I can see the effects of the balancing.


When in steady state cornering it seems to work better. It seems more controllable on the straight and through the fast sweepers but to be honest I did dial in a bit of toe out at the front after I balanced the springs and that may be causing the stability at higher speeds.

It is also more stable in the fast sweepers. I am quite happy about that. Our fast sweeper has a set of rolling bumps that can really wreak havoc at WOT. Sometimes the truck will just set down a bit wrong and it will either jump to the outside or the inside of the turn and its all over. Now it lands with pretty much the same vector it had when it took off so you don't have to be wheeling it through the turn so much. Very nice.

It seems more stable under acceleration over bumps. It kinda just gets up and goes. Not too much drama as long as there's good traction.


The only real place I would like it to work better is coming out of the turns. It seems to want to go around on me if I get on the throttle too hard coming out. I can tune the throttle to be softer of course... but I don't think that's the real solution. I think that's a bandaid.


It "looks" to me like it's transferring the weight to the front, I roll through the turn off throttle or with very little throttle and about the time I get on it it wants to break loose and come around. It seems to not be able to transfer weight to the rear tires fast enough or maybe the rear roll center is too high so the cornering stiffness is too much at that end? I have 1.5 AE spacers (I picked up some washers that are about 1/2 the thickness of the ones that came with the truck) under the front balls and nothing under the rear balls. I found that if I adopt a more "point and shoot" driving style I could run decent laps, but not fast laps.


From what I've read/understood in the thread I should either raise the front roll center or lower the rear in order to reduce oversteer. That seems to make sense because I had that thickness of spacer under the front balls with the other (stiffer) springs. I have now reduced spring rate without then raising the roll center height to bring my wheel rate back up to where I had it.


As a side note... I found that the more I turned down the dual rate the easier it got to drive. That said... It was never "difficult" to drive... just a bit touchy. Very "pointy" as I like to call it.

What about droop? Could you just simply not be transferring enough weight to the back under acceleration? Too many limiters in the front shocks?

M1Combat- Did you try adding one spacer to the rear (to lower roll center) or take one away from the front?

Something else you can try to take away exit steering is moving the rear hubs forward.

I would say add more droop to the front (probably not much 1 to 1.5 mm at most) or add more anti-squat.

You could try more rear toe, too. Then again, with much of an adjustment there, especially if the toe is gained at the arm mounts, I wonder if the springs would no longer be balanced.


Yeah, but what about all the juice we put into the batteries when we charge them?

I agree. This thread is great.

I thought I'd post this here. I've been getting lots of pm's lately asking about balancing. I have no problem at all helping people out and have gotten back to most of you. There have been some people though that have been asking stuff that we've already gone over here several times. It takes a lot of time to type all of that back out over and over again. If you have a question in regards to spring balancing, the answer is probably here somewhere. I know there are lots of pages but at some point there is also a cliff notes version hidden here somewhere too that can be used as notes to answer questions. There are several people in this thread now who understand the balancing method so if it's unclear just post the question here.

I'm not trying to be rude in any way nor am I trying to ignore anyone. I'm just pointing out that much of this has been covered already and it just takes too much time to repeat it over and over again. New questions that we haven't really touched on don't bother me. At some point we may get to them here though.

Please be aware that my wife and I just closed on a new house last week so right now is a very busy time for me which is why I'm suggesting any questions just be posted here rather than to me personally. There may be others that can help. I'm just booked right now and don't have much time to respond. I get to people when I can but I apologize if I missed you.

Anyone know how to get stuff stickied to threads? We could get the Clif's notes version stickied right at the beginning of the thread so its easy to find. Who is our moderator??

Something that may help you guys out is to do an advanced search of the thread.
Search for all posts that are written by Fredswain. This reduces the number of pages
to 7 or 8. Most of the valid questions are answered and it is sure easier to read.

I haven't contributed but I want to thank you for all of the work you've done.
I must admit that I haven't completly followed through with the method, just dabbled.
I did enough to gain a better understanding of tuning, enough to break away from the setup sheets.
Thanks again Fred.

