Q-Factor

            The previous post on crank-sets made reference to a dimension called the "Q-Factor" This raised a few questions along the lines of 'What the hell is a q factor???' So, here is the definition and why it is important.
            The Q-Factor is the distance from the point of pedal contact on one crank arm to the other, measured parallel to the bottom bracket. The little illustration below shows the measurement.
             Some people of a certain vintage refer to this dimension as the crank-set  tread, but nowadays it is universally called q-factor.
             In most cases we want the smallest q factor that is possible. The more this dimension increases the less clearance we have when cornering and for most body types the further out the pedal is the more the angle of attack under pedaling force. Think of this when you are running say, your legs prefer to function by being directly under your hips. If you widen your stance greatly you start to rock and loose some power. Also it puts pressure and strain on knees and hip joints.
             Why then don't we just make skinny crank-sets? Well we have clearance issues when building frames. We have to widen chain-stays on mountain bikes to get clearance for big tires, the chain rings have to be allowed for. All these things dictate the minimum q factor. With the compact double road bikes with minimum tire clearance we can get crank-sets with the narrowest tread.
Posted on December 13, 2012 .

New Crankset From Sugino


The Road OX801D
          Sugino, the Japanese company famed for making some of the best crank sets to grace bikes through the decades have come up with yet another innovative design that is both stylish and addresses a common problem when choosing a gear combination. Lack of choice.
The MTB ZX801D
           The new OX801D for road and the ZX801D for MTB features a 110 and a smaller 74mm bolt circle diameter that enables the use of rings only usually obtainable on a triple. This new design and the selection of rings available gives you 13 possible combinations. Perfect for those looking for the ultimate touring setup or a cross racer looking for a tweak to the standard configurations. Mtb  options for running a wide gap for a low climbing gear on a tough or muddy course. The choice is yours.
Close-up Showing the 74mm. BCD for mounting  the smaller rings
           The build quality is superb, typical Sugino, and the outboard bearing bottom bracket configuration is very stiff. The setup also gives you the lowest Q factor available when using the lower 74mm mount rings at 145mm for the road and 156mm for the mtb. Let us know what your gear requirements are and we can put together the best combination for you.
Posted on December 6, 2012 .

Bicycle Measurement

              You would think that the task of measuring a bike would be a very simple one but alas, as with most things in life, we have made it complex and ultimately very confusing. Over the years a few different ways of measuring frames, seat tube length specifically, have evolved. Sadly they have all become commonly used among the many frame manufactures out there, I have even dealt with manufacturers that have utilized 2 different methods of sizing within their range of bicycles. Needless to say this can get very confusing and needs to be kept in mind when purchasing a bike, especially when using an existing bikes measurement as the foundation for a new one. In my opinion buying a new bike in a size based solely on the fact that it is the size of the previous one is a bad way to go about things anyway but can be disastrous if the frames have been measured to different points.
 Today’s modern frames are designed very differently from the older, horizontal top tube, bikes of yesterday. The new geometry of compact frames with sloping top tubes are designed to have lots more visible seat post and can vary a lot from design to design so, again, sticking with the size of a previous one for the new and expecting it to fit like the old probably is not going to happen. Always get a new bike fit done on the bicycle style and design you are contemplating.
             The drawing below shows the various points that are used when quoting seat tube frame sizes. All have a starting point at the center of the bottom bracket but from there can be measured to the top of the top tube, the top of the seat tube itself or even to an imaginary line which represents the center of the top tube if it were a horizontal design
Click Image for full size.

There is actually another one that is only used by frame-builders when building custom frames and that is; to the center line of top tube where it will actually be. This is because we are building a bike to an individual’s body measurements and the tube dimensions are already factored in. We also work from center line dimensions when setting the frame jigs.


With all these methods you can see how varied the results can be. Looking at the frame in the picture you can see that there is quite a difference from   the shortest measurement to the longest on the same frame. I have always thought that the most important measurement on a production frame nowadays is the effective top tube length. When comparing a favorite frame to a possible new addition this is a good comparison measurement to start with, but again a proper fit is the way to go.

Posted on December 4, 2012 .

