Uncle Bob’s e-bike

   

Convertible e-bike
Figure 1 - Uncle Bob's convertible e-bike

Introduction

E-bikes (electrically assisted bicycles), have been around for many years now and are ever so slowly gaining acceptance by Australian cyclists.

 

The take up of e-bikes by seasoned cyclists, be they MTB riders, commuters or roadies is definitely lagging the significant improvements in the technology.  I see this as a kind of ‘cycling cultural cringe’ that I’m sure will change with time as more cyclists get around to experiencing the enjoyment and practicalities of an e-bike.

 

I’ve found during the short period I have owned an e-bike that, if I mention the concept of electrical assistance to fellow cyclists, it definitely has some appeal but, because most still consider the idea of power assistance to be ‘uncool’ or ‘cheating’, they shun the idea and shut their minds to this technology.

 

The overwhelming majority of Australian cyclists are male, are somewhat competitive and more than likely perceive themselves to be strong, fit and relatively macho.  They tend to visualise those who ride an e-bike to be frail old men or women that don’t have enough energy to crank their own pedals and the bikes they ride as unfashionable overseas designed uprights.  Unfortunately, this perception restricts them from embracing e-bikes as a serious form of transport or recreational cycling.  Such a shame, when our cycling infrastructure, such as bike paths, rail trails, cycle ways etc. continues to improve, and there are so many opportunities to further enjoy the great outdoors with family and friends of varying cycling abilities on an e-bike, and to commute.

 

On a rational note, the financial savings and environmental benefits associated with using a powered vehicle that weighs around 20kgs, is easy to store and to park, to move a single person from A to B relatively effortlessly, instead of one that weighs around 1.5 tonnes, are blatantly obvious.

 

This article has been written, not to be a definitive source of information on e-bikes, but to provide a perspective on this emerging technology and hopefully answer some basic questions.  It is also about how I approached the subject of having an e-bike as an alternative form of transport and recreational cycling.  Hopefully my philosophy will strike a chord with you.

 

A cyclist’s dilemma

If you are a serious cyclist, you probably wouldn't think twice about adding a compact chain ring, upgrading your rear cassette to an 11-32 or whatever, to get maximum mechanical assistance on the hills.  You also probably wouldn’t hesitate to swallow a performance enhancing substance to get that little extra energy boost.  However, you know that if you were to add a small electric motor to your bike, and told your cycling buddies you’d done so, you'd more than likely be frowned upon or viewed with suspicion.  As social beings, we all like to be part of the herd, so we don’t act.

 

My e-bike philosophy

I love my cycling groups who all ride for fitness and fellowship. And while I'm fit enough I'll continue to ride with them as long as possible without power assistance.  However, I know there'll come a time when I'll need power assistance to keep doing what I love to do.

 

After a mate gave me a ride on a mountain bike he’d converted I was intrigued.  So I took the plunge and got one.  Not to ride with my cycling groups but to use for a bit of fun when I go out occasionally on my own, be it to duck up to the shops for a coffee or just ride around to a mate’s place without having to change into my cycling clobber.  I was also keen to understand the pros and cons of this emerging technology and to grow with it.  I have an old Giant CRX3 aluminium flat bar road bike that I ride with one of my cycling groups every weekend so I decided to fit electrics to this bike with the aim of being able to use it with or without electric assistance.  My preference at this stage is still to ride it without electric assistance but know I can swap it to electric in about 5 minutes if I want to take it out for a spin.

 

I am a minimalist in terms of functionality so didn’t want racks, mudguards, paniers and a lot of the other stuff that comes with many of the off-the-shelf e-bikes.  I also liked the gearing on this bike that I’d modified over the years to give me good mechanical advantage in manual mode.

 

Why choose to have an e-bike?

Reasons why you might consider owning an e-bike can be many and varied.  Some that may strike a chord with you are:

1.                  You like the idea of commuting to work on a bike and don't want to arrive all sweaty

2.                  You are not a regular cyclist and need a bit of incentive to start riding a bike

3.                  You don't want the expense of buying and registering a motor scooter, or motorbike, having to get a licence and storing one

4.                  You live in a hilly area not very conducive to a normal pushbike

5.                  You have mates with e-bikes and want to join in on the action

6.                  You have a spouse who would like to cycle with you but he/she is a lower standard than you and is intimidated by hills and holding you back and;

7.                  You’re getting older, losing your oomph and would like to think you will be able to cycle well into the future with your mates

 

What's an e-bike?

