Any limitations on kit options for this donor bike ?

[103Alex1]

Sorry if this has already been asked in another guise, but looking at another donor bike (26" folder). Are there any specific constraints / modifications needed from these specs which might affect choice of a kit system ? I realize the controller and battery need to be accommodated (still trying to work that one out !) but as regards the motor in particular would be helpful for some pointers :

Front Brake: Shimano Disc, Mechanical

Rear Brake: Shimano Disc, Mechanical

Brake Levers: Avid FR-5

Brake Cable & Housing: Dahon LiveWire 7.0, anti-compression housing, Slick cables, DuPont L3 lubricant, alloy ferrules

Shifter(s): Shimano Alfine RapidFire plus

Crankset: Kinetix Supra, forged 6061, 39T, CNC alloy guard

Cassette/Freewheel :Shimano 18T

Rims: WTB SX24, disc only, doublewall

Front Hub: Shimano Disc 32H Black

Rear Hub: Shimano Alfine, 8 speed, 32H black

It folds like so : Cadenza XL | Dahon Global

 

[103Alex1]

Going to narrow this down ... if I understand it right, the fact that there are hub gears means a rear wheel motor is not feasible.

Am I also right in assuming that a front wheel motor @ 350W wouldn't be suitable as too powerful ?

 

[Deleted member 4366]

Going to narrow this down ... if I understand it right, the fact that there are hub gears means a rear wheel motor is not feasible.

Am I also right in assuming that a front wheel motor @ 350W wouldn't be suitable as too powerful ?

A 350w motor can be fitted, but this isn't for ham-fisted amateurs. If you're an engineer, it's pretty straight forward.


Here's one of the iterations of Saneagle's folding bike with 350w BPM in the front.

 

[103Alex1]

A 350w motor can be fitted, but this isn't for ham-fisted amateurs. If you're an engineer, it's pretty straight forward.

I suppose that rules me out of fitting it then - I'm no engineer and an enginner would probably consider me a tad ham-fisted (inexperienced if nothing else). It was just a final hope of being able to keep Alfine hub gears on a kit build without losing stability / safety via having to go with a front-wheel motor (which for some reason feels intrinsically dangerous to build / ride but can't put my finger on why ). Hub gears are really nice to ride with.

that Neo bike just got me excited again - there has to be a way to sort something ... and that bike of Saneagle's looks great btw ... !

 

[Jeremy]

I suppose that rules me out of fitting it then - I'm no engineer and an enginner would probably consider me a tad ham-fisted (inexperienced if nothing else).

I suspect d8veh was making a bit of a tongue-in-cheek comment!

Many people who aren't engineers (me included, I'm certainly no engineer by any stretch of the imagination) have built very reliable ebikes, often as good as, or even better than, some of the commercial offerings. There are a few basic things to watch, like ensuring the forks are suitable to take the motor you wish to use and that the motor axle reaction torque can be coupled to the frame without the risk spinning the axle in the drop outs, but all the parts are readily available.

The hardest part is probably selecting the right combination of bike, motor, controller and battery to suit your particular needs. A set up that suits one person's needs most probably won't suit that of another, so it's worth taking some time at the start to think about what it is you want the bike to do.

For example, none of my bikes are particularly good hill climbers, as I ride mainly on fairly level ground. I do like to be able to pedal when keeping up with traffic in town, though, so like a bike with high enough overall gearing to make this possible, I rarely do long journeys, so don't need a large battery capacity, but I do like to ride at a reasonable speed in traffic, so have a fairly fast wind motor.

I've no doubt my current favourite bike, with just two gears, limited assist power and limited power assisted range wouldn't suit some, but it is near perfect for my needs. The great thing about a DIY ebike is that you can build something that is a very good match for your particular needs, rather than accept the inevitable compromises that a ready built ebike has to offer in order to appeal to the masses.

In general terms, if you feel able to service and repair your own bike then you should be able to build a decent ebike from a kit, whether you're an engineer or not.

