Has anyone made a 2 wheel drive bike?

LR Jerry

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Fabian I think it would be better to encase the gears. Debris getting in them may not be to big of an issue under human power. However the torque and power of an engine could cause major problems if debris got in the gears.
 


HeadSmess

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i dont like the alloy exposed gears! they say they work ok, and i guess they do turn slowly, and are pretty far out of the way... but surely a neat lil carbon fibre/moulded poly cover would only cost a few more dollars?

shame the system looks to be frame specific, not a bolt on kit... now that would be something!

i know the rokon is the longest running production 2wd bike... a slow speed, climb anything, oversized minibike for dragging dead moose home with. steering isnt really a big concern.

anyone looked at the kingpin drive used on (i know this may seem a bit hillbilly to some) tractors with 4wd? use a bevel drive and shaft in the kingpin rather than a uni/cv joint...

surely the idea could be adapted to a threadless headset and forks?

gearing/drive is an issue. yamaha had the front wheel driven slightly faster, but with some "slip". the benefit of hydraulics.

too much and it wears tyres, too little and it wont let you turn properly, as every time you turn, the front wheel travels slightly further than the rear...


hence the third differential, between front and rear axles.


how much were the gears on fleabay? i have a collection of cheap grinders for that reason... the gears. looking at the prices on some some machinists supply site made me have an aneurysm. 170 a gear, and the pinion and crown have to be purchased as a set... and very few ratios commercially available.

spiral bevel/hypoid gears are the hardest of all gears to cut. beyond the scope of a home machinist...normally. straight bevel comes close second. they are just about manageable with the right setup. lot of maths!

throw in hardening and grinding...

how can i buy a whole angle grinder for $15? ????
 

LR Jerry

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HeadSmess I see you to are in agreement with me about the gears not being covered. If you look back at videos you'll see one with a flexible drive shaft. That seems like it would be the easiest one to adapt to the bicycles we use. The video was in BigBlue post.
 
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BigBlue

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Grinder gears cost $15.39 on Ebay with free shipping. I went with a 2.8" diameter gear since it is about the same size as my 15 tooth freewheel on the rear hub. The large is a 41 tooth and the small a 14 tooth. Largest diameter I could find. I didn't want to spend more on a research idea. It is for a Hitachi. Christini uses TEFNI2000 coating on the bevel gears for lubrication and corrosion prevention.

Covers? Does the Christini motorcycle have a cover on the bevel gears?

Chris
AKA: BigBlue
 

IbedaYank

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photo1.jpg
yep your really going to get an axle to go through a kingpin on a kingpin axle set up...
or what this diagram calls a spindle bolt
 

LR Jerry

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Grinder gears cost $15.39 on Ebay with free shipping. I went with a 2.8" diameter gear since it is about the same size as my 15 tooth freewheel on the rear hub. The large is a 41 tooth and the small a 14 tooth. Largest diameter I could find. I didn't want to spend more on a research idea. It is for a Hitachi. Christini uses TEFNI2000 coating on the bevel gears for lubrication and corrosion prevention.

Covers? Does the Christini motorcycle have a cover on the bevel gears?

Chris
AKA: BigBlue
Blue even if the Cristini motorcycle doesn't have covers over the gears maybe they should.
 

BigBlue

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Found this research paper that conducted a stress analysis of a harbor freight 4-1/2" angle grinder. The grinder operates at 11,000 rpms and has a rating of 3/4 of a horsepower. A Rockwell Hardness analysis was conducted on the pinion spiral bevel gear. After a conversion was completed, it was estimated that the pinion gear had Tensile Strength of approximately 106,000 psi. Probably what to expect from other replacement grinder spiral bevel gears. My hunch is that the original equipment gears will be of better quality with the name brand grinders. Dewalt makes angle grinders with ratings of 5.3hp.

Considering that the Honda GHX50 output is approximately 2.1 hp and that approximately 1 hp will be split between the front and rear drives, I think the grinder spiral bevel gears will be O.K. Also consider that the gears won't be spinning at 11,000 rpms like the angle grinder.

http://www.ewp.rpi.edu/hartford/~ernesto/SPR/Zouhri-FinalReport.pdf

Chris
AKA: BigBlue
 

LR Jerry

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Blue does this mean we're going to see you on an all wheel drive bike in the future?
 

HeadSmess

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View attachment 51177
yep your really going to get an axle to go through a kingpin on a kingpin axle set up...
or what this diagram calls a spindle bolt

everything is impossible. everything.

at first i was going to say, "nice model A pic" but then...the model A ford has the front brake actuator feeding down through the kingpin! so, other than it being old, whatever... its irrelevant :)

sorry. i wouldnt have mentioned it if i hadnt seen the actual device, as attached to a ford 2120 tractor. i believe theyre also marketed as "new holland".

2012-02-22_041404_new_holland_2120_front_axle_reduction.jpg

patented idea... http://www.google.com/patents/US2306958


http://www.google.com.mx/patents/US4301886

http://www.google.nl/patents/US4613011



well, maybe im dreaming again...but it seems at least someone worked out how to get a drive down through the kingpin...
 
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