Grassroots Motorsports

Register Log in to GRM
- Community

Birthdays
Recently on the Classic Motorsports forums

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Login to post Forums » Grassroots Motorsports » Article/Info request - Roll Bar in a Street Car

1 2 3

Sept. 17, 2009 10:15 a.m. Keith PowerDork

You can also get a dual-density pad. It's got the SFI core, but a softer layer on top. Not as soft as pipe insulation, but between the large surface area and the softer pad it's designed for street use. You can pop the big outer layer off to use it for a helmet. I use this in my caged Miata, put the second layer on for transits and pull it off for the closed stages.

1320, the FIA disagrees with you about shoulder belt placement. Ideal is a shoulder harness that is anchored between level or 10 degrees below the shoulder line, although up to 45 degrees down is acceptable. Above the shoulders is not.
Sept. 17, 2009 10:43 a.m. Rad_Capz New Reader

Keith wrote:

You can also get a dual-density pad. It's got the SFI core, but a softer layer on top. Not as soft as pipe insulation, but between the large surface area and the softer pad it's designed for street use. You can pop the big outer layer off to use it for a helmet. I use this in my caged Miata, put the second layer on for transits and pull it off for the closed stages.

1320, the FIA disagrees with you about shoulder belt placement. Ideal is a shoulder harness that is anchored between level or 10 degrees below the shoulder line, although up to 45 degrees down is acceptable. Above the shoulders is not.

Keith, Excellent point about the dual density padding! When I purchased my SFI padding I thought thats what I was going to recieve and was confused by what arrived. I needed to install what I got to go to a couple track days but I'm going to replace the SFI I already bought with the dual density because I also use the car on the street without a helmet.

The shoulder harness angles mentioned in all the information I could find from manufacturers and sanctioning bodies all agreed with keith and the FIA with level or slight downward angles from shoulder height. I have a few different attaching points at each harness point to allow for different size occupants and possible changes in what is considered optimal positioning. When in doubt go with the harness manufacturers recommendations for angles of all attaching points.
Sept. 17, 2009 12:09 p.m. dj06482 New Reader

This is an excellent and pertinent thread, as I was having an email discussion with two friends on this very topic last week. I'm trying to map out a plan for my E36 that I'm currently using as a DD in the good weather months (I'm located in CT). One of my toughest decisions is how far to go with the car, as I feel if I'm spending significant time on the track I should have a proper roll bar at the very least, along with a harness and fixed back seat. However, at that point, using it as a DD (especially for a 75 mile round-trip commute) is probably not the best idea. Still haven't made a decision, but I'm leaning towards buying/building a purpose-built track car and keeping the E36 as a daily.

Rad_capz - your build thread is excellent and the car is simply stunning - nice work!

Keith - thanks for pointing out the dual-density padding. I was looking at that last week and really liked the concept, but didn't realize you could take it apart depending on what you're doing with it.

When I was researching roll cage padding, I came across this site: http://www.stbarinc.com/orange-aid/index.html

BSCI seems to have a lock on the quality roll bar padding market, but has anyone had any experience with the Orange-Aid product?
Sept. 17, 2009 2:34 p.m. Rad_Capz New Reader

In reply to dj06482: DJ, Thanks for the compliments! If that thread saves just one person from an injury it was worth writing. I have to finish it up with bar padding info.

I think I'm going to order a stick of the Orange Aid and the dual density SFI stuff that separates and compare them. Maybe do some unofficial testing. with the 2 types of padding I already have pieces of, and the 2 others I'll buy.

I've driven my car on 2-3 hour trips with the cage installed and the only really noticable drawbacks are when getting in climbing over the doorbar, and needing to loosen the harnesses to reach anything. Other caged streetcars I've had did not have a welded door bar or full containment seats.

