Rear roll bar design

[Frank818]

I've been searching the forums but couldn't come across a clear answer and unfortunately I am curious by nature, so plz don't test your flame thrower at me. :)

In this page https://www.factoryfive.com/kits/project-818/ you can see the rectangle shape of the rear roll bar behind the seats.

In this picture you can see how Ferrari designed theirs http://www.evo.co.uk/front_website/gallery.php?id=469261

And Mazda with these Miata aftermarket roll bars http://articles.dashzracing.com/mazda-miata-stainless-steel-chrome-roll-bar/

Ok FFR is not the only one with that design, Catheram also does http://www.topgear.com/uk/car-news/First-drive-Caterham-620-R-2013-08-20 and http://uk.caterhamcars.com/, but I'm still asking. :)

What made FFR decide to go with their current design rather than something like the above 2 (which seems to be pretty common in the world of roadsters, including I think FFR's own MK4 Roadster)?

[Samiam1017]

Main hoop has to be one continuous bar with a maximum two bends to meet most race series rules (if I remember right). I think there's something in there about degrees and stuff too The miata bar has too many bends. To be legal.

[Frank818]

Oh, that makes sense! I didn't know one of FFR's requirement was to comply with some racing regulations on the S.

tnx for the info!

[blueoval_bowtie_guy]

The Miata rollbars are more commonly referred to as 'style bars'. They are not SCCA track legal. When I bought my Miata it had the 'style bars' on it. They went into the scrap pile and I put an SCCA legal rollbar in it.

[apexanimal]

those double hoop bars, especially without a proper brace to the rear, are known for actually causing deaths in a rollover because they'll collapse - possibly on the drivers head...

like samiam said, the continuous is not only sanctioned by race organizations, but is lighter, and stronger to boot...

[Frank818]

Yeah, I understand, it's different than full road cars (like the F458 Spider) which I believe most of them if not all are not designed to meet track rules, right?

It's good to know I won't die when I'll roll over my 818! lolll I didn't say that.

[68GT500MAN]

Rubber side down, NOT up!

[Racebrewer]

Ditto. Can't comment on the Ferrari, but the Miata "roll bar" is for looks only. It isn't triangulated and in a rollover with any forward motion it would just fold over towards the trunk.

The FFR bar would actually work (although I'd like it a little higher).

John

[longislandwrx]

SCCA requires the main hoop to be one piece, have 4 bends maximum, totaling 180 degrees ± 10
degrees.

Technically the S could have had a slight dip in the middle but nothing like those chrome skull crushers.

[Frank818]

The Miata ones were just exaggerated examples I agree, but the protection on the F458 seems to be hidden inside the body and considering the shape it's certainly not SCCA approved according to your rule. But, I damn hope the F458's protection is not a skull crusher. lolll

[bbjones121]

So all these exotic sports cars with double tubes (which they all seem to have) are not capable of racing in "most" race series?? I am not understanding this one. Millions of dollars went into those types of cars to make them capable of racing.

When I say double tubes, I am merely referring to two separate bar rolls behind each seat. A straight roll bar screams kit all over it.

[Xusia]

I have been wondering about that as well, though more from a HPDE (High Performance Driving Event) standpoint than a racing standpoint. It would seem ludicrous that a Ferrari - ANY Ferrari - would not be allowed to attend such an event. Isn't that what they are made for (supposedly)?

[bbjones121]

I think it became an economic issue. I have been fighting the single flat roll bar on the 818 since the beginning. I still love the car and they have done such a good job. I just wish it had a better looking roll bar.

[blueafro]

So all these exotic sports cars with double tubes (which they all seem to have) are not capable of racing in "most" race series?? I am not understanding this one. Millions of dollars went into those types of cars to make them capable of racing.

Millions of dollars went into making them great street cars, not race cars. The variants of such cars which are raced are invariably the hardtop models, with full roll cages inside.

For what it's worth, many (probably most) track days will allow cars without race-legal rollover protection, so you can take open cars like these to the track, but I doubt you'll find many if any racing organizations which would allow them to run wheel-to-wheel.


When I say double tubes, I am merely referring to two separate bar rolls behind each seat. A straight roll bar screams kit all over it.

I see it a bit differently. When I see a well-integrated double hoop like that in the 458 Spider or the MP4-12C Convertible, I think "marvelous street car with sensible compromise head protection." When I see a poorly integrated double hoop, I think "style bar bought from the cheapest seller on Ebay." When I see a straight roll bar, supported properly, I think "track car."

