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Sub 40lb Custom Gearboxx Bike

HaveFaith

Monkey
Mar 11, 2006
338
0
Sorry guys, don't have much yet in the way of updates. Funny how life gets in the way sometimes! Unfortunately a broken spoke and blown shock (yeah for when the piston separates from the rod!!??) have slowed things down.

We have however added a plate to stiffen up the brake caliper mount, as that was a bit softer than desired. I will have the bike back together this week and get some more mileage on it.

We have started on the second proto though, and have done a couple things a bit different. The lower shock "basket" will be easier to fab and weld and a few parts have had the excess material machined out. The second one should be easier to weld in general and probably a quarter pound lighter once all is said and done.

I used solidworks to design the frame and cosmosworks/Ansys for the analysis work.

As for patentable items, there is not much really, in general is a basic design with (what I like to think), a clean execution. I could persue a couple of little things, but honestly they aren't big enough to be worth it.

Again, so you dont have to search, the weight is at 42.5 lbs as is. Looking to put on an air shock soon!
 

Bulldog

Turbo Monkey
Sep 11, 2001
1,009
0
Wisconsin
Sorry guys, I wasn't talking about a patent. Just meant that showing off drawings and pics of your proud new baby could be (or already has been) used as "inspiration" for the big boys. Not much you can really do though, we live in a lawer-protected, idea-swiping country.
 
Apr 16, 2006
392
0
Golden, CO
Bulldog - "Just meant that showing off drawings and pics of your proud new baby could be (or already has been) used as "inspiration" for the big boys. Not much you can really do though, we live in a lawer-protected, idea-swiping country"

That also means its public disclosure and for a given time it's havefaith's to patent. However theres not much, if anything, on his original frame that the "big companies" would wanna steal or waste lawyers on, its just a cleany fabricated bike based on an already proven design + a gboxx. Don't be so skept. man the big mans not always after you! haha.

I was gonna say something about that rear brake mount and how i was surprised you got away with it lol. An extra forward diagonal on the forward mount hole should give you the support you need while adding minimal weight.
 
Apr 16, 2006
392
0
Golden, CO
^
I couldn't really figure out why they had that chain on there until I saw the extra output sprocket on the other side of the cranks that is cut off by the cut-away view.

My guess is that it goes from crank attached sprocket on right then to the golden driven sprocket, which is attached to the planet gears, which in turn speeds up the sun gear which is attached to the cassette to make up for what would be a low imput gearing combination with the small gear on the cranks. It then gets shifted by the parrallel arms which hold the shifting mechnism controled by the cable. the cassette in turn drives the sprocket which floats on the spindel of the cranks. That sprokect is attached to and drives the output sprocket on the other side of the crankcase which you can hardly see.

that or I could be completely wrong haha, seems like an overly complicated way to essentially achieve what the DC special 3 does, and i bet its not even rigged up to shift while coasting. Granted it will prolly have a more compact design, but it will prolly weigh more too.
 

HaveFaith

Monkey
Mar 11, 2006
338
0
Bulldog - "Just meant that showing off drawings and pics of your proud new baby could be (or already has been) used as "inspiration" for the big boys. Not much you can really do though, we live in a lawer-protected, idea-swiping country"

That also means its public disclosure and for a given time it's havefaith's to patent. However theres not much, if anything, on his original frame that the "big companies" would wanna steal or waste lawyers on, its just a cleany fabricated bike based on an already proven design + a gboxx. Don't be so skept. man the big mans not always after you! haha.

I was gonna say something about that rear brake mount and how i was surprised you got away with it lol. An extra forward diagonal on the forward mount hole should give you the support you need while adding minimal weight.
It actually tweaks because of the moment load imposed by the offset of the rotor. In the linear (more obvious) load path, its quite stiff, but it was pulling the rear mount inwards towards the wheel, effectively misaligning the caliper at the end of runs with lots of braking effort. I plated across the backside of the webs, to make it more like a semi-box section. If it needs more, I will plate the front (with .040" material) to make it a full box section.

I began reassembly last night, and once I get the shock back, it will be full-go again.

As for that gearbox, it definitely looks like a lot is going on in order to keep a system where the chain is derailed. NO MORE DERAILING CHAINS! This is one of the biggest benefits of a true gearbox bike, lets keep it that way!
 

dirtdigger

Monkey
Mar 18, 2007
126
0
N.zud
Apr 16, 2006
392
0
Golden, CO
As for that gearbox, it definitely looks like a lot is going on in order to keep a system where the chain is derailed. NO MORE DERAILING CHAINS! This is one of the biggest benefits of a true gearbox bike, lets keep it that way!

