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go1000go
03-01-2012, 06:44 PM
:thinking:Had an idea for a tandem, based on the dutchman cargo bike, so the stokers position at the rear would be the steering position, effectively a back seat driver. Not too dissimilar from Onderwater tandem, but making proper seats rather than wedgy seats.
Upfront would be one of my kids, making it easier to talk them whilst riding, but also their seat would be lower, so i could see where we going.
Also considering independent drive as per loderunner. 26 rear with disk brake and 20 front wheel.
Let me know if you think its a good idea and also whether it looks strong enough to take 2 Brads!!!!
In the photo i have added a second crossmember, not sure if it will be needed.

Shadowwalker65
03-01-2012, 08:04 PM
wow two Brads makes the work load easy lol

The Cat
03-02-2012, 05:57 AM
Let me know if you think its a good idea and also whether it looks strong enough to take 2 Brads!!!!
In the photo i have added a second crossmember, not sure if it will be needed.

"The Two Brads would make for easier pedalling" instead of you. Chuckle. Maybe put a video screen on second handle bars and a camera on front forks for forward vision. There is a "Brad" Zombied version of a Dutch Cargo Bike in the Atomic Zombie plans list that you could modify for your needs.

Sorry misread your thread see you know about "The Dutch Cargo Bike"

With Regards from South Kent England.
Thomas (The Cat)

lcdc59
03-05-2012, 10:30 PM
Intresting!!

go1000go
03-11-2012, 07:02 PM
Taken the plunge, having done a few more sketches, I started cutting metal today. Decided to ditch the suspension to keep things simple. 26" rear which I will later upgrade to disc brake. For looks and because I had a smaller bike the front will be a 16".
It is long though at almost 3 metres long, but this will allow for another adult to sit up front also.
Hadn't anticipated making it so soon so I now need to buy some more steel for the top crossbar.

The Cat
05-04-2012, 06:01 AM
To go1000go your last post was 12 March 2012 about back seat driver. Interested in how you are doing with the built? My built in back seat due to wet weather here in Kent. Hope to have dry weather this May Bank Holiday. Ichin' to see project finished. Other builts roaming in my head.

With Regards
Thomas (TheCat)

Radical Brad
05-04-2012, 09:43 AM
Looks like a good plan, and now I will be able to get twice as much done when the cloning has completed!
You may need a second spring on the back, but try it with the single one first.

Brad

go1000go
05-04-2012, 12:03 PM
Looks like a good plan, and now I will be able to get twice as much done when the cloning has completed!
You may need a second spring on the back, but try it with the single one first.

Brad

Hi all,
Build is going quite well.
Due to the overall length I decided on no rear suspension in the end.
I have made two seats by steaming and laminating 4 pieces of 4mm ply together, they have both turned out great.
Had a power tool problem, when drill, grinder and jigsaw all packed up in the same week.
Test rode the tandem two days ago, as always no brakes, silly I know, but still proved to go well, the temptation was to steer too much and when leaning also the front 16" wheel skidded, so might need to limit the amount of lock.
Just working out the brackets for the front seat.
For the front rider I am thinking of of crank, hud, similar to viking set up will it work the same, should do.
Then need to tweak the position of the sterring connecting rod.
Probably put a disc brake on rear.
Will definitely need a stand as it is difficult to lean against wall ti stqnd it up.
Will post some pics over the weekend.
Any feedback welcome

go1000go
05-04-2012, 01:05 PM
Hi all,
Build is going quite well.
Due to the overall length I decided on no rear suspension in the end.
I have made two seats by steaming and laminating 4 pieces of 4mm ply together, they have both turned out great.
Had a power tool problem, when drill, grinder and jigsaw all packed up in the same week.
Test rode the tandem two days ago, as always no brakes, silly I know, but still proved to go well, the temptation was to steer too much and when leaning also the front 16" wheel skidded, so might need to limit the amount of lock.
Just working out the brackets for the front seat.
For the front rider I am thinking of of crank, hud, similar to viking set up will it work the same, should do.
Then need to tweak the position of the sterring connecting rod.
Probably put a disc brake on rear.
Will definitely need a stand as it is difficult to lean against wall ti stqnd it up.
Will post some pics over the weekend.
Any feedback welcome