 

[103Alex1]

I think d8veh has read enough of my thinly disguised fears of technical and mechanical inadequacy to signal it might be a more complicated build ! Not completely dissuaded but expectations have been reset.

In general terms, if you feel able to service and repair your own bike then you should be able to build a decent ebike from a kit, whether you're an engineer or not.

Yup .. that's the rub - with practical experience I'm sure I could manage but only been into bikes for 3 months so everything is new. I couldn't service the suspension forks for example and wouldn't want to start opening up hub gears etc at the moment - mainly because I only have one bike and no car right now so if I screw something up I'm grounded till it's fixed. If it was a second bike I could likely afford to be more relaxed about things.

If you have someone with experience to work alongside you can learn very fast, but from books, on-line and trial/error it takes much longer and is a bit more prone to going wrong.

 

[indalo]

If you have someone with experience to work alongside you can learn very fast, but from books, on-line and trial/error it takes much longer and is a bit more prone to going wrong.

Alex, for what it's worth, I agree with Jeremy and I am an engineer though have probably no more experience of bike repair or maintenance than you. While I understand your fear of making a cock-up, there's no great mystery in creating an ebike from any regular bicycle.

To make things easier than might otherwise be the case, I'd recommend you limit your ambition in the first instance to one of the off-the-shelf kits from one of the respected UK suppliers for your first attempt. Ok, it's fairly common knowledge that you can buy bespoke parts far cheaper from the far east and create something that suits you but by buying in the home market, you will have a solid warranty and someone on the end of a telephone to talk you through any tricky bits.

Most people, even those of limited skills and lacking in confidence, ought to be able to fit a kit to an ordinary bike in the space of a couple or three hours and actually using hand tools to create something by yourself is a great confidence booster. I think what I'm saying is don't try to run before you can walk.

Always remember the old adage: "The man who never made a mistake never made anything!"


Best of luck,
Indalo

 

[Deleted member 4366]

What I was trying to say is that it can be done, but you have to proceed with caution.

It's easy to fit a 250w motor into forks provided that the drop-outs are strong enough, but you have to be much more careful with a BPM motor because of the torque. This means that you have to be sure that the drop-outs/fork-ends are large enough and strong enough to allow deepening. Some just don't have enough metal around them. You have to be accurate when widening and deepening the drop-outs, and not leave any sharp grooves in the drop-outs that can raise the stresses and cause cracking. Once the drop-outs are made to the right shape, you need to think about re-inforcement with torque arm/s. The installation of the torque arm/s needs to be robust. When everything is bolted up, you need to check that the washers/nuts fit within the dimples. If you try and tighten the wheel-nuts with the washer not inside the dimple, you can break the drop-out off by just tightening the nut. You can get round the deepening of the drop-outs in most cases by using correctly fitting eccentric "C" washers.

You often (always with the BPM) need to dish the wheel to get the rim central, so you need basic wheel-building skills. Again easy and useful for most to master, but not everybody's capable.

So, a few things to look out for, but simple when you do it right. There's less risk with a rear motor, where there's normally a lot more metal around the drop-out.

This is what happens when you don't do it right. To me it looks like the washer not fitting the dimple:
Endless-sphere.com • View topic - Catastrophic front fork failure / BMC front wheel drive
and here where it looks like he didn't evenuse washers, which puts a huge outward pressure on the front of the drop-out, and read the last post from a guy that sees it the same as me:
Endless-sphere.com • View topic - Bafang BPM 500W broke again the aluminium fork dropouts

 

[Jeremy]

Alex,

The first ebike I built (see here:http://www.pedelecs.co.uk/forum/electric-bicycles/991-recumbent-project.html and then here: http://www.pedelecs.co.uk/forum/electric-bicycles/1193-tongxin-k-nano-motor-project.html#post15348) was started back when there seemed to be little information readily available. I made some significant errors during that build, as you can see from reading those threads from 2007.