Here let me make it easier-

Spring Rate Balancing

A well setup car can make an average driver look good. A poorly setup car can make a good driver look average. A well setup car makes a good driver look amazing. A poorly setup car makes a poor driver a road hazard!

Any suspension has a natural frequency that it wants to resonate at. That is, the speed at which it will vibrate in an undamped state. To start tuning you must begin with absolutely no shock oil in your shocks. Springs only. Pick the car up and drop it. 5 or 6 inches is fine.

Make sure you drop it level. If the front and rear bounce at the same rate, you have suspension balance. You may run into a situation where one end bounces much faster than the other. This is bad and what may happen is the car will porpoise.Whichever end of the car moves up and down slower than the other with no shock oil is the end you should try to balance to. Another way to see suspension frequency is to set the car on the table, floor, etc and then push one end down all the way. Let go and watch how fast it rises. Now do the same at the other end and again watch how fast it pops back up.

Here's another thing to try. Figure out approximately where your center of gravity is. Just use a finger on each side of the chassis and try to pick the car up. Move your fingers farther back if the front end is rising first. You'll probably end up somewhere near the center of the battery in location. Once you find it, push down with 1 finger on this spot. The front and rear of the car should both go down at the same time if it is balanced. Do this on springs only as shock oil can change this a little bit.

The faster they bounce, the higher the suspension frequency.

· Typically high frequencies are used for smooth surfaces.
· Lower frequencies for rougher.

Off road cars will typically use lower suspension frequencies.
This is a technique that must be done in a certain order. Don't second guess things and don't try to do things out of order. One step at a time. That's how you know what works and how.
To find balance:

1) use different springs to try and balance front and rear, to get same suspension frequency
2) tune with lower shock location; father out = higher frequency with same spring
3) fine tune with the upper location; father out = higher frequency with same spring

Most of your balance changes will be affected by the lower shock mount positions. Moving the lower location farther out gives you more leverage and hence a higher frequency for the same spring. The top locations are for fine tuning and dialing it in. Let's say you have a setup where the front of the car bounces up and down faster than the back. You need to slow the front down. Obviously you could try to use a lower spring rate with the same locations until you find a good set to use. Another way however is to move the bottom shock location inward. This assumes of course that you can. If you can get close this way then you need to move the top over to try to dial it in. Again this assumes that you can move it and that you can find a balance point. The more laid over the shock is, the slower the suspension frequency.

Now let’s say you got it close but you couldn't quite get there. The front still moves just a bit faster than the rear and you can't slow it down anymore. Go back to the rear. Try to get the shocks more vertical. You could always move the bottoms outward if possible but this may be too drastic. If for some reason no matter what combo you try front to rear you cannot achieve balance, you need to change springs at one end and try again. This is very possible. It is far easier to hit an unbalanced setup than a balanced one.

After you have a balanced setup, adding oil
Add shock oil. I start with 20W front and rear *. Now you need to drive the car. If the front and rear bounce around too much on the springs then go up the next weight. Let's say the rear end settles down and isn't bouncing around on the springs and the rear isn't so stiff that the wheels are starting to bounce on the track. It's perfect. Leave it alone. Let's say the front is still spring bouncing though. Keep going up in oil weight until it doesn't.

· rear or front end bounces around = go up in oil weight
· wheels start bouncing on the track = go down in oil weight

* If you just drive around with this light oil, you'll notice that the car is probably still bouncing on the springs, just not as quickly. Your goal is to keep increasing the oil weight until this stops happening. It will happen at each end at different rates with the rear being a bit more obvious as there is typically more weight there. Once you find this point, it doesn't mean you've got the perfect weight.

Note about spring collars
The spring collars are only adjusted to get a level ride height. Once you have them set to give you that ride height, forget they exist.By compressing the springs more with the shock collars, you are storing potential energy. Forget what you know about the shock collars and their effect on the springs. Use them only to determine your ride height and rely on the springs themselves to determine the rate.Preload has nothing to do with spring rates, but directly affects ride height. Ride height plays a significant role in how your vehicle jumps.


