Full suspension gas tank frame design concept.

Sitherus

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Apr 4, 2016
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236
I have been working on drawing a concept of what I would like to make reality in a perfect bike frame.
I went through around 30 different designs before i settled on this one. When drawing i set my goals to make the perfect sleek looking functional and buildable frame that had all the features missing in my last build. Features that are hard to come by in a motorized bicycle frame.
I wanted a gas tank built into a frame with rear suspension. It needed to be able to support a 7 speed rear derailleur, disc brakes, and a 3.5" or less wheel.
I also wanted the layback seat post built in and a built in bearing for the shift kit.
This is what I came up with.
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I only quickly painted it to show how cool it could look.
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I put this out in the world hoping that you can offer feedback. Hoping that no one will steal it and make millions while I still sit broke.
 


The_Aleman

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May 2, 2007
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924
Rear suspension is tricky on a mid-mount motorized bicycle unless the engine drivetrain makes use of the chains that the bike was designed around. It's why most of us just prefer to spring the saddle LOL

Your first 2 bike drawings have a rear suspension that wouldn't work too well. 1, the tire is gonna rub on any bump and 2, the chain run for the engine is going to change tension with suspension travel. On a bumpy road, the chain will flutter much more than usual. Aside from that, I think your frame tank design is beautiful! A few tweaks and it would be plenty workable.

Your second post looks like some frame designs that already exist. My own (20 year-old) Nirve Knuckle is similar, as are some Felt frames and 2-stroke-specific Grubee frames. Nothing wrong with that, they look awesome in white with a black layback :giggle:
 

Sitherus

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Joined
Apr 4, 2016
Messages
236
Rear suspension is tricky on a mid-mount motorized bicycle unless the engine drivetrain makes use of the chains that the bike was designed around. It's why most of us just prefer to spring the saddle LOL

Your first 2 bike drawings have a rear suspension that wouldn't work too well. 1, the tire is gonna rub on any bump and 2, the chain run for the engine is going to change tension with suspension travel. On a bumpy road, the chain will flutter much more than usual. Aside from that, I think your frame tank design is beautiful! A few tweaks and it would be plenty workable.

Your second post looks like some frame designs that already exist. My own (20 year-old) Nirve Knuckle is similar, as are some Felt frames and 2-stroke-specific Grubee frames. Nothing wrong with that, they look awesome in white with a black layback :giggle:
the felt iron bolt frame isn't a design concept just another drawing for people to remember who i am. I built that and its what i ride now.
 

The_Aleman

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May 2, 2007
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924
I never claimed the second one was a design concept, I just said what I thought it looked like based on the wording of your post.

I (re)built my bike in 2010, not many looked like it at the time, but many have since. Including yours. I don't claim to have designed my bike, I took a production frame, a production engine kit, a production shift kit, and bolted it all together with some choice bicycle parts and a lil bit of adaptation along the way. Made it that way initially to show it's possible to build a good bike with non-custom parts. These days, mine has some laser-cut brackets on it of my own design, but still, I can't claim to have "designed" my bike. I didn't even weld anything on it. There are some real bike designers here and the bar has been raised bigtime in the last 5-6 years.

Anyway, just clarifying some things. To touch back on the rear suspension, a chain run has to accommodate the pivot point of the rear subframe. A pic of a Mongoose XR200 as an example, not mine, but I own one of these:

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The suspension pivots just above the bottom bracket, the distance the chain must travel is kept close to constant.
 

Spare_Parts

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Nov 29, 2017
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Looks like he plans to have the pivot at the bottom bracket. I have seen a frame with the pivot there but have no idea where.
 

The_Aleman

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May 2, 2007
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924
Well see, pivoting at the bottom bracket is fine in relation to the pedal crank.

If he were to run a chinagirl with standard drive, the chain would get loose under power or when the spring compresses. Wouldn't matter too much, that rear suspension design would cause the rear wheel to be rubbed to a stop by that tab under the seat. Anyway, sure he could jackshaft engine off the BB, solving the chain issue, but that rear suspension design needs a lil bit of work. Rear suspension is tricky enough with one chain run, gets much harder with 2.

I still think it's a nice-looking frame!
 

Spare_Parts

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Nov 29, 2017
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Yeah, would need to be jack shafted. Lot of stuff to put in a small space. It's a good looking concept, would like to see how it works out.
 

Sitherus

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Apr 4, 2016
Messages
236
Just to make things clear. The rear frame is jointed at the crank. All designs are meant to use a jack shaft and the motor will drive the rear wheel with the bikes chain.
 
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