If I was to do one thing differently it would be to carefully research options to best meet my needs, then do as Indalo says, buy a kit from someone from whom you can get good support if needed. I ended up selling my first motor and controller after just a few weeks, because the motor was far too powerful and heavy for the recumbent I fitted it to. That was a waste of time and money that could have been avoided had I known then what I've learned since.

It's certainly satisfying to build your own ebike, particularly when you finally get it right and find it does exactly what you want it to do. You have the advantage now of there being far more people on this forum, and others, who have gained a bit of knowledge and are willing to share it.

 

[Cyclezee]

Hi Alex,

To see what is involved with conversion, you can download a copy of our kit installation guide from our website here Downloads - electric bikes and conversion kits and if you have any specific questions please ask away.

Regards,

 

[103Alex1]

Thanks a lot for the contributions - I am really heartened and going to read through the links and specific threads posted here.

d8veh - OK I understand the mods to the wheel itself and dropouts are the key. Probably not the best project to cut your teeth on.

Indalo / Jeremy, everything you say makes perfect sense, and I've been spending many hours (days actually) researching and reading threads to get to grips with what to expect from both the process and the end result and try to choose something appropriate. I am just fighting mounting pressure to sort something fit for purpose out by Spring (family issues - enough said !!)

Cyclezee - thanks and much appreciated. However, my budget just won't stretch to your prices and I don't think the lower priced kits can work for the use the bike is going to have to contend with.

At the moment, 3 main issues are being grappled with :

1) I really need a powerful hill climber with long range and can't afford to buy one ready-made. They cost about £2k and my ceiling total outlay (including donor bike and any mods) is about £750 (only a bit more if torque sensor and power management system are needed and they really give a worthwhile end result). I have no salary and too young for a pension (all my income is in lump sums, highly uncertain) so can't really afford to spend much on the learning experience having several goes at it.

2) The UK kits which I saw as being likely to deliver what I know I will be able to use worked out at more than my total (absolute tops) budget. I am basically priced out of the market by UK sellers - both kit and ready-made bike options. Pretty much concluded that a standard rear hub-drive regular 250W UK kit doesn't seem worth fitting, even to a free bike, for my specific intended use. The resulting bike just won't hill climb and therefore won't get riden. Even some of the 350W motors will struggle with this but that is mainly down to torque sensoring and max output capability on demand. With a decent torque sensor and proper power management system all of this can be overcome but those are inevitable added complexities to build into costs. You can quash the hill climbing problem by throwing enough power at it. However, a bike which only goes 15 miles on a charge will also likely not solve enough of the real-life usage issues to be the best result (I am building the bike for Devon/Cornwall and our home there is far enough from any significant services to be considered remote). Plus there is the whole legality thing which I'm getting pretty familiar with !!!

3) The 350W+ kits which rely on thumb-throttle power management alone come with the downside of not having a user-friendly LCD sensor and torque / power management system I've got used to having and take for granted. My guess is that I will be disappointed with the result on its own (but that is only a guess).... and so the present goal is to work out how to get that same functionality built in to make the end product which is nice to ride and does more than just meet minimum needs. To me, £750 is still a lot of savings to outlay even with a heavily discounted import kit.

I'm going to test ride the e-motion Neo as soon as I can to see if this gives me what I'm looking for. That bike is UK type approved and also road legal. If it is up to what I am hoping it will be then the goal will be very specific.... build something like that performance-wise, for as close to £750 as is possible.

I'd genuinely love to have simpler needs and/or more disposable cash. Would have gone ahead and ordered a standard UK kit by now for sure, learned off it and sold it on. I don't want to erode my budget at the moment doing this though - a £200 loss is £200 less to spend on what I actually need. Sadly the difficult usage remit for the bike and limited funds have both made me ultra-cautious and now braced for a much more challenging first build attempt. It's not ideal - but there is such a wealth of knowledge and experience on this forum that I'm still confident a manageable project can be specced out.

