Colbynobo

iTrader: (21)

I was just looking at the Jconcepts Barcodes on the front of my TLR buggy. They seem to have more of a crown than any of my touring car tires which are comparatively flat. Granted, in the case of an offroad car there's decidedly less traction all around, but what can be said about a tire that yields a smoother transition? Is this abrupt change from the top to the side of the tire during a corner contributing to much of our issue? Some of the tires on my road bicycles have a different durometer in the center/crown as opposed to the sides. Could we achieve some of the benefits of a more gradual change in tire grip by doing something funky like doping the center/crown of the tire for 20 minutes, but only doing the edges for 10 minutes?

Martin Crisp

perhaps you could experiment with that...but in general I always liked to put full traction compound on the entire tire, so that I could repeat the process consistently every time. If you start to sauce just a portion of the tire, you are not going to be able to do it consistently every time, and that will produce a different balance on the car.

snuvet75

iTrader: (16)

Martin, first of all, you've already answered most of my long standing set up questions in your application that I bought today. Thank you! But I have 2 more questions:

1. Slip angle in the rear: You said in the app that "LESS" toe in in the rear creates smaller slip angle in inside wheel so that it gives maximum lateral grip. Do you mean more negative toe in by "LESS" toe in? I was confused about the "Maximum" grip cuz you didn't specify if you were referring to front or the rear traction. I assume rear traction since you were talking about rear slip angle. Then it has to be more negative toe in. But less slip angle in inside wheel means toe in close to 0. Wrong?
2. Under "Spring/push on power", You meant "same adjustment as for push off power" not "loose off power". Correct?

I'm sure I'll have to ask you more questions once I go through the entire chapters but for now this is it.

Martin Crisp

Is there much interest in a windows 8 phone edition?

or perhaps a windows 8 app edition?

corallyman

iTrader: (101)

You know I would buy one. Not sure about total sales for you though. I think the windows phone platform is slowly gaining in popularity.

Do you still have your serpents? I just put the 2mm hard chassis on mine. Felt pretty good to my friend who drove it.

Steve

frozenpod

iTrader: (1)

Windows still has a very small market share compared with Android and IOS, shame as it is pretty good.

SuperFastSnail

iTrader: (82)

Aside from the OP, I still have your book in crisp condition, pun intended. Thanks a bunch, will download the app.

Martin Crisp

re: 2 above:

yes you are correct, I meant to say it is the "same adjustment as for push off power...." sorry about that good catch and thank you.

re: 1 above:

When I wrote that I think I went way too far on the theoretical and frankly did not write it very clearly.

In all practical use. having more rear toe in will give you more rear grip when in the corners. I would imagine you can go too far with the rear toe in, where the outside rear tire has too much of a slip angle and starts to loose grip likely in the middle of the corner.

More static toe out in the front will give you more initial turn in because the slip angle is greater on the inside tire, which generates more lateral grip. This is what the carpet plots basically explain. But if add too much toe out in the front, you will go beyond the optimal slip angle for the inside tire, which means you can push more in the middle of the corner.

I think the one key take away here is not the two points above however, as we kind of already know all that without knowing about carpet plots. The key point here is that different tires will have different carpet plots and thus have different optimal slip angles. This means that a setup that works great with one tire (eg. jaco blue) may not work well with another tire (e.g. sorex 28).

I think I remember reading about some common rules of thumb related to this...

a) tires that like a greater slip angle tend to have a higher aspect ratio and rounder corners - think dirt sprint cars.
b) tires that like much less slip angle tend to have shorter sidewalls (aspect ratio) and have squarer corners.

...but this does not take into consideration the structure of the tire and it's compounds...so it is at best a high level guideline.

Sorry for the confusion in the app...I did not do a good job on that section it turns out

Cheers.
Martin.

rc car guy

Hey Martin, could you create a new section in your set up app describing the different chassis settings? In the new section that describes each of them in their category of traction type? Like lateral grip, vertical grip and such it would help me out a good amount. especially trying to tune on my car

Martin Crisp

sorry...I don't really understand what you mean.

rc car guy

Like wheelbase adjustment is not the same as track width adjustment would be an example it would just be more of a convience rather than scanning through all of the settings

san.

iTrader: (61)

+1 on the Windows Phone app.

Martin Crisp

sorry...i really don't understand what you are getting at. What do you mean by vertical grip for example? And could you provide an example of the categories you are thinking of and some samples within those categories relating to the setup changes... an example would help me better understand I think.

The app has a section that describes each of the different things you can change on setup like camber, caster, roll center, etc...and in each of those sections it describes in some detail how each of those affect the handling and how to adjust them to change the balance of the car.

Then there is a section called Setup Helper which is scenario based, in that it provides advice on what to do in the following scenarios:

1) car is loose off power
2) car pushes off power
3) car is loose with neutral power
4) car pushes with neutral power
5) car is loose on power
6) car pushes on power

For each of these scenarios is prioritizes the types of changes you should look at making.

rc car guy

never mind just keep doing what your doing

Rouge711

Hi all, i've a question for Martin.
Saing that i have fully understood weight transfer and RC theory, if you take a look at last setupsheets from several pro driver in high traction condition (carpet tracks) you can see the tendency in raising up RC putting almost 1mm under lower suspension blocks and shortening camber links which means raising again RC.
What is the goal i can't find? Why this choice?
In addition, sometimes we can read more droop in rear end like 4.8!!

Personally i have experienced in my last high carpet grip race that 1mm under suspension blocks, 0.5 antidive in front, shortening camber links and raising outer and inner camber link let the car more easy to drive.
Maybe i am wrong, in fact this seems a contraddiction to the theory which teach me to choose a lower RC in case of high grip in order to reduce lateral grip and prevent traction rolling...

Thanks Martin...