Earlier this year in September, my
girlfriend and I hired some e-bikes from Switched On Bikes down in Wellington.
We spent a pretty glorious day riding around Wellington, even if Google Maps
thinks we rode our bikes over the water a few times and went through the
restricted airport space:
We managed to ride the bikes for about 6 or
7 hours without getting tired, going up and down a couple of big hills, and
still had plenty of charge left at the
end of the day – I was hooked! When I got back to Auckland, I started
researching e-bikes and saving up…
Choice
It turns out that the massive range of e-bikes is
a bit overwhelming – without really knowing very much them, it’s hard to know
what the difference is between the bikes, and why some bikes are so much more
expensive than others. Different shops have a different variety of brands, and
then there are the really cheap bikes you
can find on TradeMe, and it definitely left me thinking “I just don’t
understand why the pricing is so different for bikes that seem to have similar
specs”. E-bikes are not cheap, so I feel like you should spend a decent amount
of time doing your research to make sure you’re making the right purchase and
getting a good deal (just like if you were buying a car). I ended up spending almost three months sporadically doing my research and talking to people before I arrived at a shortlist to take to some e-bike shops.
So in this article, I’ll discuss the
factors that most significantly influenced my final choice of e-bike. I’ll try to keep it short, but that’s
really not my strong suit, so apologies for that in advance. Probably the most
important thing to do first is to identify your use case. A daily commute from
Te Atatu to the CBD is very different to the occasional ride on the weekend and has very different needs. In my
case, I live in Newmarket and need to get to the CBD and back about 3-5 days a
week. Regularly struggling up Symonds Street was one of the big motivating
factors in getting an e-bike. It’s a reasonably short commute, but I also found
that since I don’t have a car, I would limit myself socially to not go too far
away in case I didn’t have enough energy to bike home, so it would be good to be
able to do the occasional longer trip to attend events and visit friends. Overall,
I’m not really looking for a bike that will do a long commute every day, but I do
want something that could do longer trips if needed. Also hills. The e-bike has
to be able to handle (relatively big) hills.
Folding
vs Non-Folding
My parents live on the North Shore, so
something that initially influenced my choice was the portability of the bike.
At the moment, I do walk-bus-walk to get to theirs, and it would be nice if
that could be cycle-bus-cycle instead (until the Skypath is eventually
finished perhaps). You can take folding bikes on the bus, and full-sized bikes are only
allowed on trains and ferries. Folding bikes take up much less space, and you
might feel better about the security of your bike if you can store it under
your desk at work rather than leaving it outside where the likelihood of theft
is unreasonably high. They’re also a bit lighter, which can help if you have
difficulty carrying or lifting heavy things. On top of that, folding bikes can
be cheaper since they’re smaller, with the Onya
F-19 priced at $2350 (vs. about $2750 for the equivalent full-size Onya SH1). The SmartMotion E20 is also a
popular folding option.
However, the size is also the biggest
downside of the folding bikes – most of them have 20” wheels (or even 16”) in
comparison to the >26” of the full-size bikes. It turns out that the size of
the wheels shouldn’t have much impact on the performance of the bike as you can
probably get to the same speed on both with similar motors, but the smaller
bikes have a much worse ride quality. The bigger wheels are better able to
absorb the potholes and uneven surfaces of Auckland roads better (although not
completely), and after a long journey it can make a big difference to your level
of enjoyment and happiness. So I think the general wisdom is that you should
only choose the folding bike if you have space or weight limitations (for
example, if you live in an apartment block or need to carry the bike up flights
of stairs regularly, or you’re really really keen on multi-mode transport and
want to take it on the bus). In pretty much all other cases, a full-size bike
will be more comfortable and enjoyable to ride.
Motor
When it comes to the motor, there are two
important numbers to look out for: the voltage and the power (in Watts). In NZ,
most motors are 24V, 36V, or 48V, with the vast majority being 36V. The main
difference here is how much pep the motor can give – when the motor goes, with
a higher voltage motor you’ll feel more acceleration and it might do better on hills.
However, in the vast majority of cases, 36V is enough and the main reason to
upgrade to 48V is if you want, well, more. 48V costs more too, and it’s
probably not worth it for most commuters because of the speed limits.
In terms of the power, most motors are
either 250W or 300W. Since 300W is the legal limit in NZ for electric bicycles
on the road (before they become classified as electric scooters and you need a
bunch more safety stuff), if you see a bike with more then it’s probably
intended for off-road use only. Of course, the police aren’t actually checking
every bike and probably won’t notice unless they see you speeding down the road
at 60km/h, but if you do that it’s obviously much less safe and you do it at
your own risk (I don’t endorse or encourage this at all, 30km/h is plenty fast
for me). There’s a lot of debate about what the number of W on the motor
actually means (whether it’s peak or continuous or whatever) and sometimes this
number can be misrepresented to make it look better than it actually is, so you
may need to be careful with cheaper bikes/brands that might not be telling the
full truth with this number. In my opinion, you pretty much want 300W if you
can get it – anything over $2500 is likely to be at 300W (or more).
