That's why there are pivot balls at the top and bottom, though the top isn't a true ball, unless they change that for the BB's. It allows the piston to travel square to the shock bore even if the shock itself is not square to the arm/tower. Not to say that you would want an extreme angle like 45°, but a few degrees will not hurt it.

After much thinking, fiddling, and testing I have come to another pretty set standard. At least in my opinion of course. Feel free to have your own! As we all know I am an advocate for balanced spring rates and feel that if you change the front spring rate you should also change the rear to match. I now feel the same way about shock pistons and pack which goes against what I stated earlier in the thread when I was first playing around with springs. I believe the lighter end of the vehicle should have more pack than the heavier end and if you have a 2wd where the back is much heavier then you also should have a much greater amount of pack in front. I also believe as with the springs that once you balance shock pack, if you change one end, you change the other.

This is actually sort of true. We do but we don't. Since front shocks almost always are shorter and have less total travel since they are mounted further inwards, the piston never has to move as far as the rear from full extension to full compression. This means that the piston will go a shorter distance over the same amount of time which is really just a slower piston speed. This also leads to a correspondingly slower velocity of shock oil through the holes in the piston which means less pack for the same size and amount of holes. In layman's terms, if you have the same shock pistons in the front and rear shocks, you don't truly have the same amount of shock pack. You merely have the same pistons? Still following me?

The solution to balance them out is to increase the pack at the lighter end of the vehicle. In nearly every case except perhaps with some fwd on road cars, that will be the front. The front shocks need either fewer or smaller holes in the pistons, or both, so that the actual fluid speed through the piston during shock compression, is the same as the rear shocks per the same amount of wheel (not shock) travel. Got it?

So what have people been using all these years? Well most people it turns out have much stiffer front springs than optimal and way too little shock pack up front. The higher spring rates lead to an understeer condition as a result of higher front end roll resistance. The solution for many is to add weight up front to "hold the front end down". The result is not for this reason but rather as compensation for the higher than necessary roll resistance. Moving weight forwards and doing nothing else to the setup effectively decreases front roll resistance and increases rear roll resistance which means less understeer. A rear bias car inherently understeers and shifting weight rearwards, all things being equal, results in more oversteer while shifting weight forwards results in understeer. You can see from the above why this sounds backwards. You just have to understand what else is going on. All is not always as it appears.

The lower than optimal shock pack that most run up front isn't so much felt as a problem up front but rather one at the rear. Over rough terrain the front end may seem to glide over the bumps but the rear may appear to bounce hard and become unsettled. Again, the problem isn't where is appears to be. I am still playing with ratios of shock pack on my car so I can't tell you exactly how different the holes need to be between front and rear yet but it can be quite significant on a 2wd buggy. Your shock oil weights will also need to be correspondingly different as well with the lighter oil going to the lighter end of the vehicle. This too flies against what I was originally doing during the initial spring balancing stages. Learning is fun!

Play around with this and let me know what you think. Again, this is all my personal opinion so don't chastise me if you disagree. The results I'm getting just playing around with it seem to verify the thinking. It just gets easier and easier to drive. Keep in mind I'm not a point and shoot type of driver so a different driving style may very well favor a different setup.

i have a simple question that i've possibly overlooked through all of this.

What happens if you raise or lower the camber link parallel to the angle you've already established? Or in other terms, 2mm up outside and 2mm up on the inside or vice versa?

Thanks...

This thread has helped me get better as tuning a setup,there's so much information per page!First,the usual push is gone on the 1/8 buggy and I'm trying to improve my 2wd buggy.That's the most difficult task because I can't reach a basic setup yet with spring balancing/roll centers/shock pack.Will read a little more and report on the next days.
Thank you Fredswain and other contributors,my head is cleared from most BS other people told me regarding setup.

Argh...still have too much rear traction,buggy lifts front inside wheel when turning on-power and can't slide the rear while cornering well going to try short rear camber link next.

