barchetta1

Drove my car for the first time with the roof out last weekend and noticed that there is a fair mount of vibration not unlike a wheel out of balance. I know the factory designed it to be driven this way but wondering if i'd be fatiguing the chassis by driving it this way? I guess there is fiberglass epoxied to steel frame members?

I plan to get a brace when funds allow but what are your thoughts on this?

PatternDayTrader

Drive it.

gman35

get a targa roof truss... one of the best things I bought.. I love mine.

RWDsmoke

Driving with the roof off does not cause vibration, it just lets you feel it. Find the problem (tire, wheel bearing or whatever) and fix it.

Kevova

GM brass wanted a targa once Porsche put one in a 911. There is some flex with roof off. There is a gizmo to allow hatch to vent air to reduce buffering as speed increases.

turbobuick33

where did you buy your targa roof truss?

barchetta1

Im not worried about the vibration, its the clearly twisty chassis Im concerned with.

Ive read the book, I know it was supposed to be a t top and last minute changed to a targa.

Cruisinfanatic

The twisty chassis hypochondria is out of control. Some think it needs fixing. It doesn't

Tom400CFI

The frame is strong, but it's not stiff. It will flex a lot w/the roof off, but it won't be damaged as a consequence. Drive the wee out of it.

GREGGPENN

True but vibration is still vibration. I feel imperfections in the road more...which can create intermittent vibration. Plus, flex through corners that can be unsettling if the road is potted. Constant vibration w/o the roof in WOULD be indicative of something that needs to be chased.

I agree that extra flex shouldn't cause longterm damage if you're talking a few years. How unglued these come in 50 years is still left to be seen. If you read the book, it SAYS the chassis was designed for a 20yr-life-span. Really?!?! Adhesives/glue don't last forever, I guess. FWIW, I put a camber brace on mine. Frame (X) braces and targa truss will all help. Guys named Bubba or Tom....with a welder couldn't hurt either! LOL

I don't think roads/highways are as well-kept as they used to be (either).

FASTAZU

If it bothers you that bad. I also went with one.

Truss bar

vader86

Its going to flex quite a bit with the targa out, no way around it.

Some of us just add stiffeners, like the targa truss, camber brace, cross-bar, X-frame, etc.

gerardvg

I do not notice any vibration mainly wind buffeting, I put the sun visors up a little to deflect air from cabin.
That does the trick nicely ... try it

barchetta1

thanks.. I bet it would help on the highway.. I think maybe I need to shell out for shocks. May take them off and see if they are pressurized.. I think bilsteins should extend on their own when removed from car. Either that or rebalance tires or both.

gerardvg

Yes the bilstein shock absorbers are pressurized they will extend by themselves, I find the usual vibration issues are from tires out of round or high spots.
Jack each front wheel and spin the tire, check the tread surface for any high spots.
The rear will need both wheels of the ground just run the engine in gear and check the tires for out of round or tread separation.

On average road cars out of round tires are not as noticeable, but on a vette its shocking.

I definitely have no vibration issues roof on or off

Good luck

64Scout

I've noticed mine shakes with the top off. I leave mine in more to keep the sun off me.

fake

My 1993 shook,vibrated and GM knew about it and sent the cars out for delivery!The top on mine was removed at 3000 miles on a flat surface per owners manual.. It took 2 hours to place back on the car. The dealer said good luck your problem not ours, called Bowling Green and they said bring it back to the dealer. The bracing needed (X) was eliminated by the GM bean counters because profits come before customers. Thats why after buying GM cars since 1965 )GTO) El Caminos etc, i drive Lexus .

barchetta1

So, my original question; can we do damage appears to be an unknown.

It appears your car needs to be setup perfect to avoid shaking. Any issue is exaggerated x10.

It is my contention, that without a roof brace we will be doing damage. Therefore, I will be looking to purchase a brace and I think I will put my roof back in place. I cant believe you have to use a ratchet wrench. My guess is that the engineers knew full well the car lost its integrity with the roof out and to satisfy the executive management they designed a roof that didnt just latch into place but bolted so it became a solid structural member of the chassis.

Its a shame because a T top would have been much more practical; the two panels could easily be removed by a guy as needed and allow the owner to enjoy more open air driving. Burt Reynolds looked great in his t top. Hope he is ok.

Tom400CFI

How did you come to that conclusion? Many in this thread have told you that it won't harm the car. GM themselves ran countless engineering calc's, built models to test the structure, and then validated it with over a million miles of testing -in some pretty unfavorable conditions. These cars are now 22-34 years old...yet there isn't any reported damage from roofs off. No cars have been totaled due to no-roof-running. I think that your conclusion is folly.


You're guess is right about this, but you needn't guess....Dave McLellan, the head engineer for the car admits that straight up, in his book. He literally explained the loss of structural rigidity (not the same as "strength") in both objective terms (structural frequency) and subjective terms and he talks about the structural roll of the roof as it relates to stiffness (not the same as "strength"). Finally, he expressed his disappointment in the end result.

If you want a roof brace for ride quality reasons....go for it. But you're not preventing damage to your car.

81c3

I never take my top off... 6 C4's, I can count on one hand how many times Ive had the tops off.... Its a PIA anyway to remove it....store it, then if it starts raining... meh... IMO, you want to go topless, buy a convertible....