Project: Home made velomobile design with crank or mid motor

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tahustvedt   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 10 2016 6:37am

It will be monocoque. The routed pockets will be on the inside. There will be a central structure to mount the seat and driveline to, and carbon fiber strengtheners.

I will make a differential using angle grinder gears. Two large and four small gears. http://www.ebay.com/itm/231059208016?_t ... EBIDX%3AIT

I will use a universal joint in the front wheel spindles and dogbone connections on the diff to allow for both telescoping and torque transfer.
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Re: Project: Home made velomobile design with crank or mid m

Post by nerdalert » Aug 10 2016 7:15am

Front wheel drive? Awesome. Put it away when it snows?

tahustvedt   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 10 2016 7:29am

The old velo will be the winter velo because it has very good suspension. The new velo will only have about 40 mm of suspension travel. Maybe 50.

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Wheazel   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by Wheazel » Aug 10 2016 8:27am

Samagaga sells a very nice differential for bike usage. I have one at home waiting for the winter quad project.
Unless you are manufacturing something different that requires a custom job, I would certainly go for the samagaga.
Not too expensive and alot of time saved. +it is a nice unit.

I will be driving the samagaga discbrake side with the motor, and have a cassette on it aswell.
So it will basically be a jackshaft that with gearing finds the common rpm between pedals and motor.
It works with a 219chain if I use the revolt120 i have laying around, or even easier to gear if I use an even lower rpm DD hub.

tahustvedt   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 10 2016 11:00am

I didn't know about the Samagaga diffs. They look nice. I want to make as much as possible myself, it's part of the fun for me. :)

tahustvedt   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 10 2016 6:23pm

The basic diff design is done. It will be refined for lightness when I make the aluminum version. I'm printing a plastic version for testing now.

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Re: Project: Home made velomobile design with crank or mid m

Post by nerdalert » Aug 10 2016 11:05pm

How did you mount your front wheels? I took all the guts out of a sram wheel and threw them all away in the beginning and ordered some 29.5mm od bearings because that's what the inside of the hub was showing in a quick measurement. Currently, the bearings are a finger tight slip fit but I want a press fit. Turns out the OD is around 29.55mm so 30mm bearings won't fit.

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 11 2016 7:32am

nerdalert wrote:How did you mount your front wheels? I took all the guts out of a sram wheel and threw them all away in the beginning and ordered some 29.5mm od bearings because that's what the inside of the hub was showing in a quick measurement. Currently, the bearings are a finger tight slip fit but I want a press fit. Turns out the OD is around 29.55mm so 30mm bearings won't fit.
My spindles are really bulky, and I'd like to make slimmer and lighter ones at some point. The 20 mm aluminum shaft is fed through the wheel and into the spindle and is clamped by tightening the four screws you see in this photo.
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Re: Project: Home made velomobile design with crank or mid m

Post by nerdalert » Aug 11 2016 7:53am

So 20mm thru axle hubs? ThTs what I just ordered.

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 11 2016 10:45am

Correct.

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 11 2016 1:18pm

What do the Samagaga diffs cost?

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 11 2016 1:49pm

The plastic test-version works.
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Wheazel   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by Wheazel » Aug 11 2016 2:03pm

I want to recall that I paid rougly 100 dollars for 1diff, 2 of those spline shaft ends (to make my own axles with), and shipping.

Very nice print. What printer and filament do you use?

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 11 2016 3:01pm

100 dollars is a really good price.

It's 3dnet.no PLA filament on a Wanhao Duplicator i3 printer.

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Re: Project: Home made velomobile design with crank or mid m

Post by amberwolf » Aug 11 2016 4:20pm

Angle grinder gears....Why didn't I think of that? :oops: Now you've given me dangerous ideas. :)

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Re: Project: Home made velomobile design with crank or mid m

Post by The Toecutter » Aug 11 2016 7:34pm

Those spindles are sexy. :idea:

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Wheazel   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by Wheazel » Aug 12 2016 1:24am

tahustvedt wrote:100 dollars is a really good price.

It's 3dnet.no PLA filament on a Wanhao Duplicator i3 printer.
Yes, I was surprised. And the diff itself was like 70.
You seem to have a nice design that should work just as well, and if you create your own differential I can certainly respect that.
However, personally I would put the time on other areas where I would actually need to build custom stuff to realize the project!
I will follow this with great interest!

tahustvedt   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 12 2016 6:36am

That's cheaper than mine will be. :D But still, making things myself is half the point of the hobby to me. Pretty much the only things I won't make myself are the crank, bottom bracket, pedals, derailleur, shifter brake calipers and levers and chain. I have a crank I can use.

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Re: Project: Home made velomobile design with crank or mid m

Post by nerdalert » Aug 12 2016 7:33am

What do you mean "to realize the project" ?? He's on his second car, the first of which even had a hand sewn ball cradle.

