Root Moose
NAXJA Forum User
- Location
- ON, Canada
Apologies for this long post in advance.
Now that I've started moving the tools and benches into my workshop (finally!!!) I'm starting to get serious about building the XJ. Axles get started this week. Woohoo!
I've been tossing around some ideas about doing a cage. There are a lot of cages on the market already but none of them seem to be exactly what I'm looking for. That being said, the D&C Extreme cage is pretty close to the mark. I figure for the cost of buying/conversion/shipping I can get a JD2 and some bits, etc.
Here's some of the things I've been thinking about. Comments/thoughts/experiences appreciated.
1.) General ergonomics. My XJ is used as a daily driver; most of the time my wife is shuttling our boys (3 yo and 6 mo) around with it. Needless to say, kids car seats are still very much in play. There will be another kid coming in the next two years or so. Also, my wife has to live with whatever I come up with.
I'm not a "hardcore" four wheeler or anything like that, but there may be times where I get in a situation that a cage would be good to have.
One of the things that really bothers me about the stuff that is currently for sale is the front passenger door being blocked under the dash.
What about running tube through the dash behind the AC vents at the A-pillar. Is there anything structural or HVAC related that would make that not an option? The Jeep is a 97+ if it makes a difference.
Also, how do people replace the windshield in these kinds of setups? With the tube of the cage being so close to the A-pillars is it not hard (impossible?) to gain access to the inside when gluing/removing the windshield?
An idea was to run the tube that makes the top halo over the passengers down the A-pillars and across the dash and back up the other side. This angled "U" that goes "under" the windshield would be clamped using those aftermarket roll cage clamps to connect to the vertical members that came from the floor/footwell behind the dash.
Are the aftermarket cage clamps worth a damn? If others could be incorporated throughout maybe it would be possible to "drop" the cage away from the roof for welding/maintenance/etc.
What about defroster clearance?
If this is not clear what I mean I can do a sketch or two to post.
2.) Collision damage. I've been looking at a lot of web pictures and real life wrecked XJs. It seems that the XJ "greenhouse" is not very strong at all and will collapse easily. I wonder if this vehicle was ever tested against the NHTSA/CMVSS spec that states the roof must be able to support 1.5 times the vehcile weight (static). It is probably marginal.
Side impacts and frontal impacts also seem to really hurt the XJ structure. Looking at a "modern" Jeep like a ZJ or WJ they don't seem to fare much better.
Would it be best to run tube down the side of the interior along the back side of the rockers. The vertical tubes will connect to this, then the horizontal tube can be tied into the uniframe somehow.
Is there any merit in running tube around the front passenger footwell and over the tranny hump to keep the footwell area from collapsing in a frontal collision? Is there enough room for that and the pedals, feet, etc.?
3.) Rear passenger room. The B-Pillar hoop needs to be reinforced somehow but triangulating it will really reduce DD usability. Is a mid height horizontal spreader bar sufficient? Better ways to do it?
In a frontal collision is the mid height bar going to be something that the mid bench adult passenger hits their head against? With the amount of "whip" that occurs in a collision will the outboard bench passengers hit these bars with their head?
4.) Cargo room. Most cages seem to have bars that run into the cargo area in some fashion. How necessary is this really? What about making the rear passenger shoulder strap support cantilevered off a "V" shaped piece of tube that rejoins the main vertical upright about mid height.
There is no sense in "protecting" the cargo area but at the same time will the structure forward of the C-pillar be enough to keep the structure from collapsing backwards?
5.) What is the smallest outside diameter tube that can be gotten away with for a cage like this? 1-1/4" is too small? 1-1/2" is minimum? This is a daily driver so weight is a consideration (mileage over the next 10+ years). Is there an "intelligent" combination of tube diameters that can be used throughout?
6.) Connecting to the uniframe. Is the standard "large plate welded to the unibody" method as done in SCCA racing style builds sufficient for an XJ? Should the cage be tied into the "fake" frame rails under the floor instead (also)?