I read an interesting article somewhere
that helped me understand the difference the motor power makes by talking about
it in terms of total power output. A person riding a bicycle needs to generate
a certain amount of power in order to get it moving (and keep it moving),
pushing against the various forces like friction, gravity when going up hills,
and drag when it’s windy. An average cyclist is probably producing about
100-200W of power, and the motor power goes on top of what is being produced by
the cyclist. The motor is not actually drawing 300W all the time (it
goes up and down as needed) since the power generated is partly dependent on the
level of assistance that you’ve selected,
you need more power to exert the same force because you’ve got a motor and a
battery making the bike heavier, and when you feel the motor also producing
power then you instinctively produce less to compensate. In general, it means
that the cyclist can generate less power and still get the same total power
output for the overall system. So I think the biggest thing for me is that this
means you can go much further while outputting less power, which means you get
less tired!
Battery
Capacity
The battery is generally the most expensive
component on the bike, so getting a bigger or smaller battery makes a big
difference to the overall price. The most important number here is the
capacity, usually measured in Amp-hours (Ah). If you find a bike that lists the
capacity in Watt-hours (Wh), then find the voltage of the motor, and divide the capacity by that voltage to convert it
to Ah (based on P=IV). The capacity influences the range of the bike, i.e. how
far you’ll be able to ride before you need to recharge. The capacity alone
doesn’t determine the range though – it’s also dependent on the weight of the
rider (and any luggage), as well as the level of assist being produced by the
motor. @tslumley notes that the
elevation of any hills you have to climb affects your battery use more than the
distance. The general rule of thumb in NZ seems to be that to calculate the range (very approximately), you multiply the capacity in Ah by 5km,
assuming an average-ish weight and a medium level of assist (level 2/3 out of 5). Most entry-level
e-bikes come with a 10.6Ah battery by default, which means that you can get a range of
approximately 50km. Remember that you probably want to get home as well, so
unless you can charge the battery at your destination (which can take 4-6 hours), you probably need to
divide that range by two to decide how far away you can go from your house. Always
be a bit wary of the range advertised in marketing material, as sometimes this
might be based on flat roads only or be otherwise misleading.
In my case, a 10.6Ah battery probably could
have been sufficient, but the other thing to remember is that the capacity is
also likely to weaken slightly over time as the battery gets older. This really
shouldn’t happen that quickly (and most modern batteries should support over
1000 charge cycles), but I didn’t want to get too small a battery, and then
have to replace it or upgrade it sooner when it no longer met my needs. I’d
also rather not have to worry about the battery capacity too much, and just go
as far as I want within Auckland. I opted for a 15.6Ah battery upgrade, taking
both of those factors into account. You can get even bigger ones if you want to
go further, and if
you end up with a bike with a 48V motor then you should definitely get a bigger
battery.
Throttles
Generally, the motor only engages when you
are pedalling (which is the root of a common European name for e-bikes,
“pedelecs”). This is totally fine, except for when you’ve stopped at traffic
lights on a hill, left your bike in a high gear, and then need to push off when
the lights go green. Actually, with the extra weight of the battery and the
motor, even starting from rest can be a bit challenging if you’re not already
on a downhill slope. F=ma, so you have to generate the most force when you are
accelerating from rest in comparison to when you are just continuing on at the same
velocity, and W=Fd, so more force when moving from rest means more work is done
(energy is spent), and therefore more power is needed. Hurrah for high school
physics!
Chances are, you'll struggle to get to speed at traffic lights and the cars around you might get angsty, and it usually takes a second or so for the system to recognise
that you’re pedalling and make the motor go. Most new bikes now come with
throttles, which you can twist on the handlebar to tell the motor to turn on
and push forward without you pedalling. A throttle helps in the hill start
scenario a lot (or even just pushing off normally), as you get up to
speed a lot faster and with less effort. You could theoretically just ride around with the
throttle like a scooter, but this drains the battery a lot so you’re massively
reducing the range if you do this (and constantly drawing power like that is not so great for the lifespan of the battery or motor). In my opinion, having a throttle is super
important and is one of those features that can make or break having a good
time on the e-bike, especially when you’re riding around a city with lots of stopping at traffic lights and intersections.
