half-cage recommendations

[AndyW]

So, I've finally decided I am not taking my 1er track car full cage and racing seats. I'm going to do decent dual use seats and a half cage so it's still street drivable. For half-cage I was going to get a custom one done locally, then discovered this:

https://studiorsr.com/products/studi...-cage-roll-bar

Any comments/help from the collective most welcome. TIA.

[fe1rx]

I think you can do much better.
The horizontal tube in the main hoop should support your shoulder harnesses, but theirs is much too low to have an acceptable harness angle.

[fe1rx]

You have probably seen this:

https://www.1addicts.com/forums/show....php?t=1479285

Tube lengths are approximately as follows for a 1 Series half cage:

Main Hoop - 10.4 ft
Harness Bar - 3.7 ft
Hoop Diagonal - 4.6 ft
Rear Brace - 3 ft
Rear Brace Diagonal - 3.7 ft

I used 1.5 x 0.120" tube (1.679 lb/ft). RSR uses 1.75 x 0.095" tube (1.679 lb/ft). So not really any weight difference there.

I only used 1 diagonal in the hoop and rear brace. Doing the math for the weights of all the tubes I get 50.2 lbs. Of course there are foot plates as well, but my actual weight was 51 lbs, so the math gets you close.

Adding in the extra braces used by RSR, and using their tube weight, I get 61.6 lbs, Plus they have some mighty impressive gussets (of dubious structural utility) which will add some more weight.

An "X" is 4 triangles. A single diagonal is 2 triangles. How much triangulation is enough? How much weight is too much? I guess you have to decide that.

I am not sure if you still have a sunroof (my car never had one), but the main hoop can be made quite a bit taller than the RSR cage without one.

[AndyW]

Originally Posted by fe1rx

You have probably seen this:

https://www.1addicts.com/forums/show....php?t=1479285

I had not! Amazing work. I once again wish you were my next door neighbor.

I still have the sunroof, but will be blanking it this year.

[dmytro98]

I just ordered an autopower race roll bar a couple weeks ago, but still waiting for it to be made/delivered. The design looks to be very similar to the one fe1rx made. It was also the cheapest option I could find as I was able to get it delivered for under 1k. Will report on fitment once I actually get it.

[gds52]

I have this custom half roll-bar in my 128i. It's welded-in.

Roll Bar mounted in 128i https://www.1addicts.com/forums/show....php?t=1804007

[spidertri]

I have been looking for a bolt-in rollbar for several months now, I was hoping to find an off-the-shelf solution that I liked but it hasn't happened. In my old E36 I had a 4pt Kirk Racing bolt-in that was fine but basic. I found out the hard way that if you don't adequately and completely seal the drilled holes in the floor you will have many excellent spots for rust to start taking over. The E82 is better in this regard that there is an underpanel that can be put back in place but still.

For E82 I have found the following options:
- VAC Motorsport
- StudioRSR
- Autopower
- AGI Roll Cages (Austrailian but they ship to the US)
- Wiechers Sport (German but they'll ship to the US)
- Kirk Racing (no bolt-in, but they do have a weld-in for the E82)

One thing I look at in the installation pictures, is where does the main hoop end up in relation to the dome light in the head liner. I'm 5'11" and I don't see any way where the main hoop could be in front of the dome light (like the StudioRSR bar) and my seat position working. Especially when they have an in-plane harness bar with the main hoop.

I really wish JP Marketing would have made an E82 version of their E9x bar, but they have told me that they have no plans to. I like how they pick up the rear seat shelf for additional mounting, have a large main hoop foot that picks up the seat belt mounting points and doesn't block access getting from the trunk into the rear seat area.

When I go to the track, I always have stuff in the back seat space, so for that to become unusable is unacceptable to me.

I agree with fe1rx as well, how many diagonal braces does this chassis really need and when are you just seeing diminishing returns?

[amg6975]

StudioRSR is the worst company I've ever dealt with to top off the fact that their rollbar is not all that nice. They constantly lied to me over and over about why they weren't building my cage.

It's built fine, I don't have any concerns over its construction or anything but it took me months of calling them every day to get it built. The only real concern, like fe1ix stated is the height of the harness support and the overall height of the cage could both be moved up 3". I even bought their "non sunroof 1M cage" but it's absolutely no different than the 135 sunroof unit. My seat is low enough that it's technically fine, but it could certainly be a lot better.

[gds52]

Originally Posted by spidertri

I have been looking for a bolt-in rollbar for several months now, I was hoping to find an off-the-shelf solution that I liked but it hasn't happened. In my old E36 I had a 4pt Kirk Racing bolt-in that was fine but basic. I found out the hard way that if you don't adequately and completely seal the drilled holes in the floor you will have many excellent spots for rust to start taking over. The E82 is better in this regard that there is an underpanel that can be put back in place but still.

For E82 I have found the following options:
- VAC Motorsport
- StudioRSR
- Autopower
- AGI Roll Cages (Austrailian but they ship to the US)
- Wiechers Sport (German but they'll ship to the US)
- Kirk Racing (no bolt-in, but they do have a weld-in for the E82)

One thing I look at in the installation pictures, is where does the main hoop end up in relation to the dome light in the head liner. I'm 5'11" and I don't see any way where the main hoop could be in front of the dome light (like the StudioRSR bar) and my seat position working. Especially when they have an in-plane harness bar with the main hoop.

I really wish JP Marketing would have made an E82 version of their E9x bar, but they have told me that they have no plans to. I like how they pick up the rear seat shelf for additional mounting, have a large main hoop foot that picks up the seat belt mounting points and doesn't block access getting from the trunk into the rear seat area.

When I go to the track, I always have stuff in the back seat space, so for that to become unusable is unacceptable to me.

I agree with fe1rx as well, how many diagonal braces does this chassis really need and when are you just seeing diminishing returns?

Talking About back seat space.
I have rear interior stripped out.
I put 3 tradk tires in the back seat area, wiht the roll bar. Don't ask me how I fit them there, but i manage that then 4th tire in the trunk. Then all the stuff, tools, Jack, tent (if camping), canopy tent etc, around the tires

[Jpelps]

Got an autopower half cage for my car and installed it mid march. Fitment is pretty good, some of the holes and backing plates weren't perfect but after some massaging we were able to make it work fine. The only real downsides i can see compared to some of the competitors is the weight and the passenger seat does not go back very far with the cross bar attached. If i was going to do it again I would have ordered the removable cross bar. (Only picture i have on my phone at the moment but can take more if interested)

[Ab28]

Originally Posted by Jpelps

Got an autopower half cage for my car and installed it mid march. Fitment is pretty good, some of the holes and backing plates weren't perfect but after some massaging we were able to make it work fine. The only real downsides i can see compared to some of the competitors is the weight and the passenger seat does not go back very far with the cross bar attached. If i was going to do it again I would have ordered the removable cross bar. (Only picture i have on my phone at the moment but can take more if interested)

Definitely in for more pics and some install tips.

I have the same bar coming next week (on the way from CA at the moment)

[lowside67]

I would also point out that the "X" in both the main structure and rear supports is unnecessary and extra weight with minimal benefit. One X in the main hoop is already over and above the requirement (a single diagonal).

-Mark

[Jpelps]

Originally Posted by Ab28

Definitely in for more pics and some install tips.

I have the same bar coming next week (on the way from CA at the moment)

I can grab some when I get off work tonight and post them.

Edit: Finally got a chance to grab pictures. sorry about the mess, i've been in the process of moving for the last month. Also included a picture of the passenger seat at its furthest back position