Monday 28 March 2016

My bike

Millions of readers of my blog have ask to see a picture of my bicycle. Well, one guy did. So as well as pictures, I'm going to explain what's there and how it works.

This is the bike, folded up. Because it's a folding bike, I can keep it in the back of my car (a Landrover Freelander). It also makes it possible for me to get it through metal semicircular kissing gates without having to do a strenuous lift.

You can see from this picture that it's a Haro bike, and the tires I use are Schwalbe Black Jack. I use those because they're Kevlar reinforced, making punctures slightly less likely.
What you can't see, is inside the tires. There's a thick-walled inner tube, adding to the puncture resistance, and between the inner tube and the tire, there's a gel insert, also reducing punctures. Since I adopted this system, I haven't had a single puncture. You can also see that the tread on the tire is quite knobbly. That gets me a better grip on soft ground and mud.

Here's the bike seen from the other side. You can see how the pedal is folded.

The folding pedal makes it easier to get it in and out of the car. And occasionally, folding both the pedals helps me get it across a narrow bridge.

To unfold it, first I attach the handlebars ...

Once, I put the handlebars on the wrong way round. When I applied power to the motor, it ran backwards, of course, and I fell off. I've only ever done that once!

So here's the bike fully unfolded.

Originally, it came with a kickstand near the back wheel. After I used the stand and it had fallen over numerous times, I replaced it with a much better kickstand near the center. I'm still not happy with it, though, so I often (especially on soft ground) lie the bike down while I go deal with the cache. I'm constantly on the lookout for a stand that would make it possible for me to leave the bike on the stand without it falling over. So far, no luck.

So now we look at the front wheel.

That's the motor. It's quite understated; it isn't obvious that this is an electric-assisted bike. You can also see the torque arm, and I'll explain that. The motor wants to turn, the bike forks don't want to turn. the motor axle has flat sides which slide into the bike forks, and that's almost certainly enough to resist the turning force. But if the axle does turn inside the fork, catastrophe will ensue, because the wheel can pull itself outside the fork, and now you have no front wheel. You can imagine the result if you're going along at 20 mph and suddenly the front wheel isn't there! The torque arm transmits the torque from the motor, to the bike frame, without undue reliance on the fit of the axle into the fork.

The motor is rather special; it's a dual speed motor. You can run it either forwards or backwards (the gearing transforms the backward motor rotation, into a forward wheel motion), and one way gives you a gear ratio of twice as much as the other. So low gear gets you up hills, high gear is good for tarmac on the flat. I get about 12 kph in low gear, and that's good over rough ground and grass; I get about 20 kph in high gear, which is good on tarmac when I'm covering a distance that's a lot more than the minimum distance between two caches (1/10 mile).

I can go even faster on downhill stretches, because I replaced the highest gear on the rear derailleur with an 11 tooth sprocket (the normal is 14), and when you're driving a bike via the pedals, the only speed limit is whatever the car speed limit is.  So on a country road with a good downhill, I can get over 40 kph.

Here's the back wheel.

You can see the quick-release lever for the wheel - that's also non-standard. It means I don't have to carry the spanner I'd need to remove the back wheel. I got it when I replaced the gears that had the highest as 14 tooth, with an 11-tooth, which gives me a 30% advantage when going fast.

You can also see the black bracket that supports the rear carrier. That rear carrier is important, because it supports the panniers, which contain the batteries.

The rear carrier is shown below.

The grey tape at the base of the carrier, is to avoid a problem whereby the rubbing of the pannier on the carrier, wears a hole in the pannier. On top of the carrier, you can see the bike controller. The controller is important.

Ancient electric motors had commutators, and carbon lumps (which would wear out and need replacing) conveyed the electricity to the commutator. The commutator was a mechanical way of switching the power so that the motor electromagnet was always attracted to the permanent magnets so as to turn the motor consistently in the same direction.

Modern electronics has abolished this messy solution, and now it's done digitally. There's three sensors inside the motor that lets the controller know the angle of the motor, and the controller then switches the power, using FETs (field effect transistors) so as to continue turning the motor. And the controller can choose whether to turn the motor forward or back. And that's how the dual speed motor works, via two clutches and sun-and-planet gears.

The controller is in the open so that it gets the benefit of air cooling.

Here's the rear carrier seen from the other side.

A close-up of the rear wheel ...