Cadence
vs Torque Sensor
Oddly, this is something that I think matters a lot that many people don't talk about. E-bikes will have a sensor attached to the bike
that allows the computer to figure out how much power the motor should produce
to assist the cyclist. I’m going to massively simplify the two types of sensor
here because the physics gets a bit more complicated, but there are simple-ish
explanations of the difference here
and here.
A cadence sensor essentially works by
measuring the revolutions of the chain or wheel
and using that to determine the speed of the bike. The first effect of this is
that the level of assistance is based
primarily on your speed, and the motor will just try to give you a boost up to
the target speed. This can have unintended effects, like if you are pedalling
slowly just before getting to a downhill bit and then the motor suddenly kicks
in and propels you forward. The second effect is that when you start pedalling,
you have to do up to one revolution manually before the system can recognise
you’re moving and kick in with the motor. This can make pushing off harder, and
the power can feel a lot more sudden and surprise you.
A torque sensor, on the other hand,
measures the level of force that you’re applying to the pedal, and the computer
then tells the motor to produce a proportional level of boost. In contrast to
the cadence sensor, this is not based on the speed but based on how hard you’re
pedalling, so it generally feels a bit more natural because it is amplifying your effort. Additionally, the motor
kicks in almost immediately when you start pedalling, so there is no awkward
delay trying to get the first revolution.
The problem is that torque sensors are more
expensive, so you usually only find them on higher-end bikes (the cheapest
one I found with a torque sensor was the Onya SH-1 Cross, priced at just
under $3000). In my opinion, if you have a throttle, then you can mitigate most
of the downsides of having a cadence sensor by using the throttle to manually
tell the motor to start helping. I tried bikes with both, and the torque sensor
definitely feels nicer, but if you can’t afford it (like me) then the cadence
sensor is still good enough. @AlastairGSmith says that a mid-drive motor (with a Shimano or Bosch system) has better pedal assist so that a throttle is unnecessary, and is slightly more efficient too.
Weight
Distribution
There’s a lot of argument about mid-drive
vs. rear-drive motors and downtube/mid-mount batteries vs. rear-mount
batteries, how that affects the weight distribution of the bike, and how that therefore affects the performance and ride
quality. A lot of people care about this apparently. To be honest, this was one of the least important factors for me because,
at the end of the day, the largest impact on the bike’s weight is the
cyclist. The motors are generally not too heavy, so I really don’t think mid vs
rear-drive makes a huge difference, but I could be persuaded that the
positioning of the battery is maybe more significant. The batteries are a
couple of kgs (mine feels like it could be 6 or 7kg), but at least in my (very
limited) experience, the mounting position hasn’t affected the ride too much. However,
it does affect how easily you can lift or carry the bike, and with bikes that
have both the motor and battery on the rear, it can make it a bit trickier to
pick up the bike because it’s so back-heavy.
Build
Quality and Design
I’m basically lumping everything else
together in here, and sometimes it’s just the little things that can make a big
difference. On the Magnum
Ui5, you have to turn the lights on and off by pushing buttons on the
lights themselves (which you probably can’t safely reach while riding), and the
rear light is completely separate and needs separate batteries. On the SmartMotion
e-City or e-Urban, the lights are connected to the main computer so they
draw power from your main battery and you can turn it on or off from the
handlebar. Not usually a big deal, but it’s just a minor detail that makes the
e-City/Urban a bit more usable on a regular basis.
The positioning of the brakes and the gear
levers can make the bike easier or harder to use – sometimes everything is just
cramped too tightly together because there’s not enough handlebar real estate. Some
bikes have really awful computer interfaces (the worst one I saw was literally
just a couple of LED lights for battery level and assist level), while others
have fancier LCD screens that display a lot more information (including
odometry and expected range). You might care about the number of gears available, especially if
you do sometimes want to ride the bike without electric assistance (a lot of
the cheaper ones only have 5-8 gears, while the Magnum Mi5 has a full 21!). Some
bikes have built-in rear wheel locks which make
them much harder to steal because the thief can't ride the bike away. Some bikes have the battery built into the bike so
it can’t be taken out and stolen, but it also means that you can’t separately
charge the battery without the bike. Some bikes come with a rear rack
so that you can add pannier bags easily. Some
bikes come with bells and drink bottle holders. Some bikes have better cable
protection than others (the bad ones look a bit flimsy and if a cable gets cut
or frayed, it’s probably going to be a bad time). For most of these little
things, the only way to really find out about them is to give the bike a test ride, and to get some advice from the people
selling the bikes to find out what issues they’ve noticed in the past.