Hoy Bikes

          6 x  Olympic Champion and 11 x World Champion, Sir Chris Hoy, officially launched the Hoy Bike brand last week,finally. Rumours have been flying for weeks that a bicycle venture was in the offing and now we know. Through a partnership with the Evans Cycle Shops Sir Chris will be releasing a range of bikes due to be released in March of 2013.
          Initially the range will consist of three road bikes and four city bikes however, the range will eventually be expanded so expect to see mountain as well. Even though it was denied that the range was to compete with the successful range of fellow Olympian Chris Boardman, there is already a planned release of a limited edition track bike. Should be fun to watch...
www.chrishoy.com
Posted on December 3, 2012 .

Alfine 11 Shifters.

                The recent post on the new Shimano 11 speed internal hub created quite a stir and I have had many questions regarding it. One of the main queries has been whether you can run it with a drop bar STI lever. Answer; yes you can. There has been a drop bar brake shifter around for a while as an option for the older 8 speed Alfine hubs and that manufacturer, 'Versa', produces a lever for the new 11 speed unit.
The Versa 11 speed cable actuated shift brake lever.
                However that is not the only choice, for those of you into the whole Di2 electronic shifting experience Simano produce a dedicated 'Alfine' specific electronic shifter.
The Shimano electronic Alfine 11 speed shifter and cable brake.
            Both of these options come with a matching left brake unit which is obviously just a brake.


Posted on December 2, 2012 .

Shimano Alfine 11

           As anyone who knows me will tell you, I am a big fan of internally geared hubs, from the old Sturmy Archer systems through to the new crop from Shimano, I think they are the best option for anyone who is a recreational rider, they are hassle free, need very little adjustment and are easy to keep clean. Another plus for people that transport bikes in the back of a car or pick-up is that there is no derailleur hanger to bend. Nothing screws up the shifting quite as quickly as a bent derailleur hanger.
          However, as much as I am a fan of internals for Recreational riding I have never recommended them for aggressive mountain bike applications. Except for one model, The Rohloff 14 speed internal hub. These hubs are in a completely different league and that goes for price as well, a Rohloff setup usually runs around $1400.
          Recently though Shimano has stepped up the game a little, the new Alfine 11 speed hub, although looking similar on the outside to the 7 and 8 that preceded it, are completely re-vamped internally. The 11s are even running an oil bath system just like the Rohloff. A sign that things have changed somewhat is the emergence of some cyclo-x rigs running the new Alfine 11. The hubs are also compatible with the new Gates belt drive setup. It is a bit soon to tell if these hubs have the durability required but initial feedback seems quite positive. We have a couple of projects in the workshop at the moment, which will feature a little later here on the blog, and an Alfine 11 is definitely on the short list as the drive choice.
Alfine 11. Total gear ratio of 409%.

Posted on November 19, 2012 .

Bottom Bracket Conversion

          A common problem that arises nowadays, with the influx of new bottom bracket standards is what, why and how to move from one system to another. With the threaded bottom brackets of old there was not many issues with a change to the newer outboard bearing systems but, with the move to frame specific systems, the switch is no longer as simple or, in some cases even possible.
          One of the most common issues is the press fit systems more specifically the PF30 and BB30 standard. Whilst both these systems are good and make for a solid crank interface often the issue arises because the frame has been purchased as an upgrade for a specific build kit already owned and the owner needs to convert the bottom bracket over to a threaded external system. There have always been a couple of options for this however, the good folk at Praxis Works, makers of our favorite chain-rings, have come up with a superb new conversion kit for the purpose.
         One of the biggest problems with conversions and even the press fit systems as a whole is that they tend to creak and groan. This is because the adaptors are, like the bearings, seperate from each other. With the Praxis system the cups are actually conected to each other by means of a threaded sleeve. This sleeve is very tightly machined but also as it is installed it flares out and takes care of any wiggle that may cause problems.
          If you are thinking of doing a conversion or have already performed a conversion with another product take a look at the Praxis system. It is the only way I will go in future. If you want more information or need a kit just let us know as we are Praxis dealers and use the full range of their products.

www.praxiscycles.com

Posted on November 14, 2012 .

Airless Tires in our Future

A Colorado engineer has come up with a new tire design. Not just another new tread pattern but a whole new approach. Instead of the usual threads encapsulated in rubber he has gone for the latest in carbon nano-tube technology. Result is a tire that mounts directly to the rim and requires no tube or air pressure to give it shape. The nano-tubes can be adjusted to give different ride characteristics, much like adjusting air pressure, and are covered in the rubber coating with the tread pattern. Not available as of yet but I am sure it will not be long before they are filtering through into the bike shops. In the meantime have a look at the video. If nothing else they look cool.


