Gear reduction/Titan50 to bike cassette

T

TWalker

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Ive done some searchin because I dont wanna ask whats already been answered but...I really get confused when it comes to gear reduction.

I have a rack mount which has the 5:1 PTO>10 gear output>10/10 Jackshaft>to 44 tooth drive gear very nice works well.

I want to try running a chain down to a standard bicycle rear cassette (say 22 tooth gear) roughly a 1/3 to 1/2 the size of the 44 tooth standard chingen sprocket.

Here is a video of a guy who did it but I dont know what reduction he used but you get the idea...mines just a rack mount.


  • What additional reduction would I need?
  • Any thoughts? I pretty much can figure it out if I know the proper reduction but suggestions are welcome.
 
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The original reduction was 5x(4.4)= 22.Most casettes are
14to28t ,midrange around 20,so you need at least a reduction of 4 from PTO out to the 20 t sprocket on the cassette,resulting in an overall reduction of 20.At 5k rpm your road speed would be 75x 5/20=19mph at mid range.For instance you could use 10/20t to the jack shaft and 10/20t from jack shaft to casette.If you try to put all the reduction in the drive from the jack shaft you end up with a 5t output sprocket (impractical).
 
For instance you could use 10/20t to the jack shaft and 10/20t from jack shaft to casette.If you try to put all the reduction in the drive from the jack shaft you end up with a 5t output sprocket (impractical).

Ah headache...I'm an A/B student in college and have 120+ IQ so I'm not totally dumb but...

So are you saying I could increase the size of the jackshaft sprocket? I'm thinking I need smaller sprockets to compensate for the move from the 44 tooth down to the mid-range 20 cassette.

gear reduction totally confuses me. :cry:

Thanks


Edit: Ok, so if I have a 10t engine drive gear and I connect that to a 20 tooth on the jackshaft and then a 10t as a final drive gear; I have .5:1 and 2:1 which would mean?

I add 10t and then I take away 10t so I'm at 1:1 because they cancel each other out? Doesnt make sense because im at 1:1 already with three 10t sprockets in a row.

Does anyone have a tutorial on this because Ive tried the calculators and it doesnt help either.
 
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I think Dui is saying you need to go from a 10t on your engine, to a 20t on the jack. Then a 10t off the jack to a 20t rear gear. I could be wrong (wouldn't be the first time). But it sounds about right to me.
 
While we're on this subject, has anyone tried running off a rack-mount to the front crank ala SBP Shift Kit? I like the shift kit, but I worry about getting too far out in the wilderness with the HT.
 
Okay college guy, here's some simple algebra or ratio and proportion, which is how you solve gear reduction problems.

In ratio and proportion, 5:1 aka 5/1.

5/1 (gearbox on engine) X 10/10(10t on engine/10t on jackshaft) = 5/1 X 10/10 = 5 x 1 = 5:1.

44t on wheel sprocket/11t on jackshaft sprocket = 44/11 = 4:1

5/1 x 4/1 = 20/1 or 20:1

If you reduce the 44t sprocket by 50%, then you need to DOUBLE the engine side of the jackshaft ratio. The 5:1 needs to be bumped to 10:1. Change the jackshaft sprocket that connects to the engine to 20t.

For every 20 engine revolutions per minute(20 rpm), the bicycle wheel spins one time around (1 rpm). For every 2,000 rpm, back wheel spins 100 rpm.
 
While we're on this subject, has anyone tried running off a rack-mount to the front crank ala SBP Shift Kit? I like the shift kit, but I worry about getting too far out in the wilderness with the HT.


I have both sitting in my house and I lined up a chain last night to how it would line up and it seems pretty doable. I decided though to go another route. One reason being that the tension on the chain is no longer verticle on the mount I have it would now being diagonal.

Thats not the only reason but the main one. But it seems like it would work fairly well if your willing to have that long chain stretched out near your leg on the outside chain ring.
 
Okay college guy, here's some simple algebra or ratio and proportion, which is how you solve gear reduction problems.

In ratio and proportion, 5:1 aka 5/1.

5/1 (gearbox on engine) X 10/10(10t on engine/10t on jackshaft) = 5/1 X 10/10 = 5 x 1 = 5:1.

44t on wheel sprocket/11t on jackshaft sprocket = 44/11 = 4:1

5/1 x 4/1 = 20/1 or 20:1

If you reduce the 44t sprocket by 50%, then you need to DOUBLE the engine side of the jackshaft ratio. The 5:1 needs to be bumped to 10:1. Change the jackshaft sprocket that connects to the engine to 20t.

For every 20 engine revolutions per minute(20 rpm), the bicycle wheel spins one time around (1 rpm). For every 2,000 rpm, back wheel spins 100 rpm.

Did I mention I focus on arts at school? :rolleyes:

Ok I ran the numbers through a gear ratio calculator (see screenshots below) and yes indeed you are correct, running a 20t sprocket on the jackshaft keeps it exactly the same when running to a 22t cassette sprocket.

Very nice...thanks very much!
 

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I'm a Sociology major myself, 3.67 GPA , 120+. :D

3.17 here...I struggle with Algebra...not trying to say I'm super smart, just not a total idiot.

Actually I'm a pretty sad case, I'm over 40 years old and my main focus is the women in college...

The way you just lay that stuff out is impressive.
 
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