Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc)

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Here is a pic of my trusty old Mongoose. This bike is ridden more than any I have. Imagine the engine on a rack mount further back and the derail hub basically mounted where the cross bolt is in the engine mount clamp, and engaging the tire. This really works well with a suspension bike which is normally harder to FD. Should work with a rigid frame as well but not all would have the distance needed. The derail would be mounted in a normal fashion at the hub axle and function with just a cable hook-up. Clutching is going to be an issue. A cent. clutch is the easiest/best choice and I believe can be made to work with the bike chain with a little modding. However due to the clutch drum it will have to be indexed with the chain in a straight run to either the outer or inner gear and travel away from the drum to shift. All not a big deal. The trick is in having the longest chain run possible.

All that said I have to agree with happeyvalley. This complicates the really simple, reliable concept of direct drive. As I said earlier, if Im going to travel 50mi from home it aint gonna be on my shifter bike.

Still this is an interesting concept.

 

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Forgot the pic!

 

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

I guess I need to point out my thinking is based on designing around a large 4 stroke engine. If based on a friction drive like a Staton, or DAX the the clutch issue is already taken care of. Still to shift properly a long chain run is nec., so moving the hub as far from the engine(somewhere on the bike frame) seems a must.

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

I can't draw very well, esp on MS Paint, but here's the basic idea (shown with internal gear hub)

No. The roller/hub will be closer to the seat than the engine and stock driveshaft. The hub will be turning the same direction as the driveshaft which normally would have a stock roller. As the tire rotates, the roller/hub will rotate the other way, under power, and if the tire rotates faster than the engine and chain speed, it will "coast", same as a bicycle. If the engine is turned off with killswitch, for example, and the bike is pedaled with its normal pedal system, the chain on the engine system will sit still, and the roller/hub will coast.

Reply to HappyValley. This isn't as complicated as you make it to be. It will only require one cable for the derailleur, and even low end/salvage components will work fine, like a thumbie shifter and a $5 shimano mech.

The point is that it IS a friction drive. I like friction drives. It avoids rag joints or sprocket adapters, or front freewheel systems, etc. If built well it would be just as interchangeable between bikes as any other friction drive. Also, for someone who wants to retain the intact pedal system and drag-free pedaling with the motor off or downhill (unlike the happytimes), this is a good system.

Regarding tire wear etc. I get my tires for $10 so I don't care. I can run them smooth and use them on the front a while longer for even more savings. Tires are cheap.

The main advantage to this (the reason for bothering to design it) is it will be a friction drive (fun!) with multiple gears and a HUGE gear range for maximizing the abilities of small engines. You will be able to easily climb steep grades, "overdrive" the engine to lower RPM at cruising, and shift while maxing out your engine if you want to accelerate quickly or reach top speed.

Maybe Im confused but the roller must turn CCW to drive the wheel foward. Wouldnt the freewheel just spin?

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

With the internal gear hub, assuming it will fit inside the Dax channel, I can make one of these multi speed fric drives without doing anything more to the stock kit than drilling 2 holes for the axle, and replacing the stock roller with a driver cog. The chain will be very short too, basically a jackshaft chain covering 3" between shafts. (pictures coming of mock-up). Now I just need a 3 speed IGH & shifter, and driver cog.

The average bicycle chain stays are not that long, even to run 3x9 mtn bike gears with 22/32/42 and 11-34. So just to run 1 drive gear (maybe use a cheap track hub and its gear, mounted somehow with set screws on the drive shaft), and a road freewheel (12-25 would do fine), it could have a very short chain. The tension could be kept pretty high too, by shortening the chain so the lower pulley is quite far forward at low gear.
Think of cheap kids bikes like 20" "BMX" with 5/6 speed freewheels.

I really don't think the hub would need to be fixed or frame mounted. I think it would work even 6.5" from the driveshaft, though it would be noisy and use chains.

 

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

So you have flipped the hub to drive from the left as viewed from behind? I can see with an IGH its no problem on a short chain/belt. You bailing on the derail idea?

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Here is the mockup, using a toilet paper roll in place of the hub/roller.

Another cool thing about the internal gear hub idea, is it would also allow placement of the hub roller directly under the driveshaft via extension brackets, or even behind the driveshaft, so long as you can apply the drive roller without rubbing the driveshaft.

2 pics showing mockup with "roller" forward of driveshaft.

Note: I might need to drill 2 holes in the U bar to lower the front end of the bracket a bit to change the angle. Not too radical a change.

I found this on Dax website. It says TITAN Jack Shaft Drive Sprocket 1/2in Fits
R1-R3 Titan Jack Shafts. New Style Milled one
piece. Only $9.99

I wonder if this means it fits on the friction drive shaft instead of the roller.

