Oversteer causes

[lentner3 328]

So I’ve built a bit of a Frankenstein.

started as a scale series Kyosh ultimate but due to not being able to find parts easily I used various Tamiya spares.

the gearing I’ve managed to rectify by changing the pinion and wheels but I’m suffering with bad oversteer. What’s the best place to start. I’m thinking shocks. But do I want stiffer front ? Lower tide height at the front etc.

some pointers please. 

[Jonathon Gillham 4672]

The Hudy setup guide is your friend, you can download it from the link below. This explains all the settings and changes you can make and what they do, and near the end has a reference so you can look up the issue and it suggests the changes to try in order. Very useful to get a car dialled in

https://www.sodialed.com/rc-setup-tips/hudy-touring-car-setup-book

[lentner3 328]

2 hours ago, Jonathon Gillham said:

The Hudy setup guide is your friend, you can download it from the link below. This explains all the settings and changes you can make and what they do, and near the end has a reference so you can look up the issue and it suggests the changes to try in order. Very useful to get a car dialled in

https://www.sodialed.com/rc-setup-tips/hudy-touring-car-setup-book

Thanks for the link.

Is this still applicable for RWD buggies or just touring cars? 

[GermanTA03Guy 1372]

Wow thanks for the nice book. To keep it simple as a reply, generally to invoke more understeer, go harder in the front or/and softer in the back. That refers to damping, springs, stabilizers, tires, foams, everything. Also more toe in at the rear should you be able to adjust ist, maybe also more toe in at the front. Maybe less Camber in the front and more in the back, but that Depends. If you can adjust it, maybe more caster in the front to tame it. 

With the diff etc. Its roughly the same, go harder in the front and softer in the back. 

Width go wider in the front, narrower in the back... etc. On and on. 

Just when you built a Frankenstein car, maybe it has some underlying quirky geometry ? Then alot of setup stuff is like putting makeup over it, the problem might remain...

 

Btw, most of the touring car stuff is applicable to rwd buggies in a way, as the physics are the same (all about weight shifting and weight transfer). Just the drivetrain effects are a bit special on 2wd. 

 

And with some setting it can seem weird , e.g. to a certain point putting weight in the front causes more oversteer, until it doesnt... same with on power/off power things (diff). The can have opposite effects (but for a reason). 

The best thing is it all interacts with the way youre driving it, to Mix things up a bit... 

[lentner3 328]

Very informative. I’ve right away realised the oversteer is particularly prominent during breaking which has narrowed it down. I think I have a fair amount of adjustment of the Roll Centre just from shock positioning which will hopefully give me some crude adjustments. The other finer tuning makes more sense to me with regard to camber and toe settings.

great resource. And thanks to you both for your input 

[Jonathon Gillham 4672]

20 minutes ago, lentner3 said:

Thanks for the link.

Is this still applicable for RWD buggies or just touring cars? 

Like @GermanTA03Guy guy says, it mostly is applicable.  Its a good enough starting point anyway, as physics works the same way regardless of surface.  If you're on a rough surface then building shocks is different (things like pack which I don't understand, and sometimes its the opposite of what you expect to handle bumpy terrain), but I ask others for help there.

I pulled that guide out at the onroad track and a bunch of guys were stoked, it was like I had a cheat sheet.  That guide in the back is really useful for a quick diagnosis, and makes you think about things (is the oversteer on turn in or corner exit etc).

That same guide actually works on setting up our 1:1 race car too and having read that it was easier to understand what was happening when you're sitting in the car.  Its just much harder to put a stiffer sway bar on or swap springs etc, but you can do a lot with ride height, camber etc.

[GermanTA03Guy 1372]

40 minutes ago, Jonathon Gillham said:

setting up our 1:1 race car too and having read that it was easier to understand what was happening when you're sitting in the car.  Its just much harder to put a stiffer sway bar on or swap springs etc,

Thats what i looove about rc cars. Wanna change springs ? You can do that with your thumb and your Index finger  just turn the car around with one hand 1:1 cars are a pita to wrench on a lot of times.

[Mad Ax 10026]

12 hours ago, Jonathon Gillham said:

The Hudy setup guide is your friend

Wow, I've just had a quick skim and that book looks incredible.  Thanks for the link!  I've spent a long time searching for a single resource for car setup and not found one, it's always felt like arcane knowledge to me - people at the track aren't afraid to offer tips, but getting all the knowledge in one go has proved impossible.  In fact I was considering employing one of the local racing legends to help me write a proper book on the subject!

It's amazing how you can be in the scene for many, many years and still stumble across stuff that you really should have known about within the first few months 

[Andreas W 2155]

I got that book together with the setup station and a lot of tips from the previous owner. I have only had a light scan over the problem solvang pages and tried out a little on the M-08 and the Carten M210R. It has resulted in far more controllable cars and less tyrewear. 

[Pablo68 1094]

I want to be a bit of a wag and say the cause is sh*t driving, cause I know that's usually the cause when it happens to me

[Andreas W 2155]

26 minutes ago, Pablo68 said:

I want to be a bit of a wag and say the cause is sh*t driving, cause I know that's usually the cause when it happens to me

Hehe. That should of course not be underestimated.

[Otis311 265]

On 7/16/2024 at 5:03 AM, Andreas W said:

It has resulted in far more controllable cars and less tyrewear. 

And that is a whole other thing. It's possible to make a car ride on rails but it will burn through tires in short order.

[jsven008 155]

On 7/15/2024 at 2:08 PM, Jonathon Gillham said:

The Hudy setup guide is your friend, you can download it from the link below. This explains all the settings and changes you can make and what they do, and near the end has a reference so you can look up the issue and it suggests the changes to try in order. Very useful to get a car dialled in

https://www.sodialed.com/rc-setup-tips/hudy-touring-car-setup-book

EPIC guide. Very comprehensive and impressive.

[Rinskie 851]

I had huge oversteer issues with my M08 to the point where it wasn't fun trying to drive it. After trying to figure it out for about a year, I noticed I had too much toe out. Now mind you when I say trying to figure it out....that means buying blue parts until the problem was resolved. Only after fixing the toe out issue did the thing become drivable. 

[Jonathon Gillham 4672]

4 hours ago, Rinskie said:

I had huge oversteer issues with my M08 to the point where it wasn't fun trying to drive it. After trying to figure it out for about a year, I noticed I had too much toe out. Now mind you when I say trying to figure it out....that means buying blue parts until the problem was resolved. Only after fixing the toe out issue did the thing become drivable. 

Buying blue bits is fun, but rarely solves the problem. My TA07 has every blue bit, but the only things that make a difference are the carbon fibre stiffeners and aluminiun suspension mounts. The rest is tuning, which to be fair if you are meticulous about building as per the manual will be pretty good. But get the turnbuckles out by .5mm each, the odd shim in the wrong place and its all over!

Those blue bulkheads sure look good though...