Light roll bar...
 

I am looking for a simple roll bar that will clear my hardtop. The ones on the market seem like they are very heavy being they are made out of .120 thickness tubing. My car is used for autocross only and I feel I could get away with a lighter bar yet would like to avoid the cost of having one custom made. Any ideas?

that .120 tubing will add rigidity to your car

it will also save your life if you flip over

are you competeing in SCCA nationals?

You could probably get some made out of .095, but it would be a custom job and probably fairly expensive. The weight savings is marginal and I doubt you would tell a difference.

The roll bar is not a good place to save weight.

The HardDog M2 Sport is going to be a little lighter than the M2 Hardcore, because it's 1.5" diameter instead of 1.75", and it is a safe, proper roll bar, still .120 thick. I just called Bethania for you, they say the difference between an M2 Sport w/ double diagonal and an M2 Hardcore w/ double diagonal is 5 lbs.

You're basically saying, "I really need a harness but I want to save weight and get rid of the sub strap and just use one shoulder strap." - that's about how ridiculous what you're asking sounds to most here, because a roll bar is a crucial safety item, not something you skimp on thickness (or cost) to save a few pounds, and the weight savings of a slightly thinner tube will really not save you any considerable amount anyways.

The only way to get a considerably lighter roll bar is to have one custom made out of chromoly - this will save ~30% weight, but the added skill and time necessary for the fab work are considerable, which means much more $$$.

-Ryan

Unless you want to save weight by decapitation. Especailly since a average human head weighs about 10 lbs, and that weight is right where you don't want it, up high in the car,annnnnddddd it moves around.

In all seriousness though unless you trailer your miata to autocross events a rollbar is even recommended for street driving. Mind you, the use of SFI padding is paramount so you don't crack you head open on the bar if someone rear ends you.

All it takes is you getting a bit out of control in the rain, someone t boning you, swerving into a ditch, etc etc, these cars don't roll easily but when they do they become a death trap.

If you want to save a pound or 2 before the event just take a big shit in the morning, problem solved.

Put it this way, if all you're doing is autocross and you want to save weight, DONT get a roll bar. Car won't be any safer than stock (In other words, not at all), but I HAVE seen and heard of people surviving roll-overs in stock miatas. Better that than having a possibly too weak roll bar which could crumple and take out the back of your head. Plus, no roll bar > any roll bar in terms of weight. CSP cars don't have roll bars after all.

I only attend local club events and one of the organizations is requiring I now run a rolbar though I can always throw my hardtop on. I guess I'll need to compare the weight of the hardtop verse the rollbars on the market.

From what i can remember NHRA rules for a roll bar call out a 1.5" .120 wall DOM tubing for the main hoop and rear kickers, or 1 5/8" .095 moly. All the other add-on tubes in moly can be smaller and thinner down to 1" .065. But this type of roll bar will set you back a few hundred (500-700) dollars. To save maybe 20 pounds max? So light, safe, and cheap is not attainable, unless you can perform all the work yourself.

Thanks for the input guys! Obviously I want a safe rollbar but the .120 seemed a little over kill for autocross. It sounds like the weight savings verse safety in trying to go lighter is not worth it. Thanks again.

1.75x.095 is stronger and lighter than 1.50x.120, FYI. If your sanctioning body gives you the option, go with the larger/lighter stuff.

This would be your lightest option. http://www.bespokeventures.com/blog/...ber-roll-cage/

I have seen a car roll at an autocross, without hitting anything first. It was my dad, so it was a scary moment. He still has the helmet with the big scrape on top from when it dragged through the sunroof hole against the pavement.

Granted, that was an '87 Si, so the Miata is quite a lot harder to put wheels up in an autocross setting, but I'd still run one just in case.

I'm confused. I've never heard of an autocross club requiring a roll bar. Are you talking track days or time trial? If you are competing at a high level in autocross (regional/national), then you probably don't want a roll bar for weight, but if not I always like the added protection.

Weight of hardtop is about the same as a rollbar accept the HT is higher up - plus the hard top isn't a safety device - http://www.youtube.com/watch?v=qMmjaaSQP08

Call Tom @ Bethania Garge, he can help you find the right bar - some bars are lighter than others...

1.75x.095 is more along the lines of what I was initially thinking. The carbon fiber rollbar in the link above is really cool yet likely costs as much as the rest of my car! I only race local club events and due to insurance reasons, I now need to run the hard top or a rollbar though there are zero guidelines on rollbar material/ construction. I suppose bending & welding up some exhaust pipe wouldn't be a good idea?! (Joking).

no restrictions?

http://www.duettomotors.com/miata/im...a-wave-bar.jpg

That's like making it out of mild stool (sic).

This thread is fail.