damage driving from roof out? - CorvetteForum - Chevrolet Corvette Forum Discussion

Notices
C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

damage driving from roof out?

Old 07-08-2018, 09:08 PM
  #1  
barchetta1
CF Senior Member
Thread Starter
 
Member Since: Nov 2017
Location: Fort Mill, SC
Posts: 538
Thanked 13 Times in 13 Posts
Default damage driving from roof out?

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?

Last edited by barchetta1; 07-08-2018 at 09:08 PM.
barchetta1 is offline  
Old 07-08-2018, 09:49 PM
  #2  
PatternDayTrader
CF Senior Member
 
PatternDayTrader's Avatar
 
Member Since: Oct 2008
Location: Lansing MI and Houston TX
Posts: 6,075
Thanked 590 Times in 472 Posts
Default

Drive it.
PatternDayTrader is online now  
Old 07-08-2018, 09:57 PM
  #3  
gman35
CF Senior Member
 
Member Since: Nov 2008
Location: Orange Park Florida
Posts: 754
Thanked 10 Times in 10 Posts
Default

get a targa roof truss... one of the best things I bought.. I love mine.
gman35 is offline  
Old 07-08-2018, 10:02 PM
  #4  
RWDsmoke
CF Senior Member
 
Member Since: Jan 2005
Location: San Antonio Tx
Posts: 681
Thanked 47 Times in 43 Posts
Default

Originally Posted by barchetta1 View Post
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?
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.
RWDsmoke is offline  
Old 07-08-2018, 10:05 PM
  #5  
Kevova
CF Senior Member
 
Kevova's Avatar
 
Member Since: Sep 2013
Location: near the thumb in the mitten
Posts: 3,137
Thanked 300 Times in 284 Posts
Default

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.
Kevova is offline  
Old 07-08-2018, 10:29 PM
  #6  
turbobuick33
CF Senior Member
 
turbobuick33's Avatar
 
Member Since: Jul 2003
Location: Naperville il
Posts: 267
Thanks: 0
Thanked 2 Times in 2 Posts
Default

Originally Posted by gman35 View Post
get a targa roof truss... one of the best things I bought.. I love mine.
where did you buy your targa roof truss?
turbobuick33 is offline  
Old 07-08-2018, 10:43 PM
  #7  
barchetta1
CF Senior Member
Thread Starter
 
Member Since: Nov 2017
Location: Fort Mill, SC
Posts: 538
Thanked 13 Times in 13 Posts
Default

Originally Posted by RWDsmoke View Post
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.
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.
barchetta1 is offline  
Old 07-08-2018, 10:57 PM
  #8  
Cruisinfanatic
. 1985 Original Owner .
Support Corvetteforum!
 
Cruisinfanatic's Avatar
 
Member Since: Jul 2004
Location: Clifton Pk, NY Clearwater, FL
Posts: 4,033
Thanked 167 Times in 139 Posts
Default

Originally Posted by barchetta1 View Post
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.
The twisty chassis hypochondria is out of control. Some think it needs fixing. It doesn't
Cruisinfanatic is offline  
Old 07-08-2018, 10:58 PM
  #9  
Tom400CFI
CF Senior Member
 
Tom400CFI's Avatar
 
Member Since: Aug 2004
Location: Park City Utah
Posts: 13,528
Thanked 563 Times in 502 Posts
Default

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.
Tom400CFI is offline  
Old 07-08-2018, 11:13 PM
  #10  
GREGGPENN
CF Senior Member
 
GREGGPENN's Avatar
 
Member Since: Nov 2003
Location: Overland Park Kansas
Posts: 11,280
Thanked 115 Times in 110 Posts
Default

Originally Posted by barchetta1 View Post
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.
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).
GREGGPENN is offline  
The Following User Says Thank You to GREGGPENN For This Useful Post:
5abivt (07-19-2018)
Old 07-09-2018, 07:13 AM
  #11  
FASTAZU
CF Senior Member
 
FASTAZU's Avatar
 
Member Since: Feb 2002
Location: South of ???
Posts: 10,148
Thanked 283 Times in 258 Posts
2018 C4 of Year Finalist
2015 C4 of the Year Finalist
St. Jude Donor '16
Default

Originally Posted by gman35 View Post
get a targa roof truss... one of the best things I bought.. I love mine.
Originally Posted by turbobuick33 View Post
where did you buy your targa roof truss?
If it bothers you that bad. I also went with one.

Truss bar

Last edited by FASTAZU; 07-09-2018 at 07:15 AM.
FASTAZU is offline  
Old 07-09-2018, 06:42 PM
  #12  
vader86
CF Senior Member
 
vader86's Avatar
 
Member Since: Sep 2001
Location: Athens AL
Posts: 49,776
Thanked 175 Times in 155 Posts
Default

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.
vader86 is offline  
Old 07-09-2018, 07:06 PM
  #13  
gerardvg
CF Senior Member
 
gerardvg's Avatar
 
Member Since: Aug 2009
Location: Melbourne, Australia Victoria
Posts: 3,124
Thanked 104 Times in 102 Posts
Default

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
gerardvg is offline  
Old 07-09-2018, 09:29 PM
  #14  
barchetta1
CF Senior Member
Thread Starter
 
Member Since: Nov 2017
Location: Fort Mill, SC
Posts: 538
Thanked 13 Times in 13 Posts
Default

Originally Posted by gerardvg View Post
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
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.
barchetta1 is offline  
Old 07-09-2018, 09:55 PM
  #15  
gerardvg
CF Senior Member
 
gerardvg's Avatar
 
Member Since: Aug 2009
Location: Melbourne, Australia Victoria
Posts: 3,124
Thanked 104 Times in 102 Posts
Default

Originally Posted by barchetta1 View Post
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.
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

Last edited by gerardvg; 07-09-2018 at 09:56 PM.
gerardvg is offline  
Old 07-11-2018, 07:52 AM
  #16  
64Scout
CF Senior Member
 
Member Since: Oct 2017
Location: Fort Wayne Indiana
Posts: 358
Thanked 12 Times in 12 Posts
Default

I've noticed mine shakes with the top off. I leave mine in more to keep the sun off me.
64Scout is offline  
Old 07-11-2018, 09:26 AM
  #17  
fake
CF Senior Member
 
Member Since: Jan 2004
Location: Glastonbury CT
Posts: 805
Thanked 31 Times in 30 Posts
Default

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 .
fake is offline  
Old 07-14-2018, 10:45 AM
  #18  
barchetta1
CF Senior Member
Thread Starter
 
Member Since: Nov 2017
Location: Fort Mill, SC
Posts: 538
Thanked 13 Times in 13 Posts
Default

Originally Posted by fake View Post
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 .
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.


barchetta1 is offline  
Old 07-14-2018, 12:16 PM
  #19  
Tom400CFI
CF Senior Member
 
Tom400CFI's Avatar
 
Member Since: Aug 2004
Location: Park City Utah
Posts: 13,528
Thanked 563 Times in 502 Posts
Default

Originally Posted by barchetta1 View Post
So, my original question; can we do damage appears to be an unknown.
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.


Originally Posted by barchetta1 View Post
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.
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.
Tom400CFI is offline  
Old 07-14-2018, 12:34 PM
  #20  
81c3
CF Senior Member
 
81c3's Avatar
 
Member Since: Dec 2005
Location: Royal Gorge area Colorado
Posts: 7,179
Thanked 238 Times in 203 Posts
Default

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....
81c3 is online now  

Thread Tools
Search this Thread
Quick Reply: damage driving from roof out?


Sponsored Ads
Vendor Directory

Contact Us About Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: