Rollbars, rollcages and safety issues...

[Karim E36]

Hello, I am new here,

I have been a member of the club for a few years now.
I decided to prepare my car for next season's DE's. It's not a BMW ;) but at least it's trying to be (It's a 1971 Datsun 510).

Since the interior is almost completely stripped, I am thinking about installing a rollbar or rollcage in my car.

I am hesitating between a rollbar and a rollcage (from Autopower or Kirk).

My questions are:

1 - Why is a weld-in cage better than a bolt-in? From my research, the weld-in is more solidly attached to the car chassis through thick metal plates. Why can't theses plates be welded to the bolt-in and the bolt-in cage be bolted to these plates? It seems to me that there is no intrisinc difference between a bolt-in and a weld-in and one can be converted to the other easily. Am I missing something?

2 - I read in many places that it is not a good idea to have a rollcage in a street driven car for safety reasons. A rollbar seems safer in that respect. Yet, I know of several people with experience and intelligence who have a full rollcage in a street-driven car (Lee for example). Is it really a bad idea? My car is to be driven on the street very minimally (from my garage to the track and back), but I don't want to put myself and possibly one passenger in a risky situation... What is the answer?

3 - Other than a safety benefit, do rollbars improve the rigidity and handling of a car? Even when they are not custom made (not as close-fitting)?


Thanks alot for the help.
__________________
Karim.

[Lee]

A bolt-in cage is only a compromise. Both bolt-in and weld-in are easy to ship and both are about as difficult/easy to install. The only diffferences are that the owner can easily install himself a bolt-in cage, as a weld-in cage requires... welding. But exactly because welding is involved, it allows to gusset the cage to the car, weld thicker plates to the rockers and therefore can add way m ore rigidity. To sum it up. A bolt-in cage is mostly for protection, as a weld-in cage will also bring stiffness. Because a welded cage is often custom-made, it usually fit the car better and will be closer to the shell. This winter, I will probably help/coach David at Autosport Concept when he will build cages.

As I said on the other board, a rollbar will not improve rigidity much. Old cars are never as rigid as modern cars and therefore benefit more from extra stiffness. A well built rollcage will not be intrusive, and except for the crossbraces in the door, it will not affect your driving.

[Karim E36]

A bolt-in cage is only a compromise. Both bolt-in and weld-in are easy to ship and both are about as difficult/easy to install. The only diffferences are that the owner can easily install himself a bolt-in cage, as a weld-in cage requires... welding. But exactly because welding is involved, it allows to gusset the cage to the car, weld thicker plates to the rockers and therefore can add way m ore rigidity. To sum it up. A bolt-in cage is mostly for protection, as a weld-in cage will also bring stiffness. Because a welded cage is often custom-made, it usually fit the car better and will be closer to the shell. This winter, I will probably help/coach David at Autosport Concept when he will build cages.

As I said on the other board, a rollbar will not improve rigidity much. Old cars are never as rigid as modern cars and therefore benefit more from extra stiffness. A well built rollcage will not be intrusive, and except for the crossbraces in the door, it will not affect your driving.


Thanks for your answer Lee (both here and on the other board).

In you opinion, can a bolt-in cage be easily converted to weld-in? The reason I ask this is because I know of someone selling a used bolt-in cage for a 510 from Autopower but I am leaning towards a weld-in cage. The saving is attractive but I don't want to go cheap on safety.

I also assume you think it is safe to drive (just to the event and back) a car with a full cage (provided it's padded properly). Am I right?

[Lee]

Not an easy answer. It is possible to modify and weld a bolt-in cage, but it depends on the original design. Do you have any picture you wish to share?

[Emre]

can a bolt-in cage be easily converted to weld-in?Sure. Any competent shop should be able to convert a bolt-in cage to a weld-in design. They can add some plates to the floor and side sills to box in the corners, add gussets to tie in the A- and B-pillars (if legal in your class), etc.

BTW, you REALLY need to decide what class you plan to race the car before you get into this. You wouldn't want to pay someone to fully gusset the cage and make all kinds of mods only to discover it bumps you out of your class.


I also assume you think it is safe to drive (just to the event and back) a car with a full cage (provided it's padded properly). Am I right?I would never drive a car with full cage on a daily basis. However, many people will drive their dedicated track cars to and from events. You just need to take it easy and be extra alert. Besides, a racecar covered in mandatory sponsor stickers and everything will draw a lot of unwanted attention from the cops. You need to back off anyway.

Emre

[Karim E36]

Not an easy answer. It is possible to modify and weld a bolt-in cage, but it depends on the original design. Do you have any picture you wish to share?

The cage is the bolt-in one from Autopower.

I do have pictures but not on a server. I can email them to you if you want.

Karim.

[Karim E36]

Sure. Any competent shop should be able to convert a bolt-in cage to a weld-in design. They can add some plates to the floor and side sills to box in the corners, add gussets to tie in the A- and B-pillars (if legal in your class), etc.

BTW, you REALLY need to decide what class you plan to race the car before you get into this. You wouldn't want to pay someone to fully gusset the cage and make all kinds of mods only to discover it bumps you out of your class.

I would never drive a car with full cage on a daily basis. However, many people will drive their dedicated track cars to and from events. You just need to take it easy and be extra alert. Besides, a racecar covered in mandatory sponsor stickers and everything will draw a lot of unwanted attention from the cops. You need to back off anyway.

