Building a 20" wheel tadpole e-trike from scratch

[twinkle]

Hi Folks ,


The next project is a 20" wheel tadpole e-trike that will fit easily in one piece in the boot of my mondeo estate .

I am using a Izip ezgo wheel that I will rebuild into a 20" rim and combining it with a 36v controller . Hopefully the reduction in torque using the larger wheel will be compensated by the extra power of the 36v 250w controller .

The specification of the trike will be either 9 or 12 speed , I am having a problem trying to mount a multiple freewheel on the short spindle of the Currie motor that was originally designed for single speed but I think that I have sourced a narrow 3 speed screw on free wheel unit , hopefully it is on its way from China .
This will give me gear ratios between 30" and 70" , low enough to get me up the hills around here and give a top speed when pedalling of over 23 mph .
For stopping power , it will have a pair of 160mm discs on the front and will use the original dia-compe drum brake on the rear , and use the standard cut-off brake levers and usual ebike bits with a real ignition switch .
Under Seat Steering with centre point geometry is another must have on the specification list ,
The battery is another cause of concern at the moment , I have a 26v 10 ah lipo pack but I am having problems finding a couple of 3s 5ah lipos at a sensible price to bring the battery voltage up to 36 v but I have 3 SLA batteries that I can use until a suitable pack comes along .

So where am I at the moment , The front wheels with 14mm spindles and disc brakes are built and the crucifix frame built from 16g 40mm square ERW is cut and milled out for the head tubes and swinging arm pivots and many of the small pieces are made .
Hopefully If the critical path analysis of the project is correct it should be ready to paint by the end of June unless I have got it seriously wrong .

Well they say a photo says a 1000 words so l will leave you with a few photos , not much to see at the moment but there will be more as the build progresses

There are more build details on the Atomic Zombie website on the trike

regards emma

disc brake 20" 14mm spindle wheels


small bits take time






more bits

 

[twinkle]

The frame is starting to take its shape the head tubes with their caster and camber angles have been welded into the cross boom ( which is waiting to be jigged up with the steering tubes and wheel tabs ) and the main boom has the suspension pivot welded in , waiting for the seat post to be welded

 

[twinkle]

The Currie e-wheel has been removed from the donor and mounted in my test rig and run for an hour to make sure there are no strange noises off load
all runs well and next stage is to rebuild it into a 20" 28 spoke rim , The new spokes arrived yesterday , All l need is a few quiet moments to transfer the hub into the new 20" wheel , the batteries are from the red trike before its upgrade to a lithium pack . regards emma

 

[twinkle]

Hi Folks

Today went well ,
I am still disorientated by the lost of Monday ,but I have made some progress today .
The wheel has been rebuilt into the 20" rim and trued and tensioned . The rim tape ,tyre and tube refitted and is now awaiting the arrival of the 3 speed free-wheel .
The seat post has been welded on and the ply seat form cut out and drilled and mounted .I will cover the seat later after the initial testing .
The main boom is now ready to accept the cross boom , once l have jigged up the front and aligned the wheel lugs .







wednesdayl

 

[twinkle]

Hi Folks
Came to terms with the loss of a day today , and between errands and shopping , I managed to get the cross boom jigged up and welded , and fitted the disc brakes , AND I made the adjustable bottom bracket assembly ,.
This evening I temporarily assembled it and took this







Thursday


So far that's 3 days from getting most bits , what is holding me up is the 3 speed freewheel that is not due here until mid june ,
Still that gives me time to try a source a battery, Still a lot to do ,
Under Seat Steering , track control arms and drill the bottom bracket assembly for the pinch bolts .
Cannot do anything on the gear train until I can get a freewheel , but at least it is starting to look like a trike .
regards emma

 

[Geebee]

Excellent progress in a short time, looking forward to the finished ride report.

 

[Deleted member 4366]

You make it look very easy.

 

[twinkle]

Thanks Guys

When a commercial tadpole e-trike costs well in excess of 2 grand I thought it would be a good exercise to show that an equivalent specification ( or better than some ) can be built at home using basic skills , also using commonly available bike parts modified for the project
There wont be much progress today as the Critical path analysis requires the drive train to be fitted before I can add the USS and other parts , the track rod has been cut and fabricated and the trike is sitting on a workmate so I can get an idea where everything will go . Under the seat on a uss equipped e-trike is always a cluttered area with lots going on .
I am on the hunt for a second hand 36 v battery about 10 ah , and a 3 speed freewheel if I can obtain one at a sensible price before the Chinese one turns up , I really need to get this drive train sorted so I can progress .

regards emma

 

[twinkle]

Well we have come to the end of a short week .

