dan974
1 kW
Light Mx project 2 / breizh
Proud of is celtic origins
certainly
Proud of is celtic origins
certainly
LMX P2 : Freeride trials motorcycle frame development
- Thread starter bzhwindtalker
- Start date
bzhwindtalker
100 kW
Yep Dan, proud representative of my land so that's what Bzh stands for.
Now the LMX thing stands for Lightweight MX , and that's what I have been trying to create for some time now. With the p2 I finally have a bike that is reliable, super agile and has tons of power reserve when you need it. I need to weigth the bike but I would guess sub 35kg based on the p1 that was 38kg.
The motor is pretty much stock, I will de-tune the power down to 80-100A peak on 18s to see if it handles this kind of power stock, as now with 160A peak it heats up a lot
so that's what Bzh stands for.Now the LMX thing stands for Lightweight MX , and that's what I have been trying to create for some time now. With the p2 I finally have a bike that is reliable, super agile and has tons of power reserve when you need it. I need to weigth the bike but I would guess sub 35kg based on the p1 that was 38kg.
The motor is pretty much stock, I will de-tune the power down to 80-100A peak on 18s to see if it handles this kind of power stock, as now with 160A peak it heats up a lot
bzhwindtalker
100 kW
Oh and for those not following the whole ES facebook thing, I now have a facebook page for the LMX bikes. We are gonna produce a first batch of 5 frames in July. I released for free the full components list too!
www.facebook.com/LMXbikes
www.facebook.com/LMXbikes
crossbreak
1 MW
chromo and mild steel have the same Elastic modulus...like all kinds of steel. So stiffness is the same.Tench said:
standfast
100 W
Tench said:
Machining/welding of annealed 4130 tubing is a bit different that a heat treated crash structure component on a modern car. That component of a unibody is difficult to cut for reasons that do not apply to the frame material being used on most bicycles. The crash beam and various other components are often work hardened, precipitation hardened, grain refined and various other methods of post processing to get their strength levels up.
I do agree that the frame material on a bike like this could likely just be a common 1020 DOM tubing or similar with not much difference since like you said the strength is in design. One big reason comes down to welding. When welding 4130 tubing you contend with the heat affected zone (HAZ) and it's tendency to make that area more brittle and the most likely place for the frame to crack. (right next to the weld) This is why you often see 4130 tubing TIG welded and not MIG welded on race car chassis, to minimize the HAZ by having better control over the heat. While this phenomenon affects lower yield strength materials like 1020 steel, it is not quite as significant. In terms of the general characteristics of 4130, it is a spring like material that will deform to a certain point and then just often fail by cracking. Lower grades of tubing like 1020 tend to fail by just bending until they kink assuming the HAZ of the adjacent weld is not the weakest point, whereas it would just crack there. Tench, you probably know most of this based on your aforementioned experiences but I figured it was worth pointing out.
BHZ,
I am very curious about the weight of your bike as well. 35kg is pretty light. That is with 20s 10ah right? I hope you get your battery soon, your videos are great motivation! I am also curious to see how you feel about the performance at 80-100A.
- Joined
- Feb 15, 2013
- Messages
- 1,903
the motor is from BHT DIFFUSION..
some links.. :
http://e-bike-diffusion.com/index.php?module=produit&prd_id=509&url_retour=http%253A%252F%252Fe-bike-diffusion.com%253A80%252Findex.php%253Fmodule%253Dcategorie%2526code_cat%253D24%2526page_start_num%253D1
BIG BLOCK alternative Motor: http://endless-sphere.com/forums/viewtopic.php?f=28&t=57483
LMX P2 parts list :
https://docs.google.com/document/d/1HvyRf5MLtyk07X27AzLQFBiXJ7qJ2ln5E-yve5lAJiQ/edit?pli=1
i think the seat sub frame was custom made not purchased (could be wrong??)
pedals in place of foot pegs feels great for free-riding etc.. allows body position & foot rotation while maintaining feet flat on pedals at different angles instead of uneven feet on stationary pegs when doing wheelies, getting off the back on descents etc.. SEV eTricks also uses pedal pegs so there is the precedence..
some links.. :
http://e-bike-diffusion.com/index.php?module=produit&prd_id=509&url_retour=http%253A%252F%252Fe-bike-diffusion.com%253A80%252Findex.php%253Fmodule%253Dcategorie%2526code_cat%253D24%2526page_start_num%253D1
BIG BLOCK alternative Motor: http://endless-sphere.com/forums/viewtopic.php?f=28&t=57483
LMX P2 parts list :
https://docs.google.com/document/d/1HvyRf5MLtyk07X27AzLQFBiXJ7qJ2ln5E-yve5lAJiQ/edit?pli=1
i think the seat sub frame was custom made not purchased (could be wrong??)
pedals in place of foot pegs feels great for free-riding etc.. allows body position & foot rotation while maintaining feet flat on pedals at different angles instead of uneven feet on stationary pegs when doing wheelies, getting off the back on descents etc.. SEV eTricks also uses pedal pegs so there is the precedence..
GCinDC said:
bzhwindtalker
100 kW
Thanks for the links and heads ups on the rear subframe that I forgot to include in the part list!
I finnaly managed to reprogram the controler with my cheap dongle! Not a stable connection but it kinda works. The throttle response is now much better!
Some clean pics :
I finnaly managed to reprogram the controler with my cheap dongle! Not a stable connection but it kinda works. The throttle response is now much better!