Posted on November 8, 2012 .

Park Tool Goes For Gold

           Anyone who wrenches on a bike knows Park Tool Company. Venture into the back of any bicycle workshop and it will be a sea of blue handled devices as far as the eye can see. Our workshop is no different. Well the good folk at Park will be celebrating their golden anniversary in 2013 and to celebrate the fifty year milestone they are releasing a limited edition gold plated Y wrench, or as it is called in our workshop the "3 pronger." This tool is never far from my hand or pocket and is used more than any tool on the bench. Anyone looking to honor their favorite bike mech should look no further...
The mainstay of all bike mechanics...

Posted on November 4, 2012 .

Watts to Horsepower

           
A good friend of mine recently posed a follow on question to the watts article that appeared here some time ago. He had recently read about a new small car that had an engine power output of 6.5hp. Now, Tom is keen to know if that kind of output could be supplied by pedals and a couple of willing and fit passengers. So this post is for you Tom.
            A good place to start is by looking at the definition of horsepower. Basically the answer is in the name. Back when the steam engine had just been invented there was born a need to be able to measure power. What was this boiler shaped thing, puffing steam capable of? It was all very well turning up at a mine with one in hand but unless you could say to the mine owner that this had the power of something that they already knew, it was always going to be a tough sell. Thus horsepower was born. A guy named Thomas Savery came up with the horse comparison around 1702. He used it to good effect and sold many a steam unit by saying how it did the work of 15 horses. A problem arose quite quickly however, with competing manufacturers adding an extra horse on the figures here and there. All I can fathom is either some out and out monstrous sized horses were around back in the day or the figures were being fudged a little. So along came a standardized measurement of an average horse's potential, devised by Mr. James Watt the Scottish engineer. Using a gathering of fit dray horses, a mill wheel and a measured weight they ended up with the following. It is still the standard today. They fathomed that the average horse could produce 33,000 foot pounds per minute. Anyone that knows horses will tell you that those figures are a little optimistic, especially for a longer, period but those are the numbers.
              So that is the horsepower figure and Toms little car is producing about six and a half cart horses worth. The more astute of you are probably seeing a problem already, but I will continue. How does a human stack up with a horse? And can we fit them all in the car?
              There is a basic conversion for watts into hp., I won’t bore you with it, suffice to say that 1hp is equivalent to roughly 745.5watts, sustained, therefore the 6.5hp car is equivalent to 4845.75 watts. Going back to the original post we can see that a guy of reasonable recreational rider fitness, weighing in around 185lbs will be able to sustain approximately 196.8 watts over a period of an hour or so. Looking at these figures we can see that the car will need to be the size of a school bus to accommodate our human engine. The figures look a lot better if we can convince a dozen or so tour guys to be the engine but even then it is going to get cramped and gas, although expensive, is still cheaper than steroids.
              Tom had already fathomed this out and his main question is. Would it be possible to power batteries by pedal power that in turn powers the car with the necessary wattage and equivalent hp? Answer; yes, hooray. Not so fast, yes it would be possible for pedals to charge the battery bank but it would take a long time.
Using Ohm's law (amps=power divided by voltage) we can see that the average person could quite reasonably produce a 10amp charge rate, requiring about 120watts output, this is about the same as your average car battery charger. So, looking around at some electric motors it seems that the average requirement for a 1hp output motor is around 1000 watts. I know I said that 1hp = 745 watts but there is no such thing as a 100percent efficient motor.  
Watts ÷ volts = amps. Therefore the above example would mean 1000 ÷ 12 =83.3. Your average car battery can supply about 50 to 80 amp hours of capacity each battery would then require 5 to 8 hours of charge time at your pedal power 10 amp charge rate (divide battery capacity in amp hours by the charge rate).
Our 6.5 hp car would need approximately 8 batteries. I will leave you to work out your charge routine… Now I shall go and lay down, all this math has given me a headache.
           

Posted on November 2, 2012 .

Brake Reach Pitfalls

           We have a vintage Raleigh "Competition" road bike in the workshop for a complete makeover at the moment. It is an interesting project and will probably feature again in this blog before the transformation is complete. One thing that has cropped up already and is very common when doing these kinds of makeovers is 'brake reach'. It is not however just a problem with older style bikes it can cause issues on modern frames too, especially on those catch all frames that are designed to be built up in a variety of styles and need to accommodate a wider range of tire widths than a standard 23 or 25.
            Brake reach is basically the distance between the caliper mounting hole on the bridge,  to the center of the brake wear track on the rim.