I am pretty motivatied to make this work. If I can't, then basically the family will have to live without my regular presence or sell up and move closer to me where I can manage with my current bike. So there is quite a lot riding on it. Naturally I would prefer to be able to spend more time with them and not to be the source of wrenching them out of the place they love (and I do too). But I have to be reasonably independently mobile wherever I am, have to make a living and can't make hills flat to accommodate my bike budget. So I am doing my very best to find a way.

 

[Alan Quay]

Hi Alex,

Sorry if I've missed the info, but what sort of range are you looking for, and (if its not too personal) what weight are you and luggage? Also, what hills do you need to contend with?

Does the Kalkhoff not achieve what you are looking for? Perhaps there is a way to use the Kalkhoff battery in the kit bike to improve the range/reduce the cost?

I'm also in Devon, so I can understand the problem with hills. I have used Where's the path ? to plan my routes carefully to avoid hills as far as possible.

 

[103Alex1]

Hi Alex,

Sorry if I've missed the info, but what sort of range are you looking for, and (if its not too personal) what weight are you and luggage? Also, what hills do you need to contend with?

Does the Kalkhoff not achieve what you are looking for? Perhaps there is a way to use the Kalkhoff battery in the kit bike to improve the range/reduce the cost?

I'm also in Devon, so I can understand the problem with hills. I have used Where's the path ? to plan my routes carefully to avoid hills as far as possible.

Hi Mike.

Thanks - that looks good !

Range is likely to be say 45 miles typical (22.5 there and the same back - as nowhere to recharge at the other end of my trips). I work from home when in Devon so don't have a convenient office to charge my battery at the other end of my trips. Ideally I'd be able to do Plymouth-Exeter or near as occasionally, with some regular pedalling obviously to help stretch the range and a full recharge at the other end before returning too (90 miles round trip in a day - some electric assistance is needed however willing the mind may be, the legs are only capable of so much !).

For hills, think Salcombe, Bigbury, Aveton Gifford and similar if you pan out further afield. Sometimes with a significant load.

I am a grossly underweight 57kg at the moment (hopefully 65kg in a few weeks - underway with a serious weight gain effort via local gym after finally giving up smoking ... which all this cycling is doing its very best to undo at every opportunity !!). Security chain alone for the Kalkhoff is about 8kg, typical load likely 70L of back panniers and possibly a rucksack including work papers and equipment so let's say another 25kg of stuff on average added to the 24kg bike.

The Kalkhoff lives in Gloucestershire with me at the moment. I just can't get the thing up and down on the train along with my stuff and I use it up here every day as primary transport. It's huge and won't fit in a car at either end so I have to cycle with it and anything I need to carry backwards and forwards from Newton Abbott / Plymouth stations at least 15 miles on arrival ... provided I am let on the train with it that is ! It just doesn't work on account of size.

Was looking at the folder to give me some scope for trips further afield on my own for a few days using the train (helps stop going stir crazy when you work for yourself from home and just need to get away sometimes), but I may just have go abroad for breaks every now and again instead to places I can easily rent at the other end. Much as I'd like to go touring with my new beloved bike(s) using the train, if I'm honest it's actually cheaper, easier and warmer to just fly overseas than try to do much in Britain. Even taking into account the air fares, decent accommodation is about 20% of the cost, transport hire is dirt cheap and meals etc are far cheaper too .... Very sad really.

The idea of using the Kalkhoff battery is a very interesting one - a great idea and well worth further investigation. I had kind of assumed it would only connect in to their own systems for some reason. Would certainly help reduce the cost considerably and if it sees me through the next year across both Devon and here I am quite happy to build in the cost of a new one by next Christmas if needs be. Sunk cost and all that It's only 15Ah though - so whilst it delivers great range on a very efficient crank-drive bike I am not so confident it will be enough if I end up having to fuel a high-powered climbing hub motor with it.