Today the 3 speed freewheel arrived from china ( incomplete ) so I have ordered a 16 t 3/32 standard freewheel I can run this with a Thun quad chainset . I will get 4 speed with ratios from 30 to 60 inches which should be usable until I get this free wheel sorted out or l will fall way behind . I can use the rear mech as a chain tensioner and still be okay .

Todays efforts were concentrated on the handlebars ( it would be nice if you could use a pair off a bike but not possible, so ) I fabricated the USS pivot post from a rear hub and a piece of head tube and part of a goose neck once fitted I cut and welded the track control rods for the steering.
The handle bars are part rounder bars and part bmx - cut and shut - The problem is getting the whole assembly welded up accurate . or it will be like steering a wonky donkey. the handlebars will be adjustable as the gooseneck clamp is welded to the pivot .
whilst finishing off the track rod arms I trimmed the excess steel of the front steering arms.

Now I am going biking over the weekend if the weather improves and Jig up the Bottom bracket and drill it for the clamp bolts .
.

The seating position is like sitting in a reclined armchair puting your feet on a stool and finding it is a set of pedals , dropping your arms to your side and resting on the handlebars .

More to follow next week

regards emma

 

[twinkle]

Hi Folks

Sent a message via ebay to the freewheel supplier , I had the first correspondence back and now l am waiting on a real reply , Still when the 16t arrives I will be able to get the chainline sorted and return chain guide welded in place . With 3 chains joined together , needed to drive the rear wheel from the botom bracket everything needs to be in alignment.
I have drilled the BB assembly that's it now for the weekend, and I hope to get out on a trike later today ,
I hope to restart the project on Monday

regards emma

 

[twinkle]

With the new week comes more ideas , The weekend saw the terrier ll "push" trike move on to new adventures . Thus clearing the space to store the new e-trike . So this week I hope to get the trike fully welded up and road tested.

I still need a 36v battery but I have fabricated a 2ah 10s lipo pack for the initial test ride this should give me about 3 miles of road test and prove the e-motor combination , Power wise it should cope as the lipos have been tested on my 48" span Falcon RC model aircraft that draws 40 amps on 3s . the average 10 amps on the e-motor will be like a holiday for the lipos and should give about 10 minutes of power .

The weekend saw the bb assembly drilled and the chain guide pulley guide bent to shape , this stops the chain jumping the pulley on rough ground and jamming under the seat..

Enough chat, lets start getting the trike into shape .

Photos.later

Regards emma.

 

[Cyclezee]

Hi Emma,

Very impressive work.

What's your budget for the battery?

I have a new unused eZee 37v 10Ah FP Li Ion that has sat on the shelf for about a year as everybody seems to want larger capacities.

Also a used one of the same type with silver case which is couple of years old and only used for conversion demos, £100 including delivery.

They look like this

​

 

[twinkle]

Hi Folk

Only the front chain guide pulley arrived in the post . (The Chinese supplier of the 3 speed freewheel has not come back to me yet ) so I made the executive decision and decided to press ahead with the chain line and guesstimate the positions of the freewheel ( I was itching to try the motor to see how it would perform , now it is living in its new wheel ).

First thing this morning I jigged up the crossboom and welded it in place
Then it looked like a real trike .

Then I fitted the chain guide pulley and the anti derailment keeper between the seat and the front boom, ( this stops the chain jamming or derailing over bumps ) , greased and fitted the bottom bracket .
A 48 -38-28 front chainset I had fitted with a set of solid looking BMX style pedals that had mounting holes for toe clips . Toe clips or clipless pedals are a must on a recumbent as foot suck when the foot comes of the pedals and forces itself under the trike can make a nasty job of a leg .
Next step was to run the 300 links of chain ( almost 3 chains joined together ) around the sprockets and guide pulley and through the rear mechanism, Next job was to fit the handlebar furniture and connected up the brakes and front mechanism , With the makeshift 1.8 ah battery on my lap the trike made its first trip along the road .
So now I am waiting for a few bits to tidy up the build and then, before I strip it all back down and paint it I need to get a hundred miles or more under its wheels.

The mirror post was constructed from a piece of goose neck stem and a piece of front forks . Another item you cannot buy solid enough to use without vibration

Here is the trike at close of play today
waiting for a battery and freewheel and its ready to road test before painting

 

[twinkle]

Silly thread test editor would not allow me to upload 2 photos together so here is the front view ,( then it uploaded 2 of each ) .

regards emma

 

[twinkle]

Today was my day of rest , and contemplation
It was raining and I think the weather reflected my mood .

