I've also heard from a pro driver friend that the 8ight cars start to handle best after about 3 gallons. Which meant they handled better with some slop. When the car is moving, the suspension is always cycling. Some slop will get lost in the suspension cycling, and is certainly better than when something is bound up. Even going down a straight you will never be hands off the wheel to go straight. You drive the car where you want it to go. A little slop won't stop you from being able to do this.

Yes I have. That track runs Proline slicks only and 17.5 blinky.

No expert, but one observation is that you are comparing the front kick of a TC which I believe (well in the UK anyway) is usually 4wd to the front kick of a 2wd drive buggy. Looking at the new Schumacher CAT L1 is has a front rake of 8' to 12' which is much closer to a TC.

I have also worked out, through lots of reading and trial that the more grip the stiffer spring is required to control the angle of the wheel better. I was previously running a softer spring on astro and had a situation where the front outside chassi would be bobbling. I think the tire was gripping, leaning too much so then loosing grip which allowed the chassis to raise and the whole cycle would start again. Moving to a much stiffer spring resulted in the same amount of steering but much more consistent and precise.

Just my observations.

My good friend "Sarinexia" had started this thread years ago and I followed it some after I joined but found myself getting confused (I'm not afraid to admit I'm having a hard time following the material).

I wish there was a single post which could summarize tuning from start to finish from someone (like Fred) that is clean, organized - a one stop shop reference easy to understand and apply to our vehicles. I've read quite a bit of this thread and followed it for a long time. Honestly, I'd do it myself, but I know I'd jack it up. Fred - honestly - if you took the time to make a chart, or provide an outline - a comprehensive easy to follow guide with cause and effects of each tune - I'd literally send you $$ via paypal for that.

It's not quite that simple. That's why tuning guides are nearly worthless. We never really got into much detail here and many things have changed in rc since this thread started that make some of the information obsolete. There are a lot of features about modern cars which I find unnecessary or redundant which only further confuses things.

Just found it.

Understanding and Tuning Roll Center

A simple way to remember that final part on ways to raise or lower the RC, is whether you are adjusting with spacers inside or out, or experimenting with different holes, they are all simply different ways to change the length of the rod. At the end of the day that is what matters in the adjustment. Rod length... Its 99% the same difference which method you prefer.. (Yes, their is a miniscule amount of nuance as to which method you choose, which you can look into if you see fit, but its very subtle and overcomplicates things..)

Using shim/spacer adjustments usually allows changes in smaller increments than changing holes, therefore less dramatic.

I edited and printed out that summary too and added it to my setup notes and 100% agree that it works I spent a while testing roll centre changes on my local indoor carpet track and adjusting rear roll centre once all other settings were dialed. I used rear roll centre to fine tune on and off power grip. I was suffering with off power rear grip and the car would oversteer or snap round too easily and was very unstable in chicanes. By lowering the rear roll centre by adding 2mm of shims on the inner camber link it solved the problem! You could feel it took away a little of the on power rear grip but not so much that the car ever broke free and was actually quicker once I adapted to the new handling.

On another track the rear was a little loose on power with the lowered rear roll centre but the off power grip was good. Here I increased the rear toe from 3 to 3.5 degrees and the balance was perfect.

I now use Roll centre to fine tune the car's on and off power handling on track. If changes to roll centre don't give me the required affect I use springs, roll bars, camber and toe then come back to roll centre to fine tune.

This thread literally gave me the power to set my own car up based on my own driving style and stop relying on other people's setup sheets. For a new car or if the setup has wandered off and I feel lost, I always go back to the kit setup and adjust from there. Although with the Xray T4 basic setup I always find 2.5 springs far too soft so tend to start with 2.7 front and 2.6 rear. The basic asphalt or carpet settings bring you back to a good known starting point that has often been developed by team drivers over a long period of time.

This was a very good read. For a long time I’ve been trying to bandaid tune without really understanding how and what changing a certain thing on an RC and what effects it has on drivability till I started reading this thread.
Would like to thank all the contributors in here as it has helped me learn and also understand how to read the car on the track and where to change things to improve it.
Used to change things around back and forth all the time on the track in hope that I’d wing it somehow and the car behaves as it should till now I do one lap and am able to work out what needs changing to improve it without using setup sheets as none of them have worked for me.
Many thanks to the main contributors in putting in all that effort in explaining things better than all the manuals I’ve come across
👍👍

I have the RC10B6D and I've checked my spring balance as per Fred Swain and using a setup from one of the top pros (Spencer Rivkin) and also the kit setup for the car I can tell you that the spring rates and shock locations are very close if not spot on. This is good to know.

