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I think T04 means that it will work well if the street is smooth.

But if you come across bad road conditions and offset bumps where the car hits a bump on only one side, then it will be harsher and you'll get less traction.

From my understanding, you will get less traction from a bumpy road only if you have lousy or screwed shocks.

no, funnily enough dave knows what he's talking about. increasing the stiffness using bars will reduce body roll which is good. but it also has the effect of reducing traction at that end. often when you have an understeering car, you run a stiffer rear bar. this reduces grip at the rear, and helps the front end turn.

So sway bars on a car with firm coilovers is not a good idea?

I wouldn't recommend it.

I have a set of adjustable swaybars spec'ed up by Roadholder Suspension. With my OEM suspension I ran them on the stiffest setting and they were great. Good balance, and still great traction.

When I went to Tein Flex, the tail would snap out at the drop of a hat. Even now, with the bars dialled as soft as they'll go, I still have problems putting power down around low speed corners. Part of it could be my pissweak tyres, but compared to pre-Flex I still get more slip.

What spring rates were you running with the Tein Flex?

And what thickness are your bars?

My spring rates are 5kg front 4kg rear, hence Whiteline recommended the 20mm rear bar instead of the 22mm rear bar, adjusted to full soft.

Are your spring rates and bar rates higher?

Well a friend borrows my adjustable swayabrs so when my car finally got back on the road i ran it for a few days without swaybars until i could install them again.

The car lit up the tyres like an animal. I thought the tyres must have hardened etc whilst it had been off the road. Put the swayabars back on and with the same tyres the car just hooked up like it used to. So?!?!?!?!?!

I wouldnt have expected it. As i read about drag guys removing them to save weight. If they affect traction then i cant see them doing that.

But it was even the same stretch of street that the thing all of a sudden found traction.

AS for losing traction with bigger bars. It could be right, but im not entirely sure. The bigger the bar then the less independent the suspension becomes with undulations/pot holes on one side of the car affecting the other side. But i dont htink that actually hurts traction as such, who tries to drive fast on crappy / bumpy surfaces?

Also if they reduced traction, why would race drivers bar up their car. An example i read about was the old Kmart team. Murphy like big spring rates in the car while Kelly liked less spring but more bar. Cars lapped within a poofteenth of one another so cant be that bad.

Personally i now run even bigger swaybars then most, and so far its all good. Maybe crashes over shitty roads more, but i cannot be sure as it was ages since i last drive the car and any car will feel rough after having driven a Jazz for so long recently

You have to differentiate between traction in a straight line (ie drag racing) & traction on a corner exit.

When both springs are in equal amounts of compression the anti roll bar has ZERO effect. It does nothing.

It is only when the left & right springs are in different amounts of compression (Or rebound) that the anti roll bar works. What it does is transfer load from the unladen side to the laden side (ie if you are turning right it moves load from the right hand side tyres to the left hand side). The effect of this is to diminish the amount of grip the car has. However, there are many other factors determining tyre grip, not least camber angles & tyre temps. This is where the anti roll bars help generate grip.

If you ever get to see a front wheel drive hatch on a circuit (eg a VW Golf is a classic example) you will often see that they run sufficiently stiff rear anti roll bars to completely pick up the inside rear tyre.

If you ever get to see a front wheel drive hatch on a circuit (eg a VW Golf is a classic example) you will often see that they run sufficiently stiff rear anti roll bars to completely pick up the inside rear tyre.

could you elaborate more on why picking up the side rear tyre is a good thing?

i was talking to another guy that sets up race cars (believes roll should be controlled with low speed bump) and he was telling me this is why swaybars are bad, cos under enough load the inside wheel lifts up. but if cornering load is that big and the inside wheel was still on the ground, there would be bugger all normal force on it to create friction, right?

thoughts?

Edited by salad

At the end of the day, we drive road cars which arent sufficiently rigid enough to really stress too much.

Everything with silly cars is a compromise. You can do it with it springs and shocks, but then the car will have trouble riding the different frequency road surfaces. On smooth stuff it may be ok. So comes bcak to what you want to compromise.

Im running pretty soft suspension with big bars, and im happy with it. Be interesting in the next few weeks when some friends drive it in anger and see what they think

In and of itself, it isn't. But you have to separate balance (ie understeer/oversteer) from overall grip. Front wheel drive cars (& GT-R's for that matter) have a poor weight distribution with the front end carrying 60% of the weight. Now all else being equal (it isn't, but lets pretend) the front tyres won't generate as much grip as the rears. So you need to kill some rear grip to balance the car. In the case of a front wheel drive car as long as you have sufficient rear grip who really cares if the inside rear is off the ground? It isn't doing anything after all....

The problem with the GT-R is that running a stiff anti roll bar, while it is fine for balance (Needed in fact) it hurts your traction off the corner because you can then buzz the inside rear on power down.

As for transient (ie damper) issues - these are different from steady state spring (& rollbar) issues. But you mate is right - low speed bump does have an effect, particularly on turn in.

Woah very interesting and complicated read.

At the end of it all, I still dont know whether to fit the sway bars or not given the current setup in my GTT.

My spring rates are 5kg front 4kg rear (Tein Super Streets set almost full soft), alignment done to SK's specs. Tyres are Falken FK451's which are pretty good. I have 24mm front and 20mm rear adjustable bars sitting in the garage.

Requirements: better handling overall, same-ish comfort and driveability on bad roads, dont want to lose it easily in the wet.

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