Haha agreed. I'm into the planetary/toroidal cvt combos, purely because its all mechanical. however a hydraulic transmission would be hella cool, only a few resonable models are out there, and some of the colleges in the chainless competitions have good ideas, but nothing with reasonable efficiencys sans accumulators for competitive off road mtb that i've seen.
 

dirtdigger

Monkey
Mar 18, 2007
126
0
N.zud
If you put the cassette in BB shaft, I can not use epicycle train gear to increase velocity to cog output.
oh yeah i was guna ask what those planetrey type gears were for?
how many speeds you got there?
you could run the epicycle (is that the same as planetrey gears?) gears on the BB as well?
 
Apr 16, 2006
392
0
Golden, CO
you could run the epicycle (is that the same as planetrey gears?) gears on the BB as well?

Ya man, just make the drive sproket the single sprocket on the crank spindle and run like a 18T sprocket with a 1:2 epicycle gearing combo to double the output speed (you can add a sprague clutch if you want, but you'll need to run a sold rear freewheel body to transfer movement), then run that through your derailling setup, onto your cassette. have the cassette directly attached to the other spindle, and that can be your output spindle then. It'll save alot of hassle and accomplish the same thing with exposing less external pieces like that other drive chain, not to mention save weight. You are pretty damn talented in 3D drafting however, you should pursue something crazier than the standard deraillure in a box, try and come up with your own design :thumb: (meant as a complement)
 

HaveFaith

Monkey
Mar 11, 2006
338
0
Ya man, just make the drive sproket the single sprocket on the crank spindle and run like a 18T sprocket with a 1:2 epicycle gearing combo to double the output speed (you can add a sprague clutch if you want, but you'll need to run a sold rear freewheel body to transfer movement), then run that through your derailling setup, onto your cassette. have the cassette directly attached to the other spindle, and that can be your output spindle then. It'll save alot of hassle and accomplish the same thing with exposing less external pieces like that other drive chain, not to mention save weight. You are pretty damn talented in 3D drafting however, you should pursue something crazier than the standard deraillure in a box, try and come up with your own design :thumb: (meant as a complement)
Im seriously considering this as a next step (new design). It needs to be done. It can be done. Lets freaking get it done sooner than later!
 
Apr 16, 2006
392
0
Golden, CO
Im seriously considering this as a next step (new design). It needs to be done. It can be done. Lets freaking get it done sooner than later!
Haha i thought u said no more derailling chains. Did you get a gboxx 2 for your frame? does it really have the magnetic pawls like in the video for selecting the gear combo? That seems pretty cool, can't believe nobody thought of it earlier tho haha. I want something cool for the next "revolutionary"gearbox like a purely mechanical power split planetary cvt.
 

HaveFaith

Monkey
Mar 11, 2006
338
0
Haha i thought u said no more derailling chains. Did you get a gboxx 2 for your frame? does it really have the magnetic pawls like in the video for selecting the gear combo? That seems pretty cool, can't believe nobody thought of it earlier tho haha. I want something cool for the next "revolutionary"gearbox like a purely mechanical power split planetary cvt.
The gboxx 2 has 7 parallel drive chains selected via the magnetic pawl system. The shift is really positive and feels good on engadgement. The shifter even uses magnets for the detents. Definitely a slick system, but I know it can be done lighter. The gates carbon belts are on the way, and a step in the right direction, but I still think there is weight to be dropped from the general idea of a gearchange mechanism.
 

LMC

Monkey
Dec 10, 2006
683
1
The gboxx 2 has 7 parallel drive chains selected via the magnetic pawl system. The shift is really positive and feels good on engadgement. The shifter even uses magnets for the detents. Definitely a slick system, but I know it can be done lighter. The gates carbon belts are on the way, and a step in the right direction, but I still think there is weight to be dropped from the general idea of a gearchange mechanism.

i agree, how about a carbon fibre outer shell, magnesium internals etc etc, its way too heavy IMO
 

no skid marks

Monkey
Jan 15, 2006
2,511
29
ACT Australia
Or a Rohloff with 7 gears! Even a Rohlof with one row of gears removed would be lighter,more efficient,stronger and more reliable? Does the G-Pox have as well spaced and consistent shifting as the Rohlof.
Or an Alfine where reliability doesn't matter as much because they're so cheap. Or some of Srams(Sachs) offering,8,7 or even three speed just for DH.
 
