At last, a hill-climber...

[frank9755]

The dropout problem is quite common, these motors have considerable torque. You were lucky in that the spindle didn't rotate more fully and sever the cables.

It's a good idea to fit a torque arm, locking on the spindle flats and preventing rotation. Here's an example of one on a rear wheel motor spindle:

You can see how the small bolt prevents rotation of the plate which has flats to match the spindle ones. There are various ways these can be made for front forks.

I agree with the idea of getting a torque arm. At one point, ebikes.ca were selling some ready made ones but not sure if they still are. I made one out of an old gardening tool and others have adapted old spanners...

The other thing I'd suggest is to make sure you get a steel fork, not an aluminium one!

 

[AndyOfTheSouth]

Help, please!

Got the bike back from the LBS with its new front forks (Rockshox Dart 3, I think), which with servicing, etc, came to an impressive bill.

Inspired by this to fit the Sparticle set myself and not wait to take it to TETS next week. Work out how the electrics fit together. Buy crimping tool, wires, etc in case I need them to extend the cables. Dash to Halfords to buy rear carrier and bag for new method of mounting controller and battery.

Turn the bike upside down to fit the motor wheel and… it won’t fit. Drop outs too tight. Undeterred, I decide to file them wider. No file. Find an old pen knife with file with about as much umph as a nail file. Use it anyway. Eventually, success! Big enough to take the wheel.

But then… this is the sad bit…the motor is too wide for the base of the shock absorbing forks. They don’t taper at the bottom, but are as wide at the base as at the top. End of the road for this bike and the Sparticle.

Somewhat fed up of the whole thing, I am inclined to go to Halfords tomorrow morning clutching the motor wheel and buy the cheapest reasonable mountain bike that it will fit.

Or, plan B, go to the local folding bike shop and buy a rather more expensive Dahon Expresso or Jack. The drawback with this is that they aren’t mountain bikes and are not cheap. But I would have a folding electric bike, which would at least be something.

Any comments or inspiration would be most appreciated.

 

[flecc]

I'm really sorry to hear this Andy, you've obviously put in so much effort to try to get it right. This fork width problem is very common, most motors other than direct drive too wide for standard forks.

The cheap mountain bike route can be good and the parts can always be upgraded over time. Some of Halfords cheap stuff can be very heavy though, so watch out for that.

I don't know whereabouts you are, but you may have a branch of Cycle King (southern England) or it's Hawk Cycles midlands outlets near you. They sometimes have some great bargains, many quite light, and there's much more in the stores than shown online. You can check where their branches are on this website on the left hand menu:

Cycle King

I understand Tongxin are now making a narrower Nano variant of your motor to suit most folding bike forks, but at about 80 mm that could be too narrow for your new forks which are probably 100 mm, so that's unlikely to be a solution.

However, first back to your new forks. If the fatter part at the bottom is what is overlapping and the overlap length is very short, it might be worth investigating whether it's solid at that point. If so, it might be possible to file away just enough to clear the motor sides at that point without weakening the fork legs. You'd need a decent fairly coarse file for that though, not that fold-out one.
.

 

[frank9755]

Bad luck, Andy - sorry to hear about that setback. I do sympathise; putting together a kit bike can be a series of frustrating reverses like that - however it is worth it when the thing is working.

I'd recommend fitting the motor to a non-suspension (steel) fork - either through getting a cheap new fork for your bike or the mountain bike route. People who have bikes with front motors have often said that suspension forks are desirable to soften an otherwise harsh ride. I know that on my old Powabyke this would have been a big help, and others have mentioned it in connection with the Suzhou Bafang in the Ezee Torq. However my experience with Tongxin motors is that, because they are so much lighter, there is not the same need for a suspension fork.

I've had no problem fitting a Tongxin to the front wheel of two different bikes with normal steel forks. On one I had to file the droppouts slightly, as you describe, but the other didn't need anything. Neither had any clearance issues.

As Flecc says, fitting it to a folder is probably going to be a challenge, as many have narrower forks.

 

[AndyOfTheSouth]

Thanks, flecc and Frank for the sympathy and advice, which are most appreciated.

I don’t think I could file enough off the fork without risking damaging it. Nor could I face taking this new one off for another non-suspension one, sensible though this might be.

Two thoughts occurred to me overnight. One mad but interesting, the other more straightforward.

I had ruled out trying to adapt the motor by having the projecting ‘shoulder’ machined off, since I don’t know any machine shops. Then it occurred to me I could make my own machine tool by firmly planting the old fork upside down in the ground, fitting the wheel, connecting up the electrics then running it with a file held against the protruding edge. I don’t think I’ll do this, but it might be fun, don’t you think.

The other alternative is to take the kit back to the shop. It would be interesting to see if they would offer a refund. If they don’t, I could ask them to fit the Sparticle to my Brompton. This would be straightforward since they offer kit with a specially made fork. This course of action is not what I’d intended – the Brompton works very nicely as it is – but might be useful in a different way.

 

[flecc]

Two thoughts occurred to me overnight. One mad but interesting, the other more straightforward.

Then it occurred to me I could make my own machine tool by firmly planting the old fork upside down in the ground, fitting the wheel, connecting up the electrics then running it with a file held against the protruding edge. I don’t think I’ll do this, but it might be fun, don’t you think.