            On a modern standard road bike this distance is going to be around 39-49mm and a standard short reach caliper from the big 3 will work just fine. Lots of manufacturers nowadays though are producing frames that can be equiped in various formats, a bike for all seasons if you will. This is where the brake reach figure can differ from standard and purchasing a short reach caliper is probably not going to work. The pads will hit somewhere on the tire instaed of the rim. Another problem scenario is with the older style frames as we have mentioned, the mounting bridge on these guys are usually set for the older style center pull styles that had a reach of around 61mm. Therefore a standard 39-49 short reach is never going to work.  Even what we commonly refer to as medium reach will have trouble as their range usually runs from 47mm - 57mm. The last tool in the box for a modern caliper is a long reach 55mm - 73mm.
             All this goes to show that you can never take anything for granted when changing parts on your bike. Measure, measure and measure again.
Posted on October 30, 2012 .

Check the Pads



Tis the season to pay special attention to your brake pads, wet conditions are notorious for embedding grit and debris into your brake pads, I am sure you have all heard that long shoooshing noise the first time you apply your brakes after riding through a wet section or a puddle, that is the sound of grit being sandwiched between your pad and rim. What happens next is a lot of that debris gets pushed into the rubber of your pads and from then on gets applied to your rim every time you brake. Now, what also begins to happen is that little pieces of your rim get chiseled off and they end up in your pads as well. It becomes a vicious circle.
                You should keep an eye on the condition of your brake pads throughout the year but especially after wet or very dusty rides. Keeping the pads free from debris makes a big difference to your rims wellbeing.
                If you do see some grit and rim material in the pads the easiest way to remove it is by buffing the surface of the pads until you reach new rubber, free from the junk. Use 80 grit emery-cloth on a small block, if you just use the cloth on your finger you will place a concave profile on the pad. Do not use sand paper for wood, that stuff will put more grit in than it takes out.
               Also periodically check the rims for digs or rough spots caused by contaminated pads. Any rim trouble spots can be addressed by carefully using a 120 grit cloth. If in doubt come see your friendly bike mechanic.
Before; A road pad (top) and a mountain pad (below), both with rim material embedded
After; Same road pad after some buffing. Good as new.

Posted on October 28, 2012 .

Heated Bike Lanes on the Way

             An idea being looked at in Holland is gaining ground across other EU countries that suffer from icy winters, heating the bike lanes. The small town of 'Zutphen' in the eastern part of the Netherlands will likely be the first town to be equipped with the lanes, at the moment they are waiting for a final decision.
             The technology proposed for the paths is a modified Geo-thermal energy source producing enough heat to fend off the snow and ice on the paths.
             The Netherlands has an estimated 18 million bikes for a population of 17 million people, so seems like a good choice for the initial scheme. They have around 35,000km of designated cycle paths across their nation. The cost of the heated trail has been estimated at around $40,000 - $83,000 per mile of trail.
             If the technology is successful more of Europe's bigger cities will jump on board and already there are rumors that London is looking at a version for the city center.
Posted on October 24, 2012 .

Human Powered Helicopter Challenge

         Some very smart kids at the University of Maryland are closing in on a record and a $250,000 prize put up by the Sikorsky helicopter company. The challenge, which has gone unclaimed for over 3 decades, is to build a human powered helicopter, capable of reaching a height of 3 meters for a span of 1 minute. The machine must also be controlled to stay in a 10 meter box.
        Check out the video below, they are not quite there yet but I don't think it will be long before the good folk at Sikorsky are cutting a check.

Posted on October 23, 2012 .

To Powder or Not to Powder...