Emre

The problem is I don't know what class I want to race in because I am not planning on racing anytime soon. It's hard to decide now.

However I am building the car now (for DE's for now) and I think it's good time to install a cage.
I also have the opportunity of buying a full cage for a good price from a fellow Datsun owner...

I guess I'll check the regulations for the possible classes I could fit in and see if this cage will be a problem.

I guess driving on the street with a full cage is a small safety risk that a lot of people are ready to take. I also need to think about that.

Thanks a lot for the info and advice.

One last question: Can you give me a ball park figure for the cost of welding in a cage. I know it's hard to say but just an order of magnitude would help. Are we talking several hundreds of dollars? thousands?

Thanks again.

Karim.

[Lee]

One last question: Can you give me a ball park figure for the cost of welding in a cage. I know it's hard to say but just an order of magnitude would help. Are we talking several hundreds of dollars? thousands?

Thanks again.

Karim.

Ask David Cardin from Autosport Concept.

[Emre]

One last question: Can you give me a ball park figure for the cost of welding in a cage. I know it's hard to say but just an order of magnitude would help. Are we talking several hundreds of dollars?The cost of a full-custom weld in cage would run around $1500-2000 at the very least. If you already have a bolt-in cage and just want it installed and welded in place, that shouldn't be more than a few hours labor. Last time I checked with a shop regarding the cost of welding in an Autopower type rollbar, I was quoted 4-5 hours for labor.

Emre

[Karim E36]

Ask David Cardin from Autosport Concept.

I will give him a call.

[Karim E36]

The cost of a full-custom weld in cage would run around $1500-2000 at the very least. If you already have a bolt-in cage and just want it installed and welded in place, that shouldn't be more than a few hours labor. Last time I checked with a shop regarding the cost of welding in an Autopower type rollbar, I was quoted 4-5 hours for labor.

Emre


Thanks Emre,

Now that I have more info, I can start the thinking ;)

[Andre]

The other option is to go with the Autopower for now, leave it bolt in and when it comes time to race, redo the cage properly. That way you get the extra protection a cage or rollbar affords you, you don't shoot yourself in the foot vis-a-vis the class rules and you gain experience and have the chance to discover what you really want.

When the time comes, sell the Autopower and put the money towards the new cage.

Have your cake and eat it too.
-andre-

[Lee]

If there is a thing I would not do, is to have to re-strip a car to re-do a rollcage. It is much easier to build a cage only once, while the car is not painted, then prepare the metal and spray the car all together. If the cage is to be modified later, then that freshly painted floorpan will be scratched, and burned from welding and will never look as good as job well thought and well done from day one.

[Karim E36]

The other option is to go with the Autopower for now, leave it bolt in and when it comes time to race, redo the cage properly. That way you get the extra protection a cage or rollbar affords you, you don't shoot yourself in the foot vis-a-vis the class rules and you gain experience and have the chance to discover what you really want.

When the time comes, sell the Autopower and put the money towards the new cage.

Have your cake and eat it too.
-andre-


I was actually considering that option. Well not exactly...

If I understand correctly, the Autopower rollbar (4 point) can be upgraded to a 6 point rollcage by adding the front bars.
I was thinking about getting the whole cage now (used, from the Datsun guy) and installing only the rollbar. Later on, I might install the whole cage depending on what I want to do with the car (what race class).

It seems that stripping an already stripped car to install the additional front bars shouldn't be too much of a hassle... maybe I am underestimating the amount of work involved...Lee?

[Emre]

I was thinking about getting the whole cage now (used, from the Datsun guy) and installing only the rollbar. Later on, I might install the whole cage depending on what I want to do with the car (what race class).Look, if you can get the whole Autopower bolt-in cage for a good price, I would go for it. Like you said, you can add the 4-point roll bar for now and just bolt it in place (reinforce the floor first!). Then you can decide what to do later.

If you can find one of these locally, just go for it.

Emre

[Andre]

It's probably not the cheapest (or neatest) way to go. If you know exactly what you want to do, then it is cheaper and better to do it once and do it right.

However, as you get more involved with the sport, your knowledge, experience, likes and dislikes will become more apparent. Come time to race, you will have a much clearer idea of what you want. If on the off-chance you decide that racing isn't your bag, then you aren't stuck with a full-on cage that might, no --> WILL scare away potential buyers should you ever want to sell your 510. With a bolt-in, you sell off various race bits, remove the cage and make your classic car much more presentable to a mainstream public.

Just my .02
-a-

[Karim E36]

I am still in contact with the guy who is selling it. I'll let you guys know when I make up my mind.

[Lee]

Hey Karim. Install/weld the rollbar first and spend a year or two before you are sure you want the full monty. Weld plates on the rockers and floor, weld the cage on them. Not just on the floor.

[Karim E36]

Just a little update.

I finally bought the Autopower rollcage from my fellow Datsun friend. I got it today.

It's a 8-point bolt-in rollcage (standard 6-pt cage with braces added to connect the front bars to the firewall and 2 door bars on each sides).

I will install the main hoop and rear bars for now. Then we'll see for the front bars and door bars.

I'll post pics soon. :)

[Phil]

The 2006 BMW CCA Club Racing regulations are now available for download on their website.

There are significant upgrades to the safety requirements for both car and driver.

Its worth looking them over as you install your cage and otherwise.

Good luck,

Phil

[Karim E36]

I'll check that. Thanks.

It's always good to look ahead... far ahead ;)