Lille-bror

Hi.

Any of you 1/8 offroad guys using this device?

http://www.skyrc.com/index.php?route...product_id=194

I made a simpel measurement stand and weighted all for wheels on my buggy with half filled tank. The weight of the left and right rear wheel was equal, but the front had a difference between left and right of approximately 60 grams. To making the weight equal on both wheels, I had to loosen the spring on the heavy side 1 1/2 turn and tighten the spring on the light side with 1 1/2 turn. Don't know if that's the proper way to do it, but as far as I know, thats the way they do it on 1/1 cars.

BigInJapan

iTrader: (18)

I'm assuming it's a nitro vehicle, did you factor in fuel? I would set the weight at half tank for best compromise

ozziii

Winding down or up the spring tensioners on the shocks doesn't change the weight bias, it changes the ride height, if you loosened the spring on the heavy side & tightened the spring on the light side then that will lower & raise each side of the car. To change weight bias you need to move weight around.

Lille-bror

Biginjapan: yeps, with half filled tank as written in the first post

Ozz: Ok. I maintained the same rideheight bye making "equal ±" adjustments.

It's just that I saw a Wheeler Dealers episode, where they used a weight under each wheels and a 75 kg sand bag each front seat. Using that they made preload adjustments on the little sports car, so it was well balanced for track days. Unfortunately I can't remember which season / episode / car it was

Sideshow Bob

that buggy looks close to 50/50 weight distribution...which is good imo for a 4wd car....i have done this on a few different buggies in the past...most of them were bias toward the rear. i wouldn't worry too much about that there. youll probably see that when you change the springs around it might even be different. there are too many variables to take into account. most 1:1 race car springs are matched, so it is easier to control there. Theoretically if you wanted to be 100% sure on you rc buggy, you could put 4x exact solid struts in the place of the shocks. ive read some guys in the 1/10th threads use camber links to do this.

mtpocketsracing

iTrader: (2)

Theyre adjusting the springs preload to compensate the weight difference because they dont understand how a suspension works.
You would need to change the spring weight(strength) not the preload on the spring.

30Tooth

iTrader: (1)

Sound advice here.

Lil, the on-road guys are more into this. First you should put the car on a tweak station to be sure the shocks are pressing the same amount (you gave preload to the shock that was pressing less than the other) or use camber links to replace the shocks built exactly at the same length. Then weight the car on a level surface and preferably with four equal scales. Now if the car has some discrepancy just add/move/remove weight around.

Now more into the 60gr difference, with a full tank you would see close to more ~60gr, that means a ~120gr difference when it's close to empty, that's a lot.

RobinCH

I am using the skyRC which I think is great value for money and have also currently the Tech Works station here for testing.

The skyRC is much more accurate than using a single scale four times which I used to do in the past. The thing is that every time you use the single scale and set the car down it might sit a little different and that can have a huge effect on your readings. When you have 4 scales you can push the car down and let it settle or drop it onto the scales, however you like, and the readings won't be messed up by doing it four times differently.
The Tech Works is then a lot more accurate on top of that and the software gives you great options but I first need to spend some more time testing it and calibrate it a bit better still.

I've yet to devote some more time to learning the theories involved as well. What I know is on real cars they disconnect the roll bar when doing this. To me it doesn't make sense to adjust your suspension left/right to influence weight balance since you're then also changing the whole geometry. (front/rear is fine with me though)
Maybe Paco can tell us more.

PS: It's really easy to balance out the XB8 with the right battery. There are many options available and I've tested anything from 80 to 130 grams. I'm currently testing a 2400mAh LiPo battery that we had made especially to fully fill out the battery tray and which weighs 130g and the car is just a little bit heavier on the electronics side now with half a tank.

30Tooth

iTrader: (1)

Robin, will you kindly post a pic of your XB8 on the SkyRC scales to see weight bias?

Lille-bror

Hi all. Yearh, as written in the first post, it was a test setup and I had some ±10 grams on my readings but it was still a notisable diffence. It was the cars right side that was most heavy so the difference would be less with a full tank of fuel.

Never mind me and my stupid tests.

Robin: So what exactly do you use the weights for on a 1/8 buggy?