dyno series info pg 2

• Here are the dyno results showing the compression forces for the two different shim stacks from pg 1.
• When comparing shim stacks, we always ask ourselves "how does stack 1 compare with stack 2 ?"
  • We always put the changed stack first and the original stack second.
  • In this case, the mod stack (1027) will be Stack 1, and the stock stack (1024) will be stack 2.

• Here is a description of the data table and what the numbers represent.
• The ips column is the velocity the shock is stroked on the dyno.  This velocity is inches per second.
• In this case, we made 12 consecutive runs on the dyno (one right after the other) so we have a range of velocities at which to compare compression force numbers.
  • (View the 'dyno run video' link on the left to see how the shock is tested).

• Compression force numbers for Stack 1 (the mod stack).
• The dyno strokes the shock at the given velocity, and a load cell reads the peak force from the shock.  Force is in pounds.
• The force numbers are then recorded for each velocity.
• In this case, the compression force for Stack 1 at 1ips = 25 lbs, 2ips = 42 lbs etc.
• You will notice the force increases with the velocity.  The same thing happens when riding the bike.  When you hit small bumps at slower bike speeds, the velocity is low and the damping force is low.  As you start hitting larger bumps at faster bike speeds, the shaft velocities and damping forces increase.

• Compression force numbers for Stack 2 (the stock stack).
• We are comparing the force numbers from one stack against the other.  We put Stack 1 and Stack 2 side-by-side in the table.
• You can easily see any differences in the compression force numbers.

• Differences between the stacks.
• We want to know exactly how much Stack 1 (mod) changed. 
• In the last two columns, we calculate both the pound difference (lb diff) and the percent difference (% diff) between the two stacks.
• In the lb diff column we can see:
  • At 5ips, the diff is 0 lbs.  Stack 1 and 2 are the same at this velocity. This indicates the shim changes did not influence the damping at these lower velocities.
  • At 50ips, the diff is -43.  Stack 1 lost 43 lbs damping force at this velocity.
• In the % diff column, we see the percentage Stack 1 has changed over Stack 1.
  • At 5ips, the % diff is 100%.  The compression force for Stack 1 did not change.
    • 100% = 1.0   ( 97 x 1.0 = 97 )
  • At 50ips, the % diff is 93%. 
    • ( 627 x .93 = 584 )

• Next, damping curve.  [dyno series tutorial pg 3]