Introduction: Transparent Gearbox on a Homemade Bicycle
I wantedcreate afor a long timebikewithgear boxin thebottom bracket
as IExpandeda rimrearhuband built acustomcoaster,
Icould not havegear....andI missed it!
I'minspired by oldbikes(1900),andtractor mowergearbox!
I usedbikegears,plexiglassandmachinedparts
I puttwo weeksto get the ideaand createplans
andabout 2 months torealizethe gearbox!
there are threespeeds andaxisdriveand outputare the same
theselection systemis brass
plexiglassboxisto see themechanism
Step 1:
FirstI madeplans andgear ratio
Planswere madetothescaleto facilitatemanufacturing andvarioustestsof setting up
Step 2:
the systemconsists ofa shaft on whicha gear isdrivenall the timeand the twootherturn in theblank
whenyou changethespeedwhich wasledstartsto rotatein the airand it isanother thattakes over
brasswashersavoidsusury
for machininggearssupports, aspecial machine(mortiser) was used
I had todisassemblea lot ofspeedfreewheelbikein order to makethis arrangement
Ithenjust solderthe sprockets ontheir support
Step 3:
then, and stillbrass, Imachined"sliding"
it slideson the shaftand causes afinger, whichthanks toa spring,causesthe pinionthatis desired, while leavingthe others free
just asa system oftractormower!
Step 4:
- Bottom4sprocketsrotateat the same time
-Righttherethe output gear(the piecewith theredlinesallows to seetherotation)
-Top left, the threesprocketsrotateindependentlyof each other(thebrassShiftingused to lockthe one youwant)
here you can see in works
Step 5:
manufactureof the boxto receive themechanism
I askedafriendsto machine thebearinglocation
for the restI did everythingby hand,witha hole sawand ajig saw....not easy!
canperceivethe selectorandbearing housings
space that Ishows withmy fingersused to placethe gearboxon the bike
to assemblethe pieces ofplexiglass,I used aspecialglueplanned forthis
Step 6:
tediousbutimportant step, polishing!
I used severalgradesandpaper:
100, 240, 400,800, 1000, 2500 and 4000
thenpolishhasis sufficientvehicle body
Thisisthe same methodtorenovatetheplastic headlights;-)
someonetold meit looks likeasprocketsaquarium......lol
Step 7:
I was missing6 mmin order to closethe boxproperly ....
SoI usedorangeplexiglassto fill this gap
orange ...why?
because I loveorange
becauseaccording to the angleof view, reflectionsgives the impressionthat the entiregearboxis coloredsothatthere isveryfeworange
Step 8:
a smallplexiglasscovercanmake a little moresealedall
here is general aspect
Step 9:
here is the new system
Step 10:
I dono moredetailsthan thatthe bikebecause for methe main subject isthe gearbox!
a bikecustomissimple to dofor someone whoused to doit
evenwhenI putsome pictures of thebikeas I havealso spenttime on it
on the picturesit isa friendwho drives thebike
on thevideois me

Participated in the
Instructables Design Competition
58 Comments
Question 6 months ago on Step 2
I build these 3 wheel's chopper trikes one and 2 setters that have a 2 cycle small engine kits that is more of a pedal assist.
Any way I was thinking that maybe your idea would work for a transmission behind the 2 cycle engine.
Just a thought 🤔 is all
Love your bike frame design it reminds me of an old Schwinn design from the '70s.
4 years ago
Incredible project !
I didn't see how many gears do you have there. Same a a regular bike gearbox ?
6 years ago
cool project, and not to troll you or anything, but it is little hard to read your text when you don't use space in sentences.
7 years ago
great work. how much you did gain after this gear box, could you please explain and can you please post your work with 3D animation or diagram so it would be bit easy to make it. thanks
10 years ago on Introduction
you are an ENGINEER . this is the only word i can say now
10 years ago on Introduction
SMOOTH........
10 years ago on Introduction
Beautiful work! Congratulations.
This brings me some ideas to build a quadcycle :D.
10 years ago on Introduction
First congratulations for beautiful work.
You told that “I put two weeks to get the idea and create plans and about 2 months to realize the gearbox!”
I want to Design my own gearbox. So can you tell me which books help you to get the idea or information to make or design your gearbox?
Please please please help me!
Reply 10 years ago on Introduction
I searched a lot on the internet but I have not found much information ....
I wants to make available the most interesting of my research:
system speed of tractor mower (pic 3)
bikes with the old gearbox in the bottom bracket, (pic 6-8-9)
a gearbox-chain (pic 5)
one shema gearbox compact bike that I colored (pic 4)
other system (pic 1-2)
mine is a mixture of all that
on the schema of the photo No. 7 there is a simple freewheel system
it did not suit me at first because speed we can not pedaling backwards .... therefore the coaster brake that was not possible!
otherwise it is a simple system realize!
Reply 10 years ago on Introduction
How do you calculate gear ratio, number of teeth in pinion, speed and torque etc?
And if I want to design my own gearbox what information do I need?
Reply 10 years ago on Introduction
for calculating gear ratios, it is not easy to explain with a translator ....
for example, a standart Crankset about 45 teeth
the sprocket wheel is about 15
I used the principle of:
A = 20 teeth on B = 10 teeth
axis speed equivalent, B will turn two times faster than A
after I did a lot of multiplication and division
the rest has to give you ideas, observe plenty of mechanism and keep only what can be used on your gearbox
Reply 10 years ago on Introduction
You told me that "it is not easy to explain with a translator .... "
So can you give me formulas that you use to make your gear box?
10 years ago on Step 4
You can have a setting that simply connects the pedals to the output.
That would yield 4 ratios with no more chain or sprockets. simply make engagement from the brass selector ring to the output.
Nice project.
10 years ago on Introduction
Wow! Really nice work! Very clean design. Your final project looks like a lot of fun to ride.
I have used the following page to find many calculators when designing my projects.
http://www.rbracing-rsr.com/calculations.htm
10 years ago on Introduction
félicitation pour ce montage
10 years ago on Step 4
WOW
10 years ago on Introduction
Two great concepts, the Gearbox, and the Bike, and went to my Blog.
http://faz-voce-mesmo.blogspot.pt/2012/12/avancos-contra-o-cancro-sobrevivencia.html
10 years ago on Introduction
I believe with his shown skills he might be able to make a Nuvinci style gearbox for coaster system, after all it was invented by Leonardo Da Vinci so there should be no patent infringment, and if he did not seek to market it there should not be any conflicts at all.
10 years ago on Introduction
Amazing project!
10 years ago on Introduction
incredible! well done. i hope you win something for this!