Transparent Gearbox on a Homemade Bicycle

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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:

ThenI set up atemporaryChassismechanismtotry...

- 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:

for theselector,I usedpieces ofbrassIbrazedsilver

a smallplexiglasscovercanmake a little moresealedall


here is general aspect





Step 9:

the spring of thecablenot beingeffective, I madeanother systembetter finishto tighten thecable

here is the new system



Step 10:

remains only tomount thegearboxon my bikehomemade

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


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    57 Comments

    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.

    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

    you are an ENGINEER . this is the only word i can say now

    SMOOTH........

    Beautiful work! Congratulations.
    This brings me some ideas to build a quadcycle :D.

    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!

    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!

    4904661856_9cdf0a020a_o.jpg612px-L-gear1.pngtransmission_for_lawn_mower.jpgpedalier couleurs.jpghoffmann-gearbox-003.jpgH1118-L13425964.jpgbv11.jpg128502987.oN1ekV0j.expovvwol12.jpgmagna debon.jpg

    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?

    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

    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?