Oh by the way DJ I lived very close to where you are. (I figure your SN is zip code) I was on RT 34 on the river right under the dam. Those houses where everyone goes to watch the flooding! JW Racing and fabrication in Seymour did my cage and welding work. I can't weld well enough to have my life depend on it! If you need a fab guy Joe does excellent work.
Sept. 17, 2009 3:03 p.m. 1320 New Reader

I should have written that differently. Ideal is at the top of teh shoulders. The od part is that some santioning bodies allow above and or below. Its obvious that if below the top of the shoulder, that as the belt tightens in an impact, the effective area gets shorter, meaning your spin has to get shorter too.....It very very very common in sand rails to mount below (way below) the shoulders and even more common to get compression fractures even in minor (even no ncidence) driving.

Above the shoulder has little impact on the spine deformation, but then belt seperation becomes an issue that has to be addressed in fabrication. The sanctioning bodies are afraid that the upper body could come out of teh belts if above much. Which is true depending entirely on the belt mount (wrap around) primarily.

Personally I wouldnt drive a car with a harness that has shoulder belts mounted below my shoulder. I dont need saftey items that make it more dangerous.

They probably calculate belt stretch to get the below angle number, but not something I bet on. New belts stretch like crazy, like they should, but as they get older (and they do) they sure get tight.

A good sanctioning body does a good job overall. The unregulated stuff is just scary.
Sept. 17, 2009 3:16 p.m. Keith PowerDork

The dual density stuff I've got is from BSCI, of course. I'm actually in the middle of a bunch of research on related subjects, and here's a picture of four types of padding that I took a couple of hours ago. Pipe insulation, soft rollbar pad, SFI and dual-density SFI.

1320, I wonder how much of what you're seeing is seat related? I've got a tall torso, and the holes in race seats are in pretty much the perfect spot for me. They're tall for my wife.

I also came across some information from the SFI saying the appropriate angle for the shoulder belts is 5 degrees below to 30 degrees above. So the only placement that SFI and FIA agree on is between 0 and 5 degrees below.

The document also shows the degradation of nylon belt webbing over time. It's fairly frightening. After 24 months of outdoor exposure, it's down to 20% of the original strength. Thus the 2-year lifespan of SFI belts. FIA belts use a different polyester material.
Sept. 17, 2009 8:04 p.m. S2 New Reader

Interesting topic. As far as the roll bar/cage question in a street car, both Jeep and Ruf make factory "caged" vehicles, so there has to be validity in doing so and way to do it safely in a street vehicle.

As interested as I would be in such an article, if I were GRM/Tim I'd be having a conversation with my lawyer re: liability first before publishing such a story. Of course, he's already encouraging us to fling ourselves around tracks and parking lots with wild abandon, so maybe this is a moot question. Bring it on
Sept. 17, 2009 8:10 p.m. JeepinMatt New Reader

S2 wrote:

Interesting topic. As far as the roll bar/cage question in a street car, both Jeep and Ruf make factory "caged" vehicles, so there has to be validity in doing so and way to do it safely in a street vehicle.

True. My Jeep has some very light padding over the steel bars. The SE (that is, four cylinder Wranglers) didn't even come with any padding as recently as the last generation (TJ)
Sept. 17, 2009 8:36 p.m. Keith PowerDork

Don't forget the 911 GT3 RS - Porsche does factory cages as well. Someone send me one, I promise to investigate it.
Sept. 17, 2009 9:28 p.m. dyintorace Dork

Very interesting and informative thread. I plan on having at least a roll bar, if not a roll cage, in the FC RX-7 LS1 I'm building. My goal is a streetable track car, so risks on the street will play a part in my decision.
Sept. 17, 2009 10:04 p.m. amg_rx7 Reader

Keith wrote:

Don't forget the 911 GT3 RS - Porsche does factory cages as well. Someone send me one, I promise to investigate it.

