The setup sheet is an oddity. No one measures that way except for kiyo (trf mechanic) apparently. We discussed this including me asking Jilles Groskamp direct on his FB page.

Oh, and it's 3.5mm difference between under arm and centre of pin

Am I the only one that finds the way droop is measured to be confusing?

Not just the direct measurement (under arm/hinge pin), but unless I'm mistaken, it's the limiting of the upward travel that affects handling.

However, the independent measure of (effectively) chassis to arm position is only one of three variables that affect the movement of the chassis. Tyre diameter and ride height also play a part. For example, setting the droop (as per sheet) along with ride height can be impacted by tyre diameter, yet this is rarely recorded.

What's more important? "Droop over ride height" or the three independent measures?

Am I over-thinking this? :confused: :lol:

Phil.

Since a rubber tyre is basically consistent in it's diameter, it doesn't matter. Foam tyre racers would always measure the droop over ride height rather than stick with a single droop setting.

Thanks for your replies.

Just to be sure, if I want the 5mm droop specified in the 418 setup sheet I linked to, I measure 1.5mm from bottom of chassis to under the arm?

Do you guys normally measure droop from bottom of chassis to under the arm? Seems like the easiest way to do it.

No.

As I said earlier, if it is a measurement of 5mm it is sure to have been measured from under the arm anyway.

1.5mm is a crazy setting and probably isn't even possible.

Any given tyre is going to be consistent, but different brand tyres have diameters that can be quite different. I've seen up to 1.5mm difference across Muchmore, Ride, Sorex, LRP and Sweep. The local tracks have different surfaces which favour different tyres.

Changing tyres would affect ride height, which if then adjusted, alters the droop over ride height and thus weight transfer. Could be anywhere from 0.5mm to 0.75mm or possibly more.

So, in my view, the information about tyre diameter is important in understanding the complete picture. Or, does some magic about axle height (ground to axle height - function of tyre diameter) cancel this out?

If I'm over thinking it, then that's cool :)

Of course the different diameter of some tyres requires adaptations to the droop setting - realising that is the distinction between a smart racer and the racer that thoughtlessly copies setups!

After some more google work and watching some youtube videos with Jilles groskamp I now know that the 5mm droop is measured under the arm.

And yes, 1.5mm would be a crazy setting, not even possible on my 418.

Case solved....and closed :)

I think you are indeed confused.

By two things.

It is generally accepted that rubber tires are pretty much the same diameter (unless you're running some left field tires, I don't think there's more than .2mm difference between all tires sanctioned by various international bodies to which most of the clubs worldwide adhere).

Secondly, most of the time ride height is controlled and it seems to hover around 5mm.

That takes two variables out of the equation. Measuring droop over ride height becomes then the norm (or how far arms can travel downwards from chassis bottom).

Rubber tyres are definitely not all the same diameter.

Hell, measure some RIDE Re vs Rex - quite a big difference (circa 2mm)

Alright friends, summer is nearly over and so is my fling with the wonderful 418. It's a great car, but it's time to move on to something new. I'm selling my 418 with lots of nice little upgrades for a killer price.

http://www.rctech.net/forum/r-c-item...-w-extras.html

See you guys in the 419 thread next year. :)

So you don't have a car until December/January?

Nah, got the Awesomatix for indoor season.

Has anyone tried the servo mount from the TB EVO 6 on your 418?

I will try it on Saturday on our home track.

Will that not just stick the servo more outwards effecting the balance in a more negative way?