Hillhaters Mk 3 Friction drive !

[Hillhater]

Whilst trying to distract myself from the "Sync" issues with the ESC, ..and waiting for new parts to try, i devised a Mk 2/3 b drive arrangement.
Still keeping to Keplers original "pivot" concept i stumbled across another way of mounting the drive using readily available parts.
A "recycled" head stem and a few alloy off cuts, and bearings had this rigged in a day or so.
ESC is attached (temp) to the seat post, battery's etc in a saddle bag.
Trickiest part was fitting the pivot bearings (bushes actually) in the "crossmount" tube.
I still have to install a "motion damper" and travel stop, but that is in hand.

At least this may give other DIY builders another option for mounting systems
This is much more rigid and elegant than the seat post rack on my "Mk 1"

 

[EVTodd]

Now that's a good freakin' idea! It's adjustable too! I like it.

I have a couple a spare stems sitting around here too. Hmmmm

 

[kevo]

Brilliant, looking forward to hearing how it works out but appears an excellent starting platform!

 

[Kepler]

Nice!!! Good use of off the shelf parts. I look forward to seeing how you setup the pivot stop and damper.

 

[Hillhater]

I have a couple a spare stems sitting around here too. Hmmmm

Stems seem to come in every size, length, angle, tube fitting, etc ..... that you can imagine. ! .. so chose carefully.
I just struck lucky with the odd ones lying about in the LBS.

 

[AussieJester]

Excellent use of re-purposing there! To make this idea even more 'adaptable'
to variety of bikes you could use one of the many adjustable stems such as :-

http://www.chainreactioncycles.com/Models.aspx?ModelID=39260

Look forward to hearing how it works out, Kepler seems to have sparked a new
interests in friction drives, definitely some nice looking DIY variants popping up lately
nice and light, cheap and very usable for on road commuting even in wet weather!

KiM

 

[Hillhater]

To make this idea even more 'adaptable'
to variety of bikes you could use one of the many adjustable stems such as :-

http://www.chainreactioncycles.com/Models.aspx?ModelID=39260

Damm Kim, !! I wish i had come across that in the LBS, . It would be ideal for testing with on different bikes, though i think the solid item is best for rigidity in the final set up.
These stems could be useful even if you dont use the "Bar tube" for a pivot mount. The mount has some nice solid threaded flange faces that could be used for attaching many different drive units.

 

[amberwolf]

Now THAT is nifty repurposing.

EDIT: as a matter of fact, it gives me an idea about redoing DayGlo Avenger's old v2.0.2 friction drive using the radiator fan motors, which I have wanted to get back to while using a planetary reduction on it, but didn't want to do the rack panel mounting I had before. Now maybe.... Time for a new thread if I get time.

 

[spinningmagnets]

Fantastic! But the biggest problem I see with this set-up is that...now I have to throw out everything I've done, and start all over from scratch!

Brilliant suggestion AJ, with the adjustable stem! I think that will be just the ticket to several builds that are simmering on the stove around here. Even though this configuration clearly uses re-purposed items, its so good-looking I don't see any need to cover it up with saddle-bags, like I had planned to with my hack-sawed aluminum bits that are clearly garage-made.

edit: here is a couple of sources from many, for $7 seat-post shims (split-tube adapter sleeves)

http://problemsolversbike.com/index.php/products/seatpost_shims
http://www.niagaracycle.com/index.php?cPath=108_188
http://www.niagaracycle.com/product_info.php?products_id=5339 (1.0" - 1-1/8")
http://www.nashbar.com/bikes/Product_10053_10052_175458_-1_201521_10000_200463

 

[drifter]

Brilliant idea Hillhater, I just happen to have a spare stem on hand at the moment . And like Spinner I might have to ditch my version and build one too.
Spinner, you always come up with very good links.

 

[etard]

Awesome drive Hillhater!! I had been toting with that a while back when I noticed the size of my seatpost was the same size as my stem, but I couldn't figure out how to do make it adjustable on the fly. The Kepler drive has reopened this route in my mind, and you have shown it to be sooo freakin easy. It looks great too, like everything belongs to each other. As far as the padded stop, I wonder if you couldn't drill two holes in the stem to mount something off of, it should still be plenty strong enough for the drive.

 

[drifter]

I just discovered that cheap skateboard bearings will fit nicely into 27mm seatpost tube.

