tension with tm slider and ironman


7 replies to this topic
  • 426 NOOB

Posted March 17, 2010 - 04:50 PM

#1

I have read that you should run the books chain tension specs even with the tm slider. It seems to me that since it sits higher that the chain should be ran a bit looser. I am a bit worried as i am putting an ironman on and dont want to destroy my hub. Any Thoughts?

  • tek_01

Posted March 17, 2010 - 05:46 PM

#2

It should be the same, if your worried you can always remove the rear linkage and align the front sprocket, swingarm pivot and rear sprocket in a straight line (Which is a chains tightest point) and add about an inch or so of slack to the chain like that and see what the end result is when you put it back together and measure it

  • grayracer513

Posted March 17, 2010 - 07:27 PM

#3

The slider isn't any higher at the rear bolt, so you should use the same spec as stock.

It should be the same, if your worried you can always remove the rear linkage and align the front sprocket, swingarm pivot and rear sprocket in a straight line (Which is a chains tightest point) and add about an inch or so of slack to the chain like that and see what the end result is when you put it back together and measure it

By this method, the correct tension at the tightest spot should be 1/2" of true slack.

  • 426 NOOB

Posted March 17, 2010 - 08:54 PM

#4

ok. I was worried about the height difference of the slider more than anything. Ill keep it at stock tension then

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  • grayracer513

Posted March 18, 2010 - 08:47 AM

#5

The slider is higher, but clearance at the slider isn't the issue. The 3 centers involved, the output shaft, swingarm pivot, and axle, create a triangle. Two sides of this triangle are of a fixed length; the line drawn between the output and swing arm pivot centers, and the swing arm itself can't change as the suspension operates.

The third "side" is the line between the output shaft center and the rear axle, and the length of this changes constantly. This dimension is longest when all three centers are lined up straight, as tek said, and shorter everywhere else. The concern with chain tension then is that there has to be at least a minimum amount of slack must be present at this point. The standard for this size chain is a quarter inch per running foot, so that ends up being about 1/2" on a YZF.

The first thing that happens if there is too little slack as the suspension passes the center point is that chain wear accelerates, and then of course, sprocket wear accelerates. As more slack is removed, the chain becomes physically too short to allow the swing arm to pass over center, and if it's forced to do so, something has to flex, bend, or break in order to allow it.

Example:
Posted Image

If you were to check your chain adjustment as tek_01 suggested, by pulling the relay arm bolt out of the swing arm and setting it to 1/2" while the swing arm was centered up, guess what it would measure on the stand when it was back together?

  • 426 NOOB

Posted March 18, 2010 - 11:28 AM

#6

The slider is higher, but clearance at the slider isn't the issue. The 3 centers involved, the output shaft, swingarm pivot, and axle, create a triangle. Two sides of this triangle are of a fixed length; the line drawn between the output and swing arm pivot centers, and the swing arm itself can't change as the suspension operates.

The third "side" is the line between the output shaft center and the rear axle, and the length of this changes constantly. This dimension is longest when all three centers are lined up straight, as tek said, and shorter everywhere else. The concern with chain tension then is that there has to be at least a minimum amount of slack must be present at this point. The standard for this size chain is a quarter inch per running foot, so that ends up being about 1/2" on a YZF.

The first thing that happens if there is too little slack as the suspension passes the center point is that chain wear accelerates, and then of course, sprocket wear accelerates. As more slack is removed, the chain becomes physically too short to allow the swing arm to pass over center, and if it's forced to do so, something has to flex, bend, or break in order to allow it.

Example:
Posted Image

If you were to check your chain adjustment as tek_01 suggested, by pulling the relay arm bolt out of the swing arm and setting it to 1/2" while the swing arm was centered up, guess what it would measure on the stand when it was back together?


it would measure around or at 2" correct? which is the factory spec once back on the stand.

  • grayracer513

Posted March 18, 2010 - 12:55 PM

#7

it would measure around or at 2" correct? which is the factory spec once back on the stand.

Yup. That's how they arrived at that number.

  • 426 NOOB

Posted March 18, 2010 - 01:22 PM

#8

thanks for the input guys:thumbsup:





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