How to tell if you have a good ride frequency after you've found balance
You can be balanced but not be good for your particular track. It's easiest to tell if you have too high of a suspension frequency (too stiff). What will happen is that when you first start tuning with a low weight shock oil, you'll find lots of spring bounce meaning your wheels will stay on the track just fine when smooth but the car will still bounce up and down on the springs, much like it does when driving with no shock oil.

Your goal is to get to a shock oil that stops this spring rate bounce, or minimizes it, without getting so stiff that the wheels themselves start to bounce off of the track. If you have too high of a suspension frequency you'll never find this point. You'll have spring bounce and then you'll get wheel bounce but you won't ever truly find the middle. You'd then need a lower suspension frequency. Any frequency equilibrium below this level could be used but for the most stability you want the suspension frequency low enough to effectively dampen the bumps yet high enough to conform to all terrain while not bouncing the vehicle around all over the place. Only you will be able to determine where this point is and it may be different from one track to another.


Tuning with camber
Generally a car with a lower roll center will be more stable at high speed. The chassis reacts slower to transients. A car with a higher roll center will generally be less stable at speed but will respond faster to transients. They will also be less forgiving. Modern cars with their lower roll centers feel easier to drive as a result. They feel more stable and this is important for high speed straights and big jumps. The wide track and longer wheelbases over the older cars also help this. However low roll centers come with a price. It makes it harder to turn.
Now keep in mind if you are running a certain roll center at one end, start by setting it about the same at the other. For a 2WD rear motor buggy, I'd start by setting it very low. If you have problem pushing through the corners, raise the roll center in the rear a bit until it's balanced the way you like it. Don't necessarily be content there though. You should try to then raise the roll centers all around and drive it again. You'll know where to finally stop when you are finding the car too touchy in the high speed sections.

Shock and spring stiffness also play a role. The lower your roll centers, the more the shocks and springs control the lean of the car. The higher your roll center, the more the suspension itself controls this and the less of an effect the shocks and springs have on it.

The lower your roll centers, the more important having a stiffer set of springs or thicker shock oil becomes since more forces are applied to them in corner. "But you said to adjust the shocks and springs only around how the car handles the bumps and not it's cornering ability." Yes I did. Hopefully your setup will all work out but what happens if your conditions require a fairly soft suspension setup but very low roll centers? If this happens then you need another way to control roll and that it with sway bars. Not all cars have them but some do. It's not to say you always need one either but you might. You might not need them at each end either. Perhaps you only need one in the rear or only in the front. Then how thick of one do you need? These are all very hard questions to answer but the best thing to remember is that if you need one, make it as light as possible while still getting the job done. Don't automatically assume you'll need one right off the bat though.


Camber link length
In regards to camber link length, since our roll center isn't just one static point we need to establish that it moves over a certain range. Let's say we have 2 identical cars sitting at a level with the arms ride height. Let's say that the camber links are pointing at exactly the same direction as each other. Let's just say they are perfectly parallel to the arms. As the suspension compresses, these links move too as they have to. However one of our vehicles has shorter links than the other. When the suspension is at max compression, the vehicle that has shorter links will have them pointing at a much steeper angle than the vehicle with the longer links. At this point the vehicle with the shorter links has a higher roll center than the one with the longer links, even though at our ride height they were at the same point.

· Short camber link = higher roll center
· Longer camber link = lower roll center
· moving links outwards but keeping them the same length = slightly raising roll center

· high roll center works better with a higher ride height, softer suspension,& softer tires.
· lower roll center works better with stiffer shocks, stiffer tires, and a lower ride height.

Now let's say we have 2 vehicles as above with the same setups sitting at level ride height. Now let's say they each have the exact same length camber links. One of them has it's camber links sitting exactly parallel to the arms but the other has the inside end of the links mounted a little bit lower which means the link slopes down towards the car a little bit. The one with the lower inner location has a slightly higher roll center. Now as the suspension compresses and the links move up, this one still maintains a higher roll center than the other one. The difference between them is pretty constant everywhere.