[JeromeS13]

From the NASA CCRs:

11.4.7 Roll Bars

All open cars should have a roll bar installed to help protect the occupant(s) from injury during a roll-over. The
main hoop shall be one continuous piece with smooth Mandrel bends with no evidence of crimping or wall
failure. All welds should be of the highest possible quality, with full penetration [Ref:(15.6.15)]. All cars with roll
bars are required to have adequate roll bar padding per CCR section #15.6.4. In cases where the driver’s head
may come in contact with the roll bar should the seatback fail, a seatback brace is required in conformance with
section #15.6.21. Acceptable roll bars include, but are not limited to, the following:

Which means, if it doesn't have adequate roll over protection, the top must be in place.

[bbjones121]

There is no minimum bend requirement in this and I don't see where it says it needs to be straight.


From the NASA CCRs:

11.4.7 Roll Bars

All open cars should have a roll bar installed to help protect the occupant(s) from injury during a roll-over. The
main hoop shall be one continuous piece with smooth Mandrel bends with no evidence of crimping or wall
failure. All welds should be of the highest possible quality, with full penetration [Ref:(15.6.15)]. All cars with roll
bars are required to have adequate roll bar padding per CCR section #15.6.4. In cases where the driver’s head
may come in contact with the roll bar should the seatback fail, a seatback brace is required in conformance with
section #15.6.21. Acceptable roll bars include, but are not limited to, the following:

Which means, if it doesn't have adequate roll over protection, the top must be in place.

[JeromeS13]

There is no minimum bend requirement in this and I don't see where it says it needs to be straight.

This is the guidance for HPDE. Any competition vehicle is subject to more stringent guidance (section 15.6 of the NASA CCR's).

[StatGSR]

Also, NASA is just one group, SCCA is another. And on top of that there are hundreds of hpdes out there that are not run by either group..

[Mitch Wright]

Blueafro,
At the track I currently manage and the 2 tracks that I managed prior we required open top cars to have either Factory Roll over protection as stated in the owners manual this includes Open top late model Porsches, BMW Roadsters, Honda S2000 as examples. Or a SCCA solo 1 approved roll bar for track day use. That may not hold true for some track day operators that rent a facility and host events but that I know most track operators that I talk to have requirements similar to ours.
With that said 818S roll bar meets our track day requirements with out issue.

[flytosail]

Would an added shoulder harness mounting point on the rollbar "help" with the track sign off? I noticed the added tie in point on the initial gocarted 818.

[blueafro]

Blueafro,
At the track I currently manage and the 2 tracks that I managed prior we required open top cars to have either Factory Roll over protection as stated in the owners manual this includes Open top late model Porsches, BMW Roadsters, Honda S2000 as examples. Or a SCCA solo 1 approved roll bar for track day use. That may not hold true for some track day operators that rent a facility and host events but that I know most track operators that I talk to have requirements similar to ours.
With that said 818S roll bar meets our track day requirements with out issue.

Mitch,

I don't disagree with anything you're saying. My post did not regard the 818 at all. It was simply in reply to the post about whether the double-hoop roll over protection commonly seen on exotic cars was race legal. It isn't, anywhere that I know of.

Track days are another matter entirely, and many track days will allow an open car that has such protection from the factory. Some track days will not allow them, however, as they very rarely pass the broomstick test with a helmeted driver. Some organizations will let them run but require the top to be raised. Aside from track days run by the major clubs (SCCA/NASA/BMWCCA/etc.), track days rules vary quite a lot from track to track and organizer to organizer.

[ehansen007]

Google "Miata Rollover" and I think you'll have your answer. A picture is worth a thousand words and when the image results pop up you'll see what I mean. The one I'm referring to is too graphic to post here. THAT is the difference between a style bar and a roll bar.

[Mechie3]

Would an added shoulder harness mounting point on the rollbar "help" with the track sign off? I noticed the added tie in point on the initial gocarted 818.

Not sure what you're referring to offhand, but when I asked FFR how to mount shoulder harnesses on an 818S they said you'd have to fab up a harness bar that connects to the seat belt mounting poins just above the outer shoulders of the driver and passenger. The R comes with a bar welded in to a similar location.


Google "Miata Rollover" and I think you'll have your answer. A picture is worth a thousand words and when the image results pop up you'll see what I mean. The one I'm referring to is too graphic to post here.

I think I know the one you're talking about. Haven't seen it in a while, but it's on a website encouraging miata owners to install rollbars. Think it was cyan? I do remember it being upside down with lots of red.

[Frank818]

Google "Miata Rollover" and I think you'll have your answer. A picture is worth a thousand words and when the image results pop up you'll see what I mean. The one I'm referring to is too graphic to post here.

Ugh... I've just looked at some. Pix and vids.