One photo added
The wooden piece in contact with the ground is a temporary stand whilst building. The front seat is just clamped in place but once the height has been worked out, it will have a clamp arrangement similar to bottom bracket so it could be removed and whole area used as a cargo deck, or smaller kiddy carrying area possibly.

darnthedog
05-04-2012, 02:16 PM
A possible issue with the steering might be the rake/trail- in looking at the picture the head tube angle may be too steep.
This is only a obervation looking at the picture. It may not be the issue as there is not scale of measurement on the photo.
There is a pretty good tutorial about off the main page. Hope this helps- Also this is a pretty cool build. Love the seats.

go1000go
05-04-2012, 03:51 PM
The head tube angle is 67 degrees - is this too steep - any feedback welcome

go1000go
05-21-2012, 03:38 PM
Progress so far, worked out how to mount the front crank set that drives a hub.
On the left side I welded a single gear taken from a 5 speed cassette and welded this directly to the flange where the spokes used to go.
In order to transfer the drive to the captains chainset I put a chainwheel onthe left side.
Definition of disappointment is having six chainsets and not being able to get two the same - I have learnt something - the square drive is not always in the same orientation to the crank arm. Also to have matching pedals you need two pairs.
Next job weld everything in place then move on to the front seat mount to allow it to be able to move in position to allow for different sized front stokers.

go1000go
07-27-2012, 03:47 PM
Ok here with have how it has worked out.
Got it all finished as a two wheeled long beast.
After a few test drives it did not fit the original aspirations of being fun and safe, as a two wheel it was too wobbly and scary.
Just so happened i had a quad, that the track width was narrowed, but then too narrow to be able to turn easily (body parts got in the way), so a dormant project.
Out came the saw and voila the rear end for this project.
Pictures attached, rides really well.
Few bits to finish off then paint time4782

Radical Brad
07-27-2012, 10:00 PM
Nice implementation, looks like a fun ride!

Brad

river
07-28-2012, 08:58 AM
Looks great, i bet its a blast to ride

go1000go
07-28-2012, 03:41 PM
Went for a last test drive on my daughters insistance today, it is great, really easy to talk and be able to talk and see her.
Handling is good, slight bounce in the frame, but nothing to concerning.
Fitted front derailer and tubes for all the cables.
Stripped it all down, so now to smooth things before paint, probably bright orange.

river
07-28-2012, 04:09 PM
That will really be visible and will really set it off to

go1000go
08-25-2012, 04:06 PM
Sorry River, orange became yellow.
Finally getting somewhere with the painting process so hopefully the trike will be ready for back to school and getting my daughter there.
It needs to be finished because I have now got all the parts and the plans for the front runner which I am really looking forward to building.
The only problem is, having cut up the quad to make the rear end of the trike, the left over front and the rear of the original tandem are most the bits needed for a warrior.
As always more ideas than time.5082

Intrepid
08-25-2012, 06:40 PM
What a great tandem trike! Beautifully done :)

Yellow is a good 'see me' colour to have especially when carrying children.

Mad7
08-25-2012, 06:43 PM
That look nutty fun. Great color

go1000go
08-28-2012, 04:31 PM
Assembly finally started after a marathon painting job, so many bits to a tandem trike.

river
08-28-2012, 08:12 PM
Yellow looks cool, sharp looking bike

go1000go
09-05-2012, 03:11 PM
Done, complete, test driven, happy, thrilled and even the intended audience - my two younger children love it too - biggest best bonus of all.
So to save you going through all the posts, the initial idea was to be able to be the "responsible adult" at the back, steering, braking and gear changing. Having dragged an add-on bike before I found the kids did not enjoy going out and talking became shouting. With having a youngster up front they are able to easily hear me, and i them.
But not only that I wanted them up front to be able to stop pedalling of their own choice and freewheel, or for me as captain to be able to stop them also, for cornering etc.

