Battery weight. The front tower had this change as well (ball stud mounting location raised.) The old setups had much heavier batteries and required much higher roll centers. With the move to lipo, people were running stacks of washers, hence the change.

Battery weight. The front tower had this change as well (ball stud mounting location raised.) The old setups had much heavier batteries and required much higher roll centers. With the move to lipo, people were running stacks of washers, hence the change.


Good points. I stepped away from the Elec. side for 11-12 years and much has changed in that time frame. So I still find myself playing a little bit of catch up more often than not. LOL.

With roll centers and everything else, add in that many also play with batt. sizes and things get a bit complicated.

Which gives me another question, and it does have to do with roll centers. With the vast options for batteries these days, would the weights of those batteries have to be taken in to account when playing with roll centers? I'm thinking they should, but I doubt that many would do so.

They definite affect things, but tuning roll center is the same as it has always been. Unfortunately, most people I run into are afraid of tuning ball stud washers as if it is black magic. They would rather change springs, which is a far greater change. Makes no sense, but people understand springs.

Onroad guys for sure understand tuning with ballstud washers, offroad maybe not so much. I know I still struggle with that. Mostly because I'm lazy. When I find a setup that works well for me, I rarely change it . LOL.

Tuning roll center is the same as it has always been? I'm going to say yes and no. That was part of why I asked about the different weights of batteries. I know when LiPo's were first being used in TC racing, many racers were adding lead weights to their packs to keep them all at the same weight. I know that was in part because the chassis were still set up for the heavier NiMh/NiCad batteries. Yet adding the weight to the packs made sence to me. That way you knew all the packs would feel the same in the car, and any setup changes would also have the same feeling between packs.

So now with many racers playing with full size and shorty packs, I'm thinking that the roll center needs between the two will be different to get the same "feel". So yes, you're still tuning the same way, but one will not work for the other perfectly. That's my thinking, but maybe I'm way off in that thinking..

Depends on the weight difference, but very potentially yes, and no. Here's why I say that. If you run a lighter car, you're going to need slightly lighter damping to absorb bumps. With this lighter damping, the car will roll more, but the roll potential increase may be offset by the car weighing less.

This is why I tend to not make generic statements. The roll center is the thing you tune last--once you get front/rear weight transfer and camber gain figured out. Where it needs to be is very hard to predict. I like to think of roll center as just the amount of available weight at one end of the car that is also applied to chassis roll.

Wayne

Ok so we're thinking along the same lines as far as how battery weight and roll center relate. This is something thst I see many people not take in to account when trying to determine the effects. For example, I still run full size packs (Reedy 500 and 5500) and most of the faster guys at my track all run the shorty packs. So what my car will need for a roll center adjustment vs. what theirs will need to have the same feel, will be different if all other things are equal or close to.

I think that could be why an A hub setup and C hub setup can be so different and have the roll center difference, yet still have a simular look and feel on the track. Again that's my thinking on it, but I admit I'm still learing.

Also,

The TC6.2 has three different ballstud washer sizes (.5, 1, and 2mm) do you think those would be good to use for fine tuning? I'm thinking they could work for the rear inner ballstud.

I am one of the faster guys and I still run full size packs, for good reason. Now that I've gone to big bore, I'm thinking of taking the shorty plunge because of the lighter initial damping the big bores with 1.6 pistons offer. Previously I had resisted the shorty packs because our track was previously very bumpy and any weight I removed always made the car less stable regardless of tuning around it. With the lighter damping, bumps can be absorbed via initial damping instead of extra weight, so a whole new world has opened up.

Rcaer 53 on his video says that snugging up the diff screw all the way and then backing it out is wrong really wrong as he puts it...yet Caveleri says he gets it all the way snug and backs off about a 1/2 turn as a starting point. It seems that it would be easier to do it Cavs way. Also if he backs it out a 1/2 turn, for a Mod obviously, how much would you back it off for a 17.5?

Depends on the age of your diff spring and if you compress it at first with pliers. Also depends on if you use an allen key or wrench. I tend to tighten mine down all the way with an allen key (the one key (5/64) I keep around), then I back it off around 1/8 and then adjust to feel. That's exactly like the book tells you. You just have to get used to the feel you want.

The reason he does not tighten all the way down is because it can flatten and damage the balls and rings.

And that's why I use a key instead of a wrench. Sticking a key in there long ways makes it next to impossible to over-tighten and dent the rings initially. You'll be hard pressed to damage those balls unless they're not carbide or ceramic.

I have a savox 1257tg servo. It's not listed in the manual, what servo horn and which spacer do I use?

you definatly want more rotation in a stock car, if you want loosen it a bit or try 2.5 toe. When I ran 17.5 in my b4.1 i did and it defiantly could rotate quicker then the 3.0 but since its slow theres no problem with control
.

Futuba horn, not sure of spacer. install the servo mounts and set servo in the chassis to visually check