A rear bias car inherently understeers and shifting weight rearwards, all things being equal, results in more oversteer while shifting weight forwards results in understeer. You can see from the above why this sounds backwards. You just have to understand what else is going on. All is not always as it appears.

This statement has me confused. From my understanding of what you said more weight foward equals oversteer. Mind explaining?

Typo. A rear bias car inherently oversteers all things being equal.

Thanks. Makes more sense.

Success!Managed to unhook the rear end,some things I took from the 1/8 buggy setup were:short rear camber link and shocks further out on the tower and on arm.Now I can start to finetune.Again thank you.

Scenario A-
If you draw it out on paper it should lower the instant roll center if you raise the link at both ends while keeping it parallel to the lower arm. Lowering both ends would raise the instant roll center.

Scenario B-
Trying to vision it going the other way (raising both ends of the camber link and keeping the outer end higher than the inner) would lead me to think it would lower the instant roll center. Lowering both ends would lead me to think it would raise the instant roll center. Kind of opposite of scenario A

Someone want to draw it out? I bet you will find there is a range one would have to keep within or else everything goes bonkers.

tried to draw it out but still couldn't envision what would occur. it appears that by raising the link equidistantly, that your would be lowering the "roll center" initially, however i get lost when the suspension is under compression.

The reason i ask is my SC10 seems like it wants a lower roll center in the rear, however in stead of raising the inner link, i lowered the outer link. what have i done? Maybe it's like an incremental adjustment, if that makes sense??????

I thought I learned somewhere possibly this thread that the two ends produce the opposite effect of each other. What I mean is this.

If you move the inside up, roll center goes down.
If you move outside up, roll center goes up.

Now if I have that correct, I dont know what the effect of moving both up would be. Do they cancel each other out ? lol

Hideeho
Fred, your comments about shock pack & looking @ Ty tessmans b4.1xl (in addition to a modified truck chassis he runs truck shocks & towers in the front) got me to thinking about shock length. What is the advantage of having shorter shocks on the front than the rear (there has to be some because everybody except Ty does it).

My guess (& it is strictly a guess) is that it has to do with a preference for greater shock travel on the heavier end to allow more time for the oil & piston to damp the motion. This leads me to the question if you have longer shocks (& travel) in the front wouldn't that allow you to tune the shock so it actually damps the motion instead of relying on pack to stop the travel? Wouldn't that make the front end smoother everywhere on the track?

My real quandary is why do 4wd buggies have longer rear shocks than front? They have much closer to a 50/50 distribution than a 2wd, but all of them have longer rear shocks than front (my agama has 110mm front, 163mm rear, yes they really are that big), so why not have very similar, if not the same, length shock?

From what I've seen (I don't race them, so I may have missed something) on road cars with 4 wheel independent suspension that is the same type setup on all corners have exactly the same length shocks (referring mainly to tc's as most others have effectively a live axle rear end). The t/e max has the same length shocks all around, but I hesitate to mention it as it is more a brasher than racer.

Some TC's have shorter front shocks,that's because front shocks are mounted more inward to clear the wheels when turning.That's why front springs are harder when talking about same color,because of the leverage is different front and rear.See if you can achieve same droop(not shock length)front and rear on the agama.

hideeho
I was unaware some tc's have shorter front shocks.

for absolute maximum droop as set by the shocks, not the droop screws, there is more droop available in the rear. the rear towers are taller, so its not 50mm more, but it is more. of course, using the droop screws, I can make the droop match.

I understand there is a difference when the shock length is different. why would you want that difference? wouldnt it be cheaper to build, easier to tune, easier to maintain, less different parts to keep track of if the shocks were the same length at each end? imagine using freds shock balanceing technique & all you had to do was multiply 2 numbers (rate of spring at one end X percentage of weight @ other end) together & you have the exact rate of spring you need. your done with all the droping & adjusting shock mount points.