Local idiot tries to build a tadpole

[BionicOnion]

Ok, please bear with me. I had about 10 minutes today for a very quick layout for concept. Please excuse the other mess in the garage as well.

The rear wheel is just a spare 27.5 inch i had so I used it as a general idea, may go down to 20 inch wheel or 23 inch tire size, I don't know yet. The 2 red tubes will be vertically aligned and welded with some trellis reinforcement between them. The funnel is general front seat placement. The 2 wooden boards are where the front control arms would go. And the front bike frame will be cut off so just the downtube and bottom bracket are used, which should hopefully give me a nice leg stretch out for pedaling, room for suspension and any other components needed. And behind the front seat would be a spare seat/storage in the passenger area. In the picture between the rear wheel centerline and front control arms sets a wheel base of approx 60 inches, which is inline with a longer wheelbase tadpole trike. The little red tube below the front frame represents 7 foot from the rear tire centerline, used mostly for overall scale of production.

Please chime in with any thoughts, criticism, ideas, general tomfoolery or even fun jabs and thanks you for checking in!

 

[offGridDownUnder]

may go down to 20 inch wheel or 23 inch tire size

Decide this. Changing the relative front and rear wheel height will change the steering geometry.

 

[BionicOnion]

Decide this. Changing the relative front and rear wheel height will change the steering geometry.

Well, im hoping to be able to run year round. We get snow... a whole freaking bunch, so it almost seems like the slightly taller tire may be preferred at the cost of the extra weight and whatnot... or use the smaller wheels and find some snowmobile skis and run it that way? I live in a area where snowmobile is HUGE

 

[offGridDownUnder]

Well, im hoping to be able to run year round. We get snow... a whole freaking bunch, so it almost seems like the slightly taller tire may be preferred at the cost of the extra weight and whatnot... or use the smaller wheels and find some snowmobile skis and run it that way? I live in a area where snowmobile is HUGE

I can't be certain from your reply. I meant that if you weld the geometry with a 26" wheel in the back, and then switch to a 20" wheel in back, that 3" difference will change the angles of your steering axes.

You can find that your front wheels then fight each other and steering and tire wear will then henceforth be forever bad.

If you get the steering geometry correct, then I don't think there is some issue with going from 2" tires all around to 4" tires all around, as the steering angles would remain the same with respect to the road surface.

 

[BionicOnion]

I can't be certain from your reply. I meant that if you weld the geometry with a 26" wheel in the back, and then switch to a 20" wheel in back, that 3" difference will change the angles of your steering axes.

You can find that your front wheels then fight each other and steering and tire wear will then henceforth be forever bad.

If you get the steering geometry correct, then I don't think there is some issue with going from 2" tires all around to 4" tires all around, as the steering angles would remain the same with respect to the road surface.

Sounds to me like best bet would be say game on with 20s the whole way around. Ackerman shouldn't change much but I can see caster and toe shifting. But then depending on sai there's a chance of excessive scrub. Ideally I'd like 3 tires all the same so I only need 1 spare.

This things going to be pretty well equipped with motors for speed but still want to keep efficiency reasonable. The other nice part is if I make a change later I should be able to adapt for it

 

[classicalgas]

Ok, please bear with me. I had about 10 minutes today for a very quick layout for concept. Please excuse the other mess in the garage as well.

The rear wheel is just a spare 27.5 inch i had so I used it as a general idea, may go down to 20 inch wheel or 23 inch tire size, I don't know yet. The 2 red tubes will be vertically aligned and welded with some trellis reinforcement between them. The funnel is general front seat placement. The 2 wooden boards are where the front control arms would go. And the front bike frame will be cut off so just the downtube and bottom bracket are used, which should hopefully give me a nice leg stretch out for pedaling, room for suspension and any other components needed. And behind the front seat would be a spare seat/storage in the passenger area. In the picture between the rear wheel centerline and front control arms sets a wheel base of approx 60 inches, which is inline with a longer wheelbase tadpole trike. The little red tube below the front frame represents 7 foot from the rear tire centerline, used mostly for overall scale of production.

Please chime in with any thoughts, criticism, ideas, general tomfoolery or even fun jabs and thanks you for checking in!

Building a trike that works (steering is stable, nothing breaks, corners well without tipping over, etc...) is much more difficult than you imagine. If you can't find a used one, at least buy a set of plans from Atomic Zombie. That way you at least have some chance of getting the steering geometry right. Then you have to source wheels that will take the side loads of hard cornering, figure out a seat, brake mounts...