Ohlins R&T Spring/Sway Choice

[9kracing]

Every single oe car manufacturer, from Rolls Royce to GT3RS.

What I meant is who came up with the recommended spring rates for our cars RE flat ride.

You only need your rear spring rate 10-20% higher than your fronts, and Ohlins are higher than that. So why is Ohlins not considered flat ride.

[mrgizmo04]

Because of geometry/angles/vectors (and some of those cos[theta] things), and why I "think" swaybar mounts get ripped out - is when the swaybar link is not perpendicular to the bar (or at least the line between the bushing and the endlink attachment hole).

Any angle from perpendicular is a deflection and force multiplier that sends (unwanted) force through the bushing/mount (in the fore/aft direction) vs simply rotating the bar within the bushing. So getting adjustable swaybar links is important not just for corner balancing and dialing out preload side to side, but also as you play around with different holes/stiffness settings on the bar, from soft to medium to hard holes, you introduce geometry changes with how the endlink angle changes and therefore unwanted forces multiplied and experienced at the bushing/mount.

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[Obioban]

I'm very curious who came up with this "flat ride" thing, and what testing was used to come to those conclusions.

What problem is flat ride trying to solve?

I removed my Dinan suspension setup for Ohlins R&T with stock spring rates, and the car rides 100 times better. I don't understand how lowering my front spring rate would be an improvement.

Swaybars are used to dial in and out oversteer. Having too low of a spring rate in the front, where ALL of the weight of the engine is, would cause nothing but problems from everything I know about suspensions.

If anything I'm tempted to raise my front spring rate. I will occasionally scrape on undulating roads.

Every single oe car manufacturer, from Rolls Royce to GT3RS.

[cobra]

I'm very curious who came up with this "flat ride" thing, and what testing was used to come to those conclusions.

What problem is flat ride trying to solve?

I removed my Dinan suspension setup for Ohlins R&T with stock spring rates, and the car rides 100 times better. I don't understand how lowering my front spring rate would be an improvement.

Swaybars are used to dial in and out oversteer. Having too low of a spring rate in the front, where ALL of the weight of the engine is, would cause nothing but problems from everything I know about suspensions.

If anything I'm tempted to raise my front spring rate. I will occasionally scrape on undulating roads.

I researched the origins - it dates way back, pretty interesting stuff: https://www.millikenresearch.com/Mau...WFMilliken.pdf



I am currently running Ohlins spring rates (400/630) with stock sways and I like it a lot. Not what I'd consider super compliant, but the chassis balance and response is amazing.

If you're scraping you might need to raise your car.

[9kracing]

I'm very curious who came up with this "flat ride" thing, and what testing was used to come to those conclusions.

What problem is flat ride trying to solve?

I removed my Dinan suspension setup for Ohlins R&T with stock spring rates, and the car rides 100 times better. I don't understand how lowering my front spring rate would be an improvement.

Swaybars are used to dial in and out oversteer. Having too low of a spring rate in the front, where ALL of the weight of the engine is, would cause nothing but problems from everything I know about suspensions.

If anything I'm tempted to raise my front spring rate. I will occasionally scrape on undulating roads.

[Obioban]

Got it. Thanks Obioban and eacmen .

As I understand:
The adjustable end links are ONLY intended for eliminating preload on the bar and nothing else. There are no dependencies between corner balancing and the sway bar - as long as it is a bar that has adjustable end links and it is properly installed without preload.

To do this properly, the shop will set ride height and corner balance concurrently. Then, using a sway bar that has adjustable end links they will adjust the links accordingly so there is no preload.

Do not confuse adjustable end links (side to side preload) with adjustable sway bars (stiffness)

(#tomanyconcussions)

Oh, and Ground Control gets a nod as a good front sway option

Technically, adjustable end links also allow you to get the sway bar to be parallel to the ground (where it optimally functions). That's why you need two.

But, yes, the different mount holes in the sway are to select stiffness, so you can fine tune your front roll couple (oversteer/understeer).

[OldRanger]

The purpose in adjustable end links is to eliminated preload.

Got it. Thanks Obioban and eacmen .

As I understand:
The adjustable end links are ONLY intended for eliminating preload on the bar and nothing else. There are no dependencies between corner balancing and the sway bar - as long as it is a bar that has adjustable end links and it is properly installed without preload.

To do this properly, the shop will set ride height and corner balance concurrently. Then, using a sway bar that has adjustable end links they will adjust the links accordingly so there is no preload.

