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06 999R RAD02, 06 999R, 06 999.
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Discussion Starter · #1 ·
Hey, been trying to figure out the chain length needed to go from stock 15/36 to 15/42 with a 525 chain. Been trying googling it and only tool I can find is Gearing Commander, but chain links seems to be unchanged no matter what sprocket combination I input. Anyone able to point me in the right direction?
 

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Just Visiting Your Planet
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Gearing Commander is odd that way. You have to make any changes in the Custom fields because some items are fixed even if you make changes to other items. It appears that 99 links is the number you want. Read the notes when you click on the Links hotlink popup.
 

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Just Visiting Your Planet
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10,376 Posts
Yeah, that's right. Sorry about that. I don't know why inside and outside links are counted separately. Not logical. You can't connect two outside links to each other without an inside link.
 

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If you do the geometry, this is what happens.

Every time you add a tooth to the rear sprocket, the center of the sprocket has to move 4 mm towards the center of the front sprocket. This shortens your wheelbase by the same amount.

A chain has links that alternate inner-outer-inner-outer, so in order to lengthen any chain you have to add two links at a time. The links in a 525 chain have a pin-to-pin distance of 16 mm. So when you add two links at a time, the distance between sprocket centers increases 16 mm.

Also, it depends upon the current position of your chain adjuster.

15/36 - Initial Adjuster Position
15/37 - Initial Adjuster Position minus 4 mm
15/38 - Initial Adjuster Position minus 8 mm
15/39 - Initial Adjuster Position minus 12 mm
15/40 - Initial Adjuster Position minus 16 mm
15/41 - Initial Adjuster Position minus 20 mm
15/42 - Initial Adjuster Position minus 24 mm

So,

Add 2 Links - Initial Adjuster Position minus 8 mm (i.e., 24-16)
Add 4 Links - Initial Adjuster Position plus 8 mm (i.e., 24-32)
 

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I just went to this ratio. I don't know how many links I used, but all I did was put it on where I wanted it and put the chain on whole and used the rear sprocket teeth to hold it in place while I figured out what length fit best.

Edit - Looks like I went with 100 links. It was a 110 link chain and I have 5 (colored) outer links and (5 plain) inner links left over.
 

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06 999R RAD02, 06 999R, 06 999.
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481 Posts
Discussion Starter · #7 ·
I just went to this ratio. I don't know how many links I used, but all I did was put it on where I wanted it and put the chain on whole and used the rear sprocket teeth to hold it in place while I figured out what length fit best.

Edit - Looks like I went with 100 links. It was a 110 link chain and I have 5 (colored) outer links and (5 plain) inner links left over.
Thanks. How do you like it? Have been having a really hard time deciding between 39T and 42T. Kinda ended up at 42T since supersprox doesn't seem to have a 39T sprocket.

Thank you to everyone else that added their wisdom also. Appreciate it!
 
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