LMX P2 : Freeride trials motorcycle frame development

I made this for my disk side sprocket adapter. It drives off of the star pattern because I don't like using the bolts as pins and was uneasy about the friction being enough to hold it. Its about a .003 slip fit over the hub star. Then I preloaded it against the "teeth" by twisting it CCW before tightening the bolts so it wouldn't wiggle under load. No regen or back load so it should stay loaded against the star keeping the bolts totally out of the torque equation. The real advantage was that the flange the bolts go through was super thin to get me maximum brake caliper clearance. If the flange were driving i would have needed to make it thicker to feel safe. This would be a hassle to machine for unique hubs but if you decide on a standard hub they should all be the close enough to standardize your adapter. Now If I could only find the time to finish the bike I could report on how it works. :oops:

sprock adpt.jpg
 
yes, it would be nice to not have motor cogging when off throttle, etc..
of course you could always just remove the motor chain if the battery is run flat, etc..
but maybe have the option to shift the motor chain off cog at the front motor cog? :idea: ..
(in case no commercially available freewheels are up to the task of motor power?)

Drum said:
Hi Adam, I've been watching progress on this project with considerable interest.. I think you have come up with an overall concept that is close to ideal.

I would support moving the motor chain to the left and leaving the full range of pedal-powered gearing available on the right hand side. One thing to consider though: If using the same bolts to mount both the sprocket adapter and the brake disc, the "drive" would sometimes be forward (under power) and sometimes backward (under braking). If there was any play in the mounting bolts this could quickly lead to wear. The disc and adapter should be a snug fit and the bolts should have plain (not threaded) surface where they pass through the sprocket and disc. Use high quality fasteners and loctite!

With the direct single reduction from the motor to the back wheel, it is an ideal setup for using regenerative braking. However if you had to pedal home with a flat battery you would definitely want a freewheel or disconnect in the system to allow pedaling without spinning the motor.
I wonder if there is a lockable freewheel available? I have never seen one. It would be an interesting design exercise!

Seat mounting position etc can easily be modified after experience with riding the prototype.

Like so many others, I am eagerly awaiting video....

Regards,
Dave
Click to expand...
 
M5 bolt, strength category 8.8 does 4kN preload force (VDI2230 table A7). Lets say 2000 N to be sure. 6x 2kN = 12kN.

Lets use a friction coefficient of 0.6 for aluminium/steel pairing
Maximum tangential force is 0.6 * 12 kN = 7.2 kN

At a diameter of 44mm this is 7.2 kN * 44 mm /2 = 158.4 Nm for our common 6-bolt 44mm BCD disc brake flange

Ok, this was no real calc but just guesswork, but you get the idea. Should hold up well for our needs

Edit: Shimano states a 4.5 to 6 Nm fastening torque for these bolts. according to http://www.schrauben-normen.de/anziehmomente.html
this leads to a preload force of ~6 kN. Lets calc with 4.5 kN to be sure. So end up at 356.4 Nm more than enough
 
Hi Dan,
I really like your adapter to make use of the outer shape of the disc flange as a "driving spline", and taking the torque load off the bolts.
Even without access to CNC machining to get the interior profile of the adapter perfectly symmetrical, it would be possible to roughly machine the pocket slightly oversize, coat the hub flange with release agent and bolt the adapter on with some high strength engineering epoxy filling the gap. Once the epoxy set you would have a perfect mating spline in the adapter.

Thanks Crossbreak, your calcs have made me feel a bit better about bolting the sprocket adapter to the disc flange of the rear hub on my bike.. (although Dan has got me thinking of ways to adapt his idea to my back hub.....)
Dave
 
freewheel lock
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=54599

to lock a freewheel, you just have to add a dog clutch on the same shaft. Pretty easy task (if packaging was no concern). The dog clutch could be moved by remote. Just like in an internal gear hub.
 
We'll leave freewheel lock out for now but it is indeed an interesting thing to work on! but it would have to be a rear freewheel most likely for torque levels we are working on, or a custom front freewheel attachement (but then the motor chain would still drag)
here is the teaser for the new bike :
[youtube]A80rL95_Npc[/youtube]
 
Its looking really good Adam. Well done son!

Still prefer your pedal-less bike but I can understand, function over form sometimes =)
 
Thanks for the comments guys, there won't be a moto option on this frame because it would make no sens compared to the P2 witch are way more suited to ride with high power, footpegs and moto seat anyway.
 
maybe Pablo can help?? .. http://endless-sphere.com/forums/viewtopic.php?f=31&t=67694

bzhwindtalker said:
We'll leave freewheel lock out for now but it is indeed an interesting thing to work on! but it would have to be a rear freewheel most likely for torque levels we are working on, or a custom front freewheel attachment (but then the motor chain would still drag)

here is the teaser for the new bike :
[youtube]A80rL95_Npc[/youtube]
Click to expand...
 
Well shoot,if Adam and friend(s) are able to make such a great e-bike given their youngish ages,think what they will achieve down the road!

Great work!


Tim
 
Thanks, Tim, we are in constant improvement and things have been moving fast since I started working with Lucas!

On another note, we are now online here :

www.lmxbikes.com

If you are interested to buy a frame from us, you will find a form on the website, filling it is the best way to get on the wait list ;)
 
Happy to see you are building your brand outside Facebook now. Think about it - even how mainstream face is these days about half the people do not have/use facebook. Brands must be build outside FB as well. *two thumbs up*.
 
that is sweet!
 
FelixSphere said:
Just finished this one :)
Click to expand...

congrates on this fantastic frame. having the motor in the pivot point is really nice.
you should start a thread about it with details about motor and other electronic components. i think doing so would be easier for you because you will get lots of questions about it :)
 
Wow that frame is sweet. Any more details on this build?
 
Yep,
motor is a revolt 100 pro with halls, battery is 4 times 18.5V 12000mAh, kelly kbx with 130A max. Frame is a prototype made of steel, carbon in progress. Suspension is a progressive link system with 230mm and a boxxer up front. motor is mounted in the swing arm pivot. Chain is a 219 kart one with 12/72. Rear hub and motor cage (front) are cnc'd to take the sprocket mount. Current weight is 39kg, with the carbon one it should become slightly under 30kg (steel one = 15kg currently ... :-( ). The Kelly is optimized with BT and communicates to an Iphone app for activation, logging and settings. We will test the bike over the next weeks and post our results.
Let us know your thought's guys ! :D
 
FelixSphere said:
The Kelly is optimized with BT and communicates to an Iphone app for activation, logging and settings.
Click to expand...
sounds awesome. is this something custom made or available from kelly?
 
Nice design Felix. Looks similar to the LMX2. Could you please make a new thread about your bike with more pics and info? And please post a link here. I'm keen to know more about your linkage and Iphone->BT->Kelly interface. I like you swing arm for looking so straight and simple.
 
Nice work felix, im also very keen on the kelly bluetooth work you did! There are very cheap android devices around, what information exactly can you get from the kelly?
 
Did similar interface for kelly serial a while ago. You can get almost everything from Kelly via some undocumented commands: Battery and phase currents, voltages, RPM, FET and motor temps. And program every parameter that can be programmed by Kelly software.
I am planning to use my old galaxy phone as a dedicated dashboard since it has a beautifull high contrast AMOLED screen.
In proggress of programming a dashboard app for my new 10kW Kelly.
 
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