I've Googled some pics. They seem to place the bar pretty far back and pair it with a fixed back, composite seat and harnesses. Now that I've been researching it, I suspect that these three items are packaged together for a reason. Then again, I'm just an amateur. I'd rather hear this from a professional.
Sept. 17, 2009 10:05 p.m. JeepinMatt New Reader

I'm planning on driving the E30 to the track until it ceases to be street legal, so this has got me thinking. Same goes for my Jeep; with a beefier cage and rockcrawling without a helmet.
Sept. 18, 2009 12:15 a.m. Butch_86 New Reader

amg_rx7 wrote:

I've Googled some pics. They seem to place the bar pretty far back and pair it with a fixed back, composite seat and harnesses. Now that I've been researching it, I suspect that these three items are packaged together for a reason. Then again, I'm just an amateur. I'd rather hear this from a professional.

IIRC the harnesses and fixed backs are euro only. The US version has reclining seats and 3 points. A guy at the track had one and he purchased the euro seats and imported them and had them installed by a shop here. He also put in 6 points.
Sept. 19, 2009 11:11 a.m. Varkwso Reader

Keith wrote:

Don't forget the 911 GT3 RS - Porsche does factory cages as well. Someone send me one, I promise to investigate it.

The 911 GT3 RS does not come with a roll cage in the US. Having thrown them around the track - I noticed.
Sept. 20, 2009 6:43 p.m. JoeyM Reader

Keith wrote: Don't forget the 911 GT3 RS - Porsche does factory cages as well.

I don't know if it is factory or not, but Peter Lear's GT2 (the one he and Ian Stewart used in the One Lap*) has a cage and harness. I don't remember if the seats were adjustable or not.

[*] http://www.onelapofamerica.com/history/2009/results/showResults.shtml?y=2009&r... http://www.youtube.com/watch?v=7M8kvP3WgC0&feature=channel_page (4:50 into video)
Sept. 20, 2009 7:01 p.m. mistanfo Dork

Keith wrote:

1320, I wonder how much of what you're seeing is seat related? I've got a tall torso, and the holes in race seats are in pretty much the perfect spot for me. They're tall for my wife.

But many people from the North American continent have torso lengths that are too tall for the average race seat (you commented on my torso length at the Mitty when I sat in your Targa car). customers were always fun to deal with when I worked at OG Racing, though I could empathize with them. The best bet for a lot of people is to remove the bottom pad, if that is an option on the seat. Also, Kirkey (and likely others) will custom make a seat to your provided measurements.
Sept. 20, 2009 7:12 p.m. dj06482 New Reader

Rad_Capz wrote:

In reply to dj06482: DJ, Thanks for the compliments! If that thread saves just one person from an injury it was worth writing. I have to finish it up with bar padding info.

I think I'm going to order a stick of the Orange Aid and the dual density SFI stuff that separates and compare them. Maybe do some unofficial testing. with the 2 types of padding I already have pieces of, and the 2 others I'll buy.

I've driven my car on 2-3 hour trips with the cage installed and the only really noticable drawbacks are when getting in climbing over the doorbar, and needing to loosen the harnesses to reach anything. Other caged streetcars I've had did not have a welded door bar or full containment seats.

Oh by the way DJ I lived very close to where you are. (I figure your SN is zip code) I was on RT 34 on the river right under the dam. Those houses where everyone goes to watch the flooding! JW Racing and fabrication in Seymour did my cage and welding work. I can't weld well enough to have my life depend on it! If you need a fab guy Joe does excellent work.

Rad_Capz - Thanks very much for your write-up, it definitely has a lot of good info. I'd definitely be interested to hear about your impressions of the Orange-Aid and BCSI dual-density padding.

We're about 5 miles south of the dam of of Rt. 34, it's a great area. I saw your CT plates and was going to ask where you lived in the state - great news that your fabricator is right in our backyard!
Sept. 21, 2009 11:07 a.m. Keith PowerDork

mistanfo wrote:

The best bet for a lot of people is to remove the bottom pad, if that is an option on the seat. Also, Kirkey (and likely others) will custom make a seat to your provided measurements.

