Almost there.... New trike build approaching completion/

[DannnyC61]

So, I have been working on my new trike for over a year now and as a home-builder the hobby is a lot of fun,
I have learned a lot about welding, steering design and gearing. The trike is intended to be a modest touring machine capable of reasonable speeds and with decent gearing (NOT a racer).

This is the first time (as far as I know) that a Nuvinci N380 hub has been incorporated with a Mid-drive Hi-Lo gearbox. This has been an ongoing process and a Hyperglide cassette-hub was cannibalised to provide a carrier mechanism for a mid-way gearing system providing both a high and low-range input to the N380's impressive 380% gear-range.

So, today I stripped the mid-drive cassette down and re-worked the key-way on each of the sprockets so that I could reverse the plates on the output side of the cassette (32T, 24T & 16T) so that both input side and output side (driven/Driving) have the hooking of the teeth in the appropriate direction. Surprisingly easy to do and the whole unit was all reassembled and back on the trike in about 2 hours.

I then did a little test of the changing up/down and while it is not under load, it seems to change fine.

When coupled with the Dual chainrings (53T/39T) on the Bafang up front (another fairly unique adaptation) the overall available range will be 10 Gear-Inches to 105 Gear inches.
This should be more than adequate for a touring machine (especially when a trailer is being pulled).

 

[Deleted member 4366]

The video link doesn't work. did you make it private?

 

[DannnyC61]

The video link doesn't work. did you make it private?

Hi David, Probably yes.
Have changed the setting to unlisted. Try now?

 

[Deleted member 4366]

Nice one. Can we a photo from in-line with the sprockets so that we can see what's in there, please?

 

[DannnyC61]

Here's one.
The spacers are a mix of the one's I recovered from the cassettes I plundered for sprockets and some that a friend 3D printed for me.
The block is held together with 2.5mm 12.9 hardness bolts and brass nuts.
A standard cassette cap-nut holds the re-combined set of cogs on the carrier.

 

[DannnyC61]

Oh... and before anyone jumps to the false conclusion that I am a genius. This idea was not mine. The double-ring on the Bafang was indeed my idea, but the mid-box Idea belongs to my good friend John Price who dreamt it up and it just happens that I am the first to implement it in a build.

I then wrote a little excel spreadsheet to allow me to play with the sprocket sizes and to work out both the Gear-inches and the MPH by Cadence (pedalling RPM). So it was a bit of a collaborative effort.

John made me the split-bobbin Bottom bracket insert and turned the insides of the cassette carrier out to accept standard bearings. All credit for being able to do this belongs to John really; I'm just the first to put it together. His build is ongoing too.

 

[anotherkiwi]

When coupled with the Dual chainrings (53T/39T) on the Bafang up front (another fairly unique adaptation)

<scratching head> ???

 

[DannnyC61]

Why the head-scratching?
Maybe I am completely wrong.

 

[Deleted member 4366]

We need some more photos, Danny. It looks like your bike has many interesting features, but we can't see them. How did you do the double chainring? How do you tension the second chain? Can we see the whole bike?

 

[anotherkiwi]

Double chainwheels on bafangs have been around for a few years, since the first home made spider I guess.

 

[DannnyC61]

Double chainwheels on bafangs have been around for a few years, since the first home made spider I guess.

Ahhhh.... then that's my error then. Apologies. I knew that people had mounted different spiders and alternate sized rings, but I had not realised they had done the double; but its so logical and obvious, so silly me.

 

[DannnyC61]

We need some more photos, Danny. It looks like your bike has many interesting features, but we can't see them. How did you do the double chainring? How do you tension the second chain? Can we see the whole bike?

Yes, I will put some more pictures up if it ever stops raining again.

 

[DannnyC61]

Here's a vid of the current "pro-tem" front chain gobbling derailleur.

We are looking at a more elegant and functional solution for this and I hope to have it in place before the next tour. In the meantime I will do all my drive-train testing with what I have at the moment.

 

[DannnyC61]

Here is the first testing of the rear changer and the N380.

 

[DannnyC61]

Please find below a link to the gallery of the build pics for this trike.
Please bear in mind that I am just a garage hacker and I'm doing this for the enjoyment of the build process as much as for making a bike that I will be able to go touring on. The previous trike I made was seriously flawed but it managed 2 touring holidays in Holland. This trike is light-years ahead in design and build.
https://postimg.org/gallery/2zsoihwc4/

 

[anotherkiwi]

Ahhhh.... then that's my error then. Apologies. I knew that people had mounted different spiders and alternate sized rings, but I had not realised they had done the double; but its so logical and obvious, so silly me.

That's OK I thought you must have made a new breakthrough or something, first doubles were mounted in 2014

I like your front derailleur mount, not pretty but gets the job done. I am going to mount a Sora front derailleur on a braise on mount and the extension to get it out there will be carbon fibre.

I find you are very pessimistic in bottom gear inches, is a 10 gear inches low really necessary on a 20" rear wheel trike, even fully loaded? I have climbed a 15% gradient (un-powered) with a 17 gear inches bottom gear and a 26" rear wheel. It wasn't easy to be honest but I got there eventually. With the motor I think my planned 21 gear inches bottom gear (32:40) will be plenty, it will be tested on a +25% ramp I found recently so we will see. The other options I have is to go to a 10 speed 11-46 cassette and a 18.4 gear inches bottom gear or to mount a 26 tooth granny (17 gear inches).

High end I was thinking of going to a 48 tooth but as I am hardly ever in top gear - age preventing me from pulling 48:11... - have settled for 46 tooth which means a spin out speed of around 60 km/h and 109 gear inches.

 

[DannnyC61]

That's OK I thought you must have made a new breakthrough or something, first doubles were mounted in 2014

I like your front derailleur mount, not pretty but gets the job done. I am going to mount a Sora front derailleur on a braise on mount and the extension to get it out there will be carbon fibre.

I find you are very pessimistic in bottom gear inches, is a 10 gear inches low really necessary on a 20" rear wheel trike, even fully loaded? I have climbed a 15% gradient (un-powered) with a 17 gear inches bottom gear and a 26" rear wheel. It wasn't easy to be honest but I got there eventually. With the motor I think my planned 21 gear inches bottom gear (32:40) will be plenty, it will be tested on a +25% ramp I found recently so we will see. The other options I have is to go to a 10 speed 11-46 cassette and a 18.4 gear inches bottom gear or to mount a 26 tooth granny (17 gear inches).

High end I was thinking of going to a 48 tooth but as I am hardly ever in top gear - age preventing me from pulling 48:11... - have settled for 46 tooth which means a spin out speed of around 60 km/h and 109 gear inches.

I went for a lower than usual GI because my knees are shot and my legs are weak. The statins they make you take after a heart-attack seem to lay waste to muscle tissue. Across the available gear range I anticipate 18MPH in top gear at a leisurely 60 Cadence. The trike has to be totally usable W/O the E-Assist being available. Last tour it rained so much the Bafang cut out because the thumb-throttle went belly up and on the previous trike I could not even manage the smallest of hills. Totally wrecked my knees trying and I'm never doing that again.