Gearbox gear ratio calculator.

[Anorak_ian]

Hi all,
I'm looking for a bit of software that calculates the ratios in a gearbox.

You know the sort of thing;

1st - Layshaft gear - Enter teeth [ ] Mainshaft gear - Enter teeth [ ]
2nd -Layshaft gear - Enter teeth [ ] Mainshaft gear - Enter teeth [ ]
3rd - Layshaft gear - Enter teeth [ ] Mainshaft gear - Enter teeth [ ]
4th - Layshaft gear - Enter teeth [ ] Mainshaft gear - Enter teeth [ ]

1st ratio = [ ]
2nd ratio = [ ]
3rd ratio = [ ]
4th ratio = [ ]

I have looked on the net but I can't find anything.

[Rhynri]

If someone wants to assist me with it I'll write one, I can do GUI in C#, might need some help concerning how to tell the program to do the maths or a pointer towards a good site. My wife is brilliant at it anyway, but a little foggy, I imagine on, on the functioning of a gearbox.

[coachgeo]

http://dirtjapan.com/myscript/gear_selecter.php

This one mentioned transmission while the others seemed to aim at front/rear sprocket size.

Hope it helps

[Rhynri]

I'll see when I get home if I can't tear that apart and take a gander at a few google results for calculating gear ratios. My biggest question for the audience here is, what are we looking for? Solving for ratio when speed and RPM are a given? Or do we strictly want what Anorak is looking for, something that spits out ratios when different gear teeth-counts are given. I would like the program to be as helpful to as many people as possible, so the better fleshed out we can make it the better.

[mr chips]

These any use?

http://www.johnmaherracing.co.uk/gearcalc.htm

http://www.partsemporium.co.uk/rpm&speedcalculator.htm

[Anorak_ian]

No, thanks anyway.

[Sphere]

If you can tell me the gears for instance in an Enfield 4-speeder, I could make one in Google Spreadsheet? It seems pretty trivial unless I am misunderstanding you.

[Anorak_ian]

Hi, it is for an Enfield box, I have a lot of pre 1959 gears and I thought I would make use of them and play mix and match and see what I could come up with for my next bike.

Main 31,26,21,17
Lay 17,22,27,31

4th is 1:1 of course.

I can't understand why there isn't a calculator for this; just about everything else is out there on the net.

Cheers Ian

[Sphere]

I assume that gearbox will work like a reasonably modern 4 speeder. Of which I have a PDF somewhere... how it works.

See, that is the real problem, which cogs are connected in what way in what gear. Except for fourth, where main, and lay are connected by two cogs in 1:1 ratio.

This one: http://d.yimg.com/kq/groups/1240095/132 ... earbox.pdf

[Anorak_ian]

I had that thought nagging at me as I wrote my last entry

I guess I should have asked on the enfield forums what software they use

[gearhead1951]

Check www.victorylibrary.com , Panic is concerned more with old brit and USA motorbikes and cars but the info is germaine for anyone who wants to improve a trans to match a particular engine and application !!