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Tail / Brake Light Bulbs

Posted: Tue Sep 19, 2017 9:05 am
by Our Gee
Hello all,
Sorry if this has been discussed before but here goes. I am in the process of putting together a "spare bulb kit" for our Twincam and it does seem to be a bit confusing, well to my rusty brain it does !!. (BMW no longer do a dedicated model specific Kit)
According to my Rider's Manual the bulb for the Tail light / Brake light is a P21W / 12V / 21W which I assumed would mean a Twin Filament Bulb. So with that in mind I have trawled various BMW parts suppliers Web Sites such as Motorworks, Motobins and Sherlocks and it only gets more confusing. In the end I removed the rear light cluster to see just what Tail / Brakelight bulbs are fitted. Now for the surprise. It would appear that the bulb is a "Single Filament" type which operates at two different current inputs, the lower current for the rear light and the higher current for a combined rear light and the Rear Brake. I have never come across this before. Anyone else noticed this ?.

Re: Tail / Brake Light Bulbs

Posted: Tue Sep 19, 2017 11:13 am
by simbo
Yeah I was surprised too, especially as I'd bought two twin filament bulbs to replace them both when one went.  :eggs:

Re: Tail / Brake Light Bulbs

Posted: Wed Oct 11, 2017 10:52 pm
by beemerboy9
Our Gee wrote: Hello all,
Sorry if this has been discussed before but here goes. I am in the process of putting together a "spare bulb kit" for our Twincam and it does seem to be a bit confusing, well to my rusty brain it does !!. (BMW no longer do a dedicated model specific Kit)
According to my Rider's Manual the bulb for the Tail light / Brake light is a P21W / 12V / 21W which I assumed would mean a Twin Filament Bulb. So with that in mind I have trawled various BMW parts suppliers Web Sites such as Motorworks, Motobins and Sherlocks and it only gets more confusing. In the end I removed the rear light cluster to see just what Tail / Brakelight bulbs are fitted. Now for the surprise. It would appear that the bulb is a "Single Filament" type which operates at two different current inputs, the lower current for the rear light and the higher current for a combined rear light and the Rear Brake. I have never come across this before. Anyone else noticed this ?.
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