retatctable hard top miata roll bar ???

[racecarbuilders]

i have a customer that would like me to install a 4 point in his miata ..the problem is the retractable hard top ...there is no way to get back down bars in ...i was just wondering if there was an approved variation ...and what it was ...i was thinking a normal main hooop w harness bar and diagonal ...to the floor then tie into the stock roll bar ...maybe use the next larger size tubing ..need some help on this one because i dont see how to do it and keep his top working ..

[Shawn M.]

Hard top!

[1LapSRT]

Hard top!

 

He already has a hard top.... a motorized one.

[Tirewarmer]

I haven't seen a bar for the retractable hardtop yet. Can you take any close up pics? I can;t imagine that you can build an acceptable bar without some sort of rear or front diagonal bracing.

[kbrew8991]

the cage in my MR2 has no support behind the main hoop and was logbooked this past weekend - it uses a "petty bar" diagonal for support instead.

 

The petty bar runs from the top of the main hoop near the drivers head down to the passenger side floor right where the a-pillar bar meets the floor. I can take some pics if that works better for explaining it. You will lose your passenger seat area this way however.

[TurboShortBus]

Ken, does your main hoop also attach to the stock shoulder harness mount location on each side (as is allowed for cars such as Porsche 914, Pontiac Fiero, and the aforementioned Toyota MR2 that cannot feasibly have rear kickers per CCR 2009.4, section 15.6.11.A)?

 

Mark

[TurboShortBus]

As an "it's better than nothing" suggestion, and if this car is only being used for HPDE and not for full wheel-to-wheel action, would a side bar (removable or permanent, attaching to the main hoop at the same intersection point as the harness crossbar) on each side suffice as support for the main hoop? Factory roll bars don't have rear kickers or other fore-aft support at the top of their hoops, so the amount of support would be similar to an OEM roll bar while adding the benefit of some side impact protection, and building them removable could keep the car civilized for daily use.

 

Now that I notice it, HPDE section 11.4.7 does not mention anything about rear kickers as they apply to a roll bar (not a roll cage), so in this particular instance, a roll bar (hoop) only may be sufficient, but somebody smarter than me should make that determination; I'm just putting it out there.

 

Mark

[kbrew8991]

Ken, does your main hoop also attach to the stock shoulder harness mount location on each side (as is allowed for cars such as Porsche 914, Pontiac Fiero, and the aforementioned Toyota MR2 that cannot feasibly have rear kickers per CCR 2009.4, section 15.6.11.A)?

 

Mark

 

yep, or it wouldn't have passed

 

you *can* add rear supports, they'd just need to pass through the rear glass which as I read it would be allowable in TT and PT. Cage v2.0 will take advantage of this.

[racecarbuilders]

WOW YOU GUYS ARE JOHNNIE ON THE SPOT THANKS

 

IF I GRABBED EVERYTHING NO BACK BARS ARE REQUIRED IF NOT FEASABLE IF IT TIES INTO THE HARNESS BAR ..SHOULDER RESTRAINT AREA ....AND SOME SORT OF EITHER PETTY BAR OR DOOR BAR IS ALSO NECISSARY ...???CAN THE PETTY BAR B A BOLT IN ??? THAT SEC ON THE CARS THAT REAR DOWN BARS WOULD BE HELPFUL .... AND I AM NOT SURE I CAN GET IT 2 INCHES ABOVE HIS HEAD AND STILL HAVE THE TOP WORK ...HE HAS A RACE SEAT AND ISNT REAL TALL

 

AND IT IS A PAIN IN THE A BUT YOU CAN GET BACK BARS IN A MR2 AT LEAST THE NEWER STYLE ...YOU JUST NEED TO REMOVE THE ENGINE TO DO IT ..