That's a good point, I have changed the bottom pad in my seats from a hard foam to Backsaver memory foam. Drops me down noticeably as well as makes the seat more comfortable.
Dec. 10, 2009 4:00 p.m. Chris_V SuperDork

Sorry to drag this back up, but...

Has anyone seen any studies showing injuries in dual purpose street/track cars with cages? We all know that theoretically, you can bang your head on one pretty easily if you have a minor accident, but the question is, how often does it ACTUALLY happen? Theoretically it adds risk, but does experience say that that risk is actually so small as to be a non-issue? (and I'm talking actual cages not the cheap show bars that so many rice-boys might have).

I mean, I drove my V8 RX7 for many years on the street with an Autopower 6 pt cage (and SFI padding) and no problems. But in 30 years of performance driving I've only been in a couple of <15 mph rear end accidents where I was hit at a light (and saw the accident about to happen so moved to mitigate the results), so maybe my perspective is off.

Interestingly enough, I got my Autopower cage from a guy who had had his FC RX7 wrecked on the street with the cage (it was a hit on the front corner that didn't compromise the cage at all) and he didn't talk about any head injury from it.

Only 3% of all drivers annually get into accidents, only 1.5% get into injury accidents, and only.0001% get into fatal accidents. How hard is it to remain in the 97% of drivers that almost never get into accidents, thus rendering the question of what might happen to your head and a roll cage moot? How many of you guys driving dual purpose street/track cars have ever had any injury due to it?

Is it something to be less concerned about that the dangers of driving an MGB on the street?
Dec. 10, 2009 4:54 p.m. wbjones Reader

mine in the CRX is in great need of some padding... I am fairly sure that if I get in an accident I risk head damage... I'm tall and the seat back doesn't go as high as I would like ... that said ... padding and a different seat...
Dec. 10, 2009 5:58 p.m. Keith PowerDork

There's no question that a roll cage in a Miata puts you at high risk of head bonkage. It's a small car, there's a limit to how far away you can get from that bar at the top of the window!
Dec. 10, 2009 8:09 p.m. NYG95GA SuperDork

I would argue that the kind of person who would put a bar in their car is an above average driver, in a well-sorted car. This would would negate most of the statistics concerning % of drivers suffering this or that during accidents.

My position is that if you are alert, and good behind the wheel, the chances of you're having an accident are far reduced, and the chances of your having an accident in a vehicle equipped with a bar reduces the statistical possibility to nearly zero.
Dec. 10, 2009 8:15 p.m. footinmouth New Reader

Rad Caps -thanks for the JW Fabrication info -I went to the shop to have them look at myDD /track tacoma and was very impressed . About as nice as welding / fab work gets . The nice thing about a roll bar for my truck is - my head is inside the vehicle and the bar is on the outside .
Dec. 10, 2009 9:42 p.m. billy3esq Dork

NYG95GA wrote:

My position is that if you are alert, and good behind the wheel, the chances of you're having an accident are far reduced, and the chances of your having an accident in a vehicle equipped with a bar reduces the statistical possibility to nearly zero.

The only problem with your theory is that the most likely accident scenario for noggin to rollbar contact is getting hit from the rear. That is almost always difficult or impossible to avoid, even for an alert, above-average driver in a well-sorted car.
Dec. 10, 2009 11:18 p.m. SkinnyG Reader

ReverendDexter wrote:

being able to flex your upper body can make the difference between walking away and a crushed skull.

Has anyone actually had the wherewithal to physically "flex their upper body" when rolling their car? I've had almost enough time to say "OOOHH FFFFFU" before it's already too late. Apparently I can even keep the throttle planted through the whole ordeal.

Ride along with this guy and mentally try it:

http://www.youtube.com/watch?v=2IpCIYF0lVU

1 2 3

You'll need to log in to post.