Calderone

Yes ...i was thinking this
when you convert a hardtop into Ttop you lose stability ..
what i s the difference between a Ttop car chassis and a hardtop one ....a convertible chassis is the same as the Ttop chassis ??
what will happen if a hardtop car use a Ttop chassis ??

okfoz

Several people claim that the T-tops cars used heavier sheetmetal in the unibody for strengthening the car. I think theat might actually be the case. But I have never seen anything from GM confirming this.

I know the T-top cars have an extra couple of piece at the back of the door that actually wedges the door. It is there to strengthen the body, because there is a loss of rigidity with the T-top cars. The door then takes some of the flex. Other than that I have found nothing. Both cars use the same frame connectors, so there is nothing added underneath.

There are companies that convert Hard-tops over to T-tops, and I have never heard of an actual problem with doing this. I hear lots of speculation, but no first hand experience.

John

Blue502

I think the sheetmetal thing is an old wives tale. I have both, and have never been able to notice any difference whatsoever. Like okfoz, the only thing I've ever found is the little door clip. BTW, my hardtop car is a C&C t-top conversion, and I do notice a little more flex in the body over bumps than with my factory t-top car, but that will be solved with subframe connectors within the next year.

ZZ42Fast

iTrader: (2)

You loose a lot of structural rigidity when the roof is cut into as it is the main 'meeting' point of all the stresses. To compensate for this the body is reinforced, adding weight. The convert has to be reinforced more as there is no roof and is thus heavier than the t-top car, and so on.

Hope this helps

Jim85IROC

iTrader: (2)

I suspect that there is some truth to the t-top reinforcement issue for the simple fact that all of the cars that GM sent to ASC for conversion were all t-top cars. I don't think that would have been the case if there was no difference structurally.

dnovotny

Let me reiterate what Blue502 stated on a similar post. I also have a hardtop/t-top car at home to compare. Where exactly is this reinforcement, because outside of the doors, I can see no difference in the chassis.

My suspicion as to why they shipped t-top cars. Less material to cut.

On the 4th gens, the chassis is exactly the same, and I doubt they were different on 3rd gens due to cost. It costs a lot more to manufacture two different chassis.

Later, Dave '91 GTA, '91 T/A, '01 WS6

Blue502

I think this is a pretty easy one to answer. The windshield frame is the same on the t-tops and the convertibles. The hardtops would require replacing the whole windshield assembly to make into a convertible, which would have been a ton of work.