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Sorry if I have confused. This entire thread I have been theorizing of the build with the motor and freewheel on the Left side of bicycle, with freewheel hub in front of motor.

I have very little money and my wife is The Boss right now, so I can't do the 7 speed right now, but it is a challenge for later.

I am just collecting ideas for someone who wants to build this. I would like to, but I can't buy these things right now. It is a challenge I would like to take later when I have optional cash to spend on it.

I think the IGH idea is good so I would run with that first because it looks like it would be much easier to do using the existing Dax kit I already have without complicating the brackets a whole lot.

It would give a perfect platform to test the utility of multi-speed roller gear, and the chain would be enclosed under the bracket.

If someone had one of the old style rectangle shaped Dax/Staton brackets it would give even more room for hub roller mounting because the forward corners wouldn't be sawn off.

So you have flipped the hub to drive from the left as viewed from behind? I can see with an IGH its no problem on a short chain/belt. You bailing on the derail idea?

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

For fun, 2 speed electric roller drive, shop built, with remote disengagment! Advanced Friction Drive.mp4 - YouTube

 

[happyvalley]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Reply to HappyValley. This isn't as complicated as you make it to be. It will only require one cable for the derailleur, and even low end/salvage components will work fine, like a thumbie shifter and a $5 shimano mech.

The point is that it IS a friction drive. I like friction drives. It avoids rag joints or sprocket adapters, or front freewheel systems, etc. If built well it would be just as interchangeable between bikes as any other friction drive. Also, for someone who wants to retain the intact pedal system and drag-free pedaling with the motor off or downhill (unlike the happytimes), this is a good system.

Regarding tire wear etc. I get my tires for $10 so I don't care. I can run them smooth and use them on the front a while longer for even more savings. Tires are cheap.

The main advantage to this (the reason for bothering to design it) is it will be a friction drive (fun!) with multiple gears and a HUGE gear range for maximizing the abilities of small engines. You will be able to easily climb steep grades, "overdrive" the engine to lower RPM at cruising, and shift while maxing out your engine if you want to accelerate quickly or reach top speed.

Hey no problem, in the end the only person that needs to be convinced of an idea is you, lol. In your sig it says you just got the friction drive so go for it. I've logged over 12K miles during the last 4 seasons and many of those on fd. I like them for some uses so it's not a debate on that but they have limitations and exactly why fd occupies a niche. For reasons I've already mentioned or for jumping on a bike for local runs or errands they are good. For longer trips or touring there are better alternatives and those are definitely not limited to HTs, rag joints or non freewheelers, which I've never owned. To each their own but IMO (and I'd say my 2 cents but I know it will cost more, lol) for the time and expense needed for multi speeds I'd rather have the efficiencies inherent in a system with more positive engagement. Good luck though and good riding to ya.

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Yes, I am friendly to you, HappyValley. I think this is going to rock. Fd has enough engagement for me, and I think the coated roller and low gears will help too with engines that have narrow powerbands. This is all just bench racing right now, but who knows, might find a junk bike with a SA 3spd sometime and satisfy my curiosity, or someone might have the compulsion to chop up an old friction channel and make the 7 speed.

If someone cut off a friction channel right in front of the motor mount area, that would give the "guts" of the system, and it could be positioned sort of like a GEBE kit or one of Low-racers engine brackets. If just the side of the channel was hacked off from the motor forward, a short u-bracket could be bolted to the top of it, upside down, and be perfect for a standard mtb hub and axle-mount rear derailer. With a tire narrow enough to fit on the hub, it should work. I just can't spend money on "should work" right now.

I like this website for all the tinkering and home-building spirit though. Maybe it will happen sometime.

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

I got out the spare Dax parts like the short u bracket, and a tape measure. I figured out that the derailer system will not be able to work with a derailer hub and the dax channel, because of the chainline (unless a LOT of metal was cut off the side. There is just not enough room in there, esp with a 26" 1.5 + tire.

I looked at the Sturmey 3 speed hub ($70 new ouch). It has a pretty large (2" ? barrel, and 18 tooth driver.

If you ran the driver cog (10 tooth?) as far left as you could, near the bearing, you might be able to do something with flat-bar brackets to position it under the driveshaft or close, and be able to run the chain without interfering with the tire or motor mount bolts. The gears on the 3 speed run 75%, direct drive, and 133%. That ought to do well, esp when the hub will be rotating so fast in relation to the tire.

Sturmey Archer S30 3-Speed Internal Hub - 36h, 18T Cog, No Brake




Click to enlarge
Includes shifter, cable, and mounting hardware
177% gear range
Axle length is 175mm
Sturmey-Archer S30 3-speed hub includes shifter, cable and mounting hardware.


