final gearing

[Mark Olson]

18/38 on my FJ

Oh no , that's even #'s . 

[FJ_Hooligan]

I got to thinking (oh no) about this in more detail and worked up a spreadsheet.  I was wondering what the sprocket pattern on a chain would look like.  I worked the math for a countershaft sprocket but the same logic would apply to a rear sprocket also.

Fact: A chain has the same number of links, gaps, and rollers.  (I drew a small diagram but correct me if I'm wrong on this)

I designated a chain roller as #1 and start with it meshing tooth #1 on a countershaft sprocket.  I then rotate the sprocket to see how many revolutions it takes for chain roller #1 and sprocket tooth #1 to mesh back up again.

The results were (kind of) interesting.

An 18T CCS on a 110 link/roller chain repeats every 55 CCS revolutions (1/2 the number of chain links)
A 17T CCS on a 110 link chain repeats every 110 revolutions  (same as # of links!)

An 18T CCS on a 109 link chain repeats every 109 revolutions  (same as # of links!)
A 17T CCS on a 109 link chain repeats every 109 revolutions (same as # of links!)

So it appears that even or odd doesn't matter, they both have a repeating pattern on the chain.
Although the even tooth sprocket and even link chain combo repeat more often.
The even/odd and odd/odd combos are the same.

[simi_ed]

Too much time on your hands ...   

[FJ_Hooligan]

Thanks Ed!  :-)

Oh yeah, it's pretty much the same story for the rear sprocket.

Even/odd and odd/odd tooth count and chain link combos repeat at the # of revolution equal to the number of chain links.

The even/even combo repeats at 1/2 the number of links; however, sprocket teeth that are multiples of 10 are the worst repeating at only 11 rotations of the sprocket.

This means the 40 tooth sprocket and 110 link chain is one of the worst combinations your could choose as far as avoiding a frequent sprocket/chain meshing pattern.  Which proves that this is all BS since the 40 tooth/110 link combination is out there in spades and not throwing chains all over the place.  :-)

But, the math was kind of fun.  Nothing else to see here, keep moving........

[Arnie]

Just to add more trivia to an already totally trivial thread.......

This is a "half-link" for a non-Oring 530 chain.  It is probably 40+ yrs old.



I have not seen one for a current O or X ring chain in any shop or catalog.
Without this type of device you can only have a chain with an even number of links.

Therefore, it might be possible that a wear pattern could develop in an even/even or odd/odd sprocket set eventually.  I'd guess that it would be less than significant.

Arnie

[FJ_Hooligan]

Arnie,
Are you saying that I can't cut a single link out of my chain and have 109 links?

What you show above looks like it's a whole link.  But I'm confused about the offset on the side plates.  How does it install?

I had a Hodaka that came with a rear sprocket overlay to make the rear sprocket bigger.  The tool kit included a small section of chain (I seem to recall 5 links but not sure) along with an extra master link (clip of course) to lengthen the chain for the overlay.

[Pat Conlon]

Hooli, question: on the load transfer from the output shaft to the c/s sprocket to the chain...
Does the 18 tooth sprocket add a tooth to the distribute to load on the chain vs the 17 tooth?

I've always assumed (visualizing the chain wrap) 1/2 of the 18 teeth (9) would pick up the load vs only 8 teeth on a 17 tooth sprocket. The extra tooth transferring the engine load to the chain is a good thing.....distributes the load over a larger area.

[Arnie]

Arnie,
Are you saying that I can't cut a single link out of my chain and have 109 links?

Yes, that's exactly what I'm saying.  You would have no way to join it into a loop

What you show above looks like it's a whole link.  But I'm confused about the offset on the side plates.  How does it install?

It's a "half-link".  You install it with a normal "master" on one end and a single pin that has a washer and cotter pin on the other. The offset (small end with roller) fits inside the outer link plates

I had a Hodaka that came with a rear sprocket overlay to make the rear sprocket bigger.  The tool kit included a small section of chain (I seem to recall 5 links but not sure) along with an extra master link (clip of course) to lengthen the chain for the overlay.

Your chain extension had rollers at both ends so the master link would work.

[IceFJ]

I´d like to add one thing that has not been addressed in this thread
In order to extend the life time of the chain it is preferred to use one sprocket with an even number of teeth against an odd number sprocket,
-just to throw in one more factor for you to think about 

I see that I opened a can of worms here, an other "oil" thread,  LOL!!
I did not mean to though.... 

[IceFJ]

For those of you who are still interested in the math here is a link that has been posted on some previous gearing threads www.gearingcommander.com

[FJ1100mjk]

For those of you who are still interested in the math here is a link that has been posted on some previous gearing threads www.gearingcommander.com

Yep. Including this one. Fourth post down on first page.