Bike Light: UF-2100 So Far, So Good

i bought the UltraFire UF-2100 XML-T6 5-mode at Kaidomain to use as a helmet-mount bike light for trail riding. i liked it’s small form factor and the price was hard to beat ($15.32 shipped). well, that purchase was back in April and i did get a chance to use it once in the spring, but the ride was less than ideal. it was misting and i left the house without wearing contacts and did the ride, in that mist, with glasses not meant for sports. i did my best just to survive but i was also hopeful.

fast forward to last night. we’d been bringing our lights for the last several after-work rides because of the waning daylight as we head into fall. even when we started, it looked like we’d be in the dark fast but we made it through most of the ride without the need for lights. of the four of us with capable lights, three were NiteRider systems that were less than two years old. i work in a bike shop and could have made that a fourth, but i wanted to try the method that costs a fraction of the big boys.

we stopped to light up at pretty much the lowest part of the ride so we had some climbing ahead of us. i started my light on low and that’s where i left it for all of the climbing. i have never done a run test so i had no idea when the light was going to cut out (protected Trustfire ‘flame’ 18650). all i knew was that it was mostly charged and there was a rider behind me just in case things went dark without warning. that and i had an extra charged cell so no worries. the climb went well. i didn’t think too much of the light setup except that i wish my helmet mount could point up a little. i had to crane my neck ever so slightly more than i like to in order to see a ways up the trail. not a big deal climbing since i don’t like to look up trail at more ascending. the mount is This One also from Kaidomain. the mount itself was stellar for what it cost, as far as i’m concerned. the problem was possibly my helmet not being shaped ideally for the mount to move back enough. i’ll try to tweak before the next ride…

so we pretty much finished the climb with a long stretch of slightly steep doubletrack and the rest of the ride would be mostly downhill. i switched to high and we began a rooty, rocky, dusty, sometimes steep and rutted descent. again, i was focused on the trail in front of me so i didn’t stop to think about how my light setup was performing. if anything, the fact that i didn’t have to think about it speaks to how well it worked. the only thing that concerned me was the lack of depth perception i had when riding with a light. deep roots and big rocks looked flat so i had to be careful not to get too carried away with speed. that said, my confidence was almost as high as when riding during the day. mostly thanks to the bright light on my head, and somewhat thanks to the fact that i tend to ‘dive into’ the ride when it’s dark out — or so it feels.

all in all, although the ride time with the light was short, i didn’t feel like i had many disadvantages to the other guys other than the nice features such as purpose-made mounts, battery packs, and battery indicators. the further into fall we get, the more i can provide a better comparison and maybe have a side-by-side beam evaluation on trail. until then, so far, so good…

PS: in case anyone wants to use this light — or almost any light — on their bars, i’d recommend this mount as the head swivels independent of the bar mount for bars that have any sort of sweep (which most MTB bars do). that way the light doesn’t point to one side as with a static mount like this.

Nice to read some first hand experience, because I wanna try my flashlights as bikelights.

My idea for a setup was like this:

  • a P60 host with a floody drop-in (xm-l I guess) at the bar
  • and a P60 host with XP-G R5 mounted on the helmet (using the same mount you mentioned, it is really popular) for a little bit more reach

Do you think this make sense ?

kind regards

I’m currently waiting for 2 of these from TMart - hoping they will arrive this week.
Thanks for the heads up on the mounts also.
I mainly ride road with a couple of little Ultrafire C3’s with 14500 batts. A bit of foam and a rubber O ring does the trick.
Wanted something brighter with not too much more size and hopefully a bit more run time, that I can also use on MTB.
Cheers.

nikanon, i’m by no means an expert on night riding but that sounds like plenty of light, IMO. in the few rides i’ve done with lights, i have yet to ride with anyone running a light on the bars. i don’t know why, honestly. i may give it a go one night with my Yezl at the bars. it’s a shame two of my four 18650 cells died at the same time. i assume they self discharged and became unusable. that would leave me with one cell per light if i did the two-light setup. i guess it’s time to order up!

