Ohlins R&T Spring/Sway Choice

[LSB4Me]

Any update on the e9x front springs as a better option?

Finally got back to the M3 this week.

Ohlins E9X front springs installed. The front upper rubber spring mounts was trimmed slightly and they went on without issue.

In short, the slightly softer e9X springs make a world of a difference. It was a game changer.

Disclaimer: I am (hyper) specific about suspension setup. I want things firm but compliant. I want to feel the road, but don’t want to be disturbed by it. I also like to run higher rebound than others, data be damned. At 10f / 11r clicks off from full stiff with 500lb rear springs, the ride is sublime.

[cobra]

Finally got back to the M3 this week.

Ohlins E9X front springs installed. The front upper rubber spring mounts was trimmed slightly and they went on without issue.

In short, the slightly softer e9X springs make a world of a difference. It was a game changer.

Disclaimer: I am (hyper) specific about suspension setup. I want things firm but compliant. I want to feel the road, but don’t want to be disturbed by it. I also like to run higher rebound than others, data be damned. At 10f / 11r clicks off from full stiff with 500lb rear springs, the ride is sublime.

So what rates are you running now?

I am currently on 400/630 Ohlins rates and while incredible on a smooth road, it's too damn stiff for bumpy roads.

[LSB4Me]

So what rates are you running now?

I am currently on 400/630 Ohlins rates and while incredible on a smooth road, it's too damn stiff for bumpy roads.

Bumpy roads were my problem. For those of you that aren’t familiar with Los Angeles, the roads are truly awful. Think budget cuts meets warzone. At the Ohlins stock rates (400/630), my car was constantly in motion and absorbed nothing. Felt like I was on horseback.

Current rates are 342lb front (Ohlins stock spring off the E9x RT kit); 504lb rear (Swift, 6”). Stock sway bars.

And as mentioned above, on my new setup, I’m able to happily run the damper rebound setting where I like them—fairly firm. FWIW, soft springs and firm dampers are how GT3s come from the factory.

[cobra]

Bumpy roads were my problem. For those of you that aren’t familiar with Los Angeles, the roads are truly awful. Think budget cuts meets warzone. At the Ohlins stock rates (400/630), my car was constantly in motion and absorbed nothing. Felt like I was on horseback.

Current rates are 342lb front (Ohlins stock spring off the E9x RT kit); 504lb rear (Swift, 6”). Stock sway bars.

And as mentioned above, on my new setup, I’m able to happily run the damper rebound setting where I like them—fairly firm. FWIW, soft springs and firm dampers are how GT3s come from the factory.

Interesting! Good feedback. That looks like a race track compared to many of the roads up here
The thing I've learned about going too stiff on springs is... you can't simply soften it up by softening your shocks, because you end up with a horrendously bouncy ride. With softer springs you have more room to play with adjusters, though I think "stiffening" it with damping is a good way to make it start riding harsh if you're not careful.

I was thinking of trying 350/550 or 300/475 next. It becomes increasingly hard to find springs with enough travel if you're running stock height.

[LSB4Me]

Interesting! Good feedback. That looks like a race track compared to many of the roads up here
The thing I've learned about going too stiff on springs is... you can't simply soften it up by softening your shocks, because you end up with a horrendously bouncy ride. With softer springs you have more room to play with adjusters, though I think "stiffening" it with damping is a good way to make it start riding harsh if you're not careful.

I was thinking of trying 350/550 or 300/475 next. It becomes increasingly hard to find springs with enough travel if you're running stock height.

I agree re bouncy ride with stiff springs. When on stock RT rates, I adjusted my dampers twice a day for weeks. It became really tiresome and I was never happy. Going softer in the rear conformed my fear—the RT rates were too high. The search for appropriate front springs was exceedingly tricky … until I got Barry at 3DM on the phone and discussed things at length.

You might want to try these front springs, Cobra. They are the same length as the springs on our e46 RT kit and they don’t require camber plates.

Regarding ride height, I’m enjoying comfortable compliance despite being rather low. I haven’t measured but it seems like 13.25 f / 13.0 r. Planning to go up a spline or two in the front, as my tech unilaterally reduced the front height when changing out the front springs this week.

[Grke46m3]

Finally got back to the M3 this week.

Ohlins E9X front springs installed. The front upper rubber spring mounts was trimmed slightly and they went on without issue.

In short, the slightly softer e9X springs make a world of a difference. It was a game changer.

Disclaimer: I am (hyper) specific about suspension setup. I want things firm but compliant. I want to feel the road, but don't want to be disturbed by it. I also like to run higher rebound than others, data be damned. At 10f / 11r clicks off from full stiff with 500lb rear springs, the ride is sublime.

No noise with the e9x front spring? Think Barry is able to get these? Also what's the custom trimming look like? I love my ohlins but I always feel
Like the rear is so damn busy sometimes. Not uncomfortable but just busy.


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[LSB4Me]

No noise with the e9x front spring? Think Barry is able to get these? Also what's the custom trimming look like? I love my ohlins but I always feel
Like the rear is so damn busy sometimes. Not uncomfortable but just busy.


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Yep—the busy feeling drove me crazy. The car still moves over undulations but it’s less of a disturbance now and feels
more composed.

Barry and I are connecting on Monday to discuss spring inventory. I will report back.

In terms of noise, I did notice a slight clunk or two when turning the wheels to parallel park last night. Not offensive and a trade off I’m more than willing to accept.

The trimming sounded minor, but my shop
handled it. They certainly didn’t complain about the job. I’ll ask about that as well and revert. Though I don’t think this was a custom, one-off tedious headache.

