From ECE reg 37 itself:
HB3/9005: 1,860lm +- 12% @ 13.2v
HIR1/9011: 2500lm +- 15% @ 13.2v
The worst (new) 9005 that's still legal should do no less than 1144 lm (12v, -12% tolerance)
Why suddenly switch to 12v numbers when every other number in your post is at 13.2v? The allowable intensity range for HB3 at 13.2v is 1637 to 2083 lumens; for HIR1 at 13.2v it is 2125 to 2875 lumens. Which means the worst HIR1 is practically the same as the best HB3, but since most good-quality bulbs tend to be near the middle of the spec, a "worst to best" comparison is just as unrealistic as a "best to worst" comparison.
Now in reality these numbers mean absolutely nothing
That's not the case. They mean something very specific, easy to understand and quantifiable.
Last edited: