat of a amateurish hack my writing is not on the level of some here but I repeatedly see & hear a few expressions that make me shudder. I am most fearful of my children beginning to tell me like that car you like is like totally like you know. I am so sure. Like shawwwwwww. Whatever.

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