XRAY - Model racing cars

This is a bit of a confusing question but I'll try and explain it as well as I can.

I have the new upper bulkheads and access to both 2 hole (kit) and 1 hole (option) rear hubs. Will there be any handling difference between using the R1 hole on the bulkhead and the 1 hole upright compared to using the R2 hole and the kit upright (#1/inside hole).

The camber link is the same length in either configuration, so my question is does the handling change when the entire link is moved further towards the wheel, or if the mounting position is irrelevant and only the length makes a difference to the handling.

Thanks
Craig

Hi Craig,

I have plotted the T3'2011 suspension geometry in Catia V5 so can tell you what difference the changes make.

Moving the link from the middle hole with the kit hub position to the shortest link hole and the 1 hole hub raises the static rollcentre by around 0.7mm.
It also reduces the cambergain by around 0.1 degrees for 4mm of suspension travel. The raised rollcentre should reduce the roll at the rear of the car and decreased camber gain usually results in more stability.

These figures are taken from plotting my suspension geometry exactly, and will vary slightly with rideheight, rollcentre positions, track width etc. However, the way the change effects the car should remain the same.The key is that the change will definately have an effect. The best way to learn from this now is to test the change back to back, minimising as many variables as possible between runs.

Now you know the theory of the change, you should be able to relate this to the difference in handling with each option.

I hope this helps,

Phil Chambers

Hi Phil,

as you have the Catia model for the suspension, could you test to which ammount the static rollcenter changes with L1/L2 and 4mm on the upright compared to H1/H2 and 5mm?

Would be nice, to get a feeling for the value you gave above as i assume that 0.7 in lowcenter change isn't equivalent to lowering by the -0.75 holders.

Best regards
Dennis

Moving the connection from the center gap with the pack center point position to the briefest connection opening and the 1 gap center point raises the static roll center by around 0.7mm.

It likewise diminishes the camber gain by around 0.1 degrees for 4mm of suspension travel. The raised roll center ought to lessen the move at the back of the vehicle and diminished camber gain as a rule results in greater steadiness.

These figures are taken from plotting my suspension geometry precisely and will fluctuate marginally with ride height, roll center positions, track width and so on. In any case, the manner in which the change impacts the vehicle ought to remain the same. The key is that the change will definitely have an impact. The most ideal approach to gain from this currently is to test the change consecutive, limiting whatever number factors as would be prudent between runs.

Moving the connection from the center gap with the unit center position to the briefest connection gap and the 1 gap center point raises the static roll center by around 0.7mm.

It additionally decreases the camber gain by around 0.1 degrees for 4mm of suspension travel. The raised roll center ought to lessen the move at the back of the vehicle and diminished camber gain more often than not results in greater strength.

These figures are taken from plotting my suspension geometry precisely and will fluctuate somewhat with ride height, roll center positions, track width and so on. In any case, the manner in which the change impacts the vehicle ought to remain the same. The key is that the change will definitely have an impact. The most ideal approach to gain from this currently is to test the change consecutive, limiting however many factors as could reasonably be expected between runs.

Presently you know the hypothesis of the change, you ought to have the capacity to relate this to the distinction in dealing with every choice.