60T sprocket and chain fitting

[negligent]

I was just wondering if i put a 60T sprocket on the back, will a 120link chain be long enough or will i need more linkage, 60T is a hell of alot bigger than the 47T on there now, but i dont know if that chain has 120 links or less...

[steves]

Cybers chart doesn't go up to 60 tooth... probably for a reason.

http://www.motorcycleanchor.com/katana/Katana_sprockets.html

Why do you want to run that big a rear sprocket?

Quoth the motorcycleanchor:

Large percentage (more than 8% or so) changes in either direction (from stock) can produce undesirable results.
- Large positive percentage changes can cut your top speed significantly, reduce your effective traction under high throttle applications, and may cause the front end to become light or wheelie in response to the increase in torque.
- Large negative percentage changes can actually decrease your gas mileage if you are not cruising steady (as you try to compensate for sluggish performance by giving it more gas during acceleration), and will reduce your rate of acceleration (including out of a dangerous situations).

[brooder]

Only reason I could see putting a 60T up front is to wheelie easier. +3 in the rear will make abig enough difference in bottom end torque. And if you go up 13 teeth, you need to go up 13 links, which is 131 from stock 98+.

[reconstyle]

Dayum son! That's a big @$$ sprocket!

[md86]

And if you go up 13 teeth, you need to go up 13 links, which is 131 from stock 98+.

I just read a chart that says you're wrong . Lemme see if I can find it again ......
I can't . It was some odd equation , though . Not just "if you go up this many teeth , you go up that many links . I went up 3 , and bought a 122 chain thinking that way . But when I punched the numbers into the equation , it said a 120 would be sufficient . So I gotta cut 2 links out when the chain gets here .

[brooder]

See...that's weird. You've got to have enough links for the teeth of the sprocket. And because the sprocket is bigger...hmm. That is interesting. I was wanting to get a 50t for my rear and was thinking I'd need a 121 link chain. Now I really wonder.

[reconstyle]

You'll have to go with a 132 links, they only come in even numbers...

[Black_peter]

Md is right.. remember the distance from the tangent of the front sprocket to the tangent of the rear decreases. X2 actually (top and bottom)..

Score one for Md!

[Black_peter]

I could work that out but I need lunch.. Like now!

[Black_peter]

near as I can figure:
Stock 47 tooth up to a 60 tooth. The number of teeth engaged is 30 on the 47 and 39 on the 60. and the tangent is smaller. 97% of the 47 tooth. (I say % because I couldn't get the distance between sprockets right. If someone has a stock set up and can measure between the two center points I could get exact #)

So lets see stock chain is 118 links.
60 rear set up:
Minus 8 links on the front. Minus 38 links on the rear. (46 links). 118 minus 46 = 72/2= 36 * 97% = 35 *2 =70.. 70 links + 46 = 116 links..
Weird huh.. Someone check my math..

[Mat0302]

Dayum son! That's a big @$$ sprocket!

[md86]

Yeah , I wish I could find the site that had the equation already set up . It was REAL simple math . I searched for a while but never found it .
Also , you can only have an even number of links . No 121 links . It'll have to be either 120 or 122 .

[brooder]

You can only ORDER even links. It would be 121 when I was done with it.

[Black_peter]

Here is a calculator but you need to know the distance of the sprocket centers.

http://tsubaki.com.au/tsscs/chain_length.htm

[Black_peter]

Never mind.. 27 inches..
So my calculations were wrong in that I thought the front was 18.. Hmmm
Tsubaki says 125 pitches (or links) for 15/60
Hmm how could I have been so wrong?