I'm feeling a bit nostalgic today. This thread is now over 11 years old and I remember a period of time in the early/mid 2010's when this thread was always on the front page of the Electric Off Road forum.

The information I gained in this thread from fredswain is still massively useful to me. I'll use my recent purchase of a 22 5.0 DCE as an example to illustrate. I bought the car second hand a few weeks back. I checked it over and the suspension setup was box stock. Before doing anything to the car I threw my electronics in it, mounted some tires, and drove it around on my tiny basement track. The surface is mostly smooth concrete and the grip level is a relatively good approximation of driving on a dry outdoor clay track. The car was a handful to drive to say the least. It felt super sensitive to throttle inputs in a really frustrating way, usually resulting in snap oversteer when trying to slow down before entering a corner. It was just undrivable to me.

The car came with a boat load of springs - I counted 17 pairs. I set the car on the bench and went to work using the spring balancing procedure outlined near the start of this monster thread. I use a phone to record the car in slo-mo as it rebounds from being pressed flat against the bench. As I suspected, and as is usual for all cars I've done this to, the front end snapped up way faster than the rear. Since I'll be running this car on an outdoor dirt track that tends to not be the smoothest of surfaces I decided to soften up the front instead of stiffen the rear. I wound up using what seems to be the softest front spring of the bunch, and even with that I still had to move the lower shock mounting position in one hole to get the front and rear end balanced (note: I also moved the battery fully back and added 2oz into the rear since I'll be on a loose outdoor track. I'd rather have a standup transmission but haven't bought one yet so this will suffice for now). But it was worth it.

The difference it made on my basement track was night and day. The car was so much easier to control. The driving characteristics of the car are way less affected by throttle input which for me makes the car feel so much more stable, consistent, forgiving, and predictable. Looking back at this thread I should probably do a bit more with oils and pistons but for the most part they line up with what I think they should be based on what I learned in this thread - namely the kit pistons use bigger holes in the rear shocks. That's actually rather interesting as there was a time I can remember tuning doctrine being "always use bigger holes in the front and smaller holes in the rear." The last two TLR kits I've had (the 3.0 and now this 5.0 DCE) have bucked that trend, so maybe there's hope they'll start equipping kits with more closely matched spring rates.

Sometimes I wonder why the information in this thread never took off. Every car I've ever used this method on has driven better for me as a result. Based on my experience, and the reported experience of others in this thread, it just seems like so many could benefit from it, but now that fredswain is no longer active the knowledge is at risk of being lost to time. At the end of the day it doesn't matter to me how anybody chooses to tune and run their car, but I just think it's a net loss for this information to fade away into the shadows of the past.

I still use this basic method to get a starting point for every single car I build. I've built some mid motor vintage conversions and with no test time rocked up to races with cars that handle great. Even if you choose a bench setup that is too soft or too stiff, the car will still be totally drive-able and not doing anything "weird". Some roll centre adjustments at the track and you're set!

I've just introduced a friend to the hobby and handed him some of my old cars along with a text file I compiled of Fred's posts many years ago. As a chronic tinkerer, it sounds like he is more interested to play with the setup info in the file than to actually go racing!

Hi,


Could you send me that text file, lots from this thread to work through.

Thanks,

MiCk B. :-)

lol, I also have a document full of Fred's posts for quick reference. And I've also noticed that I can just rock up to a track with a new car that's been setup on the bench using Fred's tests and aside from a few tweaks to things like camber links or toe and anti-squat, the car drives perfectly fine. His methods really do take a huge chunk of the guesswork out of setups.

Mick - if you go back to the first page of this thread and only focus on Fred's posts you'll get about everything you need in the first 10 or so pages. It will take a lot less time than you might think. But if you just want an abridged version of Fred's method it's this:

1. Get your weight placement figured out. Transmission configuration, battery position, tuning weights, wheelbase, front kick, arm length/pivot width adjustments - All of these things have to be set before moving on as a change to any one of these will invalidate every other step from here on out.
2. Spring balance - take the oil out of your shocks and put them back on your car. Your car should be at full race prep minus a body. Make sure your ride height is set, it can change when you take the oil out of your shocks. Press down in the middle of the chassis and as fast as you can release the car so it bounces back up completely unconstrained. This part happens fast so I highly suggest capturing it with a camera that has a slow motion feature. Any relatively recent modern phone should have this capability - I was doing this with budget phones even back in 2014. Only analyze the portion of time between letting the car spring up and when it hits a physical limit that prevents the chassis from springing back up even further (this point is usually obvious because the tires will jump off the bench a little bit when a physical limit is hit). If one end of the car springs back up faster than the other, your suspension frequencies are not balanced. You'll need to decide how you want to address this based on your car and track conditions. You can slow down the suspension by going to a softer spring, moving the lower shock mounting point inward (bigger effect), the upper shock mounting point inward (smaller effect), or adding weight to that end of the car. Do the opposite of these things if you want to make the suspension spring up faster. Once you achieve balance, take note. Write it down somewhere. This is valuable info that you never want to lose. After this point you will never touch your springs, shock mounting positions, or weight placements again. If you change any one of those things you will need to re-do this test (I don't strictly follow this rule, but when I do mess with these settings at the track I know when I get home I'll have to re-evaluate the car).
3. Piston initial setup - basically due to the physics of how oil flows through the pistons in your shock and the rate the pistons move relative to each other front to rear, you want to start out initially with a piston that has a smaller hole in the front and larger hole in the rear. It won't be a big difference, something like a 1.7 in the front and 1.6 in the rear is usually good for TLR cars for example. I've never had a car where I was at something like a 1.7 in the rear and a 1.1 up front. Also stick to the same number of holes front to rear. If you run a two hole piston up front, run it in the rear, too. It makes it easier to understand their relative effects on the front and rear.
4. Oils - I usually start with the same oil weight front and rear and its usually somewhere close to 30wt. You'll do the same bench test as in step 2, press the car down and watch as it springs back up. You are watching to make sure both ends spring back up at the same rate. If one end pops back up faster, figure out how you want to address that based on your car and track conditions and adjust your oils until both ends spring back up the same.
5. Piston Fine Tuning - There are two different things you can do here to see how well your pistons are balanced front to rear. One is dropping the car and watching how it lands on your bench. If one end of the car slaps and the other doesn't you don't have balance. Just like the other tests, decide based on your own car and track conditions how you want to address this imbalance. Smaller holes resist bottoming out and bigger holes make it easier to bottom out. The other test you can do is drive at a constant speed (i.e. not accelerating or braking) over something like a hose or a small wood strip - basically anything that will act like a small speed bump. Watch how the car reacts - if one end of the car pops up in the air higher than the other your pistons aren't matched. Again, smaller pistons make the car pop higher and bigger pistons make the car pop less. Of these two tests, I find the drop test to be a little easier and more consistent. After you change your pistons you will need to go back and re-do step 4 before doing any of the tests in this step again as changing pistons will affect the results of the test in step 4.

The most important and most impactful steps here are 1 and 2. You can skip out on the rest and not really miss out on anything else. But from here you have to go to the track and start tuning.

Once you get to the track, your focus for tuning will be camber links, camber, toe in, anti-squat, caster, trailing/inline, etc. Links will probably be your most impactful adjustments and what you should focus on. Links are complicated, but I've found boiling it down to these few statements has helped me think about how I need to change my car based on what its doing on the track:

1. You tend to feel the effects of link angle on corner entry and you tend to feel effects of link length mid corner and corner exit.
2. Higher Roll Centers (link angled downwards from the hub to the car) makes the car more reactive and twitchy. Lower Roll Centers (links less angled) make the car less reactive and twitchy
3. Higher Roll Centers tend to transfer more load to the outer tire as the car rolls. Lower Roll Centers tend to keep the load evenly distributed across inside/outside tires as the car rolls
4. Longer links keep the rolls center height more consistent throughout suspension travel. Shorter links cause the roll center heights to move around more throughout suspension travel.
5. Cars that have lower roll centers tend to slide/lose grip very evenly/gently and in a way that's easer to control and recover from because the load is more evenly distributed across both tires. Cars that have higher roll centers tend to snap into a spinout more suddenly because as the car rolls and puts more and more load on the outer tire, the tire reaches a point where it "lets go" all at once.

Example: I had a car that felt good on corner entry, but as the car rolled more and more through the corner it had a tendency to spin out. I reasoned that the roll center was moving too much as the car rolled and that the car needed a longer link. I moved the inner mounting position inwards one hole on the car and took it back out. Problem solved - the car was much stable throughout the entire turn.

Holy cow, I can't believe how long this ended up being. Once I started typing it just spewed out and what you see here is my best effort to keep everything condensed. I'm not 100% confident on what I wrote about roll centers and I'm sure someone will yell at me about something I wrote there, but like I said that has worked for me and it's based on my interpretation of everything Frew wrote about roll centers (he wrote a lot about them, btw).

And here's my own document that I compiled with just Fred's posts. However it doesn't have much on oils/pistons. I guess I'll have to add in those posts when I have the time. https://docs.google.com/document/d/1...it?usp=sharing