The beam from the SP40 was too throwy for my taste so I ordered some 17mm 45 degree TIR optics from AliExpress to replace the reflector. It does kind of fit but the process didn’t really go smoothly for me.
First issue was that the bezel was extremely tight (but not glued, surprisingly). I scratched up the light pretty badly trying to get it off with snap ring pliers. Eventually I heated the head up with a 1875W hair dryer, and the bezel eventually slowly moved.
Second issue was that the TIR optic I ordered was 9.7mm high, while the factory reflector was 7.9mm by gchart’s review. I had to file it down quite significantly to get it to fit. The SP40 has a centering ring around its XPL-HD emitter which adds a mm or so, so initially I tried to use the TIR with the centering ring removed. However, this led to a very bad dark spot in the center of the hotspot. The TIR I ordered was meant for XML2 type LEDs, so I’m not sure if that had anything to do with it. I found it was better when the TIR was higher, so I filed it down a bit further to get it to fit with the centering ring under it. However, I think the recess for the LED was no longer deep enough after all this filing, and it was pressing on the emitter dome. When I removed the TIR the dome came clean off with it:
It’s pretty impressive how cleanly it came off, honestly. I guess my SP40 has an XPL-HI now.
Afterwards the dark spot was a lot better. This is the beam after installing a TIR lens. In the third image that’s an SC31B 4000K on the left. It’s noticeably colder, I think Sofirn sent me a 3000K instead of the 4000K I ordered for the headlamp. Overall, I’m satisfied with the beam after the mod. It’s now more usable at close range.
Just for fun, I put the factory reflector back in temporarily to see what effect the dedome had. The headlamp is quite throwy like this, almost as much as my SC31B. Maybe this would be attractive to some but it was the exact opposite of what I wanted.
With the TIR installed, the bezel still isn’t quite flush with the body, and the glass lens presses on the top of the TIR. I can’t remove the glass because the bezel is 20mm while the TIR is 17mm, so it doesn’t hold the TIR in place. I feel that I’ve somewhat compromised the waterproofing of the light with this mod. I’d need to file more to get the bezel flush, but I think if I file down the bottom of the TIR any more the dark spot will return. Maybe I could file the top down, but I don’t know if I could do it without messing up the beam. This is my first time doing something like this, so if there’s anything you think I could have done differently please let me know.
