Bob Barry

iTrader: (22)

Too much steering = slower through corners. You might think your faster but you will be slower...

Mr. McGoo

iTrader: (23)

I 100% agree with this statement - i was having trouble with corner speed, and after much frustration, someone recommended going to a 4.5 degree front C-hub rather than my 6 degree i was currently running - with that said in the main i was roughly .2-.4 sec a lap faster - i was scrubbing speed in the corners b/c i had too much steering

CoryCraig

your car could be "too planted". Try some stiffer springs all the way around ( go up the same increment on both ). Normally i would say try a harder tire, or insert, but since its a spec tire, try to loose grip that way. I know most people are always looking for grip, but on carpet most people are looking for ways to get rid of it.

PS - you may have to go up 5 wht on the oil to keep the shock rebound the same. Usually for every 2 notches i move in spring i change my oil 5 wht.

Jack Smash

iTrader: (35)

That is pro-dive or kick-up, anti-dive is with the front of the arms pointing down.

rockdog200

New to TC racing what is roll center and how do you change it? Ok flame me but I would like to know.

asw7576

I know, I'm using the term anti dive similar to Hudy Setup Book or HPI Pro4 manual book. So there is less confusion if someone read and compare to Hudy book.

I know the term pro dive is the correct name.

CoryCraig

Roll center is the point on which the suspension rotates and rolls on ( hence the name "roll center", its the center point the car will roll on ). If you draw a line straight through the suspension arms ( looking at the car from the front or rear ), the point those lines cross is the roll center. If you raise the roll center it will take more force for the car to roll the same amount as before( IE makes the carroll less ). If you lower the roll center it takes less force to make the car roll the same ( IE makes the car roll more ).

You change it by raising ( raising roll center ) the arms at the inner hinge pins, or lowering ( lowers the roll center ) the arms at the inner hinge pin.

anthony390

does the line go perpendicular or along with the suspension arms

a bit

ChadCapece

The roll center is an imaginary point in space, look at it as the virtual hinge your car hinges around when its chassis rolls in a corner

The theorem of Kennedy tells us that if three objects are hinged together, there are at most three poles of movement, and they are always colinear, i.e. they are always on one line. in the case of the roll center we only need two dimensions at first. So a pole of an object (or a group of objects) is like the center point of a circle it describes.

The suspension of a touring car, with a lower A-arm and an upper link, yo see a bunch of objects that are all hinged together. These objects include the chassis, the upper link, the A-arm, and the hub. For now we consider the hub, the axle and the wheel as one unit. First, let's look at the chassis, the upper link and the hub. They are hinged together, so the theorem of Kennedy applies. The pole of the upper link and the hub is the ball joint that connects them, because they both hinge around it. The pole of the upper link and the chassis is also the ball joint that connects them. If you now look at the chassis, the upper link and the hub, you can see the two first poles , so if there is a third one, it should be on the imaginary line that connects the other two.

Basically, on a bumpy track, you can use a high RC (roll center) and soft springs. And on smooth tracks, a low RC and stiff springs

ChadCapece

Either one. Two of the 3 poles are the arms and turnbuckles.

If you make the turnbuckle more parallel to the surface, then you raise the roll center. If you make the arms more angled like ^ then you raise roll center.

Mdoc

iTrader: (29)

everyone has told him how to fix the car...but he hasnt even said what it does wrong.....if you try to go faster/use more throttle, what does the car want to do...go straight, spinout, or tractionroll ? once that is known it would be easier to try and help you fix it.....just seems that way to me anyway lol

teamgp

This was a mis-print in the Hudy Setup Book. It has been noted in the XRAY FAQ thread and will be corrected in the new book. We apologize for the mistake.

CoryCraig

Mdoc - he said the car felt fine, that it wasnt loose and didnt push, it just didnt have the corner speed he feels he should have, hence dfferent ways to try to gain corner speed.

Mdoc

iTrader: (29)

if it isnt loose and wont push , and he has extra throttle, why would his corner speed be down? If he only needs more power thats one thing, but if he has more power, and uses it, it will either have more corner speed, push, or be loose, unless it traction rolls......

rockdog200

Ok I'm confused about changing the roll center. Lower arm parallel to the track and upper link parallel where is the roll center? Lower roll center is the car freer in the corner? I'm running on a small carpet oval.