No, that's not right. The same amount of weight transfers no matter what. That's due to the springs. The rate at which it transfers is due to the shocks. The harder the shocks, the faster it transfers.

 

Mike, it's hard to really tell from the video because we can't see any steering inputs and it's a bit grainy from the compression. It seems the spin happened rather slowly. The car appeared to porpoise after going over the bump (under damped) but that may just be the camera. If the weight transferred repeatedly front to back it's hard to tell exactly which end the problem originated. Your setup should have some inherent understeer. With that being said you probably had more than enough steering input so when the weight went to the fronts they gained traction then the rear tires spun up because you were on the gas and around it came. I'm going to stick by my original prescription of tightening the front shocks. On the plus side if that is not right it should be evident rather quickly (that's only turn #2).

 

This weekend I'll be in Spokane, actually.

 

Yeah, you are right, but your are not.

True, the weight transfer is the same. In theory. But in reality, you rarely get to see the maximum possible weight transfer. Usually the turn is long gone before you can get to fully settle on the springs.

Although the transfer of weight from one area of the car to another is "faster" with stiffer shocks, it takes FOREVER for the maximum possible weight to get "loaded".

With softer shocks however, the rate of transition (from one side to the other) may be slower, but the "loading" is faster and you get higher amount of weight transfered, therefore more traction.

In your case, under hard acceleration, stiffer shocks would still be "deflating" and slowly transfering more weight to the rear.

Had you had softer compression, your car would've been squating and having more weight "loaded" to the rear tires by then.

That's why stiffer shocks are better for faster changes in direction (slalom). While softer shocks are better for traction out of a turn (acceleration).

It's always a compromise between rapid direction changes (stiffer) and acceleration (softer).

Your problem didn't happen while rapidly changing direction. In fact, you were correcting a change of direction by unwinding (I'm assuming it wasn't a driver's error). It happened while accelerating. Meaning, you need to go softer.

That's exactly why we all go "softer" under low traction conditions (rain).

 

This particular turn is a very long sweeper. The car is totally set and I'm on maintenance throttle just waiting for when I can accelerate.

Hey, I'm no expert at shocks -- far from it. But, as often happens, what we have here is various people saying completely opposite things. What you are saying goes opposite the normal theory and also opposite what makes sense to me. You might be right, or you might be wrong. But what you are describing is not very convincing.

Looks like I'll have to do some experimentation this weekend.

 

No. Your car was not set. At least from the video, you were just starting to accelerate and your RPM's started to climb. Meaning, you were transfering weight to the outside rear (and if you were unwinding like you should have, you were also starting to load the inside rear).

When you spun, it was not a "steady state" turn. You were actively shifting weight around, from front to back.

I don't know what doesn't make sense to you.

Let's say, when you "increase compression", what you are actually doing is increasing resistance of the shock to compress (by "closing" valves within the damper). So if you exert "x" amount of force over that shock, now it will take you longer to shorten it to its minimum length. Correct?

This resistance to compress will allow you to transfer this "x" weight from side to side faster. But once leaned on one side, it will be slower to compress the spring to its minimum length.

Now let's complicate things even more. On the car, that "x" force is dynamic. The more the shock/spring is compressed, the higher the value of "x" is. Just because the car is leaning more towards that specific corner. The more you lean onto something, the more of your weight will exert pressure over it.

The angles have a lot to do with it. Like when two people are carring a piece of furniture upstairs. The one on the bottom carries significantly more weight than the one above. The steeper the angle, the more weight the bottom support will bear. Meaning, the more the car leans, the more weight is transfered.

When you "decrease compression", you decrease the resistance of the shock to compress. So with that same "x" force in the example above, your shock will shorten faster. Right?

That may slow down the tranfer of weight from side to side, but once leaned on one side, the shock/spring will compress faster.

So, in your case, let's say you decrease the compression in the rear. Now when you accelerate, your car will squat more, therefore, tranfering more weight to the back (because it will lean more). And faster (because your shock will offer less resistance).

Does that make sense?

 

Naka, your explanations are inconsistent and even contradictory at times. Could you reference some of this information (esp. the stuff on angles), or is it all from what seems logical to you?

 

 

What doesn't make sense is that who cares now long it takes to compress the spring to the minimum length? I don't believe that the weight transfer due to body angle of the car is very significant. I suppose I could be wrong.

What you are talking about is a situation where the spring is extremely overdamped by the shock. That can cause problems, but I don't think that's what's going on in my case.

 

I vote the track was contaminated.



(thats what I blame my problems on, because the way I set up the car and drive is perfect... all the time)