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      06-03-2020, 09:41 PM   #1
leadfoot12
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Ohlins Road and Track Coilovers Spring Rates

I'm looking into Ohlins Road and Track (BMS MP00) coilovers for my 340i.

I noticed the front spring rate of the kit is 60N/mm which seems kind of low especially considering the application is the same for the 328i/335i/340i etc..

Does anyone have experience replacing the front springs in the kit with 80N/mm?

I had one vendor tell me I could do the swap through Ohlins but Ohlins would also insist on revalving the shock (due to higher spring rate) for an additional fee.

Ultimately this car is my daily driver so I'm not looking to go super stiff but at I want the car to handle "sporty" and also not dip/wallow terrible on driveway entrances. I do quite a bit of high performance driving events as well so I need a spring rate well suited to that as well.
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      06-04-2020, 12:39 AM   #2
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You think 60N/mm is soft? Lol
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      06-04-2020, 11:02 AM   #3
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I have Ohlins R&T. Donít worry about them not being firm enough.
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      06-04-2020, 11:10 AM   #4
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Quote:
Originally Posted by FaRKle! View Post
You think 60N/mm is soft? Lol
Haha all I've got to go off is some other folk talking about them on this forum. I'm honestly a noob when it comes to coilovers, this will be the first set I've ever bought.

So I take it 60N/mm is pretty stiff and the fact that Ohlins specs the same rate for the 4cyl/6cyl applications isn't a big deal?
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      06-04-2020, 11:11 AM   #5
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Originally Posted by DSH7 View Post
I have Ohlins R&T. Donít worry about them not being firm enough.
hah good to hear! How do you like them overall?
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      06-04-2020, 11:23 AM   #6
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Quote:
Originally Posted by leadfoot12 View Post
Haha all I've got to go off is some other folk talking about them on this forum. I'm honestly a noob when it comes to coilovers, this will be the first set I've ever bought.

So I take it 60N/mm is pretty stiff and the fact that Ohlins specs the same rate for the 4cyl/6cyl applications isn't a big deal?
I recommend you take a look at the suspension ride frequency calculator to see how the Ohlins R&T spring rates stack up against others. If anything, it's more ideal on RWD 6cyl vehicles because it maintains flat ride.
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      06-04-2020, 03:56 PM   #7
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Originally Posted by leadfoot12 View Post
hah good to hear! How do you like them overall?
I love them. I had B16 comforts before and Ohlins are miles better in terms of a buttoned down sporty ride. It's definitely firm, but they have a big range of adjustability and the adjustments are very noticeable. I settled on 15 clicks in the front, 22 in the rear (clicks from full stiff).

My only complaint is that the rears are pretty much impossible to adjust with the wheels on.
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      06-04-2020, 04:01 PM   #8
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The Ohlins R&T kit for my car (330d Touring) came with 70N/mm front springs. I prefer a firm suspension setup, and I do track my car a few times each year, and I felt that the front was under-sprung.

I had the front springs swapped for 90N/mm units and the front-rear spring rates feel far better matched as a result. I have the front and rear dampers at 9 clicks from full stiff - the dual-flow valves allow for a softer secondary ride and deal with the larger primary undulations very well.

There are several threads which include useful information regarding R&T.
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      06-05-2020, 07:51 PM   #9
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Quote:
Originally Posted by FaRKle! View Post
I recommend you take a look at the suspension ride frequency calculator to see how the Ohlins R&T spring rates stack up against others. If anything, it's more ideal on RWD 6cyl vehicles because it maintains flat ride.
Wow this is an awesome resource! Thank you for this.

Time to do some reading on bounce frequency!
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      06-05-2020, 08:41 PM   #10
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I run the Ohlins R&T kit on my F30 335i, and yes, the front spring rates are too soft. After getting the kit installed, I noticed on the drive home from the shop that the car was prone to oversteer. After discussing it with the Ohlins rep, and running corner weights and spring rates analysis numbers with the Swift springs rep, I settled on leaving the rear 16k springs alone, and swapping out the front 6k springs for 8k Swift springs (and going with 7" rather than 8" length to allow for raising the lower spring perch to free up some space for wide tires). This made all the difference in the world; on track, the car is perfectly balanced and neutral.

