build blog->fully aluminium trail/freeride BHT Frame

jackjetful

jackjetful

100 W
Joined
Feb 15, 2013
Messages
158
latest pic____________________________________________
IMG_9682 (2).jpg
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Hello guys its been a while scince my last post
This build thread should describe my latest build; all the improvements i wanted to make on my old frame and all I've learned from my last homemade frame

To make it short :) :
This was my last and first frame built:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=50819
https://www.youtube.com/watch?v=N6I05G5x81Q

Had a lot of fun building, and also riding it. Final setup was:
- Kelly KBS 4805
- 9C Motor 2kw
- 48V 10Ah LifePo4

Issues with this bike:
- high weight (steel frame)
- bicycle parts such as rear derrailleur and chain broke under full load!
- high center of gravity

I bought a BHT big block a year ago and wanted to eqip my frame with this motor
______________________________________________________________________________

-> decided to build a complete new frame:
-> fully aluminium
-> BHT motor on swingarm
-> low center of gravity
-> made the first sketch:
Image.jpg

-> 3D CAD modelling over two years now ---> came to this results:
[/attachment]V11.PNGV11_3.PNGView attachment 5

-> built a CNC plasma cutter (2x1m) :D
1548074_853125008083385_1607369793146818412_o.jpg

-> bought 6mm Aluminium (Al Mg 4,5 Mn) -> plasma cutted forst parts:
IMG_7844.JPG
View attachment 3

---->> welding is almost done .... more pics will follow soon
 
Commendable steel build and presentation!!!!!

'bht' caught my attention, as I think it holds great promise.

What wheelbase are you going for in the new frame?
(I'm currently trying to mod my bike from 39" to 45")

Did you work a proposed current for the motor and a reduction yet?
(I'm planning 44- 66v ~60a, 1:5.4 to 26")

Have you worked out a right side dual freewheel hub?
(I have gone with an xt hub modded with a freewheel hub to thread on motor drive freewheel, and then 6,7,8sp freewheel threads to that.)

Chain?
(I went with #35 for it's commonality and strength)

BB?
(I found I needed to get a 73/145 extended bb if I wanted the motor anywhere near the pedals- should have about 6.5" between the pedals with std 1" offset cranks- I also may have to omit the front derailer)

Have fun with the build!!
 
Schoenes build und Video! Sollen das BHT benutzen, wie LMX hat. War das Video mit einem/n/r Gimbal gemacht?
 
Yeah plasma cutter is working great ... the 6mm Aluminium plates will be quite solid!! ... I designed all the plates of the frame to fit inside notches in the side plates. So welding will be a lot easier. And it gives extra strenghth!
It is not really lightweight; because of thie solid frame; depends on the battery. But i wish to have around 30kg! :D
2.jpg
What wheelbase are you going for in the new frame?
Click to expand...

Wheelbase is very short. Evrithing is designed to be really compact which makes the wheelbase around 1000mm ... with my RockShox Domain RC 180 it is 1100mm.


Did you work a proposed current for the motor and a reduction yet?
Click to expand...
I will use a Kelly KBS72121X .. at around 50A ... bought 20S headway... fit insede the frame!

Have you worked out a right side dual freewheel hub?
Click to expand...
Chain?
Click to expand...

I use normal freewheel hub ... but solid one from brave machine with 219 Go Kart cahin!
View attachment 1
My BB is around 160mm (~6.5")? .... i made my one tool to cut the BSA thread!
 
awesome project! looking forward for the finished bike :)
 
Thanks for answering my queries!

I would love more details on the hub at a later date- I think mine could be improved.

Currently I am fighting with a different way of mounting the motor and routing chainlines-

Making a frame from scratch must be so rewarding!!!

That is good engineering to keep the wheelbase smaller- I think yours will be the first custom frame with single reduction bht while keeping the pedals?

Thanks again, have fun!!
 
it looks awesome. congrates!
can the motor be removed or is it welded to the swingarm?
how wide is the frame (between knees)?
 
http://www.brave-machine.com/

Hey Jackjetful, is this the company for your hub/freewheel? I don't see it on their site.
I see Drum used an ost hub, but aren't they too wide to use with multi-speed freewheel in 135-145mm dropouts? Plus there is no freewheel for motor sprocket.

I tried my bht yesterday with 1:5.4 @4200watts. WOW! 1:5 or less is prob more adequate for even for torque/speed in a 26" wheel.
Torque was so much it made 3 new threads into the freewheel hub portion, then seized the freewheel.

I am totally looking for a more solid hub/freewheel, or even a strong hub to bolt sprocket direct.
Any suggestions are welcome.

Hopefully it's okay to add the pics here? If not I can remove them.
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Very impressive project! Keep up the progress updates, very keen to see how it turns out :)

Awesome that you even cut it all out yourself. It's quite a unique design, there are plenty of 'monocoque' type frames recently that have begun to look very same-ish. It's also weirdly similar in some shapes to what I've been sketching for the past few months, very nice.
 
Loooking good! Keep up the good work.
Interesting build :)

David Raaymakers
 
Thanks; I'm nearly finished now; but not in my workshop at the time so i can't really upload new pics...

Hey Jackjetful, is this the company for your hub/freewheel? I don't see it on their site.
I see Drum used an ost hub, but aren't they too wide to use with multi-speed freewheel in 135-145mm dropouts? Plus there is no freewheel for motor sprocket.
I tried my bht yesterday with 1:5.4 @4200watts. WOW! 1:5 or less is prob more adequate for even for torque/speed in a 26" wheel.
Torque was so much it made 3 new threads into the freewheel hub portion, then seized the freewheel.
I am totally looking for a more solid hub/freewheel, or even a strong hub to bolt sprocket direct.
Any suggestions are welcome.
Hopefully it's okay to add the pics here? If not I can remove them.
Click to expand...

no problem haha

those are my wheels (really solid downhill stuff :) ) Use them with 3" tyres
Unbenannt.PNG

just tested the wheels on my downhill bike but didn't test the single freewheel under motor load. ... maybe I will change to a direct drive later!
 
t looks awesome. congrates!
can the motor be removed or is it welded to the swingarm?
how wide is the frame (between knees)?
Click to expand...

Yess Motor can be removed... it is integrated in the frame; thats what my fram is about!.... there is also a lot battery blace in front of the motor. Motor will "swing" inside the frame; but mounted on the swingarm!
Swingarm.jpg
swingarm 2.jpg
 
Frame is 142mm wide! ... less is not possible with the BHT!

I'm a little jealous here-
conception, design, creation of an entire bike using pesky aluminum
Congratulations!
Is this your first single reduction mid? (I call them Middirect drive)
I for one can't wait to see how the design and that motor play together!
Click to expand...

Yes, It's my first aluminium and first single reduction mid driven E bike I've built!

As I said, a lot of accurately constructionwork was required to come to this result; there are just a vew components left now; I further have to decide how I will attach the freewheel for pedalling to the rear hub.
The easiest way would be to attach it zo the side of the disc brake; so on the left side! ... I dont want a secont freewheel on the motor shaft becaus that would cause "delay" on the motor output.

But still want this bike pedal as a normal bike! ... in fact this is a mix of trail/freeride/downhill... exactly what i wanted!
 
Fantastic frame! Do you have a weight so far? Whole bike look awesome!
I'm really waiting for some video footage :)
 
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