Apr 16, 2006
392
0
Golden, CO
Or a >=90&#37; efficiency cvt weighing <=3 lbs haha.

I'd bet the Gboxx 2's shifting quality is as good as or better than the rohloff. we just need something smaller... alot smaller. something with the size to weight scale of a car lol. And 3 speeds may be pushing it, we as humans have a pretty broad power spectrum, but i think we're optimum around 70-80rpm. 3 speeds means our "powerband" needs to be much larger then the conventional 9speed. at least with 5 speeds we get to narrow our powerbands towards optimum cadence. Nico vouilloz i think ran or is still running a 5speed drivetrain at some point and said it was fine.
 

HaveFaith

Monkey
Mar 11, 2006
338
0
I like the Sea-otter story.
It's kind of inspiring.
Thanks dude! It was definitely a rush of work and was tough getting it done, but it felt soo damn good to finish it. Looks like I may be buying an air shock today and doing some more testing tomorrow.

For the gearbox ideas, I definitely agree that 5 speeds is enough, as Ive seen some research that shows we can put out similar power numbers from lower cadences up to like 100rpm, sometimes more!

The shifting quality on the G-boxx is fantastic, much better feeling than even my full x0 setup on my trailbike.

I like where things are headed though, and I think we can continue to push the direction of the bike industry. It just needs to be more and more visible to the industry, with people really voicing their opinions...
 

Segunda

Chimp
May 7, 2007
76
3
Or a Rohloff with 7 gears! Even a Rohlof with one row of gears removed would be lighter,more efficient,stronger and more reliable? Does the G-Pox have as well spaced and consistent shifting as the Rohlof.
Or an Alfine where reliability doesn't matter as much because they're so cheap. Or some of Srams(Sachs) offering,8,7 or even three speed just for DH.
Yup, I personally would kill for a simple 5 speed Roloff with disctabs and standard QR or even 135x12 (M)axle, these guys at Rohloff seem to be more into commuters and the like though :banghead:
 

LMC

Monkey
Dec 10, 2006
683
1
they probably have to cater to the commuters etc, as they are the majority of buyers. The cost for tooling and design for a 5 speed version, which is going to satisfy the smallest of markets is not going to be worth it. Even having space for a 12mm axle would mean redesigning the entire internals.

They are however making a lighter version with a claimed weight of 1100g (a speedhub is currently 1600g)
 

HaveFaith

Monkey
Mar 11, 2006
338
0
they probably have to cater to the commuters etc, as they are the majority of buyers. The cost for tooling and design for a 5 speed version, which is going to satisfy the smallest of markets is not going to be worth it. Even having space for a 12mm axle would mean redesigning the entire internals.

They are however making a lighter version with a claimed weight of 1100g (a speedhub is currently 1600g)
I disagree with the cost of tooling etc. If done correctly you could probably utilize much of the existing componentry, pay less for machining and material (less gearing) and still charge a similar price. Not only that, the high end DH market is actually fairly strong. I could easily see people dropping the cash on a rohloff equipped downhill frame rather than the $2.5k-$4k they are spending on other brands.

Its not like the rohloffs are really flying off the shelves at this point in high quantities anyways. They still cater to a very limited market in the grand scheme of things.

There are just too many companies out there that are unsure of the risks etc and dont have the balls to go for it.
 

HaveFaith

Monkey
Mar 11, 2006
338
0
sweet bike.
What tube sizes did you use for the front triangle? (i.e. Wall thickness, O.D.)
The down tube is .080 wall and 60mm OD i think, the top tube is a double butted tube from Fairing at 38mm OD. The seat tube is .075 wall and 40mm OD.

Those are off the top of my head, I have the specs at work.
 

Ozzer

Monkey
Dec 21, 2003
611
3
Life Ends at 619
Colin, this is a nice bike. I had a chance to play on it today. I hope you're not in a hurry to get it back. ;)


After tweaking with the rebound setting, it was a well balanced bike on and off the ground.


I can't wait until I get more comfortable with the geo. Noentheless, the bike handled real well.



squeezing the last light..