The bike has a two-wheel drive - the motor drives the front, and the pedals drive the rear. A lot of electric bike owners much prefer to have the motor drive the rear wheel, but they aren't geocachers. I'm often going over soft ground, mud, or ground thoroughly chewed up by horses, so a two wheel drive gets me a much better grip. Again in the picture above, you can see the grey tape that I use to stop the carrier rubbing holes in the pannier, and the way that the carrier attaches to the bike frame. That attachment is non-standard - there's a lug near the axle of the bike where the carrier is supposed to attach. There's two problems with that. The first is that the bolt holding it on has a tendency to work loose, the second is that if you try to screw it in really tight, you strip the thread.

You can also see the rear gear changer. You might recollect from a recent post, that the gear changer got broken, and I sorted it out by taking parts from the old broken gear changer, and from another one that was faulty. It's always nice when you can use old parts to repair a break.

A quick view of a pedal that's folded ...

Here's how the carrier attaches to the back of the bike:

That's also a bit of a bodge; there needs to be ample clearance between the carrier and the seat post, otherwise the carrier knocks against the seatpost every time I go over a bit of a bump, which is very frequent on rough ground.

You can also see the blue EC5 plug that leads to the controller, and is there to plug in to the battery pack. The leads from the controller are encased in old inner tube, which I hope will tend to keep the wet out.

And you can see the big spring for the rear suspension. I was going over a rough track once, and there was a "SPROING CLUNK CLUNK" noise. I stopped to see what had gone wrong, and it was that spring, it had broken. Like many things about a bike, it was really cheap to repair; a replacement was £7 for the whole suspension unit.

 The saddle.

I would, of course, prefer a saddle made out of rainbow and stuffed with cloud, but I've not been able to find one on Ebay, so I have to make do with springs and gel. This saddle is really comfortable. I have it a lot lower than most cyclists, because A) I'm stopping and starting a lot, and B) on really rough or soggy ground I help the bike along by hobby-horsing with the feet, and C) I really really hate falling off.

The red things attached to the seat post are red LED rear lights. If I'm still on the bike after dark, then I want any motorists behind me, to be certain to see me. For the front light, I carry a powerful head torch, which I'll show you later.

So now to the control of the bike, which is done, of course, via the handlebars.

The lever on the head post is because the handlebars are detachable for folding up; that lever is for tightening the bolt that holds it together. Another unusual feature is the grey tape at either end. That is there to protect my Freelander, which, although bought second hand (they don't make them any more) was in pristine condition, and I'd like to keep it that way as long as I can. My previous Freelander was somewhat scratched by the handlebar ends from leaning it against the car. Also scrunched by an anonymous person in a car park who didn't apologise or leave contact details. And then there was the time a cow fell in the car.

So let's look at the handlebars more closely.

The main control there is the left handbrake, which controls the rear brake. That's the brake I mostly use for slowing down - the front brake is used when I need to stop more rapidly. You can also see the bell. When I'm coming up behind a pedestrian, I ting the bell to let them know I'm there, because I don't want a situation where, just as I pass them, they suddenly notice me and step to one side, and if that's the wrong side, it could be catastrophic.

There's also the gear changer for the front gears. That would be useful if I need a really low gear, but because I have electric assist, that's rarely needed.

In the middle of the handlebars, you'll see this.

On the left, there's a switch that's connected to the controller, and selects the motor gear; low, high or automatic. Automatic means low gear until I get to about 12 or so kph, then it switches to high hear. I mostly use low gear, but if I'm going some distance on tarmac, I'd use automatic. You really feel it when the gear changes, it's like an afterburner just kicked in.

You can see the controller screen. That shows how far I've travelled, and I've done about 2500 kilometers on this bike. The most useful display there is the battery voltage, because that tells me roughly how much I've used, and how much is left. It starts at 50 volts, and when it gets down to 42 volts it's nearly empty.

Above that screen, you can see a bracket. I put a PDA holder on that bracket, to hold my Fujitsu Loox navigation device, which tells me how far away the cache is, and in which direction, together with an OS map of where I am. The holder isn't there permanently, because it's really fragile, and after I'd broken a few putting the bike in and out of the car, I adopted this solution.

Here's the right side of the handlebars.

On the left of this picture, there's the gear changer, which lets me run from low gear to high, in seven steps. The bike came with a twister gear changer, but I much prefer the kind that clicks between gears. So I replaced the original changer with a clicky one, which also includes a brake lever that controls the front brake, which I don't use much.

