Strickly Setup

[werner1619]

:D

How about a forum entry only for discussing rc Setup theory and principals?
I know all car owners discuss it in their particular make tread, but I mean discussing the theory of handeling and setup as suppose to setup for a particular car...?

Any takers
:)

[Col]

http://users.pandora.be/elvo/

Everything you'll ever need to know...

[werner1619]

Your the man

[Col]

Not me, my friend, Elvo the man:D

[Arn0]

Elvo website is The reference with every bit of details about vehicle dynamics.

I use to give this reference book also as it is simplier, you can bring it with you and it is made for beginner but helpful for everyone: RC Handbook (http://www.petitrc.com/reglages/RC_HandbookV3-2.pdf). I'm thinking about doing an update with some lines about BL and on an internal ratio chart for buggies. If so, check this page (http://www.petitrc.com/view_news.php?id=5357), I will delete the previous version.

[werner1619]

Thanks for the link,

Don't know what you mean" lines about BL " ?

The thing is, sometimes all the info is just to much with all the variables, so I get lost and can't make up my mind about what adjustment would be the best option for a certain problem?

Please think about his and give me your explination:

**You are racing your 4WD buggy on astro turf and all is good. During the Qualifiers you fall behind, you sum up the problem to not keeping enough corner speed. Now, lets assume you only want to adjust your shock springs.... do you go harder or softer on the spring rate to keep more speed in the corners?***

Take into concideration all the effects you will have on the buggy as a whole by adjusting the spring rate. I know you would need more info to make an informed decision, so please humour me.

Thx

[sosidge]

**You are racing your 4WD buggy on astro turf and all is good. During the Qualifiers you fall behind, you sum up the problem to not keeping enough corner speed. Now, lets assume you only want to adjust your shock springs.... do you go harder or softer on the spring rate to keep more speed in the corners?***

I like setup chitter chatter as much as the next man, probably more, but this question is not posed very well.

Firstly, I would never limit myself to only changing shock springs. Everything on the car can affect something else, not always to an overall benefit.

Secondly, a lack of corner speed may present itself in many ways. Too much under/oversteer perhaps. Or the correct balance but not enough momentum/grip through the apex.

If you can be more specific about the handling issue it is easier to be more specific about what solutions you might seek.

[werner1619]

As said earlier, I know you would like to have more info, but would like if you would have a Stab at it if you don't mind.

I want to explain more why I ask this question in this manner, but feel I might lead you in a certain direction and thus not getting right answer....

Think weight transfere and how harder or softer springs would effect your corner speed...

[sosidge]

Ok then, here is an answer for you.

Run stiffer springs all round.

[PaulRotheram]

You can't answer that question correctly, there are too many unknowns! Track type, track condition, amount of grip avaliable, size of track, flowing, technical, temperature etc etc..

Give some variables which are more specific and the change can be discussed further.

[werner1619]

Ok,

Track surface: astro turf, swept clean
Traction: Med
Temp: 28 degrees C
Track layout: medium size, 1 lond straight and tight infield

Does it help..?

[sosidge]

It's not really about weight transfer. Weight transfer is more or less the same. It's about how the chassis responds to the weight transfer. It's about stopping the car from rolling too deep into the suspension and wasting energy, and helping it carve through the turns. If the grip is up then harder is better until you start losing grip.

This is obviously assuming the track is perfectly smooth. Hard springs are less good over the bumps.

[werner1619]

Thank you for the explanation,

This is what I thought...

SOFTER SPRINGS.
you would have more weight transfere, more turning power in the corner allowing you to use less steering to complete the corner. less steering would result in less drag, less speed being scrubed off...

HARDER SPRINGS.
Car would respond quicker to input, as you said does not roll as deep into the suspension so less time spent recovering from the weight transfered, might have less traction of weight transfere resulting in more slip, more slip would create more friction, more friction would create more traction and ultimatly more cornering power.

.........???

Which way...........???

[sosidge]

Well, there are a couple of things there I would not agree with.

More weight transfer with softer springs? Not significantly. Weight transfer is mostly down to the acceleration/braking and cornering forces. Since you are probably driving the track the same each lap then these will remain constant as the setup changes. There will be a small change in the static weight distribution as the car rolls but that is pretty insignificant.

What will happen with the weight transfer is that it will be transferred to the tyres more slowly with a softer spring, this will keep the grip up for longer before the tyre overloads and goes into slip.

Less steering input required with softer springs? Probably not, assuming you go up by the same rate all round and the balance is constant.

