This sample for review is thanks to www.jet-beam.com

The ST CYCLER is Jetbeam's new dual purpose cycling lamp. Its looks will be familiar to Jetbeam enthusiasts as the well proven and liked Jetbeam III PRO ST body shape has been used.  That said, this is a totally new light using a XM-L T6 LED and a new interface designed for cycling and outdoor sports. 
The new ST CYCLER has some very impressive technical data that I will put to the test later on in this review.

Manufacturer Data

LED: CREE XM-L T6
Reflector: Aluminium reflector
Lens: Coated mineral glass
Material: Aero grade aluminium alloy
Finish: HA III Military grade hard anodized
Battery: CR123*2 or 18650 Li-ion*1
Dimensions: Tube diameter 25.4mm; total length 121mm
Weight: 70g (without battery)
Waterproof: IPX-8 standard waterproof
Accessories: Lanyard, spare rubber tailcap switch cover, spare O-ring

· Adopt premium CREE XM-L LED
· Maximum output of up to 425 lumens
· Maximum runtime of 1 hour 30 minutes
· Rapidly switch between Outdoor mode and Cycling mode
· Special designed user interface for cycling and outdoor activities
· Customized flood-type reflector produces a wide range of spill beam
· Compatible with both CR123 and 18650 Li-ion rechargeable batteries
· Built-in over-discharge protection circuit for 18650 Li-ion rechargeable battery

Initial overview

The light is compact (121mm - 25.4mm OD), streamline and fits comfortably into the palm of your hand as well as creating very little drag once fitted to your cycle helmet or handle bar. The light body (70 gr) comes in the typical Jetbeam dark grey colour with HA III military grade hard anodized finish. It has a low profile but effective antiroll design as well as tail stand capability.  Both will be well appreciated during your camping trips. The body and tail cap knurling is not overly aggressive but helps in giving you a positive grip. The clicky rear switch is easily accessible and  the tail cap has lanyard attachment slots.

What's in the box

Usual accessory pack which includes an olive drab lanyard, two replacement O-rings and a tail cap switch boot.  A Jetbeam registration card with unit serial number was also included as an instruction booklet in my review sample. 

Settings

Jetbeam has created two totally separate mode platforms activated by tightening or loosening the head. Within these modes you have separate settings giving you an overall total of seven different light settings.

The first mode level or outdoor mode is obtainable via fully tightening the head then using the rear clicky switch to select your desired setting. 
This mode level has a memory, so any mode selected will be held in the memory and activated next time you switch your light on.

Within this mode four different settings are obtainable:

The first one is turbo with a 425 lumen output.  This will be used by mountain bike cyclists on downhill or technical fast trail riding where a lot of light is required.
The second setting (high) is a very respectable 190 lumen with a long run time of 3.5 hours.  This will be favoured by many who want a decent output with an extended runtime and, again, will used by MTB'ers, road cyclists as well as campers, dog walkers, cave explorers etc.
The third setting (medium) is giving you 50 lumens and a run time of 14hours. This has well is also ideal as a marker light for cycling.
The last setting is the strobe light, which is very common with all Chinese built lights. This, I am sure, will be the least used of all the different settings, but could perhaps be used to deter an assailant.

 The second mode level or cycling mode is obtainable via loosening the head about one-eighth of a turn.

The first setting is a low 10 lumen.  This has an incredible run time of 45 hours and may be used as a marker light for cycling but I personally think that this is better suited around a campsite for tasks where not much light is required. 

The second one is a slow but very powerful flash (425 lumens) ideal for cyclists in urban areas where it is more important to be seen than to see in front of your wheel. Due to its high power flash output, this can be used effectively during day light.

The third setting is an innovative warning light setting with a powerful 270 lumens combined with an inbuilt slow pulse.  This gives you the best of both worlds in that it is a riding light with a warning device built in to it.  The light pulsation is quite discreet and will not interfere with your normal riding night vision. 