 

[amberwolf]

Just do NOT squeeze those bearings at all--the races deform VERY easily. Those are what I used on Crazybike2's steering tie rod at first, and regretted it several times
(like here: http://electricle.blogspot.com/2009/03/fairing-concepts-second-steering.html )
before I replaced them with good ones out of a junk skateboard. Even though the bearings from the skateboard were a bit rusty, they were WAY better than the brand-new crappy ones from the skates.

http://electricle.blogspot.com/2009/04/uphill-downhill-skateboards-and.html

 

[TylerDurden]

+1

Those aren't bearings, they're placeholders to illustrate where to put real ones.

 

[silence]

Hello to everyone!
Great forum,brilliant ideas.

Maybe a noobish advice,but...
Instead of roller bearings, why not to use car suspension part (Ithink it's called silent block - something like this).
Should act as some kind of "motion damper" too, perhaps?

Excuse my bad English

 

[etard]

Welcome to the forum Silence!

That picture looks to be of a car bushing, that would probably work great for the Kepler swing pivot if kept lubed up. The dampener missing from Hillhater's drive is one that stops the motor from forward motion, similar to a door stop, to keep it from hitting the wall, which gives me an idea! What about an RC car tire? You could even use the suspension coil for additional padding if the tire doesn't provide enough "cush". Might be able to run it directly into the can on the motor, would probably wear out quick that way though.

 

[silence]

Hi etard!

that would probably work great for the Kepler swing pivot if kept lubed up.

Actually i meant using this kind of bushing without any lube.
Outer metal part secured into the stem and inner one between the side plates, so the only travel would be the deformation of rubber, like it works on it's original place - under a car.

 

[etard]

The Kepler drive style requires a good bit of movement to work. When off, the motor rests detached from the tire, when you throttle the motor on, the centrifugal force swings the motor into the tire where the frictional forces of te motor spinning takes over to rotate the tire.
Perhaps I should Wiki that part, does it have an internal stop that keeps it from rotating past a certain point? Is this what you are saying? If so, I think that is an excellent idea. It would keep the drive looking very minimal and clean, just the way it is.

 

[spinningmagnets]

Here's 38 pages of stem choices, thanks again for the idea Hillhater. And AJ, I didn't even know adjustable-angles were available! Also a direct link to a $17 adjustable-angle unit:

(EDIT: Here is the adjustable-angle stem I chose http://endless-sphere.com/forums/viewtopic.php?f=28&t=21365&start=60#p324661 )

http://www.niagaracycle.com/index.php?cPath=129&sort=2a&page=2
http://www.niagaracycle.com/product_info.php?products_id=433729
http://www.jensonusa.com/store/sub/147-Stems.aspx
http://www.sheldonbrown.com/gloss_st-z.html#stem proper "stem" terminology from bicycle guru Sheldon Brown (RIP)

DJ, DH, and BMX fixed stems can be very strong and short. They are available with zero rise like this, so you can reverse them if it helps your particular application. LIKE THIS: (thanks, Gwy!) http://endless-sphere.com/forums/viewtopic.php?f=28&t=22245

I have scanned through the Niagra bike site, and have listed the available dimensions and ID's of adjustable-angle stems here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=21365&start=45#p318293

 

[veloman]

I like it a lot. Being able to easily adjust height and alignment is very valuable.

 

[EVTodd]

I have around 50 clamp on BMX stems from back when I was designing racing parts. They're REALLY strong and beefy. I've been hoping to find a new use for them some day. Maybe I'll try to match one up to my sliding mechanism.

 

[drifter]

I didn't say the cheap skateboard bearings were any good, I just said they fit. Anyway I think they will be good enough for this purpose, they don't have to do much work and if they give me trouble, I will give them the flick, like my first wife.

 

[sharp21]

Forgive the noob question...

From the pictures it looks like the motor casing itself is what rests on the wheel? So you have the motor's internals mounted up solid & the casing spins around that?

Is that a specific motor design, that turns the whole unit instead of just a shaft?

S.

 

[Hillhater]

Forgive the noob question...

From the pictures it looks like the motor casing itself is what rests on the wheel? So you have the motor's internals mounted up solid & the casing spins around that?

Is that a specific motor design, that turns the whole unit instead of just a shaft?

S.

Yes, its termed an "Outrunner" design motor.
It is built with the magnets in the outer casing , with the coil windings on the "stator" in the centre.
Note, both the outer casing, one end bell , and the shaft rotate together with the other end bell being the fixed mounting face.

 

[sharp21]

Thanks for the clarification. I really like your design!

So will it ride on the tire all the time, or will it sit just off then "snap" onto it when you roll on the power? I'd like to build something very similar...

S.