Sway Bar Quesiton (1 Viewer)

[ToyotaIsLife]

I recently got rid of the KDSS sway bar system on my 200 series land cruiser, while it did improve small bump compliance over washboard roads and uneven terrain, I noticed that the tires would drop much faster when going over a pothole, ditch or even when the tires are free like driving out of a ledge at high speeds. Tires pop out very abruptly, Similar to an effect of having very light/soft rebound damping.

At first I thought more rebound damping was needed, which was true, but I did not realize that the sway bar delete caused this. A local mechanic brought that into my perspective by explaining how my sway bar delete was causing the tires to be unrestricted thus move uncontrollably. Do sway bars really do provide that much resistance?

Heavier rebound damping did fix this issue(had to go much much heavier tho, 100% increase)

What do you guys think about sway bar deletes for better offroad comfort?

 

[Taco2Cruiser]

Depends on what you consider off road.

For you, and wanting to go fast... yeah, no KDSS is better. My old FJ had long travel front and rear, 15” travel up front, 30” travel in the rear. Sway bars are a distant memory. Yet I can run very, very fast, while quite composed.

Yet if off-road means what it means to me, back country exploring, big rocks, highway in the middle, and when in the desert now, I stay below 30mph and refuse to jump it. KDSS will be much better.

I think it’s important to acknowledge that the KDSS is exactly what it is. It changes based on the terrain, to make driving safer. Don’t be surprised when it wants to keep you stable at speed (which is what you noticed when you dropped it), but open up at slower speeds for greater articulation (which is not really in Qatar... I used to live there)

So yes, KDSS is going to increase dampening. The engineers figured the majority of owners would want stability at moderated open desert driving than the few that want to go as fast as possible through the desert.

I think for you and your style, dropping KDSS and doing your current suspension tuning is the right way to go.

 

[UCrazyKid]

This is no surprise as it is what sway bars were designed to do. They are an inexpensive way to control wheel movement by tying the left and right wheels together with a torsion spring.

In automotive racing it is ideal to remove swaybars and go with independent suspension with lots of adjustability for rebound and damping and ideal spring rates. This allows for maximum tire contact.

It is hard to design an affordable suspension that works appropriately across multiple applications. There will always be compromise in a stock configuration.

 

[TeCKis300]

I'm sure you have an idea of how the sway bar works. Per axle, it connects the left and right suspension such that they lose some of their independent-ness. KDSS can act to increase or reduce this connection.

To clarify: When encountering a hole at lets say the passenger front of the vehicle, the wheel at that position will obviously drop into the hole. The wheel at the drivers front will compress a bit as it has to support the full weight of the front end.
With sway bar:
1) The sway bar will take some of the compression at the driver supporting wheel position, and translate that to the dropping wheel. To your point, effectively reducing the spring rate at that dropping wheel position, which will slow its drop.
2) Looked at another way, the dropping wheel will extend its suspension. With a sway bar, that extension will translate into increased spring rate at the supporting wheel position.
Without sway bar, they act completely independently.

Now the question for me is what about the wheel dropping is your concern? Is it dropping into deep hole and causing bump steer? Is it upsetting the chassis because the dropping wheel is "catching" the hole more? Or is it both the dropping wheel catching on the hole, and the front end diving because of the reduced support at the drivers wheel (#2 above).

 

[UCrazyKid]

Deleting double post.

 

[ToyotaIsLife]

@Taco2Cruiser @UCrazyKid @TeCKis300 Very good information, thank you very much.

 

[ToyotaIsLife]

I'm sure you have an idea of how the sway bar works. Per axle, it connects the left and right suspension such that they lose some of their independent-ness. KDSS can act to increase or reduce this connection.

To clarify: When encountering a hole at lets say the passenger front of the vehicle, the wheel at that position will obviously drop into the hole. The wheel at the drivers front will compress a bit as it has to support the full weight of the front end.
With sway bar:
1) The sway bar will take some of the compression at the driver supporting wheel position, and translate that to the dropping wheel. To your point, effectively reducing the spring rate at that dropping wheel position, which will slow its drop.
2) Looked at another way, the dropping wheel will extend its suspension. With a sway bar, that extension will translate into increased spring rate at the supporting wheel position.
Without sway bar, they act completely independently.

Now the question for me is what about the wheel dropping is your concern? Is it dropping into deep hole and causing bump steer? Is it upsetting the chassis because the dropping wheel is "catching" the hole more? Or is it both the dropping wheel catching on the hole, and the front end diving because of the reduced support at the drivers wheel (#2 above).

I just wanted to confirm my theory that removing sway bar caused the tires to drop much more abruptly (faster), It seems obvious now that it did contribute to slowing down the wheel. Thanks a bunch. Significant increase in rebound damping made it stable again.