E-bikes are normal bicycles as we know them, be they commuter bikes, mountain bikes, folding bikes, hybrids or road bikes with a few minor differences.  An e-bike has an electric motor either on the front or rear hub (hub motors) or either underneath or within the bottom bracket (centrally mounted). To power the motor there is a rechargeable battery mounted somewhere on the bike. Common mounting locations include the top of the down tube, the rear of the seat tube, a tray over the rear wheel or even in a backpack the rider wears.

 

You can engage the motor either through 'pedal assist' (an electronic sensor detects when you are pedalling and sends power to the drive motor) or via a hand throttle.  You can adjust the amount of assistance you'd like by programming the motor controller via the LCD electronic display mounted on the handlebar.  The motor control box limits the power to the pedals and throttle and restricts the maximum speed at which power assistance is provided.

 

Do an on-line search under ‘buy e bike’ and you’ll find a plethora of frame options and prices.  Frame options include hybrid, commuter, mountain and folding flat bar bikes and prices range from around $2,000 to $10,000.  But don’t be surprised if you can’t find any turned down handlebar road bikes with electrical assistance.  I guess this is because this market segment is almost impossible to crack at this point in time in Australia.

 

Battery options available are mainly Lithium Ion based.  Battery voltage is generally 36V although 48V and 52V batteries are required for the larger motor options.  Voltage choice depends on the motor you need to drive. A 36V 17Ah battery will add around 3.3 kgs to the weight of the bike. It should also be noted that e-bikes generally do not recharge their batteries when rolling along with no application of power assistance.

 

You have a choice of battery capacity to suit the type of cycling you do. For example if you just want a basic recreational e-bike or commuter to use for shorter runs (say up to 60kms with pedal assist) you could target a 250 watt / 36V motor with a 13Ah battery.  However, if you’d like to do longer runs between charges for the same situation (say up to 100kms with pedal assist) you’d do better to go for a 17Ah battery.

 

Motor sizes vary from 200 watts to 1000 watts (200 watt motors are rare) to cater for both on road and off road cyclists.  But, if you intend to ride the bike on public roads or bike paths and not have to register it, pay particular attention to the legal requirements for motor size and how power is delivered to the wheels (e.g. via the pedals, via a throttle or a combination of both).

 

Most e-bikes marketed today have the motor centrally mounted within the bottom bracket where the frame has been purposely designed to house it.  However, if you choose to retrofit a centrally mounted motor to an existing bike, it will need to be mounted under the bottom bracket.

 

With pedal assist, power is delivered to the motor by the battery via a sensor that detects pedal rotation.  The power delivered can be set within a range via the programmable LCD display on the handlebar.  The advantage of this is that if you wish to achieve maximum range from your battery or put in the extra work to improve your fitness you can set it at a low setting. Mine has a range from 1 to 9 that I usually set at 5.  Alternatively, I can just turn the power assist off altogether should I choose to and do all the work myself.

 

If you choose to retrofit an existing bike with an electric bike conversion kit, a typical conversion kit, including fitting, will cost you upward of $1300.  I chose to do this through a man named Ewan Maxwell at eMax eBikes in Alexandria. http://emax-ebikes.com.au and was very pleased with the outcome.

 

What is a legal e-bike?

Most Australian states are aligned on what they consider to be a legal e-bike.  However, there is significant dissent within the e-bike industry on the legal parameters that restrict upper limits on motor size and the use of a hand throttle. Two such examples are, 200 watt motors are difficult to obtain and may not provide sufficient power to assist a larger rider or a rider carrying loaded paniers.  Limiting the speed that can be achieved using a hand throttle to a maximum 6 kms/hour is also considered far too restrictive.  The value of a hand throttle comes into its own when getting up and rolling from a standing start (eg at traffic lights).

 

Ideally, if we choose to buy an e-bike to ride on public roads, we would prefer not to have to register it and be confident that it would satisfy any inspection by the authorities to verify that it meets the state’s legal requirements.

 

Generally, in Australia, the relevant state motor authorities refer to a non registerable e-bike as either a Pedal Cycle or a Pedelec. 

 

A Pedal Cycle

A pedal cycle is a bicycle fitted with one or more auxiliary propulsion motors with a maximum power output of 200 watts.  Auxiliary here implies that the primary form of propulsion is from the rider pedalling and the motor provides additional power.  This auxiliary power can be engaged either via pedal assistance or a hand throttle.