The blue collar is to keep the rubber handlebar grip in place. Just under the blue collar, you can see the throttle lever. It's a thumb throttle, and I've become very used to that. The more I push it down (it's on a slight spring) the more power is fed to the motor.

So that's the bike. But there's more. Here's the pannier.

It's quite big. In it, there's the batteries for powering the bike, a tool kit, and more.

It's heavy. Very heavy. It's about 12 kilos, depending on how many batteries I'm carrying. It detaches, though, very easily, so that if I have to lift the bike over an obstacle, I don't also have to lift that heavy bag. If necessary, I can divide the load beween two bags; if I'm doing 60 caches on the trot on a hot summer day, then I'll need a lot of batteries, and a few bottles of water. I can go without food until I get back to the car, but water is needed while I'm out.

Let's look inside it.

Hmm. A bit of a mess. Let's unpack it. First, the batteries.

This is a light, hard plastic box. It's just the right size to contain two of the battery packs that I use, and it will give the batteries some useful protection against the possibility of me coming off the bike (which has happened, a few times). So let's look at the batteries more closely. Notice the S&S International sticky tape!

These are Hobbyking Multistar batteries. Each of those three gives 10 amp-hours at a nominal 14.4 volts (which means 16.8 fully charged, 12.8 when discharged). These give the best power-to-weight performance of any kind of battery. You can get them for £21 each. I put three together in series to give me a start at 50 volts.

The batteries come terminated with a yellow XT90 connector, but I've standardised on EC5 for everything, so I add a cable that has an XT90 at one end, and a blue EC5 at the other. I tried a number of different connectors, and I chose EC5 because they're easier to pull apart than the others I tried, and because of the way I use batteries, I'm all the time connecting or disconnecting.

This turns out to have another useful effect - if the battery pack parts company from the bike (and that's happened to me a few times) then instead of the cables ripping apart, the EC5s disconnect, and it's easy for me to reconnect them.

You can also see the balance wires, those are the thin wires, too thin to carry the substantial current to power the bike. I'll explain about those soon, they're used for recharging.

Also in the pannier, I have these:

The blue and yellow zipped bag, contains geocaching stuff that I don't need often, but which could be useful. For example, spare batteries, multitools, sting relief, plasters, biro, pencil, string, safety pins and other stuff I've needed occasionally. The stuff I need all the time, I keep in my shoulder bag, with very easy access.

You can also see a fairly substantial combination lock. That's in case I need to leave the bike for any length of time - for example, if I need to trek a couple of hundred yards to get a cache, into a muddy field where a bike is a very bad idea. Or if the bike suffers a catastrophic failure that makes it a good idea to abandon it, walk to get the car, and then pick up the bike from where I left it. I did have a bike stolen once (it wasn't electric, so not too big a loss) and that was because the lock I used could be broken with the application of a couple of bricks.

Repair kit.

Ladysolly gave me this bag - it's leopard-skin makeup bag. No actual leopards were involved. It had a price-tag of £130, but she got it free with something, and it's probably worth about £0.50. Less now, it's become a bit grotty.

Inside, I keep my bike repair tools. I have all the spanners I'd need to remove either wheel, a puncture repair kit, a spare inner tube, tire levers, a pump, an adjustable spanner and a 46-way bike multitool that can do anything except get stones out of horses hooves. There's also some electrical stuff (wire, connectors, an adaptor to power the PDA for any battery, fuses) a handy selection of nuts and bolts (which have proved vital in the past) and various other bike-saving bits and bobs.

On my head ...

At this time of year, this is what protects my skull. I only have one head, and I'm very attached to it. I think it's actually a skate-boarding helmet. I also have a conventional bike helmet, which lets in a lot more air; that's for summer. And in the depths of winter, I wear a world war two flying helmet; leather on the outside and sheepskin on the inside. That keeps my ears and cheeks a lot warmer.

On my hands I wear fingerless cycling gloves unless it's very cold, in which case I wear sheepskin gloves (or similar). In really bitter weather, I wear the fingerless gloves *and* mittens, so that when I take off the mittens to sign a log, I don't get instantly frozen hands.

So how do I connect the bike to the batteries? With this. Reading from left to right ...

