Bonneville America Forums Forums Technical Forums Accessories Modulating Tail Light Bulbs

I think the issue was with older Triumphs.
The diff between the older and newer units (10W vs 20W) is as follows.
The 10W is just like the bulb in your bike now, an 1157 (I think) but it modulates. When it burns out you replace the whole thing.
The 20W uses a base that has the modulating feature in it but has replaceable halogen bulbs (G4). This way when it burns out you replace the G4 bulb and the modulating piece stays put.
Oh...and the 20W comes with an extra bulb.