 

[Alan Quay]

Your main advantage here is your own low weight. I would have thought that if you added another 15ah battery (giving you 30ah total) then you would get somewhere near the range you are looking for, assuming a fair amount of leg work.

Just for reference, I have a 250 watt motor, and 15ah of SLA (probably same weight as 30ah of Li-*) and a range of about 15 miles. You can expect a bit more range/ah with Li-*, and you have a significant weight advantage over me - I'm 120kg with boots on.

I have no idea what connectors are on the Kalkhoff battery, but it would certainly be electrically suitable for the project. Worst case you would need to mod the battery to provide a suitable generic connector.

As far as weight gain goes, gym is surely the wrong place for this. I would have thought doing reps between the pub and the pasty shop a more effective solution.

 

[Jeremy]

Alex,

Have you taken a look at the ebikes.ca simulator, here: ebikes.ca Hub Motor and Ebike Simulator ?

It's pretty good for getting a feel for range and performance for the motors, controllers and battery packs they have listed, plus you can use your own controller and battery parameters to get a feel for what changing things might do.

My experience has been that the simulator usually gives a pretty accurate indication of speed but tends to slightly under estimate range, as it takes no account of pedalling. You can compensate for this to some extent by assuming that you are inputting around 100W and then do a rough adjustment by factoring the power down by about this much.

 

[103Alex1]

Your main advantage here is your own low weight. I would have thought that if you added another 15ah battery (giving you 30ah total) then you would get somewhere near the range you are looking for, assuming a fair amount of leg work.

Just for reference, I have a 250 watt motor, and 15ah of SLA (probably same weight as 30ah of Li-*) and a range of about 15 miles. You can expect a bit more range/ah with Li-*, and you have a significant weight advantage over me - I'm 120kg with boots on.

I have no idea what connectors are on the Kalkhoff battery, but it would certainly be electrically suitable for the project. Worst case you would need to mod the battery to provide a suitable generic connector.

As far as weight gain goes, gym is surely the wrong place for this. I would have thought doing reps between the pub and the pasty shop a more effective solution.

Heck, Mike - that range is super-low. It sounds like your battery may be getting on a bit or maybe the bike motor is inefficient. Don't know much about SLA batteries but I've got about 70 miles out of a 36v 15Ah (540Wh) battery including some moderate but decent hills round here on the way and running mainly in 'Sport' mode (mid-level assist) with a 250W motor. If I bang up the power to max assist that falls to about 50 but it's still a heck of a lot more than your battery is delivering. The weight is 2.9kg

I expect a branded connector housing would have to be bought to receive the Kalkhoff battery and then try to adapt that .. would have to see what parts are available from Derby Cycles.

LOL @ the pub and pasty shop runs .. sadly I stopped drinking and can't eat much heavy food so neither are getting visited these days ! I'm taking solace in the thought that the kilos getting put on are of the "heavy matter" variety and will hopefully help me pedal more efficiently at those moment when I wind up "on my bike without a motor" !

Alex,

Have you taken a look at the ebikes.ca simulator, here: ebikes.ca Hub Motor and Ebike Simulator ?

It's pretty good for getting a feel for range and performance for the motors, controllers and battery packs they have listed, plus you can use your own controller and battery parameters to get a feel for what changing things might do.

My experience has been that the simulator usually gives a pretty accurate indication of speed but tends to slightly under estimate range, as it takes no account of pedalling. You can compensate for this to some extent by assuming that you are inputting around 100W and then do a rough adjustment by factoring the power down by about this much.

That's interesting - I'm not really familiar with most of the combinations listed on there but I'll definitely come back to this.

 

[Alan Quay]

Slight correction - My SLA is 14aH
The battery is good, but it illustrates the differences that weight/Li-*/power management can make. My 14aH SLA weighs in at a massive 12kg.
I agree that the motor is probably not very efficient (its about 4 years old, tech moves on). Also, I have no power level control, and use it pretty much all of the time I'm riding, as I'm only above the 15 mph threshold when going down hill.

