A while back I installed an NRG short hub and deep NRG wheel in my E30. NRG didnt do a very good job of providing a way to retain the horn function so I just skipped it. After a while, it became obvious that living in Washington State requires a horn to honk at the idiots. I decided to fix the issue and do this write up for everyone else.
I'll start by saying that I installed an NRG 002 3" deep dish wheel with the short hub but no quick release. This is only a write up on how I got the horn wired and not on anything else on the install.
I decided to utilize the factory slip ring from my M tech wheel.
Its BMW PN 11528964
Flipping the NRG short hub over we see that it measures roughly 44.8mm
Flipping the slip ring over we see that the ID measures approx 46mm
The tab for the horn ground on the upper left will be going through the hole on the NRG hub.
First: Cut the top of the slip ring off removing the turn signal cancel tab
Second: When flipping the ring over you'll see the locating pin molded into the ring. Cut this off too.
Third: test fit the ring on the hub and mark your hole locations. Make sure the connection tab is centered in the through hole so it doesnt ground out while installed.
Drill and tap small screw holes at the locations you marked. I used 4-40 flat heads because thats what I had on hand
Flipping the hub over you can see how the conneciton for the slip ring at the upper right is perfect
Finally in order for the horn to work, the hub must be grounded to the car. With the anodize, it cant. You need to sand or in my case I wire wheeled the anodize off the face as shown to get it to ground while mounting.
Now, installed, you'll see that grounding the black wire to the slip ring connection will ground the circuit and work the horn. Now you can intstall your wheel, horn, etc
Here is the pic of the wheel installed in case you want to see the final result. I chose the deep wheel and short hub because it comes to almost exactly the same point from the dash as the factory wheel did. In order to use this combo I had to make a custom 3/8" thick spacer from the hub to the wheel due to the steering shaft hitting the horn button and bottoming out.
I'll start by saying that I installed an NRG 002 3" deep dish wheel with the short hub but no quick release. This is only a write up on how I got the horn wired and not on anything else on the install.
I decided to utilize the factory slip ring from my M tech wheel.
Its BMW PN 11528964
Flipping the NRG short hub over we see that it measures roughly 44.8mm
Flipping the slip ring over we see that the ID measures approx 46mm
The tab for the horn ground on the upper left will be going through the hole on the NRG hub.
First: Cut the top of the slip ring off removing the turn signal cancel tab
Second: When flipping the ring over you'll see the locating pin molded into the ring. Cut this off too.
Third: test fit the ring on the hub and mark your hole locations. Make sure the connection tab is centered in the through hole so it doesnt ground out while installed.
Drill and tap small screw holes at the locations you marked. I used 4-40 flat heads because thats what I had on hand
Flipping the hub over you can see how the conneciton for the slip ring at the upper right is perfect
Finally in order for the horn to work, the hub must be grounded to the car. With the anodize, it cant. You need to sand or in my case I wire wheeled the anodize off the face as shown to get it to ground while mounting.
Now, installed, you'll see that grounding the black wire to the slip ring connection will ground the circuit and work the horn. Now you can intstall your wheel, horn, etc
Here is the pic of the wheel installed in case you want to see the final result. I chose the deep wheel and short hub because it comes to almost exactly the same point from the dash as the factory wheel did. In order to use this combo I had to make a custom 3/8" thick spacer from the hub to the wheel due to the steering shaft hitting the horn button and bottoming out.
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