Anyone Running Power THRU the Bottom Bracket?

[Captain Rainmaker]

How do you plan to keep the crank arms 180 degrees apart from each other? If they're both on freewheels with nothing else connecting them, they'll be able to spin independently of each other and just flop around all willy-nilly, which is no good.

Now I'm confused.
Please explain "mutually exclusive".

It basically means two things that can't exist together. You said in one post that your plan was to simplify things, then you said in another that your design was very complicated. Those seemed like contradicting statements.

 

[mark20]

How do you plan to keep the crank arms 180 degrees apart from each other? If they're both on freewheels, they'll be able to spin independently of each other and just flop around all willy-nilly, which is no good.

It basically means two things that can't exist together. You said in one post that your plan was to simplify things, then you said in another that your design was very complicated. Those seemed like contradicting statements.

If the freewheels are going the same direction, they would be on the same spindle, and acting like a regular bike crank

 

[5-7HEAVEN]

How do you plan to keep the crank arms 180 degrees apart from each other? If they're both on freewheels with nothing else connecting them, they'll be able to spin independently of each other and just flop around all willy-nilly, which is no good.

It basically means two things that can't exist together. You said in one post that your plan was to simplify things, then you said in another that your design was very complicated. Those seemed like contradicting statements.

Deja vu all over again!(Yogi Berra)

I just remembered something.

I posed this exact question about five years ago and went thru the same lengthy discussion.

Then someone on this forum asked me the exact same question and stumped me.

I recall that there WAS a way to overcome this, but it cost several hundreds to over a thousand dollars to do so.

Fact or fiction.....

Can you run power thru the bottom shaft while keeping the pedals operational?

Sadly, no.
I was beginning to believe that it could be done, lol.

Mahalo for your time, fellas! I've enjoyed the discussion!

Now, if it wasn't for the pedals...........

 

[FurryOnTheInside]

Let's not forget about tandem bicycles. Some of them do indeed allow the pilot to do all the work while the stoker has a rest.
Few of them actually do this. Usually the stoker must continue to pedal (or ghost pedal) whenever the pilot is powering the bike. Much simpler.
Now, whether the power can be transferred from left hand side to right hand side in a set up that allows the stoker to rest.... yeah maybe that's all rhs drive at that point. Its what we're looking for, though? That might be the expensive thing, might even require a special BB shell built into the frame.
I cba checking it out thoroughly right now, I came here for something else and got completely distracted lol.

@CrazyDan it seems you have a simple Y arrangement there as opposed to the Z arrangement on the Shift Kit by Sick Bike Parts. That's just great. Its an ideal set up, and no obvious problems that are difficult to overcome other than it needs a JS mounted freewheel adapter for regular direction freewheel on the outer rhs JS sprocket to take power from the pedal sprocket, which you can get from SBP or Stanton, i believe.
Sprocket maximum sizes being limited by proximity to the engine or other parts, and the minimum of the freewheel adapter.
I would love to see one of these Y arrangements again. I saw just one photo of one of these, ages ago on the forum, it was a custom (long) frame bike that raced..Green bike, idk if you saw.
Engine power goes through only 2 chains and 4 sprockets with 1 reduction and 1 set of dérailleur gears (or internal gear hub that can go either way but from the 16t freewheel its going to want to be mostly reduction, and why use a IGH on such an efficient set up. Maybe a NuVi?), as opposed to the Shift Kit with 3 chains and 6 sprockets with 2 reductions and then a... gain?
Build it please! And win with it!!

 

[5-7HEAVEN]

Success is built upon failure after failure.
If at first you don't succeed, try, try again.

I just love stuff like this!

 

[FurryOnTheInside]

Success is built upon failure after failure.
If at first you don't succeed, try, try again.

I just love stuff like this!

I am going to disagree with you. Sorry!
Proper planning! Less broken stuff that way. Less accidents, hopefully.

I'm very into planning and making sure everything is going to fit exactly right first time, before I start building.

That's why I'm going to have to chop pieces off my downhill mountain bike frame now lmao.
I admit I failed to plan properly today

 

[5-7HEAVEN]

FOTI.....aha!
Lol.

 

[5-7HEAVEN]

The best laid plans of mice and men often go awry.
I'm still in my planning stages of shift-kitting the 212.
Just got sidetracked.
No big rush to finish my build.

 

[Captain Rainmaker]

Came across these photos while looking for parts. It would seem there's at least one other bike running a Y setup.

Unfortunately, I have no idea who built this; it was in a "customer photos" section on this page.

It does look a fair bit cleaner than the SBP setup, although not as easily adaptable.

 

[CrazyDan]

The reason I want to do it is there is less hp lost getting rid of 2 sprockets, a shaft and a chain from the engine to the rear wheel, but retaining the pedals. I accelerate much faster and can maintain a higher speed up a hill with my pedals, Don't want to lose them. Even with a 212 on a shift kit you will notice a slight power increase when you pedal, similar to a small nitrous shot. Also, as I said, pedals are a must for the socal races.