In terms of cornering power, two otherwise identical cars, one with soft springs and one with hard springs will create more or less the same amount around a constant radius corner at a constant speed (this makes a few assumptions about tyre grip remaining constant etc). That is to say that when the forces are balanced springing doesn't really make any difference.

There is often an instant at the apex of the corner where the car will be balanced in this way. Mid corner performance is a big indicator of overall balance.

What we are aiming to do with suspension settings is adjust the "feel" of the car as it changes from cornering to accelerating and braking and cornering again.

This is why it can ultimately be a very subjective thing. One driver may like the feel of a soft spring, another may like the feel of a hard one.

Sorry I am rambling a bit here but I hope I have made a valid point.

[werner1619]

I think I follow, you think that spring stifness is more an adjustment for the feel of the car as suppose to the actual amount of weight that does transfere...?

Ok, check this,
I Have 100% steering angle with hard springs in my car, I go around the track as I feel, placing it anywhere I want. With softer springs I dial the steering down to 50%, the car can't even complete a circle as the turning diameter is to large, but can place the car anywhere on the track while going round.

So, long story short. I shaved 1 sec of my fastes lap time for that track with this trick. Less steering angle = less scrubbing and more corner speed.
This result, less steering angle, would not have been possible if the softer spring did not allow more weight transfere and create more cornering power.

Realy try this, softer springs to have more steering power but use less steering angle, you will find it amazing.

[sosidge]

Softer springs all round? Or just at the front?

[werner1619]

Worked better for me with just softer in the front. tried all round, but the arse of the car just takes to long to recover from all the weight transfere...

[sosidge]

Worked better for me with just softer in the front.

Bingo.

By only changing the front you have changed the balance of the car. So now it steers more.

Essentially your problem was understeer, not a lack of fundamental corner speed. If you had asked me how to cure understeer I would have said softer front spring.

With softer springs on the back as well it no doubt feels pretty much the same in terms of balance as with the original springs, but rolls more, is more sluggish to respond, but probably soaks up the bumps a bit better.


Although personally speaking I never set the car up with limited steering lock, I always have enough steering to turn the car full circle in the narrowest part of the track.

[werner1619]

Yeah,
I am trying to get the most speed out of the thing so I try to keep all the things that work for me going.

And, more steering can also be obtained from placing a harder spring in the back.

Have you any particular settings you have found to cut down on your times...?

[sosidge]

Have you any particular settings you have found to cut down on your times...?

The only thing that will ALWAYS save time is to build the car right and keep it in good running condition.

Depending on the car I have done many different things to get them to my liking. I let the car do the work on the track, I just point it at the corners with the sticks.

[werner1619]

When I started rc, I use to adjust the car to what the fast guys where doing, never realy worked for me, but recently have realised that I should adjust it so I can drive the beast, with as little effort as possible. Consistency went up and times came down...
:)

[chris_dono]

Yeah,
I am trying to get the most speed out of the thing so I try to keep all the things that work for me going.

And, more steering can also be obtained from placing a harder spring in the back.

Have you any particular settings you have found to cut down on your times...?

under what circumstances would you go softer in the front compared to stiffer at the back ? Is there a difference or would they have the same effect ?

[sosidge]

With the buggies you have to keep in mind the bump handling and the traction you get, stiffer on the back of the buggy could make it a bit skippy.

By the same token softer on the front can make it dig in and feel sluggish.

Every change has a small affect on something else.

Really the best thing to do is to give all these settings a try, after a while you will get a good feel for what each change does and how it feels for you, it will make the decision making a lot easier.

[werner1619]

Yes, I find myself boged down with all the theory some times, but all I really need to do is do and drive the buggy, make changes that make it easier to drive and keep me fast.

I would tend to rather harden the back of the car, as it also helps with quick transitions, from left to right, and also opt for the adjustment that would suite most of the track and 8/10 times there are more corners on a track than jumps...

Well try both and see what works the best...

[Arn0]

Don't know what you mean" lines about BL " ?
Just writing some explanations about BL motors as it's done with brushed motors, maybe in a way simplier way! Part of an updating project for the document.

[werner1619]

The more we know the beter we will do...!

or was it the more we will forget..?

either way it would be an interesting read :)

[werner1619]

Would anyone run a solid axle in the rear and a oneway up front at the same time?

[25pie]

Would anyone run a solid axle in the rear and a oneway up front at the same time?

works really on on-road high grip conditions, not quite sure of having a spool at the rear though as when cornering the car would probably not turn as there is no slip like you would have in a diff, this system however would be probably excelent in pulling out of a corner, as the rear and front will be locked but remember the car will understeer like crazy...