My bike is simply not built for long range, but then again neither am I.

 

[103Alex1]

Slight correction - My SLA is 14aH
The battery is good, but it illustrates the differences that weight/Li-*/power management can make. My 14aH SLA weighs in at a massive 12kg.
I agree that the motor is probably not very efficient (its about 4 years old, tech moves on). Also, I have no power level control, and use it pretty much all of the time I'm riding, as I'm only above the 15 mph threshold when going down hill.

My bike is simply not built for long range, but then again neither am I.

With 12kg of battery on top of the bike I think you could be forgiven for not exceeding 15mph ! I saw on another post recently the SLA batteries are only supposed to be good for about 150 charge cycles so the range loss may be significantly driven by battery exhaustion (you lose Ah over time / use if I understand it right) rather than being down to 'rider features'

 

[passpato]

I don't believe ANY ebike can do that range over that terrain for very long. I think you need to find a way to charge before your return because its going to cut your costs by about a third.
You will also need to leave a charger at either end of the journey as they don't travel well. You also have to build in extra capacity for when your battery gets older and no longer holds the same amp/hours
You need very high reliability and puncture proof tyres as you can't easily remove the motor wheel on the road.
I live in Minehead and I know the Journey you are attempting. Have you considered the bus? If you can start your journey from the top of Haddon hill it would be possible. Or are you going along the coast?
If you are serious about this you need about 30 amp hours of lithium. Lead is too heavy.
I have built a hill climbing very reliable 20 mile (25 at your weight) bike within your budget. Pm me if you need tips.

 

[103Alex1]

I don't believe ANY ebike can do that range over that terrain for very long. I think you need to find a way to charge before your return because its going to cut your costs by about a third.
You will also need to leave a charger at either end of the journey as they don't travel well. You also have to build in extra capacity for when your battery gets older and no longer holds the same amp/hours
You need very high reliability and puncture proof tyres as you can't easily remove the motor wheel on the road.
I live in Minehead and I know the Journey you are attempting. Have you considered the bus? If you can start your journey from the top of Haddon hill it would be possible. Or are you going along the coast?
If you are serious about this you need about 30 amp hours of lithium. Lead is too heavy.
I have built a hill climbing very reliable 20 mile (25 at your weight) bike within your budget. Pm me if you need tips.

Thanks for this passpato. At the moment I'm resolving the issue by not being in Devon at all and it's become clear that I'm likely not going to be able to move back permanently unless I get a car. I'll try to do more regular trips to stay with family and help out this year once I get a working eBike to leave down there. That means I can go on the train, get picked up from the station and have the bike there to use on arrival. It's the only thing that's going to be manageable for long and I'll just have to turn down work any distance from home. Being car-less is proving shockingly expensive in lost earnings now !!!

Don't have any long trips I have to make on a daily basis down there - I was trying to open up possibilities which are proving too difficult / expensive. Buses are out - there are none for several miles from the house. So with no car it is bike all the way or not at all.

I've reset my range target to 25-30 miles round trip with pedalling effort allowing very steep and prolonged hills. That will get me to Kingsbridge or Plymouth and back. Little prospect of a recharge at the other end because I don't really stay anywhere long enough when down there and the places I go to change (it's not like going to a fixed place of work where you have facilities at the other end you can use). The battery or batteries taken must last the whole trip and back home again. When I use the bike for leisure I go to the sea where there are no electricity supplies available to charge the bike anyhow

I'm pretty much resigned to having to carry at least a 20Ah battery so got a relatively lightweight bike (under 11kg) to help take the extra battery weight, which I'm hoping will be a successful donor bike. Need to leave any battery on it as I'm usually active at the other end (not going to an office) and couldn't carry it about. All things considered I reckon this is the tops I can go for.