I thought I would share my experience from the last few days in trying to replace my old K1100LT tail light bulb; maybe it will keep others from making the not so bright mistake that I made. I had read several threads on various K11 sites where people were asking what kind of bulb could be used in place of the stock bulb, and came to the conclusion that some people were successfully using a 1003 bulb. I don't have a dealer anywhere near me, so I wanted to find an acceptable bulb that I could buy in town, or find when on the road traveling.
I got a pack of two Phillips 1003 bulbs, put one in, and carried the other as a spare. I found the specs for that bulb on the Phillips site, and it was 10W, so all was good, for a couple of days, then the bulb burned out.
When I pulled it out, it was white, and there was a circle broken out of the top (rear) of the bulb. Hmm, not good. On closer inspection, I found that the clear, faceted, plastic piece that sits just inside (in front of) my red outer lens, was warped to the point of cracking, and had a round melted section where it had contacted the bulb. There were other indications of heat inside the fixture also.
The problem was not the wattage of the bulb, it was the size. The 1003 is 8mm longer than the stock bulb, so it either touches, or comes very close to touching, the inner clear plastic piece.
Anyway, I ordered a couple of stock bulbs from BMW, at $10 each with shipping,
and found a replacement tail light fixture on Ebay. I started to research bulbs, and here's what I found. I think an acceptable substitute is a #97 single filament bulb. It is .7mm shorter than the stock bulb, and 9.3W. A #67 bulb would even work in a pinch, it's about the same size, but only 8W. If I need to find a bulb on the road, I will use a #97 from now on, as they are available everywhere.
Once I put a #97, or now the stock bulb, in my old fixture, I found that I probably didn't actually need to replace the fixture, but I already bought the one on EBay. The correct length bulbs don't come anywhere near the plastic. I just didn't pay close enough attention when putting in the 1003 to notice that I was creating a problem. Anyway, that's my take on this question, and I hope it keeps someone form making the same mistake I did.
I got a pack of two Phillips 1003 bulbs, put one in, and carried the other as a spare. I found the specs for that bulb on the Phillips site, and it was 10W, so all was good, for a couple of days, then the bulb burned out.
When I pulled it out, it was white, and there was a circle broken out of the top (rear) of the bulb. Hmm, not good. On closer inspection, I found that the clear, faceted, plastic piece that sits just inside (in front of) my red outer lens, was warped to the point of cracking, and had a round melted section where it had contacted the bulb. There were other indications of heat inside the fixture also.
The problem was not the wattage of the bulb, it was the size. The 1003 is 8mm longer than the stock bulb, so it either touches, or comes very close to touching, the inner clear plastic piece.
Anyway, I ordered a couple of stock bulbs from BMW, at $10 each with shipping,
and found a replacement tail light fixture on Ebay. I started to research bulbs, and here's what I found. I think an acceptable substitute is a #97 single filament bulb. It is .7mm shorter than the stock bulb, and 9.3W. A #67 bulb would even work in a pinch, it's about the same size, but only 8W. If I need to find a bulb on the road, I will use a #97 from now on, as they are available everywhere.Once I put a #97, or now the stock bulb, in my old fixture, I found that I probably didn't actually need to replace the fixture, but I already bought the one on EBay. The correct length bulbs don't come anywhere near the plastic. I just didn't pay close enough attention when putting in the 1003 to notice that I was creating a problem. Anyway, that's my take on this question, and I hope it keeps someone form making the same mistake I did.