 

A Pedelec

A Pedelec is a power assisted bicycle that complies with European Committee for Standardisation EN 15194:2009 or EN 15194:2009+A1:2011 Cycles - Electrically power assisted cycles - EPAC Bicycles).

 

To comply with EN 15194:

                     The motor must be electric

                     The maximum continuous power output of the motor cannot exceed 250 watts measured at the wheel

                     The rider must pedal the bicycle to activate the motor

                     The motor must cut-out once the bicycle reaches 25 km/h, or sooner if the rider stops pedalling

                     The bicycle must be certified by the manufacturer, and labelled as complying with EN 15194. The label must include the manufacturer’s name, the motor’s cut-off speed in km/h and its continuous rated power in watts.

 

A legal power assisted e-bike, as defined by Transport Roads and Maritime Services NSW, is outlined in a document titled Vehicle Standards Information No. 27 (Published 8 Dec 2014 | Rev 4) – Refer Reference 3

 

It should be noted that, Pedelecs may be equipped with an optional low-speed start-up mode that allows the motor to power the bicycle up to a maximum speed of 6 km/h.  This mode can be activated by the user (eg by a hand throttle) either when riding without pedalling or when pushing the bicycle.

 

 

 

 

 

 

 

 

European style Pedelec
Figure 2 - A Typical European style Pedelec

Key differences between a Pedal Cycle and a Pedelec are: a pedal cycle can receive auxiliary power by a hand throttle alone hence not requiring the need for the rider to pedal at the same time, it must have a lower output motor (200 watt maximum power instead of 250 watt continuous power for a pedelec) and does not have to comply with the European Standard EN 1594:2009.

NB Petrol driven push bikes are no longer legal in NSW

E-bikes don’t have to be heavy

With the improving sophistication of e-bikes, comes more bells and whistles and invariably more weight.  As for modern cars, many of the bells and whistles, provide minimal value adding and, in my opinion, make them unnecessarily heavy and cumbersome.  Many of the ready-made e-bikes on the market include this sophistication to attract a particular type of customer, quite often based on the perceptions of someone in a foreign country.

 

Adding more weight is perceived to be the enemy of the serious cyclist in Australia, as many have paid a premium to get their cycling equipment down to the minimum.  The more weight you add, the more weight you have to push up those hills using your own energy and the limited output from a small electric motor.  However, more weight can be of value for stability and comfort on dodgy roads and when descending hills.

 

To give you some idea of the necessary weights and measures.  My converted Giant CRX3 weighs 13.8 kgs in manual mode after I remove the battery and swap the front wheel back to the original.  It weighs 19.2 kgs when I ride it in electric mode with the battery attached and the hub drive front wheel mounted.  The standard front wheel (without the motor) weighs 1.2 kgs while the front wheel with the electric hub drive motor weighs 3.3 kgs.  The battery weighs a further 3.3 kgs.  Hence by removing the battery and swapping the front wheel back to the original to use the bike as a standard bicycle, I shed 5.4 kgs (6.6 kgs less the added 1.2 kgs for the swapped front wheel).

 

Two front wheel options
Figure 3 My two front wheel options

Who Needs Another Bike?

Bikes require storage and, if like me, you love your pushy and don't want to buy and store another bike, here's a simple solution. Retrofit an electric motor kit to your current bike with a new front wheel containing a hub drive motor and keep your old front wheel as is. To ride your bike as an e-bike, simply replace your original wheel with the motorised one, push connect the male electrical lead plug extending from the front hub to the female wiring socket clipped to your front fork and clip on the battery.  To ride your bike as your old pushy, simply disconnect the electrical lead extending from the front hub, swap the front wheel back to your original one and detach the battery.  The only extra weight you'll then have to deal with will be some lightweight electric cabling, a small control box, the LCD display mounted on your handlebars and a few other light weight electrical bits.  This is what I've done and I refer to my bike as either in 'e minus' mode or in 'e-plus' mode –‘e-minus’ without electric assistance and ‘e plus’ with it.

 

Uncle Bob's e-bike
Figure 4 - Uncle Bob's e-bike in 'e minus' mode

Subtleties about a front hub drive

A front hub drive requires shorter spokes.  This creates a stiffer wheel that amplifies minor imperfections in the road surface through the handlebars to your arms and shoulders and makes for a very uncomfortable ride.  To overcome this I replaced my existing rigid front fork with a sprung front fork.  Wow! What a difference this made to the comfort of riding my bike both in ‘e-minus’ and ‘e-plus’ mode.

