I am the owner of a 2000 Yamaha YZF-R1 motorcycle. I added the aftermarket Dussault Undertail to the bike, and was very happy with it, except for the intensity of the brake lights and turn signals. (go to the bottom of this webpage for late breaking information on new turn signals) The undertail came equpped with red brake lenses, and a pair of red LED brake lamps (aka 1157 bayonet bulbs), and for the turn signals it has clear lenses and a small orange colored wedge bulb. I spoke with Robert Dussault at Graphic Art Moto Design about the problem, and he suggested I replace the "Taiwan Special" LED 1157 bulbs, with some new bulbs available from Ledtronics . The specific bulbs he pointed me to were the 15mm Bayonet Based Red LED Lamps . Although Robert had not tested with these himself, by the looks of the design and the specifications, he suggested they could have upwards of twice the luminosity of the bulbs he supplies. These 24-array superbright red LED's looked great, the industrial packaging was clearly superior to anything else I've seen, but they were priced at $48.50 (US) each!!!!! Yikes!

I asked Robert for other options, such as replacing my red tail light lenses with clear, but Robert suggested all other changes would not result in a brigher tail light for braking. Well, I ended up purchasing two of these new LED array bulbs for testing, after speaking with several reps at Ledtronics, Some pictures and comments about my testing are below.

Here's what the new ledtronics bayonet bulbs look like:

Upon inserting these bulbs into my R1's aluminum cylinders in the undertail, I discovered that the bulbs are not perfectly cylindrical. They are slightly larger towards the bayonet end, and were very slightly too large to fit in the opening of the cylinder. I used a Dremel tool to enlarge the lip of the cylinder just slightly in order to have the bulbs fit:

At this point, I was ready to test. I put one of each type of bulb in to compare. The result was much more dramatic than I expected. The new bulbs are MUCH brighter. This picture is with the running lights on.

The Ledtronics Bulb is on the left, the Taiwan special is on the right. Notice the much more intense light produced by the additional led's in the Ledtronics bulb. To the naked eye, the difference was easily twice as bright. It's hard to quantify and hard to see just from the pictures, but the Taiwan bulb with only 4 LED's illuminated, produced a very mild and diffuse red light. The Ledtronics bulb was very bright, as you can see over a dozen of the LED's are illuminated when just the running lights are on. I was blown away by the difference.

The next comparison was with the brake engaged. Again, a very dramatic difference. The Ledtronics bulb on the left was literally painful to look at directly when fully illuminated.

Recommendations
If you are looking to increase the visibility of your taillights, especially when your brakes are engaged, then I highly recommend shelling out the roughtly $100 US dollars it will take to get a pair of these Ledtronics AUT1157 bulbs. Given they will last a lifetime and are dramatically brighter than the alternatives, the cost seems justified. These bulbs can be returned to Ledtronics if you are not satisfied for a 25% restocking fee. I feel much safer on the bike now that I'm running these bulbs.