I also appreciate the firsthand experience. I'd recommend you consider swapping emitters to neutral white (or pick up a light with a neutral white LED already while you're getting more cells if you're not interested in modding yourself. I think neutral white will help a lot with depth perception as well as making out details.

-Garry

that’s good info, Garry. anyone have recommendations for dropins for the 2100?

Contact E1320 here on BLF and he'll hook you up! He can even swap out the driver if you like. I don't think you'll find anything ready made to just "drop-in".

-Garry

I use the UF-2100 on night rides too. It works well and is light and compact. However, I agree that the cool white tint does not provide good depth perception. Also, the small reflector does not provide a well-defined hotspot. Which is why I sometimes prefer to use my Ultrafire 504b with the neutral white IOS drop-in.

Got my 2100’s this week.
Tried them with my Trustfire flames (protected and button-top) and nothing.
Put in an unprotected flat-top and bingo. For a while.

I’ve pulled them apart, cleaned everything and tightened everything up as suggested in other posts.
Although they seemed to work fine in the hand, once on the bike, they fail.

After stuffing around with them, it seems they run when either the head or tail-cap is loosened (unscrewed), but once tightened back up, they shut down.

Can anyone give me any guidance?

welp, got in another quickie ride that finished in the dark. more opportunity to critique this setup. the light, with cell, might be a wee bit heavy for my liking. i’m going to compare to my friend’s NiteRider Race but i think his will be lighter by a good margin. i mentioned that the mount points a little low for my liking so i slid it back as far as my helmet vents would allow and all seemed OK when i turned on the light, but once things got rolling, the mount slid forward again to it’s natural resting position. again, not too too bad, but noticable. i really don’t think i can get much lighter than this setup so i got to thinking it’d be cool to remove the battery portion of the body and rig a battery pack that would take the weight off my head and give me additional uninterupted runtime. i really wish i knew the first thing about electronics so i could do this! anyway, still haven’t done a static side-by-side comparison of lights. with the speed night overtakes us nowadays, it’s just a matter of getting in a longer ride.

I seem to remember E1320 doing something like you say about having a "remote" battery tube wired to a light head. I think it was formed out of an Ultrafire 501/502/ or something similar. Don't remember where it was posted or how to even search for it. Perhaps he could chime in.

-Garry

update: i went on a ride that included some technical, rocky, bumpiddy bump downhills. this time, i had the light mounted to the bars with my Yezl XM-L on the helmet. all was fine until we started hitting the rough stuff, then my UF-2100 went wonkers changing modes on every decent bump and even turning on when i got sick of riding with a strobe lighting the way. i like this two-light setup as it gives some dimension to the rocks and roots, but this light doesn’t seem to be meant for bar mounting. the Yezl is bigger and heavier, but a more powerful light so i may try that on the helmet with no bar light. it’s just a little spotty for my tastes. or maybe i’ll swap the two.

the ride was two hours and i didn’t need to swap batteries in either light. i ran on low for all of the climbing and med or high for the downhill/technical stuff. i did swap near the end since i completely turned off the UF-2100 at that point and wanted to make sure i didn’t end up in the dark.

I had a C8 that kept changing modes. The problem turned out to be the head was not screwed in well and was not making contact. After a bit of tightening, the lens rattled a bit but no more mode changing.

I also have a 2100 for the helmet. If you want a reliable light, Jetbeam and Shiningbean S-Mini also have similar form factor. S-mini is a bit smaller and lighter. My ideal helmet light is fixed diameter barrel (not large diameter head), diameter max of 1” and maximum length of 4”. I think I would find a C8 or even a Solarforce P60 host too large/heavy for helmet. My commute is only about 40 minutes.

I’ve been away from flashlight forums for a while. Looks like XM-L T6 and 3000 mAh batteries are now outdated :slight_smile: I get to read and learn all the latest great budget lights out there. I’m still loving my Kaidomain C8, but might have to pick up a U3 led light.