Overton's rr

[95shaw]

If you can achieve desired wheel weights in dynamic, bumps and limiters are not needed. Might be what Rumley achieved with his "device".
Near as I know, current setups use these as most means to arrive at those desired wheel weights have been outlawed.

Dirt late model racing is headed to a formula type arrangement.

[95shaw]

As a side note, karting is able to reach those dynamic numbers without separate suspensions.
They effectively teeter as well.

[MasterSbilt_Racer]

If you can achieve desired wheel weights in dynamic, bumps and limiters are not needed. Might be what Rumley achieved with his "device".
Near as I know, current setups use these as most means to arrive at those desired wheel weights have been outlawed.

Dirt late model racing is headed to a formula type arrangement.

Modern dlm suspension makes actual suspension function compromises to aid aero attack angle. Due to the fact we have lost every rule the suppressed aero downforce, the strategy is effective. That's where it is like formula.

It's not really about mechanical wheel loading. It's about producing the correct thrust vector from the rear tires at the right time. This means there are plenty of load and alignment combinations that will achieve the same result for the driver.

Rumley device, in short, was acknowledgement that the suspension works in both the compression and rebound directions and only looking at "getting up on the bars" means you may be screwing a lot of other stuff up.

[95shaw]

Please do tell.

How are you achieving torque thrust vectors without mechanically loading the tires?

The tires are the only contact with the track surface.
Mechanical linkages are the only connection between chassis and tires.
Yes, aero surfaces can help aim the chassis around the track. But is intimately connected to track by tires
.
I concede there are various ways to get the car around the track, but can still not see how visual cues give indication of how chassis is working the tires.

[MasterSbilt_Racer]

Please do tell.

How are you achieving torque thrust vectors without mechanically loading the tires?

The tires are the only contact with the track surface.
Mechanical linkages are the only connection between chassis and tires.

I never said tires were not loaded. I said there wasn't one magical set of numbers for the 4 wheels. The alignment of the front and rear axles changes the ideal load division.

I'm also going to say running on a stop, either in compression or rebound, leaves the suspension less able to handle surface irregularities than a suspension that is still working.

I'm also gonna say a car with a lower rr dynamic ride height and the lf off the ground will be beaten by a car with the same rr dynamic ride and the lf still aiding steering, all else being somewhat equal.

[ZERO25]

Since his lf is on the ground, whats your best guess how he's keeping it there?

[MasterSbilt_Racer]

Since his lf is on the ground, whats your best guess how he's keeping it there?

It doesn't share dynamic roll centers with the other cars. You can work on either end of the car, or both to achieve that.

His lf still comes up, just not as bad as it should.

[JustAddDirt]

Since his lf is on the ground, whats your best guess how he's keeping it there?

heavy suspension parts, heavy tie down/limiter.

[95shaw]

More rf travel. Less lr travel.
More left weight. Different spring rates.

Pretty long list of things can change chassis attitude.

[MasterSbilt_Racer]

More rf travel. Less lr travel.
More left weight. Different spring rates.

Pretty long list of things can change chassis attitude.

If speaking in generalities, yes. Ghopper has already narrowed it down.

[ZERO25]

More rf travel. Less lr travel.
More left weight. Different spring rates.

Pretty long list of things can change chassis attitude.

So, how has Overton figured out how to get more rf travel than the other top LH cars?

[MasterSbilt_Racer]

So, how has Overton figured out how to get more rf travel than the other top LH cars?

He hasn't. Getting the rf lower just moves one end of the roll axis lower. You can always move what hits and get more travel, but that's not it.

[ZERO25]

He hasn't. Getting the rf lower just moves one end of the roll axis lower. You can always move what hits and get more travel, but that's not it.

How do you know he hasnt?

[MasterSbilt_Racer]

How do you know he hasnt?

Doesn't look like it me me. If he did, it doesn't explain the way the chassis works.

[Ltemodel]

I'm thinking Overton is looking at ways to get around the droop rule and get more aero angle on the deck.
I think the biggest question on my mind is, did he move his RR bars up to compensate for the difference in push point angle?
The smash loads we are seeing on these smashers are nothing more than we used to adjust on scales except, if done right and we know the finished height the car is running at, we can closely predict the spring load on the tire.
To keep the LF on the ground we can do a bunch of different things.
As far as RF compression now, I think our new stopping point is the rack.
I already saw in Florida, a couple of teams cutting their bumpers back and putting more spring steel holding the RF nose up, only to let it collapse as it hits the ground. This would get us around any RF nose height rule by just letting the RF self adjust to any height it wants.