Carbon Fiber Fun

mzweili

mzweili

Guru
an intermediate solution would be to pressfit a bushing across.
Without a bushing, the axle that goes through the aluminum frame has to fit as tight as possible into the hole to reduce the wearing out of the hole.
And no screw threads where it touches the aluminum hole.
 
Rick Youngblood

Rick Youngblood

CarbonCraft Master
RojoRacing said:
I agree the method of drilling and adding a pin through the frame where you did is not ideal. I feel the CruzBike frames use a thicker alloy then is needed adding to their weight over DF bike but at the same time that also mean you probably won't have any issues with your mod. If the frame was as thin as most of the high end mtbs I've seen then you could expect the drilled holes to oblong over time with every shock load from lumpy roads.

Now if you were to weld in a hollow alloy shaft through frame you could then use a pin without any worry of deformity over time. Sadly welding alloy is hard to do for an amateur and we can't be proficient at everything.
Click to expand...

What I did do was shape and mold a piece of delrin plastic to the inside dimensions and inserted into the frame for support (see photos above). Then drilled through the side walls of the frame and delrin. This should keep the side walls from obloning and spread out the weight of the load, keeping the frame from deforming.

I agree ideally the sulolution would be to weld a hollow tube that passes through the frame as other recumbents manufacturers do.
 
Rick Youngblood

Rick Youngblood

CarbonCraft Master
mzweili said:
an intermediate solution would be to pressfit a bushing across.
Without a bushing, the axle that goes through the aluminum frame has to fit as tight as possible into the hole to reduce the wearing out of the hole.
And no screw threads where it touches the aluminum hole.
Click to expand...
I actually did do this as my first solution, but then changed to the molded delrin plastic solution instead.
 
super slim

super slim

Zen MBB Master
Rick, as long as you needed Ratz's rubber mallet to force the hard delrin into the frame, then this is a solid solution as it spreads the load into the base as well as the sides.
 
Bentas

Bentas

Well-Known Member
The fork is made from seat stays from doner Carbon frame, epoxied into cut down doner Carbon fork, then drop outs epoxied to seat stay ends, wrapped all with a few layers of Carbon fibre sanding between applications.
Sorry about the quality of pics ,the derailier hanger is part of doner Carbon chain stay ,so just bolt on.
 

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Charles.Plager

Charles.Plager

Recumbent Quant
Bentas said:
The fork is made from seat stays from doner Carbon frame, epoxied into cut down doner Carbon fork, then drop outs epoxied to seat stay ends, wrapped all with a few layers of Carbon fibre sanding between applications.
Sorry about the quality of pics ,the derailier hanger is part of doner Carbon chain stay ,so just bolt on.
Click to expand...

Ahhh... Very cool!
 
Bentas

Bentas

Well-Known Member
Nearly Spring here in oz , build nearly complete, I set myself a goal to have it ready by September , I'm a bit over building and winter, just want to go ride my bike!
View attachment 5418 image.jpeg I can't remember where I found this little orange beast but it looks carbon maybe ,way cool me thinks!
Is it just me or does his riding position look like he could generate some serious power .
Especially if he carried a smaller lunch box.
 

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ak-tux

ak-tux

Zen MBB Master
Bentas said:
Nearly Spring here in oz , build nearly complete, I set myself a goal to have it ready by September , I'm a bit over building and winter, just want to go ride my bike!
View attachment 5418 View attachment 5419 I can't remember where I found this little orange beast but it looks carbon maybe ,way cool me thinks!
Is it just me or does his riding position look like he could generate some serious power .
Especially if he carried a smaller lunch box.
Click to expand...
Wow! That's a seriously oversized boom! Must be quite rigid with serious power transfer. Are you going to trim and plug the hole at the bottom end of the boom?
 
Bentas

Bentas

Well-Known Member
Yes , will have my light mounted in there eventually, front end is super stiff, and light ,boom is part of a failed carbon racing oar .
 
Bentas

Bentas

Well-Known Member
Thanks for the positive feedback,
If you don't like sanding until your fingers bleed don't build with carbon fibre, been building recumbents for 12 years ,started with steel ,then alu ,now cf,
This one has been the most challenging ,I have no idea how it will stand up to my 85 kilos, praying that I haven't built a death trap.
Not going to weigh bike until I finish it, was about 21lbs before rear seat stays were added and extra layers on down tube
Still have front derailier , rear brake and left shifter to add,
I'm guessing around 24 lbs is probably realistic, using 105 brifters and no name brake callipers ,the wheels are great everyday hoops but definitely not light as carbon wheels go.
As for performance, I have not racked up enough klm's ,or fitness to guage if it's faster than my alu mbb
What i can't stress enough though is the quiet ,plush ride that a carbon recumbent provides
So much so that my main reason for making the bike out of carbon initially was the weight advantage ,but the real bonus is ride quality .
This was unexpected, being longer wheelbase than my previous is probably a factor also.
 
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ak-tux

ak-tux

Zen MBB Master
Another 9.6Kg (21 lbs )Carbon MBB using a BMC frame by Marco Ruga! Seat recline angle looks like the mid 30s. Probably 35deg.

IMG_20171006_190102.jpg


Blog (In Italian, may need google translate)
https://biciclettereclinate.blogspot.co.ke/2017/10/rev-bmc.html
 
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