You can see the three blue EC5 connectors, which let me connect three 16.8 volt batteries in series to give a single 50 volt battery. That three-to-one adaptor feeds into a 30 amp fuse (it's never blown, but a fuse is surely a good idea) which connects to a big circuit breaker switch, and then to the EC5 connector that connects to the bike. While the switch is off, there's still a connection from the batteries to the bike, via a 100 ohm resistor. So with the switch off, I connect up the battery to the bike. Then I switch the switch, but by the time I do the switch, the capacitors in the controller have charged up via the resistor, so there isn't a big spark when I switch on.

The thinner wires connect from the balance leads of the batteries to the small black rectangles, which are alarms. When any cell of the battery falls from the original 4.2 volts down to 3.2 volts, the alarms starts to beep. It's not a good idea to run a LiPo cell below about 3 volts, so it tells me to change the battery.

Here's another thing that I carry in the panniers.

This is one monster head torch, a real night-into-day. There's also a red LED at the back, in case I'm on a road, so that car drivers can see me.

This is how I recharge the batteries.

There are all sorts of battery chargers for LiPo batteries (it's *very important* to use a LiPo charger, not any random voltage source), and most of them are quite expensive. I do have these complex and expensive chargers, but these days, all I use are these very simple chargers that cost about £6 and will change my batteries (or any 2S, 3S or 4S battery) ... but slowly. They will output about 1 amp, so a 10 amp-hour battery will charge in 10 hours. But I don't see that as a problem. If you need to fully charge batteries like this in a short time, get the complex expensive chargers.

Typically, I'll come back from an outing with two of my battery packs at least partly used. My batteries are made from three 4S batteries. So I use six of these little chargers (nine if I used three battery packs). They connect to the balance ports of the batteries, which means that it's very easy to plug in and unplug, and it means that the batteries are fully charged, and balanced, each time.

Important - I disconnect the batteries from the three-to-one series cable before I plug in the chargers. This is to avoid the possibility of a catastrophic short circuit, although when I think about the connectivity, I don't think that's actually necessary. Still, I'm cautious!

I power the chargers from old PC power supplies.

And you can also see a big fan that I use to blow cool air over the chargers. Not vital, but I like things to run cool.

I also have smaller batteries, these are five amp-hours, half the capacity.

Those are the batteries that I used before the Multistar became available, they're only 5 amp-hours, and are a little heavier per watt-hour than the Multistars.

How far will the batteries take you? That's a very difficult question. I would average about 40-50 caches with one set of three batteries, but that's over rough ground, with starting and stopping. On tarmac, you'd get 10-20 miles. The reason why I'm being so vague, is that this is a bicycle. You could go from Lands End to John O'Groats on a bicycle, and the same on an electric bicycle, except that part of the journey would be easier.

So what does this paragon, this queen of bikes cost? You should be able to get a 26 inch wheel folding bike for around £50 from Ebay; £20 if you don't mind a non-folder. The dual speed motor, built into a 26 inch wheel, andincluding the controller and other bits, will be £225 from Panda (less if you haggle). The batteries will be £63 for 10AH, or if you want a huge amount of battery, £126. Six chargers will be £36. From Ebay, a rear carrier £9, panniers £7. Total £325 to £450.

My bike.


  1. Who are these millions of readers?

  2. The are imaginary readers. You remember the imaginary pony?

  3. Potentially, millions of chinese readers via the 风骚达哥 SPAMvertising comments?

  4. I delete those whenever I see them.

  5. I recall one of your bike blogs which had a link to a conversion motorised system driving the front crank, but can no longer find it. Are your search tools any better than mine?

  6. It's OK - I found it "Bike porn" 31 Jan 2014. No longer on sale though.

  7. There's lots of motors that drive the crank, they're caled mid drive motors. Google "mid rive motor uk".

    I've thought of going that way - if I did, I'd get a kit without a battery and use LiPos, The advantage of mid drive, is that the drive goes via your existing gears, so you have seven (or however many) gears for hills. The disadvantages are 1) One wheel drive, not a problem unless you're going on soft and soggy ground like I do, and 2) if something catastrophic happens to the drive train, then you can only walk the bike.

  8. If you want a better stand try a Pleischer two legged. I use one on my tandem, worked fine for over a year, rated to 25kg and cleverly folds away both legs to one side.

  9. Thanks for the suggestion, I'd already thought of that.

    I bought a Pleischer but there's no way yo attach it to my bike :-(