Not a mad thought at all Andy, it was thoroughly practical, and I've done similar when I created my T-bike, using a front hub motor as a rear wheel one by adding the necessary threaded section. This necessitated removing a projecting central steel and alloy region from the hub motor wall. Here's the description from my T-bike article:

The freewheel mount was machined from a DMR revolver alloy dual thread hub, seen below, but the motor sideplate had to prepared for it by grinding away the projection at the side plate centre. To do this I packed hard wax against the side plate bearing, then ran the torq front wheel at full throttle with the bike upside down, using it as a capstan lathe, facing off the projecting alloy and steel area with an angle grinder to achieve a flat face for the freewheel mount.

It's best with a grinder as described though and you could hire one from a tool hire shop. Using a file would take forever as it's remarkably ineffective at the wheel speed.
.

 

[AndyOfTheSouth]

Hi flecc. Thanks for the comment on the machining idea. It is reassuring to think that it would work. I am tempted, but I would worry that I might damage the motor. Interesting to hear about the grinder, though – I’d have used a file and wondered why it was taking so long!

I contacted TETS (they don’t half need a good short version of their name, don’t they?). First, they weren’t wildly enthusiastic about the idea of a refund and I thought it premature to press the issue. Second, after my angst at converting my Brompton, this turned out not to be an alternative anyway because mine is the wrong type of motor for this conversion.

They did, however, offer that if I got the bike and kit to them, they would sort it out. This means either ‘persuading’ my new forks to accept the motor (shudder) or, I suspect more likely, they would fit a rigid fork of their own. My Rockshox Dart 3 fork would then become a valuable addition to my Foolish Purchases Collection. Since I’ve paid for the fitting already, this is the sensible option.

Of course, if, before I send them the bike and kit, I am in a bike shop and see an interesting bike and I happen to have the motor wheel with me, as one does, I might be tempted to check that it fits and…. and… no, stop, that’s where madness lies… Just let them sort it out!

 

[flecc]

Glad to hear that there's a way out now Andy, these things are a nightmare for a while, but they don't look so bad once through them with a solution. Hopefully you'll be electrically propelled soon while the nice weather is around.
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[daniel.weck]

Bouncing from a recent post by someone else, here's a supplier for various versions of the 24V 200W Heinzmann motor:

Electrically assisted pedicabs and rickshaws from Maxpro

...although their technical data is for 24V. For 36V, this appears to be correct:

[870-00-751-6022] –-> 43Nm, 25A, 290rpm (synthetic/nylon internal gears), claimed 12% climbing ability, 14mph in a 26” wheel.

[870-00-751-6622] –-> 50Nm, 28A, 189rpm (steel gears), claimed 15% climbing, 13mph with 26” wheel.

[870-00-751-1122] –-> 53Nm, 33A, 179rpm (steel gears), claimed 15% climbing, 15mph in 26” wheel.

Used in real workhorse conditions

Maxpro EcoCargo - quality cargo tricycle

UK source:

Heinzmann E-Bikes & Retrofit Kits - Emotive Control Systems - Estelle Electric Bikes - Pedelecs - Recumbents - Heinzmann Hub Motor


I also recently came across this Heinzmann-enabled Montague Folding Paratrooper mountain bike, which looks like quite an exiting machine !

electric mountain bikes, electric bicycle, electric bike kits, folding bicycles

Untitled Document

http://www.pedelecs.co.uk/forum/electric-bicycles/2695-montague-folding-paratrooper-mountain-bike.html?highlight=army#post34703

Cheers, Dan

I added the Heinzmann hill climber version hub to my basic 8 gear hybrid as outlined above using Kinetics in Glasgow.

It was an expensive exercise (£1,300) but the bike has proved a solid dependable workhorse. The noise is there but is doesn't seem to bother me, perhaps because my main use of the bike is in traffic for a fair amount of the time. My journey is 13.5 mile each way commute into Glasgow which takes under an hour without working up a sweat.

It takes me up most hills I have tried to tackle at around 13 to 14 mph with no serious additional effort from on the flat.

The weight of this bike is around 19 kgs, including a fairly hefty battery.

 

[OneWayTraffic]

You can find plenty of information on Endless sphere regarding front forks, dropouts and hub motors. I strongly recommend that you go visit, as they have a lot more experience than the average pedelecs member on faceplants and what have you. Comes from the high percentage of high torque conversions.

I don't have any personal experience but I can distill the general advice for you:

1. Cheap steel is best. Steel has a more forgiving failure mode, while Aluminium or Carbon fibre will just snap. You really don't want to lose the front wheel going at high speeds in traffic.

2. A good install is critical. Make sure that the fit of the washers against the dropouts is absolutely flat. A common problem is quick release forks not allowing a nice flat fit. The nuts have to be torqued up really tight and flat as that friction is what keeps the hub on the bike. The dropouts themselves can't resist the torque of most hub motors, unless they're made from 1/2 inch steel.

3. A torque arm is good insurance. Remember that the torque arm will spin the opposite direction from the wheel so secure it appropiately. You can order from several US suppliers if you can't get it in the UK. Try ebikes.ca
The torque arm may keep the wheel on the bike but it won't protect against a poor install. You can also get c shaped washers from ebikes.ca that allow a flat fit in QR fork dropouts.