Chain slack newbie question

[BonkersAtHeart]

diagram is confusing. 
 

chain slack should be 55-60mm

do I only take the measurement with chain pushed down not up or both measurements down and up 

[RideWithStyles]

Normally Primary down but you can just check the upper afterwards incase it catches on the swingarm.

 

but as the diagram says its a total upper and lower movement of 55-60mm, place a ruler underneath the swing arm, middle length down the S A. Gently pull and raise as far as it will naturally go and take the measurements from there.

example 1:  of 20mm raise while lower of 40mm equals 60mm will be on the limit. 
example 2: of 30mm raise while 50mm 

Lower equals 80mm will to too slack.. is that clearer?

Edited December 20, 2023 by RideWithStyles

[BonkersAtHeart]

26 minutes ago, RideWithStyles said:

Normally Primary down but you can just check the upper afterwards incase it catches on the swingarm.

 

but as the diagram says its a total upper and lower movement of 55-60mm, place a ruler underneath the swing arm, middle length down the S A. Gently pull and raise as far as it will naturally go and take the measurements from there.

example 1:  of 20mm raise while lower of 40mm equals 60mm will be on the limit. 
example 2: of 30mm raise while 50mm 

Lower equals 80mm will to too slack.. is that clearer?

 

so I just add the upper and lower number. Together for the whole number value and don’t subtract anything ? 27mm raise 53mm lower is 80mm ? as a whole but feels tight as anything. 

[Nick the wanderer]

Hi,

yes, if you have 80mm worth of slack and the manufacturer recommends 55-60mm you will only need to tighten it very slightly. If you think it is tight enough then run with it as is.

[Mississippi Bullfrog]

I just use one measurement. Push the chain up as far as it will go, then down, measure the distance and that's it. Holding a ruler can be tricky so I make a ply measure with the limit drawn on it. It's easier to hold that on the swingarm than a ruler.

 

Also, don't just take one measurement. Chains don't wear evenly so you will have tight spots and loose spots. It you set it on a loose spot then the chain will be too tight.

[onesea]

You are talking VERY fine adjustments on the rear axle, 1/4 turn can make a difference.

My suggestion is in time you learn to feel when the chain is to loose. A snatchines when chaining gears is my warning it’s subtle. It doesn’t take long before your lifting it with your foot and saying yup or nay.