The two settings above are designed for general road cycling and are safety modes, this can be seen in my mini video clips

The last setting is an SOS mode.  Hopefully this will never be required, but it is reassuring to know that in an emergency you can use your light as an SOS beacon for rescuers to locate you.  

I think Jetbeam have made a very good choice by not giving a memory to its secondary mode and of placing its low light (10 lumens) as their first light setting. 
With the head is in the unlock position, you are guaranteed to have an eyesight friendly output when the light is turned on.  This is especially important if, for example, you need to get up in the middle of the night as you do not get blinded as soon as you switch it on.

 All settings are easily obtainable by simply half pressing the rear click switch when the light is on.  The two different mode levels are obtainable by slightly screwing or unscrewing the head.

More clever stuff

The ST CYCLER has a purpose designed new reflector designed for cycling and other outdoor activity giving you a fairly large bright central 
area as well as good peripheral lighting. 
This is ideal for mountain bike trail riding where a combination of the two is required.  

White ceiling,  turbo beam, photo taken at 44 inches

Rain will not be a problem as the ST CYCLER is submersible up to two meters and complies with IPX-8 waterproof standard .

The light is also fitted with the double spring system which should absorb shocks and always gives a good battery connection.  It is rated at 1.5m impact resistant
 and has a built in over discharge system for 18650 rechargeable Li-ion batteries.  This will give you a blinking warning when the battery is nearly flat (for me this is another safety factor because by giving you prior warning you are able to switch  to the 10 lumen low mode to give you more run time).  
(Note this system does not work with some of my cheaper rechargeable batteries, this is obviously a battery problem)
The light can also run on two CR-123.  There is no voltage data in the instruction manual, but I have contacted Jetbeam and I have been informed that the light will take up to 9V ie two CR127 rechargeable (total of 8.4V)

Photo of the ST CYCLER mounted on my "lid".  This light is well suited as an handlebar or helmet light

MTB riding with the ST CYCLER

This has been tested during a night ride in Friston Forest in the UK. The light was powered by a 2400mAh AW rechargeable battery. During the night ride, the light was positioned on my handlebar.  I used the various settings on forest trails and was able to ride safely and happily with the turbo, high and warning lighting when going downhill.  The medium setting gave me just enough light on the wide uphill fire track. For its relatively small size, the ST CYCLER gives a large bright beam with a very respectable throw in the turbo mode. I was also using my old, faithful Jetbeam III PRO ST BVC which has a more narrow and far reaching beam, ideal to see around corners. The ST CYCLER was used for over an hour on the turbo setting without any noticeable loss of brightness during that time. 

Home test
A while back I made a DIY integration sphere that I now use to take my LUX  readings. This allows me to make fairly accurate comparisons between my various light outputs and run times. On a year and half old AW 18650 2400mAh battery, in the turbo setting I got a constant 40000lux for one hour, then a drop of only 15% in the next 30 minutes (34000lux) and the low battery warning was activated after 1 hour and 49 minutes showing at the time 175000lux. For an XM-L led, I believe this is the best regulated 18650 light that I have used so far and is certainly well suited for cycling. 

Please note the lumen is a measure of the total "amount" of visible light in some defined light beam. 
The Lux indicates the intensity of light at a given point which can be easily  measured by a light meter. Figures given have been taken out of a home made light box

Indoor and outdoor beam shots

 For/Against
For: Multi purpose cycling light, which can be used has a normal flash light once off of your bike.  Very compact and slimline.  A good choice of LED with a well designed and easy to use interface as well as a good multi level of brightness and setting.  Good runtime, steady output and cycling warning feature.  Can tail stand.  

 Against: so far, nothing really except that I am not that keen on the strobe light setting, although this is my personal opinion.

This is a well designed cycle light, giving  you a choice of 
high power output, long run time and safety high power flash. 
The ST CYCLER will certainly help you to stay safe on the road or on forest trails.