C3 Convertible Drivers - we have a problem!!!

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Nov 1, 2004 | 08:57 PM

#41

stingry

Drifting

Joined: Mar 2003

Posts: 1,608

Likes: 3

From: Canberra AUSTRALIA

St. Jude Donor '05-'06

Chris,

Would you mind sending me some more photos of the roll bar you installed. Also are they C5 seats?

Thanks.

Pete

Quote:

Originally Posted by 71roadster

This has been discussed many many times over the 4 years I have been a member. I, like many others gradually watched my car get faster, my skills get more honed, and my need for speed less and less satiated, to the point I decided to do something about it. The problem is that there was no good way to do it with out seriously cutting up the car. And you need all the leg room you can get you have to cut into the deck lid, but it can be done cleanly.

After looking long and hard, I made my own. Granted, it is a compromise, but it is far far better than nothing and a hell of a lot better that something that bolts to the birdcage.

Cheers
Chris

Nov 1, 2004 | 09:34 PM

#42

Red73Vert

Thread Starter

Intermediate

Joined: Jan 2004

Posts: 41

Likes: 0

Hans - I'm 6' and don't want to give up any leg room either. It sounds like you have thought through this a bit - I like the idea of a second hatch cover and at least a partially removable rollbar assembly. If you intend to make it removeable then it sounds like you are thinking of bolted connections somewhere in the rollbar assembly (welding and cutting out could get tiresome quickly). Can you do this in way that passes tech inspection? (i.e. NHRA or SCCA?). Any ideas on design/ tie in points yet?

Chris - I'd greatly appreciate any additional photos you have as well.

Thanks
Rick

Nov 1, 2004 | 10:00 PM

#43

71roadster

Burning Brakes

Joined: Apr 2000

Posts: 1,145

Likes: 1

You are all going down a well traveled path.

1. No sanctioning body I found will accept a bolt in roll bar.

2. A roll bar tall enough to be legal will not work with the top.

3. A roll bar that has back braces high enough to be legal would require seriously deep notches in the deck lid (or a barce to the front - seen it, not bad, but seriously reduces passenger comfort)

4. A roll bar that does not cut the deck seriously reduces leg room and puts the bars very close to your head. High seats help a lot.

5. The quotes I got were $700 - $1500 but not one builder gave me the confidence he could get the radius as tight as I wanted or that he would get as clean an installation as I ultimately got.

I have 95 C4 seats. I LOVE em!

Here are some more pics...

Chris

Nov 1, 2004 | 10:01 PM

#44

68/70Vette

Team Owner

Joined: Jul 2004

Posts: 40,381

Likes: 789

From: Redondo Beach, California

I really like my 1968 Convertible, but I consider it from a safety standpoint to be a 4 wheeled motorcycle. It has no rollover protection, and in a major body impact, I think the body would just fracture loose. For rear end protection, the gas tank is a worry. I would in principal like a roll bar, but I dont' think one can practically be added - at least none that I've seen. Anyhow, it's a blast to drive, and I've never had a major accident anyhow so maybe I shouldn't worry. I guess the perfect safety feature would be a 0/0 ejection seat but that might be a problem under a freeway overpass or in a tunnel.

PS: About the motocycle comment. Actually it may be less safe than a motorcycle since a motorcycle has some latitude of maneuvering that a car doesn't have!!!!!!!!!!!!!!!!

Nov 1, 2004 | 10:32 PM

#45

ZD75blue

Race Director

Joined: Nov 2000

Posts: 16,416

Likes: 1

From: NC,USA

Quote:

Originally Posted by joe73vette

Vettes are one of the least likely cars to roll, with the wide stance and low center of gravity. Don't worry about it, because as people said above, there are 20mph fatals and 100mph walkaways. You can't drive a tank on the road, or wear a suit of armor all day. Live life and enjoy it. Joe

While quite true... our cars do not have as wide a wheel base as others... We are quite a bit closer to the Cobra than we are a humvee, which also has a very low center of gravity!

I've thought about installing a roll bar in the 75... which is a coupe! I have heard that the fiberglass/bird cage can handle the weight... but I'm more concened about getting t-boned! SUV bumpers at eye level?

Nov 1, 2004 | 10:42 PM

#46

jcswm

Melting Slicks

Joined: Jan 2004

Posts: 2,527

Likes: 1

From: St. Petersburg, Fl///Columbus, Ohio

Quote:

Originally Posted by 68/70Vette

PS: About the motocycle comment. Actually it may be less safe than a motorcycle since a motorcycle has some latitude of maneuvering that a car doesn't have!!!!!!!!!!!!!!!!

I Do not agree with that.... anymore!!!!
A motorcycle has a better chance of avoiding a collision, but a 45mph impact on a bike is almost always fatal.... I know ..... I T-boned a toyota at @50mph & I was lucky to survive.

Nov 1, 2004 | 10:58 PM

#47

Ran-D

Racer

Joined: Apr 2004

Posts: 336

Likes: 0

From: Tucson

I have a 73 and a 2001. I'd be more concerned about the number one safety item in your car... the driver. If someone rolls a car, they don't know their car, the road, their own limitations. I'd rather keep my car on all four wheels and in original condition. And besides, you roll your car with a rollbar, great for you, but how about the unlucky person(s) you just wiped out?

Nov 1, 2004 | 11:03 PM

#48

dtengle

Instructor

Joined: Aug 2003

Posts: 132

Likes: 0

From: Orlando FL

Why would you say that? If you were going to hack and weld into your beautiful vette you should have supported the roll bar at the top of the hoop (this is not an attack just stated from an engineering standpoint). The way you currently have the roll bar supported, i.e. at the base of the hoop, you really don't gain that much more of an advantage from it being bolted to the bird cage. The shear strength (the weakest loading direction of a bolt) of a grade 8 3/8" bolt is approximately 10,000-lbf. Multiply that by 4 and you have approximately 40,000-lbf of shear resistance. I would be more worried about the hoop bending either forward or backwards during a rollover. Depending on the quality of the weld between the roll hoop and the cross bar, you could have porosity in the weld which could lead to stress concentrations which could lead to cracking and thus failure. This therefore in my opinion would be the weakest link of any two point "roll hoop style" system during a rollover.

Quote:

Originally Posted by 71roadster

Cheers
Chris

Last edited by dtengle; Nov 2, 2004 at 09:00 AM.