....more pedal time tomorrow.

cheers!

all pics taken by The Sluck
 

skg6

Chimp
May 28, 2008
5
0
Hi to all...

this is my 1st attempt tp post reply. The reason for the 1st post was that i am very attracted to the gearbox bike. I really like it. It looks awesome. The project was so detailed and all the explanations are in order. I will give the bike a 9/10 for looks. It looks super sweet. Hope the owner really satisfied with the project.

Congratulations.
 

HaveFaith

Monkey
Mar 11, 2006
338
0
Colin, this is a nice bike. I had a chance to play on it today. I hope you're not in a hurry to get it back. ;)
G]

After tweaking with the rebound setting, it was a well balanced bike on and off the ground.

I can't wait until I get more comfortable with the geo. Noentheless, the bike handled real well.


squeezing the last light..




....more pedal time tomorrow.

cheers!

all pics taken by The Sluck
Dude, ride it for the week. What are you up to next weekend? Maybe I can make the trip down there for some ride time on a few new trails, talk about tweaks for the bike etc...

Thanks for the pics!
 

Mumbles

Monkey
Jul 17, 2002
236
0
Minneapolis, MN
Dude, ride it for the week. What are you up to next weekend? Maybe I can make the trip down there for some ride time on a few new trails, talk about tweaks for the bike etc...

Thanks for the pics!
firstly just want to say that i'm very impressed with your whole process, start to finish and that i really dig the bike!

question: i may have just missed it while reading the thread, but why did you choose the integrated seat mast?
 

Ozzer

Monkey
Dec 21, 2003
611
3
Life Ends at 619
Dude, ride it for the week. What are you up to next weekend? Maybe I can make the trip down there for some ride time on a few new trails, talk about tweaks for the bike etc...

Thanks for the pics!
I have no idea what's cookin for next weekend yet.
The bike was fun on the rocks.

I have your box of goodies too...rim and shock.
 

BlackHornet

Chimp
Feb 25, 2008
25
0
that thing is awesome, if i could afford it i would totally throw away my derailleurs and pick up a frame with a gear box, man that would be so nice
 

Bighit138

Chimp
Mar 8, 2007
38
0
I saw that at fontana, The only thign that scared me were some of the hardware. Obivously that hasnt afercted the bike RIGHT ON!
 

Luniz82

Chimp
Jul 7, 2008
6
1
Hi HaveFaith, big respect for what you put together there!

I've got another suggestion on how to design a gearbox for your bicycle: When reassembled my historical motorbike a few weeks ago, I thought that the system it uses for transmission could be a fine solution for bicycles as well.
(I hope I'm getting this right as I'm from germany and my technical english skills are not that profound...)
It uses a 5-speed spur gear transmission which is shifted through a hollow shaft with a draw key inside. The position of the spline determines, which of the gears is engaged. So basically it works quite similar to the GBoxx2 concept, just without this complicated system of magnetic bits and pieces and belt drives. Of course you would have to switch the direction of rotation at some point, as a single-stage gear transmission obviously turns the direction of rotation the wrong way round.
But the advantages of this design are quite obvious: the space needed is relatively small, the width of the transmission I have in that old motorcycle is about 4", and it can be shifted with just one cable which makes it work with a regular trigger!

But anyway, thanks for the pics and the fantastic story!
 

jonKranked

Detective Dookie
Nov 10, 2005
85,573
24,191
media blackout
Hi HaveFaith, big respect for what you put together there!

I've got another suggestion on how to design a gearbox for your bicycle: When reassembled my historical motorbike a few weeks ago, I thought that the system it uses for transmission could be a fine solution for bicycles as well.
(I hope I'm getting this right as I'm from germany and my technical english skills are not that profound...)
It uses a 5-speed spur gear transmission which is shifted through a hollow shaft with a draw key inside. The position of the spline determines, which of the gears is engaged. So basically it works quite similar to the GBoxx2 concept, just without this complicated system of magnetic bits and pieces and belt drives. Of course you would have to switch the direction of rotation at some point, as a single-stage gear transmission obviously turns the direction of rotation the wrong way round.
But the advantages of this design are quite obvious: the space needed is relatively small, the width of the transmission I have in that old motorcycle is about 4", and it can be shifted with just one cable which makes it work with a regular trigger!

But anyway, thanks for the pics and the fantastic story!

I'm pretty sure he only designed the frame, and obtained the transmission from G-BOXX. But still... that's a VERY intriguing idea. Do you know of anywhere online with diagrams of this?