Golf GTI - Rear Sway Bar - What thickness??

[Sirocco20348]

Hey everyone!

Whiteline offers an adjustable 22mm, an adjustable 24mm and a non adjustable 22mm...

What is the ideal thickness of a rear sway bar for a GOLF gti?

Do i really need the 2 other adjustment points?

My car is a daily ride, which makes it to the track maybe twice a year.

Thanks for the advice.

[kaanage]

How much understeer are you experiencing and at what points (which phase) in the corner?

[Sirocco20348]

Its most notable in the wet, exiting corners I try to apply the throtle gently and the car just starts to slide diagonally. I really have to wait til im straightened up and then I can apply throtle again.

Most other times, since my car is on stock suspension, The car rolls too much to want to push it really hard through corners. I thought maybe the sway bar would flatten out the car a bit through corners.

[dylan8]

I was going to do 22 up front and 26 in the rear when i got around to new bars
being the mk4s only have a bar up front as standard, guess any size on the rear will be helpful and a improvement. maybe the 22mm adjustable out back so you can change settings if you are not happy with it.

I upgraded mine to a 22mm adjustable up front, then later removed all the bars and while i found the body roll increased, the under steer seems to have corrected it self a fair bit even compared to stock. might have to put the stock wheels back on and throw the car around to see how it behaves now

[Sirocco20348]

So i assume the thicker the bar, the stiffer the rear will be?

Some guys on vwvortex are running 28 and 30mm rear sways. What situation would you be running such a thick bar? Or is it an american thing to run the biggest bars going around?

What rear sway bar are other people using on their golfs?

---------- Post added at 07:49 AM ---------- Previous post was at 07:41 AM ----------

If you don't have a stabilizer bar, you tend to have a lot of trouble with body roll in a turn. If you have too much stabilizer bar, you tend to lose independence between the suspension members on both sides of the car. When one wheel hits a bump, the stabilizer bar transmits the bump to the other side of the car as well, which is not what you want. The ideal is to find a setting that reduces body roll but does not hurt the independence of the tires.

I think ill go with the 22mm adjustable just to be safe....

[kaanage]

Remember that the greater the roll stiffness, the more weight will be transferred to the outside wheel so you will lose grip at that end (since the tyre's coefficient of friction will fall off as loading increases). Massively thick anti-roll bars are great if you want a car that slides easily and, all other things being equal, predictably but you need the roll stiffness to be similar at front and rear so that the car is balanced. The car will get slidy before you notice the bump transfer effect very much (except on a tall SUV with heavy anti-roll bars where you will feel the sideways pitching with bumps and pot holes).

Unless you are going to uprate the front anti-roll bar, you wouldn't need to get more than the minimally thick, adjustable rear bar and start with the lowest setting since you don't suffer from terminal understeer except with traction loss (only a LSD and mybe better tyres will help with this). Too much rear stiffness will cause power off oversteer which is great fun when you do it intentionally but can be a problem if the situation is forced upon you (which is why the manufacturers build in inherent understeer).

[Shadow_Rusty]

I'm interested in this topic too for my Bora...
I think I have a stock 19mm (Maybe 16mm) up front...

I'd like to up it to a 22mm up front, and then add a 18mm rear...
The rear bar helps to keep the power to the inside front during cornering...

[VDUB-BUD]

I put the 22mm whiteline rear sway bar on mine, massive difference from no bar. its currently on the middle setting.

I would go 24mm adjustable if you go to the track.

[kaanage]

The rear bar helps to keep the power to the inside front during cornering...

Not really - it balances the grip levels front to rear by reducing rear grip so you get less understeer. The resulting lower front slip angle allows for better traction.

[Sirocco20348]

Thanks for the advice kaanage.

[dylan8]

think the 22mm adjustable in the rear would be right if you are going to keep the front stock (its fairly small from memory)
kaanage makes a lot of good points there. if its just for road use you want to keep it feeling a bit like a road car

[Whiteline]

Hi All,

Just remember that some of the 26-28mm rear bars you refer to are hollow at times and will only have the same deflection rate and performance of our 24mm solid steal sway bars.

We just thought we would point that out as a rear with 28mm solid sway bar would aactually reduce grip levels too much and cause slower lap times or speed in corners and have bad lift off oversteer.

Bigger is not always better as we have proved with our suspension data logger when at the track.

The theory is to have heavier spring rates at the track with matched dampening and run say 22 or 24mm sway bars .The sway bar acts llike an extra spring in corners and if both the spring and sway bar are at high rates the shock dampening maybe out during corners and cause less grip.

The best thing is to let the coilover or spring with damper adjustable shock do the work. Also the heavy bars and spring rates you see on some cars may also be track related cars that run good semi or slick tyres with great side wall construction that allow the use of these rates.

most street driven cars are better off with a softer spring rate and a hevier sway bar to keep the comfort but have lateral grip with the sway bars.

We hope this information may help !

[noone]

I have played with my Sways on the Polo quite alot. Definately adjustable so you can tinker. As for which size, I can't comment.

As for the results, I don't know about how they affect track use as I've not had enough track time. They make suburban driving a lot more enjoyable and despite the discussions around grip, etc, you can get more power down out of a corner with a sway over no sway.

Enjoy.

Forgot to add, as the majority of the weight is up the front, this is where I think you would benefit most from a strong swaybar. This is the setup I have found that works best for my car and mods.

[Sirocco20348]

Does anyone know the STOCK FRONT sway bar thickness on a 2001 vw golf? Im replacing my rubber bushes and they are saying there are 21mm and 23mm factory variations. I dont have any digital vernier calipers handy to me...

Should i go rubber or polyurethene? Im thinking just rubber as i want the original feel..