Some clean pics :
i very like the frame and the Big Block mid drive.
do you have plans to improve the chainline or do you leave it as it is?
imho a bigger front and rear sprocket would lower the chain noise and improve a bit efficiency (less rubbing against the plastic part above the swingarm bearing).
with a very big rear sprocket (1:10 reduction) and higher voltage the power would be crazy
, but forced motor air cooling would be necessary i guess..
you did a good job. thumbs up for this build!
do you have plans to improve the chainline or do you leave it as it is?
imho a bigger front and rear sprocket would lower the chain noise and improve a bit efficiency (less rubbing against the plastic part above the swingarm bearing).
with a very big rear sprocket (1:10 reduction) and higher voltage the power would be crazy
, but forced motor air cooling would be necessary i guess..you did a good job. thumbs up for this build!
skeetab5780
1 MW
madin88 said:i very like the frame and the Big Block mid drive.
do you have plans to improve the chainline or do you leave it as it is?
imho a bigger front and rear sprocket would lower the chain noise and improve a bit efficiency (less rubbing against the plastic part above the swingarm bearing).
with a very big rear sprocket (1:10 reduction) and higher voltage the power would be crazy
you did a good job. thumbs up for this build!
with a SS 1:10 reduction wouldn't he need to run about 40S (168vdc) lithium to get only 35mph...or am I thinking of something different
~also curious if larger sprockets will cause chainline/swingarm interference
skeetab5780 said:
you right, maybe 1:10 is a bit too torquey :lol: this would ba an option for the higher speed Big Block motor.
indeed there semms to be not much space for bigger sprockets. the chain will rub against the swingarm. imho bigger sprockets are less noisy (especially on the motor side).
bzhwindtalker
100 kW
New video, Still on 12S, (shipping issues with new battery)
Enjoy
[youtube]liBSTavzhjM[/youtube]
Enjoy
[youtube]liBSTavzhjM[/youtube]
r3volved
100 kW
Nice one! You got some wicked music choices in your video. Found and liked your LMX Bikes on FB too!
Looks like you get a lot of gawkers hanging around eyeballing your tricks. Any run-ins with Johnny law?
Looks like you get a lot of gawkers hanging around eyeballing your tricks. Any run-ins with Johnny law?
bzhwindtalker
100 kW
I weighed the full complete bike at 32kg! This is with only 12s but 18s should add less than 2kg so my goal of minus 35kg is well reached
bzhwindtalker
100 kW
As far as jhonny law, the campus is private land and I'm in good terms with the security guys
bzhwindtalker
100 kW
I received my 18s lipo batt, things will get really interesting now
bzhwindtalker
100 kW
New 18s battery testing :
The good :
Super cheap
10Ah cells in 6s packs makes wiring easy
Quite compact
Seems to do high peaks no problem without heating
The bad :
12 awg pack leads
Shipping was terrible (they have been working on improving this says the seller)
Quite a lot of sag (0.55v per cell at 12C at 75% SOC)
The cells leads are super fine and blow under high amps ( 160A made two connections blow) They also may be subject to mechanical fatique, there is no PCB.
So far I think those packs would be a good option for 12s 10AH for exemple on a GNG with 45A peak
On 18s the bike is stupidly powerful
Some pics :
Peak before blowing :
Peak while accelerating on level ground :
The good :
Super cheap
10Ah cells in 6s packs makes wiring easy
Quite compact
Seems to do high peaks no problem without heating
The bad :
12 awg pack leads
Shipping was terrible (they have been working on improving this says the seller)
Quite a lot of sag (0.55v per cell at 12C at 75% SOC)
The cells leads are super fine and blow under high amps ( 160A made two connections blow) They also may be subject to mechanical fatique, there is no PCB.
So far I think those packs would be a good option for 12s 10AH for exemple on a GNG with 45A peak
On 18s the bike is stupidly powerful
Some pics :
Peak before blowing :
Peak while accelerating on level ground :
r3volved
100 kW
That's a nice modular pack design!
I always show off the LMX to people here trying to explain the difference between what they view as an ebike (scooter) to what I view as an ebike (LMX)...people are loving the design. Tons of potential...with no peddles, it nearly fits into the limited motorcycle class in Ontario. Just needs some compliance mods (lights/plate/mirrors/etc)
I always show off the LMX to people here trying to explain the difference between what they view as an ebike (scooter) to what I view as an ebike (LMX)...people are loving the design. Tons of potential...with no peddles, it nearly fits into the limited motorcycle class in Ontario. Just needs some compliance mods (lights/plate/mirrors/etc)
Nice figures Adam, I can imagine how that power feels in such a light bike! The max amps and low volts will coincide so multiplying them will give the Watts power, it equates to about 9bhp on the flat and 12bhp under your max load conditions!
Watts/3 x 4 = bhp
Watts/3 x 4 = bhp
bzhwindtalker
100 kW
Thanks guys I would really like to put the bike on a dyno to know the actual wheel hp and do some proper optimization!
I would really like to put the bike on a dyno to know the actual wheel hp and do some proper optimization!
SolarRay
100 mW
bzhwindtalker
Good ebike.
Sprockets 13 65 #219?
Good ebike.
Sprockets 13 65 #219?
bzhwindtalker
100 kW
Thanks it's 13-60 yes #219
it's 13-60 yes #219
standfast
100 W
Where did you get the 13t #219?
bzhwindtalker
100 kW
It is a "rotax" karting gear from ebay
bzhwindtalker
100 kW
The tubing and welding supplies are ordered! Big order...
