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***Roll Cage FAQ's***

404K views 601 replies 194 participants last post by  Deleted member 74842 
#1 ·
Thanks to Gilsbach for making this a sticky.

Everyone seems to have a lot of the same questions about cages and chassis' on a regular basis. Let's see if we can put them all in here so everyone has one central place to look.
 
#2 ·
I guess to start things off here's some quick points. Anyone and everyone, feel free to add because there's going to be a ton of questions and answers.

You can only go 11.50 ET (1/4 mile) before having a rollbar in a hardtop car, 13.49 in a convertible.

6 point is good to 10.00 ET/ 135mph (1/4 mile) in a hardtop car. Not sure for convertibles, anyone feel free to chime in on this.

10 point good to 8.50 ET / 150mph (1/4 mile) in a hardtop car, after certification. Need some help on the convertible ET spec....

SFI 25.4 / 25.5 good to 7.50 ET / 180mph @ 3600lb maximum after certification. Can be Chromoly or Mild Steel construction.
SFI 25.3 good to 6.50 ET @ 3600lb maximum after certification. Chromoly roundtube construction only
SFI 25.2 good to 6.00 ET @ 3200lb maximum after certification. Chromoly roundtube construction only
SFI 25.1E good to 6.00 ET @ 2800lb maximum after certification. Chromoly roundtube construction only
 
#15 ·
I guess to start things off here's some quick points. Anyone and everyone, feel free to add because there's going to be a ton of questions and answers.

You can only go 11.50 ET (1/4 mile) before having a rollbar in a hardtop car, 13.49 in a convertible.

6 point is good to 10.00 ET/ 135mph (1/4 mile) in a hardtop car. Not sure for convertibles, anyone feel free to chime in on this.

10 point good to 8.50 ET / 150mph (1/4 mile) in a hardtop car, after certification. Need some help on the convertible ET spec....

SFI 25.4 / 25.5 good to 7.50 ET / 180mph @ 3600lb maximum after certification. Can be Chromoly or Mild Steel construction.
SFI 25.3 good to 6.50 ET @ 3600lb maximum after certification. Chromoly roundtube construction only
SFI 25.2 good to 6.00 ET @ 3200lb maximum after certification. Chromoly roundtube construction only
SFI 25.1E good to 6.00 ET @ 2800lb maximum after certification. Chromoly roundtube construction only
where did you get the 180mph spec?
 
#3 ·
I'll prime the pump with a couple of softball questions, and tomorrow when I have my rulebook in front of me, I'll look up the 'vert info.

First question:

Is there a disadvantage to converting a 6-point bar to a 10-point cage later on? Are you better off going with a cage from the start if you think the car may eventually need it, even if you don't right now?

Second question:

Is there a big difference in safety and chassis stiffness between a bolt-in 6-point and the equivalent welded bar?
 
#4 ·
first: The major disadvantage to converting from a 6 - 10 pt is that a 6 pt has to be 1 3/4" compared to 1 5/8" on the 10 pt. Plus it is way more expensive to add the conversion than what it would have been to do it all at once. Plus, you have to make sure the guy doing the 6 pt made it in a manor that would be acceptable to be converted. So Yes, if you think you may go faster later, you would be much better doing the whole cage the first time.

Second: Yes, a fully welded bar will stiffen a car much better than a bolt in bar. As far as safety, it would really depend on how it was bolted in. Did they bolt it in properly with plates underneath. I would still believe the weld in is safer.
 
#9 ·
OK, looking at my 2008 rulebook...

Section 5A.4 says that a 6-point roll bar is mandatory in convertibles running 11.00 to 13.49 in the quarter (7.00 to 8.25 in the 1/8 ) and a roll cage is required for any convertible running quicker than 10.99 (7.00 in the 1/8 )or faster than 135 mph.

Chassis stickers are required for all cars running between 7.50 and 9.99 (4.50 and 6.39 in the 1/8 ).

The Advanced ET section 5B calls out SFI chassis specs for cars running between 6.00 and 7.49 in the quarter (3.66-7.49 in the 1/8 ).

So there ya go.
 
#30 ·
this may be a stooge-like question but:

do you have to have a cage attachment/mount on the back of an aluminum seat like a Kirkey? or is that only required for plastic seats. I know alot of guys do it regardless, but just wondering if you HAVE to have it for alum seats.

Thanks
 
#38 ·
General Regs 6:2 (excerpt)
Except as noted in SFI Specifications, seats must be bolted with four bolts (and nuts and washers) on the bottom and one bolt in the rear into crossbar; all bolts must go into frame or crossbraces.
No exceptions to this rule for seat material as far as I see.
 
#32 ·
Are there any rules regarding the rear bars not having bends? I keep hearing this but mine do and it was certed but doesn't mean it should have been.
no, if that were the case alot of guy's would be phucked
 
#34 ·
Are there mph limits to any of the SFI 25.X chassis specs? Or is it all based on ET?
 
#41 ·
Is it SFI acceptable to substitute CMoly pipe with equal wall thickness , but has larger diameter? For example: Say if have a SFI bar that calls out 1 1/2 diameter with .063 wall. Can I use 1 5/8 with .063 wall?
Thanks
Eddie Wilson
as long as the wall thickness is equal or greater yes it's just fine
 
#42 ·
what are the rules for 1/8 mile. my chassis is certed to 8.50 but I can run faster. I want to lean on it harder and run x275 class which is 1/8. If I was to say run in the 5.20's to the 1/8 would that be legal?
 
#46 ·
I believe 5.45 is the 1/8 mile equivalent to an 8.50 1/4 mile pass. 10 point will get you to 5.45, anything quicker and you'll need to upgrade to a 25.5 at minimum
im really not understanding this part. nhra says i can go 8.50 @ maybe 145mph but the same cage cant go faster then 5.45?? if it is built to handle a 3000lb car at 145mph shouldnt you be able to run 145mph in the 1/8??? it would be the same impact if anything would happen. just saying
 
#44 ·
can the floor plates for the main hoops diag bars that run to the driveshaft tunnell be cut. they are 6x6 plates. i need to cut off one corner to make it fit the floor all the way back on the s10
 
#49 ·
Really? You can't figure out for yourself that a car doing 145 at half track is going to have a shit-ton more power and traction than one accomplishing that at the quarter mile? Think it through - If you were racing fuel cars to the 60-foot, would it be ok to build them to 100mph safety standards?
 
#50 ·
The fact is the rules were meant to be safety rules to protect the driver in case of an accident..

the 1/8th mile rules are stupid.. using ET to establish safety rules is stupid..

right now you can have a basic 10 point cage in a car that is all fiberglass with aluminum floors and run 170 mph and be safe..

Yet a full bodied car with a stock floors and roof with a funny car cage isnt safe to run 135 in 1/8th..

The rules need to be based off the the maximum MPH a car is safe to run.. how quick you get to that MPH has nothing to do with how that car will withstand a crash
 
#51 ·
(snip)

The rules need to be based off the the maximum MPH a car is safe to run.. how quick you get to that MPH has nothing to do with how that car will withstand a crash
I strongly disagree. The chassis rules aren't just important for how the car performs in a crash - they're important for avoiding the crash in the first place by having a car that's strong enough handle acceleration, torque loads, tire shake, and so on, too. This is especially true in tire-limited classes like 10.5 and drag radial racing where trap speeds aren't a particularly good indication of how much power the car is making.
 
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