Sturmey-Archer S30 3-speed hub includes shifter, cable and mounting hardware.
Axle length: 162.7mm
Hub Shell Material - 6061 Aluminum
Axle Diameter - 13/32" Slotted
Axle Length - 175mm
Over Locknut Dimension - 127mm
Spoke Holes - 36
Spoke Compatibility - 13g or 14g
Sprocket Teeth - 13T through 22T
Weight - 1050g
Overall Range - 177%
Gear 1 - 0.75 (-25.0%)
Gear 2 - 1.00 (Direct Drive)
Gear 3 - 1.33 (+33.3%)
Includes 18-tooth cog
Axle length: 162.7mm
177% gear range
Axle length: 175mm
Item Specifications
Color Silver
Weight 1300g
Intended Use Road
Hub Drilling 36spokes
Rear Axle Type 13/32"
Cassette Body Type Single Cog Driver
Hub/Brake Compatibility Rim Brake
Rear Hub Spacing 127mm
Skewer Included NA, Bolt-On

$69.89

 

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

If I have done my calculations right, using 7500rpm as an average, and a reduction of 1.8, the top speeds should be in mph, 18.6/low, 24.8/direct, 33/ high. should climb pretty well in low. This is almost exactly the top speed I have with a direct drive 2.1 roller and 2.5hp. It would be even faster if the engine turns more. To obtain these speeds with direct drive it would require 3 rollers, a 1.6, a 1.8, and the 2.1. Thats pretty cool, all with the click of a lever!

 

[silverbear]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

I've been thinking about the vintage 3 speed Sturmey Archer hub as a drive roller and wondering about what kind of power plant options there might be. Would this work using the hub driven by an in frame Happy Time motor? I'm wondering if the engine were mounted in frame normally and the hub was mounted low on the frame behind the seat tube... could that be made to work? I know so little about this and am no mechanic, but if there was a way to use a simple HT motor with the manual clutch, a freebie 3 speed as the hub and capable of three gear ranges... it seems almost like a dream come true. Maybe I'm not understanding how things work... the hub is reversed so that the sprocket is on the engine side and somehow the sprocket of enough diameter has to be mounted to the hub (how to do that, I don't know) and the direction of the roller turning against the tire propels the bike forward. I'm not seeing this very clearly... is this right, is this possible? Before this thread I had thought that a jack shaft was necessary and am trying to wrap me little brain around the hub used in this way. If it isn't workable, then I need to stop thinking along this line, so please correct me. Thanks!
SB

 

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Sound feasible. What needs consideration with an HT engine is the final reduction, It just might be low enough to drive the small sprocket normally found on the 3spd hub. Any one know the final reduction?

 

[cannonball2]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

In its normal mount position the HT truns the wrong way, turned around and mounted from the rear would work(drive on the right side of the bike).

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

HT's are heavy though! You would have to have it mounted so far left it would fight with you going down the road.
Plus, it would require a pull starter.


Yes, the plan is to use a weeder motor in the back, to turn a bicycle hub in the middle. The hub will be going opposite the rear tire direction, as it will be used as a friction drive roller.

In the thread this branched from, I was discussing making home-made rollers, 2 pieces that clamshell together with 4 bolts, which would pinch over the 1" standard roller. So in just a couple minutes you could add the new roller and double your top speed, but still have a 1" roller mounted on the fric drive kit.

 

[silverbear]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

In its normal mount position the HT truns the wrong way, turned around and mounted from the rear would work(drive on the right side of the bike).

What if the HT was in frame, but reversed? I like the look of an engine in the frame, can't help it. So, the carb would be in front and the exhaust coming out the back. I don't think the HT is all that heavy and has pretty good power for it's size. I like that it has a built in clutch. Could it work that way? Would the 3 speed hub need to be the free wheel type or could it be the coaster brake type as well? As long as we're thinking outside of the box, might as well consider things in backwards land, too.
SB

 

[happycheapskate]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

The coaster brake type could work but the coaster brake shoes need to be removed as there is no way to activate the coaster brake for any use and the shoes could drag and create unnecessary friction.

There is no way to use the HT in frame with this design, unless you can operate the engine rotating the abnormal direction .

Perhaps an HT could be used to belt-drive a whizzer type sheave or something though. I have always wondered why there were no HT belt drives.

 

[bowljoman]

Re: Insane 7 speed friction roller drive with common engines (tanaka, pocketbike, etc

Been there done that.... Not worth it.

You want reliable? Start with a 49cc scooter motor.
1) Chain only. 2) internal gear hub as jack shaft, 3) 5-to 1 reducer tranny w/ 12 tooth 410 sprocket on the motor 4) Run kmc510 chain.

I can boast several hundred miles without a single adjustment and 30-40+ cruise speeds. WIth the multi speed jack shaft, it slipped exponentially just as the wind resistance increased. The only rubber I found to survive high power is stainless steel braided hose. Bare metal roller was better just because it didnt melt after 100 miles.