[mrgizmo04]

I'm not 100% sure, but I *think* I want to make it clear to those reading this thread, that, "optimizations" being discussed in this thread to lower all rates to have the ride be less jarring over imperfection on LA roads and wherever else, apply to "straight" line driving. Running 300-350 front and 450-500 rear springs with beefed up front bar will make the car VERY understeery in twisties/track/autox. I would also note that, Ohlins, due to their SUPER limited front damper travel, are not ideal to optimize for poor roads where you may actually need to run softer springs but need more travel (the lower in lbs you go, the more inches you need to absorb enough energy to rebound). Also, front end busyness goes up significantly even with 300 front springs, given you are > 2x stock rates, while rears at 600 are still within the progressive stock range, -ish.

There is a lot of Frankenstein-ing going on.

That said, Swift and Hyperco make a lot of springs in a lot of rates and lengths. I don't know what everyone is after, but there are choices. You'd probably feel more comfortable dropping the front rates below 300 at appropriate length/ride height to help with poor roads.

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[OldRanger]

I’m curious: is it possible to install the 3DM spacer on the bottom of the strut without removing the three nuts from the top the strut tower? I’d like to add the spacer, but I don’t want to have to deal with all the alignment variables to sort out after I do it.

My car is basically stock up front in terms of weight on the suspension. I have the Ohlins RT front 400# springs with a Vorshlag camber plate. I had a reputable shop/dealer install them. They set the ride height at 13.25 - 13.5 inches. I have the Ground Control front sway at nearly full soft. The link bracket is about 1cm from the end of the bar.

Here’s the issue: mid-turn I have some understeer and I speculate it’s because the inside wheel is getting too light. Here’s what I found when looking at relative bump/droop: the Ohlins RT 400# spring supporting a car with stock weight on the front ‘axle’ at 13.25-13-5 ride height only has about 1” of droop travel. This equates to only 27% of the total travel, and based on opinions here, is not an optimal amount of droop for traction mid turn.

Droop should be more like 1.5 inches (40%) right?

[Obioban]

I’m curious: is it possible to install the 3DM spacer on the bottom of the strut without removing the three nuts from the top the strut tower? I’d like to add the spacer, but I don’t want to have to deal with all the alignment variables to sort out after I do it.

My car is basically stock up front in terms of weight on the suspension. I have the Ohlins RT front 400# springs. I had a reputable shop/dealer install them. They set the ride height at 13.25 - 13.5 inches. I have the Ground Control front sway at nearly full soft. The link bracket is about 1cm from the end of the bar.

Here’s the issue: mid-turn I have some understeer and I speculate it’s because the inside wheel is getting too light. Here’s what I found when looking at relative bump/droop: the Ohlins RT 400# spring supporting a car with stock weight on the front ‘axle’ at 13.25-13-5 ride height only has about 1” of droop travel. This equates to only 27% of the total travel, and based on opinions here, is not an optimal amount of droop for traction mid turn.

Droop should be more like 1.5 inches (40%) right?

Yes, you can add it just from below. Doing so without any other changes will raise your ride height.


Agreed that doesn’t sound like enough droop travel.

[eacmen]

I'm curious: is it possible to install the 3DM spacer on the bottom of the strut without removing the three nuts from the top the strut tower? I'd like to add the spacer, but I don't want to have to deal with all the alignment variables to sort out after I do it.

My car is basically stock up front in terms of weight on the suspension. I have the Ohlins RT front 400# springs. I had a reputable shop/dealer install them. They set the ride height at 13.25 - 13.5 inches. I have the Ground Control front sway at nearly full soft. The link bracket is about 1cm from the end of the bar.

Here's the issue: mid-turn I have some understeer and I speculate it's because the inside wheel is getting too light. Here's what I found when looking at relative bump/droop: the Ohlins RT 400# spring supporting a car with stock weight on the front 'axle' at 13.25-13-5 ride height only has about 1” of droop travel. This equates to only 27% of the total travel, and based on opinions here, is not an optimal amount of droop for traction mid turn.

Droop should be more like 1.5 inches (40%) right?

So my experience with the GC front bar and Ohlins was that the general rule of thumb for front sway adjustment didn't apply. If the front sway is too soft you will induce too much roll in the front and lifting the inside tire too much. I forget how much front sway but I think it's between 1.5 and 2 inches from the end on each side seemed to be the sweet spot. Try to stiffen front sway to see how it feels, can't hurt and it's free!

[tnord]

maybe I'm remembering things wrong, but if he's already having issues with understeer then stiffening the front bar will make that worse.

maybe stiffen the front and rear bar?

[eacmen]

maybe I'm remembering things wrong, but if he's already having issues with understeer then stiffening the front bar will make that worse.

maybe stiffen the front and rear bar?

Stiffening front bar typically will make understeer worse, unless your understeer is caused by too much roll and lifting the inside wheel. It's a rule of thumb but not a hard and fast rule.

[tnord]

I get it, but how much grip can that unloaded wheel that wants to come off the ground really give you even if it does brush the surface?

Not saying it's not worth trying, but I'd be prepared to make additional adjustments to balance things out. Tire staying on the ground is good, but it may end up with even more understeer.

anyway, sorry, didn't mean to derail.

[eacmen]

I get it, but how much grip can that unloaded wheel that wants to come off the ground really give you even if it does brush the surface?

Not saying it's not worth trying, but I'd be prepared to make additional adjustments to balance things out. Tire staying on the ground is good, but it may end up with even more understeer.

anyway, sorry, didn't mean to derail.

Good ref here from speed secrets:

https://speedsecrets.com/q-how-can-i-use-the-anti-roll-bar-to-reduce-understeer/

what i'm saying is that with Ohlins and their short travel that it ends up being “the exception and not the rule” category especially with relatively soft springs.