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Before welding in your roll hoop, set it in place, add the seat, and give the car the "broomstick test." That's where a broomstick is sat on top of the rollhoop and the nose of the car. Your head (helmeted if you're planning on driving on track) must be 2" or more under the stick.

My brother assembled a well-known Locost kit and said it was way too low for him, so he raised it 2" to give himself more space. I saw the car later and didn't notice anything worth mentioning, but should have...

For an upcoming event, he learned the organizers are going to actively enforce the broomstick test. So he finally (after driving the car for two years) did the test himself and was shocked to find that he's still way too close. He's going to have to extend the hoop another 2". Modifying it now is going to be a big PITA due to the angled downtubes, since they'll miss the raised cross tube.

It's something he should have double-checked during construction, but also something the manufacturer dropped the ball on. While they can't be expected to know how tall buyers are, it's a cop-out to assume everyone's 5'-6". They probably pulled this stunt because the car looks better with a low bar, and costs less to make and ship. They could have asked how tall he is and and made the bar accordingly, or at least noted the issue in the instructions. However, in the end it's up to each builder to check for himself, since it's his head on the line.

Hi Kurt,
Since your brother will have to do some cutting and welding anyway, I wonder if it wouldn't be too much more trouble to add a forward hoop/bars to make a full roll cage..? It would fix the 2" clearance problem and provide all the other benefits of a full cage too, of course.

It seems that many cars have this problem. I've seen a lot of on-track pictures of cars with driver's heads that are higher than the car's roll bar. I'm surprised that the track day organizers let them run.

I've also seen cars with two small hoops (one for driver, one for passenger, or even just one for the driver only) added to the top of the existing roll bar to add a few inches of height. As long as the upper end of the diagonal braces will still be within 6" of the top of the roll hoop with the addendum hoops added, I think this might be a legal, and minimal work, way to fix the problem..?

Dean

That's exactly what he did, adding a little "bump" tube on top of the existing bar right above his head. Aesthetically, Locosts don't look good with roll hoops or cages, especially tall ones. It's probably why the mfgs cheat the way they do, but it seems like a risky sales tactic considering what's on the line.

Each individual absolutely needs to be responsible for reading and understanding the rules layed forth by the specifics sanctioning bodies that they plan to run any type of performance events with, and to choose/design/build their car accordingly. Not meeting on-track rollbar requirements without modification is not something I would assume to be unusual for most street-oriented replica/kit cars, nor would I expect otherwise. Realistically it would probably surpass most of my street expectations if it clears the top of the unhelmeted head of a 95th percentile male height.

Different sanctioning bodies each have differing requirements on the "broomstick" type tests for a given typ of event, if they they call for one at all. However in regards to roll bars, as opposed to cages, I believe many organizers simply require that the measurement be taken from the horizontal line across the top of the main hoop, as that is the most realistically feasible way to measure a complete car in an unbiased and efficient manner before an event. And while some events/organizers only require it to be "higher" than the top of the helmeted head, others require a specified minimum (usually 1-3 inches) height above the helmeted head.

Hey Kurt

Are we talking broomstick resting on top of the nosecone? Or broomstick resting on "substantial structure", which a little tougher to find in a 7.

Cheers, Ted

Maybe he should lower the seat? My race car has a low seat, but I never fail to wish to be lower as I'm getting up to speed on a track. Locosts seem to have a seating position which appears painfully upright...

Don't know. They probably just set it on the top of both the hoop and nose, and I absolutely agree that's the wrong way. Ain't no way a fiberglass nose is going to support any weight. Seems like it should be from the bottom of the hoop and the front-most bulkhead, but I don't make the rules.

I made that suggestion about his seat, but it's already within 1/4" of the floor.

Do the organizers of this track day require all convertibles to remove their windshield/frame in order to pass tech, or just your brothers car? I don't know what kind of seats your brother is currently running, but is there any possiblity of a thinner seat?

I see where you might be going with this, the broomstick test is more about liability than reality. Track days I attend they use rollhoop to top of windshield frame as their broomstick points -- no way in heck the frame on a B or Midget will do diddly but a British engineer signed off on it 30 years ago, so...

Same goes for cheesy unsupported factory hoops in Mustangs and BMW Z cars, they don't even have to pass the stick test since they're factory pieces.

t



Side mount them and drop them through the floor?

But that's kinda like swimming naked over sharp rocks, with your valuables being the most likely to catch on something...

Hmmm. My understanding of the "broomstick test" was that your head did NOT have to clear the broom by 2", but just be under it.

From the 2009 SCCA GCR: "The main hoop must be high enough that a straight line drawn from the top of the main hoop to the top of the front hoop would pass over the driver’s helmet and steering wheel when the driver is seated in the normal driving position.
Additionally, the top of the main hoop must be at least 2 inches above the driver’s helmet as illustrated in figure 10."

Confirms this, your head must be 2" under the top of the main hoop and clear a line or broomstick between the front hoop and the main hoop. NOT clear it by 2", which would be a hard test for almost any low front cage design to pass without a main hoop way higher than 2" above the drivers head.

That SCCA spec is only for wheel-to-wheel racecars, which are required to run a full cage. The SCCA's rollbar requirements for Level 1 and 2 PDX (HPDE) are simply "The top of the roll bar shall not be below the top of the drivers helmet" with it only being "recommended" that it clear the drivers helmet by 3 inches.

After doing a little research, I've found that the SCCA is generally the standard that most of the stricter (apparently not strictest though)organizations will use, due to their safety/legal reputation. NASA doesn't even specify a min roll bar height for open cars at HPDE track-days, just that you need one. PCA does require the "broomstick" test for open cars without factory rollbars at HPDE, but defining it exactly as I would expect: "The driver's helmeted head is below a bar placed on top of the rollbar and windshield."

I am having a hard time coming up with any more reputable track-day organizations than these to which manufacturers should even consider adhereing to.

I have only ever seen the "broomstick" test for roll bars to be performed from horizontal or the top of the windshield frame, and never before to the nose, or any other part of the chassis. It appears that Kurts brother mainly needs to try finding just about any other club to run with.

Just for laughs:

http://www.wscc.co.uk/floors.htm

Though I do agree with what you're saying about the inherit dangers of such a strategy.

t

I am in the process of starting the build of my cage. I don't have a helmet yet but how much height can I expect a helmet to add to the top of my head?

evo

It depends on the helmet and the head! A good rule-of-thumb is that the helmet will add from 2 to 3 inches to your seated height. Are you planning on a DOT approved motorcycle-type open face helmet? They are not always as "tall" as a road-racing helmet, or a closed face model. It does vary a bit by manufacturer. Wouldn't hurt to go try on a helmet of the type you're considering and do some measuring!

JD "Big Head" Kemp