Weights for the Track Day Roll Bar and the Track Day Rollcage

[Pokey]

 

Here are the weights of Caterham's SV Track Day Roll Bar and Track Day Rollcage measured during a recent swap:

 

• 18.2 lb / 8.3 kg for the Roll Bar
• 26.6 lb / 12.1 kb for the Rollcage

 

Difference between the two is 8.4 lb or 3.8 kg.

 

The swap was straightforward but difficult as the cage's mount points didn't align well with the chassis, and the carbon fiber sill protectors must be shortened or replaced.  If there is interest I'll be happy to elaborate, but my advice is only do this if you truly feel you need the cage.  I'm selling the dedicated track car so felt replacing the roll bar with a cage made sense for me, but it wasn't long in the process before I was thinking about just keeping the track car.

 

Edited Monday at 11:04 PM by Pokey

[redursidae]

I would appreciate more information on what was required for the swap as I intend to do the same eventually.

[Pokey]

54 minutes ago, redursidae said:

I would appreciate more information on what was required for the swap as I intend to do the same eventually.

 

I'll start small and if you want more just ask.

 

Supplies:

• The (2) M10 x 60mm w/ washer and nuts from your rollover bar
• The (2) M10 x 20mm  caphead bolts from your rollover bar
• Two (4) M10 x 16mm bolts.  I sourced mine from McMaster https://www.mcmaster.com/nav/enter.asp?partnum=98093A610
• 5/32 x 47 rivets to replace however many you choose to remove from the interior door panel
• Waxoyl if you are that kind of guy
• Tape and towels to protect bodywork
• Black silicone sealant if conturing the sill protectors rather than replacing -or- Catherham's shortened sill protectors for cars outfitted with a cage

 

Tools:

• See the picture of most of what was involved
• Rivet gun
• Assorted socket and box wrenches
• You might need a ratchet strap to aid in the fit into the rear mounting brackets
• Something like an engine crane to hold the cage while working (picture)

Steps:

 

1. Put the rear of the car on stands and remove the rear wheels and shocks
2. Remove the rollover bar
3. Remove the sill protectors if replacing with the shortened versions, or loose-fit the cage to mark where to cut the sill protectors
   • I'm assuming you have carbon fiber sill protectors
   • If removing be aware that in addition to the rivets there is a very tough rubber adhesive to overcome
   • There is a very real possibility of breaking the sill protector during the process
   • I had my best success using a box cutter and patiently scoring rather than sawing or grinding (pictures)
4. Gently pry back the door panel to locate the interior chassis boss and locate its position on the panel
   • I estimated the position and used a punch to check alignment, adjusting as needed before making my final punch to drill
5. Drill the door panel, enlarging the hole using step bits, and then debur
6. Run a punch through the hole in the door panel and the interior and exterior chassis bosses to mark where to drill the skin
7. Drill the skin as you did the door panel
8. Install the cage
   • Leave all bolts loose until all are installed, then torque to spec
   • Fit is determined by your chassis and cage so I can't tell you in advance what you might need to do
   • I would fit the two bolts that go up and into the verticals of the cage first, but leave loose
   • The left (driver side) rear chassis bracket needed to have both holes elongated, and even then it took creative work with a ratchet strap to make fit
   • Only one of the four front bolts aligned without modification - the other three bracket holes needed further elongation
   • Be aware that the above steps make it sound like it was a measure twice and cut once operation, whereas in reality placed and lifted the cage dozens of times while aligning
9. If you cut the sill protector in situ then a little black silicone sealant provides a nice optional finish (picture)
10. Note that clearance between the windscreen is minimal, likely contacting in some places
    • I've run foam tape across the top of the windscreen but only time will tell if this is a good solution
    • My plan (hope) is to attach the rearview mirror to the cage to minimize vibration and to allow for easier swaps between the windscreen and aeroscreen, but that clearance is an issue
11. Reinstall the shocks and wheels