What am I forgetting?
Now that I've started moving the tools and benches into my workshop (finally!!!) I'm starting to get serious about building the XJ. Axles get started this week. Woohoo!
I've been tossing around some ideas about doing a cage. There are a lot of cages on the market already but none of them seem to be exactly what I'm looking for. That being said, the D&C Extreme cage is pretty close to the mark. I figure for the cost of buying/conversion/shipping I can get a JD2 and some bits, etc.
Here's some of the things I've been thinking about. Comments/thoughts/experiences appreciated.
1.) General ergonomics. My XJ is used as a daily driver; most of the time my wife is shuttling our boys (3 yo and 6 mo) around with it. Needless to say, kids car seats are still very much in play. There will be another kid coming in the next two years or so. Also, my wife has to live with whatever I come up with.
I'm not a "hardcore" four wheeler or anything like that, but there may be times where I get in a situation that a cage would be good to have.
One of the things that really bothers me about the stuff that is currently for sale is the front passenger door being blocked under the dash.
What about running tube through the dash behind the AC vents at the A-pillar. Is there anything structural or HVAC related that would make that not an option? The Jeep is a 97+ if it makes a difference.
Also, how do people replace the windshield in these kinds of setups? With the tube of the cage being so close to the A-pillars is it not hard (impossible?) to gain access to the inside when gluing/removing the windshield?
An idea was to run the tube that makes the top halo over the passengers down the A-pillars and across the dash and back up the other side. This angled "U" that goes "under" the windshield would be clamped using those aftermarket roll cage clamps to connect to the vertical members that came from the floor/footwell behind the dash.
Are the aftermarket cage clamps worth a damn? If others could be incorporated throughout maybe it would be possible to "drop" the cage away from the roof for welding/maintenance/etc.
What about defroster clearance?
If this is not clear what I mean I can do a sketch or two to post.
2.) Collision damage. I've been looking at a lot of web pictures and real life wrecked XJs. It seems that the XJ "greenhouse" is not very strong at all and will collapse easily. I wonder if this vehicle was ever tested against the NHTSA/CMVSS spec that states the roof must be able to support 1.5 times the vehcile weight (static). It is probably marginal.
Side impacts and frontal impacts also seem to really hurt the XJ structure. Looking at a "modern" Jeep like a ZJ or WJ they don't seem to fare much better.
Would it be best to run tube down the side of the interior along the back side of the rockers. The vertical tubes will connect to this, then the horizontal tube can be tied into the uniframe somehow.
Is there any merit in running tube around the front passenger footwell and over the tranny hump to keep the footwell area from collapsing in a frontal collision? Is there enough room for that and the pedals, feet, etc.?
3.) Rear passenger room. The B-Pillar hoop needs to be reinforced somehow but triangulating it will really reduce DD usability. Is a mid height horizontal spreader bar sufficient? Better ways to do it?
In a frontal collision is the mid height bar going to be something that the mid bench adult passenger hits their head against? With the amount of "whip" that occurs in a collision will the outboard bench passengers hit these bars with their head?
4.) Cargo room. Most cages seem to have bars that run into the cargo area in some fashion. How necessary is this really? What about making the rear passenger shoulder strap support cantilevered off a "V" shaped piece of tube that rejoins the main vertical upright about mid height.
There is no sense in "protecting" the cargo area but at the same time will the structure forward of the C-pillar be enough to keep the structure from collapsing backwards?
5.) What is the smallest outside diameter tube that can be gotten away with for a cage like this? 1-1/4" is too small? 1-1/2" is minimum? This is a daily driver so weight is a consideration (mileage over the next 10+ years). Is there an "intelligent" combination of tube diameters that can be used throughout?
6.) Connecting to the uniframe. Is the standard "large plate welded to the unibody" method as done in SCCA racing style builds sufficient for an XJ? Should the cage be tied into the "fake" frame rails under the floor instead (also)?
What am I forgetting?
) but would like to minimize weight gain without sacrificing safety.