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Wheazel   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by Wheazel » Aug 12 2016 8:23am

nerdalert wrote:What do you mean "to realize the project" ?? He's on his second car, the first of which even had a hand sewn ball cradle.
He wants to build version number two, and I am saying that I personally would not invest time in custom manufacturing of parts that I can get for reasonable prices that is more or less the same thing I would be custom making. My philosophy is that a part I am custom making needs to add something more. Be it looks, functionality etc.etc. The reason for this approach is my limited time.
I would simply focus on areas that needs to be custom made, because they are unique. And there are plenty of these parts on a velo like this!
On the other hand I can wholeheartedly understand the joy in making every part, the completed build will be even more satisfying.
I guess I am anxious to see the velo rolling finished :).

I have been thinking of making a velo myself for years, but always been put off by the width of the ride. Afraid to take too much space on roads with narrow edges.
The same applies to rigid 3wheel cargobike ideas I have been thinking of.
However this new design is starting to get into the territory of slim enough.

@Tahustvedt
Do you have any comments regarding my concerns, since you have been riding the pretty wide version 1 on Norway roads? (my experience with Norwegian roads are; next to no roadsides at all)

tahustvedt   10 kW

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 12 2016 9:37am

Almost all the bike paths here are at least twice as wide as my first velo, even with the 110 cm track. I ride in the road instead when there's less room or when there are a lot of pedestrians on them. Pedestrians in Norway are mostly mindless drones who don't give cyclists room for safe passing, even on roads made for both bikes and pedestrans. I wish the paths had a center line to encourage sharing. My new velomobile will be about 74
cm wide, which is about the same as handlebars on a regular bike.
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Re: Project: Home made velomobile design with crank or mid m

Post by Wheazel » Aug 12 2016 10:29am

tahustvedt wrote:Almost all the bike paths here are at least twice as wide as my first velo, even with the 110 cm track. I ride in the road instead when there's less room or when there are a lot of pedestrians on them. Pedestrians in Norway are mostly mindless drones who don't give cyclists room for safe passing, even on roads made for both bikes and pedestrans. I wish the paths had a center line to encourage sharing. My new velomobile will be about 74
cm wide, which is about the same as handlebars on a regular bike.
Yes this aligns with my experiences of Swedish bikepaths aswell. People get surprised by a bike approaching on a bikepath...
And I am very carful to not approach too fast from behind with my silent cargobike. And when I ring the bell to alert zombies, even if I am like 30-40meters behind, they go like WHOA! and some literally jump to the side for no reason. A lot of drones staring at the screen of their phone, walking in the middle of the bikepath playing pokemon go.

When I built the tilting wintertrike, I had roughly my shoulders as guideline for the width. The handlebars are slightly wider.
I think this is an acceptable compromise, because even if the bike might be just as narrow as the body, having a trackwidth still makes the ride take more space. With the cargobike I can theoretically ride with almost half the vehicle "outside the road" So what I conclude is that going from 110cm to 74cm must be huge.

Ever considered 4 wheels for the wintervelo build? My experiences with the wintertrike leads me to a quadbuild. The main reasons being better tracking in snow with only 2 tracks instead of 3, and an easier time to avoid obstacles. Sometimes the winterroads have wheelpaths (from carwheels) in a ~5-10cm thick crust of ice, and 3 tracks can be very tricky to ride. (The front trackwidth won't fit in the wheelpath, but are to narrow to ride at either side. And with one wheel in the wheeltrack and one ontop of the crust, the rear wheel goes on the icy crust slope sliding all over the place.) Very unpleasant, and pretty common for countryside roads here at wintertime.
With 2 tracks I can ride one in the wheelpath, and the other ontop of the crust. This might be an extra significant problem for the particular trackwidth of my wintertrike. (50cm). Your velo version 1 should be able to ride with the front wheels at either side of the wheelpath and the rear wheel in it. To assure a somewhat stable ride.

Can you ride exclusively on bikepaths and go wherever you need to?

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 12 2016 10:35am

The velomobile is used for shopping and stuff like that, and for that kind of use I can ride on bike paths all the way.

I have looked into converting it to four wheels. It's never going to be a fast velomobile anyway, so the extra drag isn't going to matter much.

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Re: Project: Home made velomobile design with crank or mid m

Post by nerdalert » Aug 12 2016 4:49pm

The design of the ride is always dependant on the locality. I used to live in the southeastern USA and my velomobile would have never been an idea because there are almost zero bike paths/lanes (literally) and down there, the car rules the road. Pedestrians watch out for cars, not the other way around. Now that I moved to the northwest USA the bicycles rule the road, even when there's no bike lane. It can be obnoxious stuck behind a bicycle on a road that was designed for automobiles. Most of the roads here have designated bike lanes, so I'll have a free path all the way to work and around town. The bicycle lanes have a legal width, so I had something to design within. 43in/110cm is my current track width as well. At a ride height where I can hop curbs, I find it a little tippy already, but I drive it like a f1 car. :) Keep your COG as low as possible on the next build if you are reducing your track width.

Are you making any significant suspension / spindle changes?

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Re: Project: Home made velomobile design with crank or mid m

Post by tahustvedt » Aug 13 2016 5:34am

Yes. The new one will have mcperson suspension and completely different spindles. The rear will be a single carbon fiber swingarm.

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