[rbx]

After many years of suspension analysis i came to the conclusion that in order to have zero pedal feedback with high amounts of antisquat and active braking i needed to ditch the chain.

Aim of the design

First proto will be an AM design
-use a rohloff hub mounted above the BB driven by the cranks via chain/sprocket.
-Send power to the rear via telescoping alu. shaft
-All of this mated to a 4bar linkage.

This will be a rolling labortary to test my theory,weight will be a crucial factor

Right now im in the stage of calculating and configuring the linkage to get the right amount of anti-squat with shaft drive.

All in good fun

 

[jonKranked]

Sounds intriguing. This telescoping shaft, I'm guessing it's going to be splined in some manner in order to transfer power from the Rohloff to the rear wheel, and also to prevent it from buckling/having other problems as its length changes?

 

[rbx]

Sounds intriguing. This telescoping shaft, I'm guessing it's going to be splined in some manner in order to transfer power from the Rohloff to the rear wheel, and also to prevent it from buckling/having other problems as its length changes?

Well for the time being for weight and ease of fabrication the male part of the shaft will be slotted the female part will have hole, a bold going thru both of the pieces will act like a key, with a rubber CV boot for mud protection.
There will a nylon sleeve between the two pieces to minimize friction, cycling the suspension reveals about 1/4" of translation between the two pieces

The shaft will have universal joints at both end(alu preferably)

 

[Stray_cat]

I assume you'll be using bevel gears? If so will it be an open system, or oil bath?

 

[rbx]

I assume you'll be using bevel gears? If so will it be an open system, or oil bath?

bevel, spiral if i can find some with the right diametral pitch

 

[ridiculous]

didnt jeep try something similar to this on a hardtail to make it 2wd?

 

[LMC]

didnt jeep try something similar to this on a hardtail to make it 2wd?

thats the bike i thought about when reading this thread, about shaft driven bevel gears and the like. The bevel gears are exposed on both wheels but i remember reading a bike review and nothing was mentioned about the exposed nature of the drivetrain affecting performance.

AFAIK Jeep rebadged the bike from Christini who make all wheel drive kits for motorbikes and MTBs, theres a full sus version too.

 

[Stray_cat]

bevel, spiral if i can find some with the right diametral pitch

Yeah, spiral is the way to go, much smoother and quiter. Be wary of the boundry conditions of your grease, or oil and the Q factor. I'd be excited to see how you implement it.

 

[Whoops]

On a proto I'd give up worrying *too* much about weight. Leave that for v2.

 

[rbx]

thats the bike i thought about when reading this thread, about shaft driven bevel gears and the like. The bevel gears are exposed on both wheels but i remember reading a bike review and nothing was mentioned about the exposed nature of the drivetrain affecting performance.

AFAIK Jeep rebadged the bike from Christini who make all wheel drive kits for motorbikes and MTBs, theres a full sus version too.

The christini just plugs a shaft drive to a chain drive, so you still getting pedal feedback!

This is a totally different animal, think of a rocky mountain ets-x meets a mac truck shaft drive

 

[LMC]

sounds good

have you got any sketches/cad models you can post?

 

[ridiculous]

The christini just plugs a shaft drive to a chain drive, so you still getting pedal feedback!

This is a totally different animal, think of a rocky mountain ets-x meets a mac truck shaft drive

for some reason I thought of a diesel honda civic when I read this. Sounds like a cool project though, would love to see the concept.

 

[wrestlemania]

on page 8? in the gear box thread. I had this idea once that I thought was original, spent a lot of time designing am close to fabricating just to type it in to the web and bam there it is sure enough someone has a web page claiming the patent on it. Oh well I still intend on building it once I get my machine and lathe.

 

[Rover Nick]

how efficient would it be? Isn't one of the reasons bicyles use chains is due to efficiency? We don't produce alot of power so we certainly don't want to lose much in that department.

 

[w00dy]

I competed in the Human Powered Vehicle competition a few years in a row. I've seen it done and I can saw that bevel gears eat up a lot of energy. It does make a huge difference on something you have to pedal.

 

[rbx]

I competed in the Human Powered Vehicle competition a few years in a row. I've seen it done and I can saw that bevel gears eat up a lot of energy. It does make a huge difference on something you have to pedal.

Effiency numbers should be near chain drive maybe 2-4% less, but chain loses alot once it starts getting dirty.

That orange bike pic is close to what i want to do, but i will be using 4 bar design(better braking and anti squat control)

 

[w00dy]

Post pictures if you make this thing. You've got some very ambitious plans and I'd love to hear how it turns out.

 

[KenW449]

Where did this ever end up?

 

[WestCoastHucker]

2 more weeks...

 

[manhattanprjkt83]

last time i saw the word 'shaft' in an RM thread was the lounge during '05.