stiffer rear springs

[sambb]

Anyone tried taking the route of running stiffer rear springs instead of installing a stiffer rear anti-roll bar?

[brad]

Anyone tried taking the route of running stiffer rear springs instead of installing a stiffer rear anti-roll bar?

lower springs or coilovers *are* stiffer 99% of the time.

[seangti]

As said, lowered springs are typically stiffer. Though you'd be spending the same coin on springs as you would a rear sway bar, and fitting the sway bar is very simple, swapping springs is more cumbersome. Plus you get adjustability in the sway bar. The sway bar route also provides compliance on when going straight ahead, it just loads up the springs when cornering.

So the question would be - would are you trying to achieve?

[sambb]

agreed. Two straight forward ways to reduce understeer (by increasing rear roll stiffness) in an otherwise standard car are to run stiffer rear springs OR a rear anti-roll bar. The rear anti-roll bar route is pretty well trodden here, but I'm intersted if anyone has run stiffer rear springs. Provided the average ride isn't too harsh there are lots of advantages of doing it this way.

[sambb]

seangti - yeah the main thing for me is that when you hit a one wheel bump mid corner with stiffer springs, the rear wheels are still able to act somewhat independently. With a rear sway bar its more of a recipe for been spat sideways - but yeah in general driving the ride is more comfortable with the RSB. Atleast thats what I always found the main difference to be on my past cars.

[seangti]

seangti - yeah the main thing for me is that when you hit a one wheel bump mid corner with stiffer springs, the rear wheels are still able to act somewhat independently. With a rear sway bar its more of a recipe for been spat sideways - but yeah in general driving the ride is more comfortable with the RSB. Atleast thats what I always found the main difference to be on my past cars.

Yup, that is true. RSB should really be used for fine tuning, rather than compensating. I run my rear bar on hard and can invoke lift off oversteer on the street, for street driving I wouldn't typically suggest running hard as the road variables can result in unbalancing the car mid corner. On the track, it's exceptionally well balanced and mid corner adjustable on the hardest setting. Though on the track you're also not likely to lift off mid corner.

[flat6]

I have the ultra racing rear sway bar, stiffens up the rear end so much that when going through multi story car parks up hill you can make the car lift, very tight.

Overall driving experience on the road has been great, keeps the car planted and tight feeling through out cornering when installed with the front strut bar, feel leans more towards oversteer but without the strut bar it creates more under-steer

Probably a lot cheaper than springs to

[sambb]

flat6 - because it has no pivot points, curious does your UR bar creak?

whats the consensus on UR 18mm versus whiteline 20mm (on soft). Which is the softest rear bar? anyone driven them back to back or on identical cars?

[flat6]

I did have an issue with it creeking a while back but fixed this by using some locktite on the bolt threads and spraying lithium grease in between contact points, havent had a creek since.

My bar isnt adjustable like the whiteline, but i imagine it to be similar to it on its stiffest setting, like i said, you can lift the car going up steep corners like in carparks, but havent experienced any lift off over steer as yet in normal conditions

[brad]

I run stiffer Eibach wagon springs on my Octy sedan.

I prefer to start with springs as it keeps the IRS de-coupled & works going in a straight line as well as when cornering. Also stops the tail from excessive droop when I fill with fuel, people or bails of hay / mulch / concrete, etc.

I've gone from 19mm to 21mm (both hollow) on the RSB which is about a 40% increase in torsional stiffness of the RSB (swaybars gain stiffness to the 4th power as diameter increases). I also modded it to allow a 2 position adjustment which is worth another ~5% stiffness.

If I'd just used an RSB to achieve the same outcome I probably would have had to go to a 23mm or 24mm solid RSB. I've done similar on previous vehicles & it reduces the comfort of the IRS through potholes or when taking speed humps at an angle.

I'm not sure how this would affect a Polo - are they still a beam axle at the rear?

Flat6, I can't see how adding a strut bar at the front would increase over-steer & removing would create understeer. Generally stiff rear, soft front = oversteer; stiffen front creates understeer.

[Tom87]

I'd be looking at shocks closely too, I've had great experiences with solid axles and Bilstein's high pressure digressive valve mono tubes. Really can't afford the axle jiggling around more than it has to seeing as it is connected to both wheels.

[flat6]

I run stiffer Eibach wagon springs on my Octy sedan.
Flat6, I can't see how adding a strut bar at the front would increase over-steer & removing would create understeer. Generally stiff rear, soft front = oversteer; stiffen front creates understeer.

I understand the physics to it, rear affects the front vice versa and in most situations your right, but the front bar definitely sharpened the turn-in on this car

[sambb]

agree with you totally regarding consistent ride heights and the fact that you still keep a degree of independent-ness to the beam axle rear end without the RSB. They turn in differently with stiffer rear springs too I reckon - you have a stiff rear already in action the moment you turn in, no delay for the roll to begin before the RSB adjusts the rear axle.
Is your octavia a twist beam or IRS? Yeah 9N3's have a twist beam rear end like the MK4 golf, skoda Fab and polo 6R so a spring swap should be pretty painless.
Was looking at k-mac custom springs (30% uprated) but it might be cheaper to just hang out for a set of eibach's and use the rears (20mm drop). I'll have standard springs/ride height up front.

[brad]

I understand the physics to it, rear affects the front vice versa and in most situations your right, but the front bar definitely sharpened the turn-in on this car

turn-in is different to understeer/oversteer.

sambb: IRS

[sambb]

Brad you got me thinking about running wagon springs. Anyone here know if the Skoda Fabia wagon runs the same beam axle as the hatch? If it did, those rears would be uprated for sure.