The last thing that’s really important is
the general availability of the brand and people willing to service those
brands. This is probably the most important reason to stay away from the very
cheap end of the market because if you
have an issue with one of those, chances are no one will be able to source
replacement parts for you (especially if you buy it online from overseas
instead of from a brick-and-mortar shop). If you can find the brand being sold
by multiple shops, then that’s probably better long-term as it can give you
some ability to shop around (both in terms of the initial purchase and in terms
of servicing).
Price
Of course, everything else is superseded by
a fixed budget of what you can afford. In my mind, there are a couple of
classes of e-bikes that you can aim for: there
are the cheap bikes from unknown manufacturers that don’t have any good
reputation and are a risky purchase that sit
around $1500-2000, entry-level bikes that go from about $2500-$3000, and then
“good” bikes like the SmartMotion
Pacer which are $3500-$5000. Beyond that, we’re talking bikes that are
probably being used for off-road mountain biking purposes that are really
expensive, in the $6000+ range.
After saving for awhile and dipping into my savings, I had a budget of about $2700 for a new e-bike. I did
check TradeMe, and even won an auction for a relatively new
but second-hand bike for $1400, but the
seller in Blenheim never replied to any of my e-mails so I assumed the trade was off (and in retrospect, I
would have been pretty nervous about sending that amount of money in case it
was a scam). I did also consider getting an e-bike kit and installing it on my
existing bike, but decided that my $100 fourth-hand bike is already old enough and has enough issues like
certain joints being rusted tight that I might as well get a new bike.
Evolution
Cycles did have a 10% sale for Boxing Day too, which messed with the
economics a little bit but ultimately wasn’t enough to put the next class of
bikes within reach. Financing can change what is and isn’t affordable if you're okay with regular payments instead, but I
learnt a personal finance rule that you should never go into debt for
depreciating assets because you generally lose money in the long-run, so I
would rather buy the bike outright. As a plus, Mercury
Energy has been trying to encourage
people to use e-bikes, and their customers are eligible for discounts on a
pretty wide range of bikes from most e-bike shops. The discount is usually
$250, although for certain models the discount goes up to $500.
Actually
Buying the Bike
I went to a couple of different shops to
have some chats, and it was helpful in the sense that they were able to answer
some of my questions about things like ride quality and give recommendations,
but also unhelpful in the sense that different salespeople gave contradictory
advice. For example, one salesperson said that the Magnum Ui5 was
the most popular e-bike in NZ and outsold everything else by a factor of five,
while at a different store they said that Magnum bikes were pretty poorly
designed and actively steered potential customers away from them (even though
they had them in stock too). Another salesperson was talking quite quickly and
pressuring me into making fast decisions. I think the lesson here is to just
take everything that you hear from the salespeople with a grain of salt and be
careful – you’re the one spending a lot of money, so take your time (which you
are entitled to) and don’t let a salesperson force you into a decision that
you’ll regret later.
After test riding a couple of bikes, I
settled on the Onya SH-1 Cross
at Bikes and Barbers Newmarket,
mostly because it has a torque sensor and I was told that the price was $2750
(which in retrospect, did seem like a “too good to be true” deal). It turns out
that the pricing was wrong (actually $2990 with a 13Ah battery, and it would
have cost about $3250 in the
configuration that I wanted with a bigger battery and maybe a 48V motor). They couldn’t sell me the bike that cheaply (they're good people, everyone makes mistakes sometimes), so I
switched to a SmartMotion
e-Urban instead. The e-Urban and e-City bikes are essentially the same except for the frame (the e-City is step-thru while the e-Urban is, uh, not). The e-Urban and e-City bikes are very popular, and have also been battle-tested as hire bikes for several operators over long periods of time. As a bonus, SmartMotion bikes are designed in New Zealand too, and use the same underlying drive system that NZ Post uses for their e-bikes.
I’ve ridden it for two days so far, and I’m
enjoying it a lot. It is quite back heavy, which is fine when riding but makes
carrying it up and down steps a bit difficult. The wide battery at the back
also makes it a bit harder to get on the bike, with an increased likelihood of whacking your shin on it
if you’re not careful, which
might be an argument in favour of the step-thru frame on the e-City. Once I
got used to the throttle, riding has been really easy, and I’m able to maintain
an average of about 25km/h on most roads, and about 15km/h on some pretty steep hills. I’ve travelled approximately 15km so far on the first full charge,
and still have about 80% of the battery
left (mostly on an assist level of 2 or 3 out of 5).
Hopefully, this article has been somewhat helpful to someone! I’m always happy
to try and answer any questions that you might have about e-bikes if you’re
thinking of buying (although I’m still not as knowledgeable as the people in
the shops) – you can find me on Twitter as @andrewtychen.
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