Last edited by DVC; 06-08-2020 at 09:45 PM..
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      06-06-2020, 12:59 AM   #11
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Quote:
Originally Posted by DVC View Post
I run the Ohlins R&T kit on my F30 335i, and yes, the front spring rates are too soft. After getting the kit set installed, I noticed on the drive home from the shop that the car was prone to oversteer. After discussing it with the Ohlins rep, and running corner weights and spring rates analysis numbers with the Swift springs rep, I settled on leaving the rear springs 16k alone, and swapping out the front 6k springs for 8k Swift springs (and going with 7" rather than 8" length to allow for a higher lower spring perch to free up some space for wide tires). This made all the difference in the world; on track, the car is perfectly balanced and neutral.
Mind if I ask where you bought the spring perch which mounts higher up the body of the shock?

EDIT: actually with a shorter spring you'd just screw the perch up as if you were lowering right? You don't actually need a new perch?

Last edited by leadfoot12; 06-06-2020 at 01:23 AM..
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      06-06-2020, 02:27 PM   #12
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Somebody said that ohlins used a 320d to develop the coilovers for the f30, so if that's true then the front springs might be a little soft with the bigger engine of the 335i sitting on them? Or maybe because the rears are 3 times as stiff as the front in the standard road&track kit?

Anyway, can anyone tell me if there is any truth to the rumor that the coding for adaptive suspension can't be turned back on if one codes it out? It would be cheaper than using an EDC delete kit, but I am thinking that if circumstances change and I have to sell the car one day, it would be nice to return it to stock suspension.
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      06-08-2020, 09:34 PM   #13
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Quote:
Originally Posted by leadfoot12 View Post
Mind if I ask where you bought the spring perch which mounts higher up the body of the shock?

EDIT: actually with a shorter spring you'd just screw the perch up as if you were lowering right? You don't actually need a new perch?

Correct
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      06-08-2020, 09:42 PM   #14
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Quote:
Originally Posted by Jvac View Post
Somebody said that ohlins used a 320d to develop the coilovers for the f30, so if that's true then the front springs might be a little soft with the bigger engine of the 335i sitting on them? Or maybe because the rears are 3 times as stiff as the front in the standard road&track kit?

Anyway, can anyone tell me if there is any truth to the rumor that the coding for adaptive suspension can't be turned back on if one codes it out? It would be cheaper than using an EDC delete kit, but I am thinking that if circumstances change and I have to sell the car one day, it would be nice to return it to stock suspension.
Yes, Ohlins developed the F30 R&T kit on a 320d; not sure about the weight of that engine, but the front needs a bit stiffer spring on a 335. But the rear will still be much stiffer based on the location of the rear spring inboard of the damper.

I have not heard that EDC dampers can't be coded back in, and I doubt that's true.
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      06-09-2020, 12:46 AM   #15
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Quote:
Originally Posted by DVC View Post
Quote:
Originally Posted by Jvac View Post
Somebody said that ohlins used a 320d to develop the coilovers for the f30, so if that's true then the front springs might be a little soft with the bigger engine of the 335i sitting on them? Or maybe because the rears are 3 times as stiff as the front in the standard road&track kit?

Anyway, can anyone tell me if there is any truth to the rumor that the coding for adaptive suspension can't be turned back on if one codes it out? It would be cheaper than using an EDC delete kit, but I am thinking that if circumstances change and I have to sell the car one day, it would be nice to return it to stock suspension.
Yes, Ohlins developed the F30 R&T kit on a 320d; not sure about the weight of that engine, but the front needs a bit stiffer spring on a 335. But the rear will still be much stiffer based on the location of the rear spring inboard of the damper.

I have not heard that EDC dampers can't be coded back in, and I doubt that's true.
Many thanks dvc. The second bit sounds a bit suspicious to me, too. Every other coding change I've made is easily reversible so why should EDC be any different?
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      06-11-2020, 02:14 PM   #16
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Quote:
Originally Posted by DVC View Post
Quote:
Originally Posted by Jvac View Post
Somebody said that ohlins used a 320d to develop the coilovers for the f30, so if that's true then the front springs might be a little soft with the bigger engine of the 335i sitting on them? Or maybe because the rears are 3 times as stiff as the front in the standard road&track kit?