Cost to Convert my Existing Bike

It cost me around $1300 to retrofit my old flat bar road bike. I paid a bit more than this as I had the motor fitted to a new front wheel so that I could keep my existing front wheel intact.  I also opted for the larger 17.5 Ah battery to give me maximum range.

Included with retrofitted e-bike kit was a motor cut out switch that detects when the rear brake is applied.

A further additional cost was the expense of replacing my fixed front fork with a generic sprung front fork for around $300.  I chose to do this after the electrical conversion for ride comfort reasons – not mandatory but a very worthwhile additional investment indeed.

With the electrical assistance cutting out at 25kms per hour, if you ride up hills at speeds greater than this, you'll be pushing a much heavier bike with little or no assistance.  As riding hills at speeds greater than this is rare, this is not too much of a limiting factor.

Motor Location Options

There are 3 motor location options to choose from:

Front Hub

Simplest if you want to have the option of changing from an 'e plus' to an 'e minus' bike or vice versa. Think we would all prefer to remove and refit a front wheel rather than a rear to avoid the added complication of wrestling with the chain gears. This is the option I chose for my e-bike.

Rear Hub

As most of your weight transfers to the road via the rear wheel, there is a benefit in driving the rear wheel on loose surfaces to minimise the chance of wheel spinning.  However, wheel spinning is generally a low risk except on very loose surfaces and climbing steep gradients.

Bottom Bracket

This option is the best if you intend to only use your bike as an e bike as it is not practical to remove the motor and convert the bike back to your old manual push bike.  To leave the motor attached, when in manual mode, adds significant extra weight (approx. 3.3kgs).

 

An advantage of the sub bottom bracket is that it spreads the additional weight of the motor evenly between the front and rear wheels making the bike more balanced and, because the motor operates through the front chain rings, you get additional assistance through the gearing.

Throttles and Pedal Assist

Throttles

There are commonly 3 types of hand throttles: push button, twist grip and thumb lever. A throttle allows you to pedal or simply, do nothing. and let the motor do all the work.  Similar to a motor bike, the twist grip and thumb lever can be used to vary the power from the motor.  A push button throttle, not so common, will just turn the power on and off.

Pedal Assist

Pedal assist relies on sensors to determine whether the crank is turning to apply electric power to an e-bike.  Two such sensors on the market are: the cadence sensor and the torque sensor.  A cadence sensor provides assistance based on the level of assistance you have selected via your programmable LCD display.  It will not vary the power assistance depending on how hard you are pedaling.

A torque sensor determines the effort you are applying to the pedals and increases / decreases the amount of electrical assistance based on this.  Torque sensor pedal assistance has a more intuitive feel about it and is generally found on the more expensive e- bikes and e-bike kits.

Conclusion

E bikes are not only fun but also provide a practical approach to commuting without the strenuous activity associated with standard bicycles.  They also provide an opportunity to further enjoy the great outdoors and cycling with family and friends of varying cycling abilities.

To have one and avoid the hassles of having to store and maintain another bike, there is a strong argument for simply converting one of your existing bikes and being able to operate it either as an electric bike or as a standard bicycle.

E bike technology and cycling infrastructure have improved significantly in Australia in recent years, however the take up of e bikes still lags mainly due to the poor acceptance of their merits by experienced cyclists.

References 

  1. Wikipedia, the free encyclopedia - https://en.wikipedia.org/wiki/Pedelec
  2. Mopeds and Power Assisted Bicycles - http://www.rms.nsw.gov.au/documents/roads/safety-rules/standards/vsi-27-mopeds-power-assisted-pedal-cycles.pdf
  3. Bike Exchange website: https://www.bikeexchange.com.au/s/electric-pedelec-power-assisted-e-bikes
  4. Emax Ebikes website: http://emax-ebikes.com.au/
  5. Throttle vs Pedal Assist: http://electricbikereport.com/electric-bike-throttle-pedal-assist-pedelec/
  6. Australian State Laws: http://www.zbox.com.au/legal.htm

 

About the Author

 Bob Elsworth photo The author is currently a member of Ku ring gai Rotary Club and the marketing team for the Bobbin Head Cycle Classic 2017.  He is a regular group cyclist and cycles 3 to 4 days a week with different groups in Sydney’s northern suburbs.  As well as his weekly routine of cycling he has completed numerous intrastate, interstate and overseas social cycling events.  He rides essentially for pleasure, fellowship and fitness. 

 

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