          

A recent post on inner tubes "Latex v Butyl" has created interest in another of those topics which can stir passionate debate, whether to use talcum powder on inner tubes. So I shall offer my views on the subject and you can make your own decision.
           I shall state from the outset that I do not usually use powder when installing tubes. That being said I have customers that do and I have a canister of 'Johnson's' in the cupboard so, if requested, I can powder up a tube to keep everyone happy.
           Firstly, what are the reasons behind some people’s choice of using powder? Well, powder can make the tube easier to glide around against the tire when you are trying to wedge everything together. I know many people have trouble when trying to poke a tube into the tire and pinching the tube under the bead of the tire is a common problem for some. Also, when removing a tube from a tire, it is easier when dealing with a tube that was powdered. I have also heard the argument that when a tube is powdered there is less friction between tube and tire and less likelihood of failure from abrasion. Finally people see that there is often some trace amounts of powder when you get a new tube out of the box so therefore powder must be good.
            Okay, I think that covers most of the arguments that commonly get mentioned for the use of powder, now for my rebuttal.
            Starting from the bottom of the list, the reason manufacturers use powder is actually during the manufacturing process itself, it is not as some suggest them pre-powdering the tube for you. When the tubes are made the rubber becomes very hot, even by the time the process is over there is still considerable heat left. The powder is actually used on the inside of the tube so that when the tube is folded flat and pressed into the packaging the two sides of the tube will not bond together. Next time you have an old tube at hand cut through it and you will see a fine white powder coating the inside.
            Friction. I have never quite got my mind around this one. If anything you are creating a scenario to create more friction by using powder. When a tube is correctly inflated inside of a tire there really is no room for any movement between touching surfaces. Also we have all seen how a tube bonds slightly to the tire, if there was a need for any movement it would be very slight and the tube would be much better flexing instead of sliding against the surface as the powder argument suggests. And before the cries of tubes completely bonded to tires rises to crescendo, this never happens to the extent of tossing a tire away because of a tube that cannot be removed. I have replaced more tubes in my life than I have eaten hot dinners and never have I had a tube that refused to “Part Company” with anything more than a sharp tug. In fact that slight bonding helps out in another way too. When a puncture does occur, due to an errant thorn or some such, having the tube attached to the tire means that the air only comes out through the hole at that spot around the thorn, if you powder the tube and there is no bonding the air will escape from the tube into the cavity and be gone much quicker.
             Lastly, the installation. Here at least I do see a benefit for those who struggle with tube replacements. However, if you follow a set of rules such as, inflating the tube enough to give it body, make sure to get it seated up into the tire before popping the final bead on and never sticking tire irons in there, you should be fine. Most issues come when popping the last 6 inches of bead on and no amount of talc is going to help you there.

Posted on October 20, 2012 .

Sturmey Archer 3 Speed Hubs



Have been working on a renovation project this week, a Raleigh 20 folding bike. The bike was complete and looked to be in pretty good condition, apart from renewing the usual tires, tubes and cables, everything else has cleaned up nicely and gone back together without replacement of any internal parts. Back in the day they built things to last.

The Beast Laid Bare
                 As is often the case with bikes like this, I am the first person to see the inside of them since they were put together, this bike was no different and when it came time to open up the 3 speed Sturmey hub I was not sure what to expect. The hub was still working, albeit a little clunky in the changes, nevertheless I took that as a good sign. As is usual with the big hubs all the grease that had been originally packed in there had long since turned to a wood like consistency but, once all that had been chipped out of there, the parts showed very little sign of wear. These hubs never fail to disappoint, I have lost count of how many of them that I have rebuilt over the years but I have never had to scrap one.
The Gear System. 2nd gear is direct drive, 1st gear is a decrease of 25% and 3rd gear is an increase of 33% over direct. Clever stuff.

Posted on October 19, 2012 .