I feel that I want ( not need ) a few more gears than just the 3 so I am looking into making a jackshaft and fitting the freewheel for the rear mech in the rear triangle where the original Bottom bracket would have been .
This alone will be an interesting project in itself .
I am still on the hunt for a 36v battery 10ah ( and charger ) and I am waiting for the freewheel to arrive , The safety checks have been done and I am waiting rather impatiently for a test ride .

 

[twinkle]

Jackshaft is now under construction and The NEW bottle mount battery has been ordered , Just out of Budget but its new , UK sourced and does not need mounts etc made up and didnt come with hidden extras .Free wheel I hope will arrive soon , with the jackshaft freewheel I hope to have 12 speed from 30 to 90" , If I fit the thun quad chainset between 24 "and 86" and have 16 speed rather than 12 speed .

Still well in budget for the build price of the trike .

Still raining here and it looks like its in for the day .........Never mind !

More Photos when the bits arrive .( controller box , freewheel and battery to come and it should be on the road for road testing .
It fits happily in the boot of the car and without battery and the missing bits l can lift it into the car on my own .

Rechecked the front brakes and the rear , the front brakes use standard bike cut-off levers but have been modified to accept dual front brake cables ,
I might need to extend the home built handle bars to raise them a couple of inches to give more clearance on the track control arm .

Regards emma

 

[twinkle]

The MKl jackshaft has been built out of a couple of BB cups welded back to back and a spindle and spacer to space out the mountain for the rear gear hanger the 4 speed block with a 21t final output drive sprocket will adjust the overall gear ratios to that similar to a 26" wheel bike

The jackshaft freewheel has been stripped had its pawls removed and reassembled with the sprockets that will suit the trike and situation.

The Postman never delivered my 16t freewheel or nuts and bolts , the battery i don't think will come till Friday . might be a fun weekend .

The Chinese company refunded my outlay for the duff freewheel , so I am not out of pocket just frustrated because of the time wasted because the alternative bits are not here .

Here is today photo of the jackshaft and modified freewheel

upload pictures online

 

[twinkle]

Still no sign of the freewheel but the jackshaft is fitted , I had to get another freewheel and chain so I can continue with the build tomorrow. Once the final drive is complete I hope to post more photos . I would like to get the trike ridable tomorrow all being well.

I was donated a large car style mirror from my local car accessories shop ( speedie spares ) so the mirror and flagpole are sorted together with the uncovered headrest , this only leaves the rear rack to modify ( from a 20" folding shopper ) and to get the show on the road

 

[twinkle]

Hi Folks
Together with the freewheel all the other bits turned up
I tighted the freewheel on its midshaft mounting bush and shortened the chain and routed the gear cable to the mid mechanism as the 16t 3/32 Freewheel turned up today ( took a week to come ) I fitted it and checked the final drive chain line before fitting a second chain from the middie drive to the rear hub , armed with a 10s 1.8 ah lipo pack made from 4 model flight batteries I nursed the trike around the block to test the 12 gear set up , all is now working gears both front and "rear " and the front discs work well and as usual with a trike the back brake locks the rear wheel up without hesitation. .The new bottle mount Battery ( from cedar-tree ) arrived as promised dispatched overnight included in the price with charger and mount with all the necessary bits to fit ,Thanks Mark now the battery is fitted and has been charged and is ready for its first real test ride , unpainted without a seat cover I hope to get 100 miles on it before stripping and painting .

Ridden wih the baby battery ( on the seat ) and waiting for the Bottle Battery to arrive .

The mid drive can be seen below the seat back

regards emma

 

[twinkle]

Hi Folks
The e-trike's battery is fitted and the trike was given another full safety check before taking it out again the gears were checked and adjusted , the rear 16t freewheel being new was full of grease and this make back pedalling derail the chain ( on the jackshaft ) . We did about 10 miles yesterday after the rain locally around the blocks and the trike went well for a 250watt trike , TBH it could do with a few more watts, or a different motor fitted at a later date but it is perfect as electric assist and on the run down hill I reckon 30 mph was possible with a little pedal input . the front brakes are smooth and powerful and stop from 20mph in 15 foot but the band brake on the rear seems to have three positions , off , slows you , and skids the rear wheel .
Now all is left is to remanufacture a USS pivot point to steering arm control rod as the studding used for the adjuster seems rather soft and bent on full lock , Only a minor setback and a thicker rod with heavier duty rod ends will cure that little problem.
Then its a case of let the mileage begin and get about 100 miles on the clock before stripping it down and painting it , Probably in Rosso racing red with black trim and cream seat and headrest , The mirror fouls the longer handlebars and will be modified to be further away from the offside fork/head tube and a short piece of7/8 bar welded on a flat plate just in front of the cross boom for the speedo or mobile phone .