· Lower inside end of camber link = higher roll center
· Higher inside end of camber link = lower roll center

Alright so now you're wondering how to dial in the roll stiffness using your camber links.
First off, by this point you should have your shocks and springs sorted out. The car should handle the bumps and landings well. If you changed any of your shock or spring settings based on its cornering ability, change it back!

I prefer to start with a ride height where the arms are level. At this ride height I also like my camber links to be level. I generally set them for about as long as I can get them provided they aren't longer than the kingpin to kingpin distance on the arms. When you push down on the vehicle at each end, any camber gain (wheel lean) you get should be equal front to rear. At least at this point it should be.

This is just a starting point. Things are going to change quite a bit before we are done.
Now go drive it. Try many things. Go fast into a corner and hit the brakes hard. Does the car plow through the corners or does the back end swing around? Accelerate hard out of the corners under power. Does the car have severe push where the front inside wheel comes off the ground or does it over steer?


Coming out of a corner
Let's say under hard throttle out of a corner the inside front wheel lifts off the ground and you get severe under steer. Most people would be tempted to stiffen the rear springs. Don't do this! You do need more roll stiffness though so start raising your rear roll center. I prefer to keep the links level at level ride height so I'd start shortening the links. Keep testing out of a corner. Does the problem fix itself or does the wheel keep coming up? Can you lower the front roll center? Can you make the front link longer? This will reduce some front roll stiffness allowing the front to roll more. You want all 4 wheels on the ground in a corner!

· Understeer out of corner = increase height rear roll center, decrease front roll center
· Oversteer out of corner = lower rear roll center, increase front roll center


Going into a corner
What happens if you are going hard into the corner and slam on the brakes? Does the rear end fly around resulting in a spin? If it does you may need to compromise on some things. If this scenario takes place, too much weight is transferring forward which means less front end rake is required. (TRL22 has adjustable rake) So for the rest of the world who can't correct this issue, what can we do? Well one thing I didn't get into is the front caster blocks. Play with different types here as they each have a different effect on off throttle turn in vs on throttle turn exit. You may also need to dial out some of the rear roll stiffness again to get some inherent on power turn exit under steer back. You are going to have to adjust your driving style.

· More caster = more stability on straight and going into corners, less steering mid corner
· Less caster = less stability on straights and going into corners, more steering mid corner

Bookmark, copy & paste, do whatever works for you.
Next- Paypal Fred some $$ for his knowledge!

This seems to contradict itself.

Okay, lets all give KC's post the once over, discuss the results and get it pinned to the beginning of the thread. Does anyone know who the moderator is for this thread? Or if we have one? I know Fred's in the process of moving (congrats!!!!) so if anyone else knows how this works, speak up. Lets do this the right way.

Yup. #3 is wrong.

The more laid over the shock is, the slower the suspension frequency.

Fred said it & I believed it. It does sound contradictory until you dig deeper. Here is what I found by using mathematical calculations for finding suspension frequency. (Yes, it's rocket science. All you 'engineering' guru's probably know the formulas.)

The lower shock location changes suspension frequency more than the upper. If you calculate suspension frequency mathematically the truth comes out.

Perhaps it should better be written as-
In general the more laid over the UPPER location is the slower the suspension frequency. And, the closer the LOWER shock mount is to the chassis the slower the suspension frequency.

**tune with lower shock location; farther out = higher frequency with same spring and upper location

**fine tune with the upper location; farther out= higher frequency with same spring and lower location
It might be possible to come close to the same frequency by mounting the shock in two different locations-

Inner upper and outer lower vs. Outer upper and inner lower.

Have I confused you yet? Mathematically I found if you want the lowest suspension frequency mount the lower (bottom) end of the shock on the inner most position at the a-arm and the inner most position at the top.

I'll go edit the previous post.

^ It should say farther out, not "father".

Thank you Fred. It's hard to do this at work. Ooops! Did I just say that?

Let me thank you again Fred for provoking me to think and do some research. Your sharing of the basic methodical knowledge of where to start has helped me tremendously!!!!