Butyl versus Latex. The Great Debate



Every year, as sure as leaves turn and fall, the perennial debate of "what are better butyl or latex tubes?" rears its head in the store. This year is no exception, brought to life by a group of riders traveling across the country and looking for a mediator.  Now I have learnt long ago when to keep my head down and look busy and this was one of those times. The rest of their trip gives me a headache just thinking of it. Anyway I thought that I might offer my thoughts on the subject here, where it is quiet…
                Firstly a little history, back in the day, the only game in town was latex rubber, basically latex is the stuff you pull out of trees and plants that can be formed into a rubber. Most plants exude some form of latex when they are cut or injured in some way. One tree in particular ‘Hevea brasiliensis’ was found to have great potential for commercially made latex rubber. Now I am no chemist so I will cut the lesson short on manufacturing natural latex, suffice to say it is produced from trees.  I should say that natural latex is, as it can be synthetically manufactured as well but originally everything from gloves to tires to condoms were made of natural plant based latex. Now everything was progressing fine until the advent of WWII. Amid worries about supply of rubber for everything from tire tubes to condoms a push was made for a substitute. Along came butyl, proper name Isobutylene Isoprene Rubber. The basis for this compound was developed by the German company BASF in the early thirties but was developed into what we know as butyl today by a couple of guys at Standard oil just before the onset of the war. Anyway I think that covers the how and the why but what is the difference and benefits of the 2 when it comes to your bike.
                I will agree that there are benefits to a latex inner tube and paired with a suitable tire they can be felt by most competent riders. The benefit comes in the form of better rolling resistance due to better or faster elasticity. When rolling, the tube is compressed and then, as it rolls along it springs back to its original profile. At the contact point the tire has a portion of its profile squashed to the road, obviously tire pressure and profile all factor in but as it is rolling the section that is leaving contact has to bounce back, the quicker this happens the less contact patch there is and by default the less drag. Latex is like a huge tight spring and it snaps back quickly. Butyl on the other hand acts like a hydraulic shock and bounces back slowly and in a controlled way, the energy is absorbed along with the heat.
                Other benefits include better feel when generally riding, for the reasons mentioned above, the tube also benefits cornering and basic feel.

A few things to consider when running Latex tubes.

·         Compared to butyl air leeches out quicker from a latex tube. Get used to pumping them up before the event to ensure proper psi.
·         Because of the high permeation rate, as mentioned above, do not use CO2 to inflate them. CO2 permeates through latex much quicker than regular air which is predominantly nitrogen.
·         They are lighter than a regular butyl tube, although some of the ultra-lite butyl are comparable. I have never been a big fan of the ultra-lite butyl tubes, they are extremely flimsy and the failure rate on them is very high which in my opinion negates any gain, especially on race day. Latex tubes in comparison, despite their delicate nature are surprisingly durable. They will shrug off lots of abuse. They will find any weaknesses in your rim tape though so be careful to install good tape well.
A standard Latex tube.

A latex tube will be beneficial to any good road race tire to a certain degree. That gain can vary from about 1.2 watts to about 2.8watts. Using a supple, high thread count tire makes a big difference. On tires utilizing some form of protective aramid belt or a thicker rubber tread the benefit will be considerably less.
Over the years latex has been definitely pushed under a rock when it comes to bicycle inner tubes and, honestly, that is probably the best for most riders. Butyl is much more suitable to the needs of most cyclists. It is thick and offers a little more protection and durability than latex. Butyl holds air better, it still needs topping off regularly but compared to latex it is significantly less permeable.
 Latex still has a place though, for those riders looking for ultimate performance from body and machine latex tubes can be a benefit. At this level any performance gain is always minimal but it is there. Running a quality latex tube in a quality race tire on race day is another of those gains.
Posted on October 15, 2012 .

Tour of Britain 2013

The 2013 Tour of Britain dates have just been released and mark the 10th anniversary of the event. The route will be finalized and made public next spring but the dates are as follows; Sunday September 15th to Sunday 22nd September. The tour this year will also team with the ride London event that will take place in August.
www.tourofbritain.com
www.ridelondon.co.uk
Posted on October 11, 2012 .

Aston Martin Bikes

News this morning from the good folks at Aston Martin, builders of some of the best looking cars on the planet and of course James Bond would be walking everywhere if not for them. Well it seems that they felt the need to design a bike worthy of their name and came up with the "One-77" limited to a run of 77 and with a price tag of 25,000 pounds, roughly $40,000. Their website is a little sketchy on details but heck they look cool.

Posted on October 10, 2012 .

New Lights

Another light, well it is the season, the Cateye "Nano". Lots of lights to choose from these days, the usual standard aa and aaa battery units, these are fine but the cost adds up quickly replacing batteries every five minutes. Rechargeable ones, with the battery pack that hangs in the bottle cage or a little bag under the top tube are o.k but a little inconvenient. Until this year the usb rechargeable units were not that great, now however we have a 600 lumen light without the added weight or hassle of a connected battery pack that can be quickly charged via a standard usb port on the computer. The nice features are the standard flash mode but also a setting that flashes one led while having the other shine a constant beam, see and be seen.




Helmet Mountable
Run Time High: 1.5 hrs
Run Time Low: 4 hrs
Hyper-Constant: 2 hrs
Flashing: 35 hrs








Posted on October 4, 2012 .