Tweet
I totally agree about the conflicting advice given by various shock manufacturers. It sometimes makes me wonder if THEY even know how to use their own products. I, too, have several examples of conflicting advice for the same condition from various shock "tuning" charts.
Stated simply, I use shocks to alter/adjust/change a condition known as, "Instantaneous, Dynamic, Diagonal" - hereinafter refered to as "IDD".
The Cup guys get into suspension lockdown and other concepts for aero purposes, but my work is on the short tracks where the car often comes in with slightly different "aero" shape than it went out with after a 15-lap qualifier .
Okay, got your fresh cup of coffee and a notepad?????
Picture a car sitting on four wheel scales. This car has absolutely equal weight distribution, so all four wheels weigh exactly the same.
Now, if you were to push down on the exact center of this car, all four wheel scales would increase equally.....everybody agree?
If I were to add shocks to the RF and LR that had high - or higher compression values, and I pushed down on the center of the car, what would happen????
That's right....The RF and LR scales would show momentary increases over the other two scales due to the resistance of the two shocks, but everything would even itself back out again after the shocks bled down, and all four wheels would be equal in weight again......OKAY???
What happened here was a change in the IDD. For just an instant, there was more diagonal - or crossweight - with the RF and LR momentarily being more heavily loaded than the other two wheels.
But, once the shocks bled down, the setup returned to the equal-wheel-weights setup.
Now, go the opposite way.....lift slightly on the car.
All four wheel scales should show equal reduction of weight on all four wheels.
Add shocks with more REBOUND to the RF and LR, then lift again.
The RF and LR scales should show a momentary, increased reduction of weight over the other two scales until the shocks allow the wheels to go into full droop.
In this case, we have, momentarily, reduced the diagonal - or crossweight - for an instant.....
......which explains - for those of you who have read the Penske shocks setup manual - the suggestion to set the car up with a slight push on turn entry, dialing it out with LR rebound.
LR rebound induces a momentary reduction of crossweight upon turn entry, but allows the suspension to return to its original setup for turn exit.....effectively giving you one diagonal - or crossweight - for turn entry and a different one for turn exit.
A reduction of RF compression would probably serve the same purpose, but I am most comfortable working with rebounds - although I WILL monkey with compression when my back is against the wall.
With the right shocks, you could actually instantaneously DECREASE the diagonal or crossweight for turn entry, and INCREASE it for turn exit - or vice-versa.
The above is an over-simplified example of how it SHOULD work, and as we all know, nothing in racing is really "simple."
But, if you can get the concept of "controlling" body roll or weight transfer out of your mind, and visualize instantaneously - and momentarily - increasing or decreasing the diagonal or crossweight for better turn entry or exit, and you SHOULD begin to grasp the concept of shock tuning....
....and, by the time the car rolls into your pit stall, you'll have a pretty good idea of what sort of change you'll want to make without needing to dig out a chart.
After talking to the driver on the radio and observing, I usually have a shock ready before the car stops, and we can often make a fairly quick change and get back out top practice....depending, of course, on exactly which type of car/shock mounts I am working with and the abilities of the crew.
I hope this helps....
Stated simply, I use shocks to alter/adjust/change a condition known as, "Instantaneous, Dynamic, Diagonal" - hereinafter refered to as "IDD".
The Cup guys get into suspension lockdown and other concepts for aero purposes, but my work is on the short tracks where the car often comes in with slightly different "aero" shape than it went out with after a 15-lap qualifier .
Okay, got your fresh cup of coffee and a notepad?????
Picture a car sitting on four wheel scales. This car has absolutely equal weight distribution, so all four wheels weigh exactly the same.
Now, if you were to push down on the exact center of this car, all four wheel scales would increase equally.....everybody agree?
If I were to add shocks to the RF and LR that had high - or higher compression values, and I pushed down on the center of the car, what would happen????
That's right....The RF and LR scales would show momentary increases over the other two scales due to the resistance of the two shocks, but everything would even itself back out again after the shocks bled down, and all four wheels would be equal in weight again......OKAY???
What happened here was a change in the IDD. For just an instant, there was more diagonal - or crossweight - with the RF and LR momentarily being more heavily loaded than the other two wheels.
But, once the shocks bled down, the setup returned to the equal-wheel-weights setup.
Now, go the opposite way.....lift slightly on the car.
All four wheel scales should show equal reduction of weight on all four wheels.
Add shocks with more REBOUND to the RF and LR, then lift again.
The RF and LR scales should show a momentary, increased reduction of weight over the other two scales until the shocks allow the wheels to go into full droop.
In this case, we have, momentarily, reduced the diagonal - or crossweight - for an instant.....
......which explains - for those of you who have read the Penske shocks setup manual - the suggestion to set the car up with a slight push on turn entry, dialing it out with LR rebound.
LR rebound induces a momentary reduction of crossweight upon turn entry, but allows the suspension to return to its original setup for turn exit.....effectively giving you one diagonal - or crossweight - for turn entry and a different one for turn exit.
A reduction of RF compression would probably serve the same purpose, but I am most comfortable working with rebounds - although I WILL monkey with compression when my back is against the wall.
With the right shocks, you could actually instantaneously DECREASE the diagonal or crossweight for turn entry, and INCREASE it for turn exit - or vice-versa.
The above is an over-simplified example of how it SHOULD work, and as we all know, nothing in racing is really "simple."
But, if you can get the concept of "controlling" body roll or weight transfer out of your mind, and visualize instantaneously - and momentarily - increasing or decreasing the diagonal or crossweight for better turn entry or exit, and you SHOULD begin to grasp the concept of shock tuning....
....and, by the time the car rolls into your pit stall, you'll have a pretty good idea of what sort of change you'll want to make without needing to dig out a chart.
After talking to the driver on the radio and observing, I usually have a shock ready before the car stops, and we can often make a fairly quick change and get back out top practice....depending, of course, on exactly which type of car/shock mounts I am working with and the abilities of the crew.
I hope this helps....
Comment