My question is: why is this car still up for sale?

[Mechie3]

Most accidents likely don't cause rollovers or flips. Same could be said for any convertible without integrated roll bars: Miata, Sebring, Mustang, Camaro, etc.

[Frank818]

It's still interesting, those sports cars (ok Sebring is not sports! lolll) usually don't have much of an integrated roll bar (recent T-Bird as well doesn't I think), but if you take a look at the convertible PT Cruiser, it has a roll bar very similar to the 818's! lolll

Anyway, what matters is the 818, that's why we're here. :)

[bbjones121]

I just hope it truly is the case that the rollbar must be straight to race. If that is the true, than sweet, i love the straight bar. I can tell people there is actually a purpose other than saving money. For some reason though, I get the feeling that it may be people only interpreting the rules as requiring a straight rollbar to justify the cheap look of it.

[longislandwrx]

I just hope it truly is the case that the rollbar must be straight to race. If that is the true, than sweet, i love the straight bar. I can tell people there is actually a purpose other than saving money. For some reason though, I get the feeling that it may be people only interpreting the rules as requiring a straight rollbar to justify the cheap look of it.

Again, SCCA requires the main hoop to be one piece, have 4 bends maximum, totaling 180 degrees ± 10 degrees. I don't have the book in front of me.

NASA says: The main roll cage hoop should be as wide as the full width of the interior and must be as close to the roof as
possible without violating CCR section #15.6.20 Inspection. One continuous length of roll bar tubing shall be
used as the main hoop. The main hoop must consist of not more than four (4) bends maximum, totaling one
hundred eighty (180) degrees +/- ten (10) degrees

15.6.20 says a 3/16 inspection hole must be drilled so they can verify tube thickness.


THERE IS a provision,

15.6.19 Bending Allowances
If the maximum number of bends permitted for any one bar is exceeded, all required components shall be made
from the tubing size listed for the next heavier category and must be approved by a NASA race tech shop or
scrutineer.

Since the next category still has 1.5x.120 it seems that you'd just need someone to sign off on it. Which is probably easier said than done. I don't think SCCA has that provision.

[bbjones121]

Okay, then I guess the single bar is pretty cool because it defines it as a "race" car.

[tmoretta]

Just received a nice poster from FFR. Beautiful pic. of the 818R. The roll bar pictured, however, is different. It has two small hoops welded to the main overhead hoop. Anybody know what this is about? Looks like it provides more helmet clearance. Will it be available on the S model?

[Frank818]

By any chance are you allowed to post that pic here?

[C.Plavan]

Just received a nice poster from FFR. Beautiful pic. of the 818R. The roll bar pictured, however, is different. It has two small hoops welded to the main overhead hoop. Anybody know what this is about? Looks like it provides more helmet clearance. Will it be available on the S model?

100 bucks its the computer cad design picture. Not the actual 818R.
Does the poster look like this? http://factoryfive818.wordpress.com/

[Silvertop]

100 bucks its the computer cad design picture. Not the actual 818R.
Does the poster look like this? http://factoryfive818.wordpress.com/

You would win the $100 bet. I just got one of these posters in the mail too, apparently as a reward for buying a downloaded 818 Manual. It came with a promotional letter personally signed by the ACTUAL Dave Smith of FFR, encouraging us to become part of the FFR community by joining the forum and buying a kit (Thanks Dave, but I'm already a member and you are shipping my kit next week!):rolleyes:

The CAD representation that showed up on the poster predates the actual 818R prototype, and it is highly unlikely that this version will ever be produced. Looks cool, but I don't think the roll bar would be SCCA or NASA legal for racing. Nice poster though. I'll be putting it in a frame and hanging it out in the garage to serve as motivational therapy for keeping my 818S build on track! :)

[bbjones121]

I hope mine comes today.

[Xusia]

I know that roll bar isn't SCCA or NASA legal, but since I don't plan to race mine I sure wish it was an option nonetheless!

[flytosail]

Wife commentated that something came from FFR. Will know in a few hours.

[bbjones121]

I got mine today! Just in time for my garage remodeling.

[bbjones121]

I do wish there was an option to get the roll bar tucked inside the rear head cowels like in the poster.

[Grintch]

I am not sure the rear bracing would satisfy a TT tech inspector, but it would probably be OK for most HPDE events.

[SnakeElvis]

Anyone know who makes a square roll bar like this ??46947

[Lumpyguy]

Just have a local race shop make you one with the OE (FFR tubing specs) give them the measurments then cut it off and re weld it on if you are good at fabing and welding. I changed mine to 2 double humps like Aloha did. I think the double humps look better than one bar. check out my build blog.