Do not confuse adjustable end links (side to side preload) with adjustable sway bars (stiffness)

(#tomanyconcussions)

Oh, and Ground Control gets a nod as a good front sway option

[Obioban]

For the subject of corner balancing with Ohlins R&T and removing preload from the front (only) sway bar: Is the adjustable end link on the rear bar required?

Im checking myself on my 3D thinking…because I haven’t found the value in an adjustable rear sway bar and end links unless I want stiffer rear. Which I don’t at this point.

The purpose in adjustable end links is to eliminated preload.

[eacmen]

My car is not stock ride height. Installing the stock rear sway bar does require a bit of finagling (removing the bracket). It also made a rear upper/outer ball joint replacement a PITA

eacmen - did you stick with the GC front sway? (It's what RRT sells, and therefore recommends…and I like the ride height and performance on track with the way they setup my car)

My OEM front end links are toast. And one of them was banging around (loose) in the bracket on the strut/damper. So, I'm going to go in there and likely replace with the GC option. Just wondering if the rear is really needed.

If installing the rear sway requires any force to install the end links then you are adding preload to the sway which is what you dont want.

I still have the GC front and rear sway. Both are set at nearly full soft. The softest adjustment on the rear sway though won't work as it will end up hitting the axle at full compression. The front sway I think is their “race” product which is quite stiff even at the soft end of the bar.

I would recommend keeping the stock rear sway and just getting the adjustable end links.

If it is banging around in the strut then you need to tighten them up. But even if they are banging around it shouldnt affect performance. I've seen several race cars that just have a dowl and cotter pin to connect the sway bar end link to the strut for quick removal. It ends up clanking but it doesnt affect performance.

[OldRanger]

However, I suspect that if you're running a coilover setup then you're probably not at the stock ride height? I doubt the stock endlink would slip in at anything other than stock ride height.

My car is not stock ride height. Installing the stock rear sway bar does require a bit of finagling (removing the bracket). It also made a rear upper/outer ball joint replacement a PITA

eacmen - did you stick with the GC front sway? (It’s what RRT sells, and therefore recommends…and I like the ride height and performance on track with the way they setup my car)

My OEM front end links are toast. And one of them was banging around (loose) in the bracket on the strut/damper. So, I’m going to go in there and likely replace with the GC option. Just wondering if the rear is really needed.

[eacmen]

For the subject of corner balancing with Ohlins R&T and removing preload from the front (only) sway bar: Is the adjustable end link on the rear bar required?

Im checking myself on my 3D thinking…because I haven't found the value in an adjustable rear sway bar and end links unless I want stiffer rear. Which I don't at this point.

If you put the car on the ground and the stock rear end link goes into the bar without needing to bend the bar to make it fit then its fine.

However, I suspect that if you're running a coilover setup then you're probably not at the stock ride height? I doubt the stock endlink would slip in at anything other than stock ride height.

[OldRanger]

For the subject of corner balancing with Ohlins R&T and removing preload from the front (only) sway bar: Is the adjustable end link on the rear bar required?

Im checking myself on my 3D thinking…because I haven’t found the value in an adjustable rear sway bar and end links unless I want stiffer rear. Which I don’t at this point.

[SQ13]

curious, but if you had to do things over again. would you stick with the 8" swift swing at 336lb/in? or would you go to 392lb/in?

also, is the spring ID 65mm?

thanks for sharing

I wouldn’t change a thing. I like the current spring and sway setup. I did some spirited driving on a twisty road a couple of weeks ago, and the car handled great. Still no track time…maybe this winter after I reinforce the RACP and install CF roof.

Yes, 65mm.

[ugaexploder]

Photos of the car at 13.5”F and 13.0”R (left side 1/16 to 1/8” higher to account for 160ish lb driver). Springs are 336 lb/in 8” Swift springs up front and stock Ohlins 628 lb/in springs in the rear. I may end up raising the car 1/4” on all four corners.

As far as ride quality and comfort goes, it feels much better than my old MCS 2WNR setup on the street with 600/700 and 400/700 springs. While it does handle larger road imperfections well, don’t expect it to feel like an SUV. It does feel a tad more firm than my other M3 with PSS10s, but that car has 550 lb/in rear springs and OE RTABs and FCABs. The silver car has TMS spherical RTABs and FCABs. One issue I have is that at parking lot speeds, the front end is clunky going over road imperfections. This was also present when I had the MCS setup, so I suspect the noise is coming from the FCABs, which I will probably replace with OEM.

curious, but if you had to do things over again. would you stick with the 8" swift swing at 336lb/in? or would you go to 392lb/in?

also, is the spring ID 65mm?

thanks for sharing

[Grke46m3]

How much movement is there without the rubber mount?


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