Coilover Traction Loss

[Didz]

I am inclined to agree with tinkerbell, if the cause of the lack of grip is the suspension even welding the diff won't make it grip any more. If for example a particularly vicious bump on corner exit upsets the tyres and chassis enough that the inside wheel will start spinning then an LSD would help, but it isn't the underlying issue.



Good post guy. One thing though, your use of the word droop is correct, but the situation I have bolded above is not a good example of damper droop travel limiting suspension movement. When one goes diagonally into a driveway for example, and one of the rear tyres lifts off the ground it is not the damper hitting the limit of it's droop travel that causes this, it is the sway bars and/or mismatch in front to rear roll stiffness. The significant compression experienced at one of the rear wheels in the above situation is transferred to the other rear wheel through the torsion spring that is the rear sway bar and that lifts it off the ground. So a car with swaybars should rarely hit the limit of it's droop travel in roll or over uneven bumps. If you are doing jumps though that is a different story.

However you are correct in my opinion; with the minimal droop travel a normal Japanese/Tiawanese (height adjustable independent of spring preload/damper stroke) coilover will have if the spring is slightly preloaded it seems feasible that in a variety of conditions the damper may top out, which isn't great for traction as you rightly point out. This is part of the reason that I don't run my springs "pre-loaded", if I jack my car up the springs are loose and can rattle around slightly. I am sacrificing a small amount of bump travel by doing this but my bump travel is limited by the tyres running into the chassis anyway. Unfortunately I have no data on this, logging suspension displacement data is on my long list of things to do.

Also on the subject of "preload", it is possibly the most misleading term in the entire internets, or at least the part of the internets dedicated to automotive suspension.

Thanks guy, I was was hoping you would agree haha.

You are correct, it is not a good example. I was mainly using it as a way of getting my point across of what I believed to be droop travel. Perhaps a better example could be: If there was a pot hole on the road, if you drove your front wheels over it, the lack of droop would either cause your car to drop in the hole (lifting a rear wheel in the air) or the car would be stable but one of the front wheels would not be touching the ground.