Roll Cage: Fitting the Seat

I’m a little behind on updates.  These pix are from last weekend.

I’m to the point where I’m ready to cut things to final lengths.  That means that I need to finalize the seat location.  So, I temporarily held the cage bits together, and set the seat into place.  I needed to decide where the drivers cage side would meet the main-hoop.  I could either go higher or lower on the upper radius.


When I first set the seat into place, I found the the halo was hitting the cage side bar.  The rear seat humps were keeping the seat too tall.  I tried getting in the seat and putting on my helmet.  I made contact with the cage side before I touched the halo padding!  Not good.  I tried lots of different positions of the cage side, and the seat…but nothing would gain enough clearance to the bar.  Finally I gave up on the idea of keeping the seat humps.  So, I cut them out with the angle grinder.  when I set the seat back into place I found the seat was hitting the bump on the trans tunnel.  So, out comes the hammer!


Next I set the seat back in place.  The clearance was much better, but as you can see the bar is still intruding into the halo head-space.  Add the SFI padding and there still wouldn’t be much room for the helmet…especially when I twist my head to look left/right.  It would be a lot better if I could move the seat over a couple more inches.


Before I moved the seat over, I wanted to see how it would line up with the steering column.  So, I got out a plumb bob and marked the axis of the steering column on the seat brace.  I set the seat back into place and found that the seat wasn’t centered on the steering column.  It was still to far outside of it.  That’s good news really because that meant that I could move the seat over AND improve my alignment on the wheel.  I was afraid that I was already inside the wheel…and moving it was going to make the situation worse.  Again, hammer time!


So, I banged and banged.  I got the seat to the point that it is centered on the wheel…but, its still not over far enough.  It’s “okay”, but if I can go over another inch or so I won’t make contact with the bar at all.  The steel is starting to tear where I’ve stretched it too much.  I think its time to actually cut the steel and make a real notch.


I talked to Dave at Advanced Autosports…he said that he always notches the trans tunnel to install a halo seat…and he also keeps the cage bar down low on the main-hoop radius.  Otherwise its just impossible to keep the bar out of the head space.  Next weekend I’ll cut the seams and make a real notch.

3 comments to Roll Cage: Fitting the Seat

  • So cool. It truly is starting to look like something from the Cosmophere! I love it!

  • Dave Hughes

    Cool blog! I’d be interested in hearing about what kind of welding equipment you’re using. I hate to ask but what design margin are you impinging on by moving the transmission tunnel a couple inches to the right? And, excellent catch by considering where the seat is relative to the steering wheel. That’s the kind of thing I always miss in the excitement of solving the “other” problem… I’ll be following your progress this as I need to do a similar thing for my jeep.

    • Tom

      Hi dave-

      It’s a harbor freight mig welder 120 amps. I’m going to have a professional do all the finish welds.

      I didn’t mention it in the article, but the issue underneath is the exhaust. It runs down the drivers side of the tunnel. The cat converter is centered on my hips. More details to come once I finish the article from today’s work.

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