5157 and this is what it looked like 23 June 2012.
The idea worked, but....... it was far too wobbly and setting off a few times nearly ended up with us crashing, so not the complete solution by far.

Two builds earlier I had tried to make a quad, narrow enough to fit through some metal barriers we have on cycle tracks here. Finished it but unpainted, because by being so narrow the steering was poor and having limited movement. Until now it had been sat in the garage - slowly rusting, so the back end would become the rear for the tandem to become back seat driver trike.

So now the rear wheels are a rachet drive, thanks for advice for other threads, meaning the outer wheel slips when cornering, not a differential. It was actually very easy to make.5160

So here is the end result, seats made from steaming ply and glueing together in a jig, then covered with PVC.
5159
Just need some lights fitting now - but ok for the odd school run for now.

Last question what section of the gallery should I post the photo's to ...

Ticktock
09-05-2012, 11:42 PM
Hi,
I would say it should be in Delta Trikes, as we don't seem to have one for rear drivers (yet)!
Well, done --very unusual approach to a very common design problem.
I would be a little suspicious of the long "drop arm" as a lever--not too sure how it would take a hard knock on front wheel.
Be very carefull on blind corners, as that front wheel is a looong way in front of you--I learnt passing buses in Beijing!
When the kids get a big bigger it will be relatively easy to convert this to totally independant drive simply by connecting each drive train direct to the "differential" (two fixed cogs on the diff) rather than have them connected to each other.
But while you want to be in control, I agree with your logic. The two discs would stop any one peddling anyway.
Two questions if I may? How long is it (guess is 14 feet), and what is the turning circle like?
I reckon with a good hard shove on the peddles you may be able to lift the front wheel with just you on it (now I"m not trying to give you bad ideas--just suggesting it may be possible)
Good work,
Steve G,
Beijing

go1000go
09-06-2012, 02:16 AM
Hi Steve G,
9foot long. The turning circle is not too bad, able to turn in a road width, ie estate road just two cars wide.
The main area intended to pedal this is the school run and cycle tracks, not in traffic.
Take on board the concerm about the steering, I may well have to modify the steering rod, but I am going to see how it goes.
Tim

Ticktock
09-06-2012, 06:26 AM
Hi Tim,
I was guessing at a 20inch front wheel, and then did a rough scale from there. 9foot overall is about one foot longer than my tandem, if you stop at the end of the frame and don't count the crank, so it's not as long as it looks.
Guess the turning circle is about the same, if my memory of English roads is any good, except I have to balance the tandem.
Just to make sure we have the same language-- the bit I am worried about is the long vertical (nearly) extension on the steering arm at the base of the steering column. Guess if it dosen't bend its OK, and if it bends it needs attention!
I should imagine it rides very well, especially for what you designed it for.
Keep on cranking,
Steve G,
Beijing

graucho
09-06-2012, 08:25 AM
Beautiful!
It's great to see someones vision come to life. It's a head turner for sure!

Radical Brad
09-06-2012, 09:30 AM
Nice work!
So many cool tandems coming together lately.

Thanks for the pics.

Brad

go1000go
09-06-2012, 12:53 PM
Hi Steve G
The extension you refer to on the steering, it is made from 3/4" dia solid bar, but I take your point so I will watch it next time we are out to see if it bends.
Thanks to others who have posted also, it is a real boost.
Tim

Ticktock
09-06-2012, 08:11 PM
OK--if that bends I don't want to be on the bike when you do it!!!!!
It will be something else that gives before that one bends.
Thanks
Steve G,
Beijing

Ticktock
09-06-2012, 10:17 PM
I was a bit slow--I see the reason for your question as to which gallery!!
It is a Delta trike, but its also a Tandem! I did not think of my Trike as a tandem, as the passenger is just a passenger.
Be dareing---put it in both!
Steve G