Anyway, can anyone tell me if there is any truth to the rumor that the coding for adaptive suspension can't be turned back on if one codes it out? It would be cheaper than using an EDC delete kit, but I am thinking that if circumstances change and I have to sell the car one day, it would be nice to return it to stock suspension.
Yes, Ohlins developed the F30 R&T kit on a 320d; not sure about the weight of that engine, but the front needs a bit stiffer spring on a 335. But the rear will still be much stiffer based on the location of the rear spring inboard of the damper.

I have not heard that EDC dampers can't be coded back in, and I doubt that's true.
'nother question - I remember you listing some pretty extensive mods including several to the rear suspension setup, so your car may behave differently from stock. Do you think any of those mods contributed to the oversteer tendency, or was it just the spring rates front vs rear?
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      06-11-2020, 03:23 PM   #17
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Quote:
Originally Posted by Jvac View Post
'nother question - I remember you listing some pretty extensive mods including several to the rear suspension setup, so your car may behave differently from stock. Do you think any of those mods contributed to the oversteer tendency, or was it just the spring rates front vs rear?
He also has H&R sway bars, but I don't know if the Ohlins came before or after them.
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      06-11-2020, 06:38 PM   #18
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All of my suspension mods were one at a time, so I have a pretty good sense of how each affected handing individually. I had H&R front and rear sway bars with OE EDC dampers and Dinan springs for a while before getting Ohlins coilovers... And the Megan Racing rear arms were well after Ohlins. It was purely the Ohlins spring rates that shifted the handing toward strong overseer.
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      06-11-2020, 08:06 PM   #19
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Quote:
Originally Posted by DVC View Post
I had H&R front and rear sway bars with OE EDC dampers and Dinan springs for a while before getting Ohlins coilovers... It was purely the Ohlins spring rates that shifted the handing toward strong overseer.
Another method to reduce oversteer could've been to remove the H&R rear bar and go back to the OE one instead of increasing the front spring rate.

That's the method I used on my vehicle when I had oversteer issues. When you get to as high rear spring rates as we have (I'm running 900lbs/in, 16kg/mm too), you really don't need much rear bar.
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      06-12-2020, 08:04 AM   #20
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Quote:
Originally Posted by FaRKle! View Post
Another method to reduce oversteer could've been to remove the H&R rear bar and go back to the OE one instead of increasing the front spring rate.

That's the method I used on my vehicle when I had oversteer issues. When you get to as high rear spring rates as we have (I'm running 900lbs/in, 16kg/mm too), you really don't need much rear bar.
I have a similar experience.

My F31 330d MSport suspension history has gone like this :

Fully OEM springs, dampers (EDC) and bars.
EDC dampers + AC Schnitzer springs + H&R front & rear bars (28mm / 20mm).
Ohlins R&T (70N/mm F / 160N/mm R) + H&R front & rear bars (28mm / 20mm).
Ohlins R&T (90N/mm F / 160N/mm R) + H&R front & rear bars (28mm / 20mm).
Ohlins R&T (90N/mm F / 160N/mm R) + H&R 28mm front bar + Eibach 16mm rear bar. This is my current setup.

With the 20mm H&R rear bar I could really load the outside rear tyre in cornering to generate great grip and traction. The car felt very stable. The limits of grip were higher BUT the car was prone to snap oversteer if the grip on the outside tyre was overwhelmed. Even thought the car has a Quaife LSD the transition from grip to slip was sudden and often uncontrollable (DTC required).

Switching to the 16mm rear bar has made a significant difference :
  • The rear of the car feels more supple and there's much less lateral rocking through the chassis on uneven roads.
  • Traction has improved under some conditions, i.e. uneven corners where the very stiff rear bar was prone to lifting the inside tyre off the road surface.
  • Loss of lateral grip now occurs at lower speeds and the rear of the car is more mobile - the car overseers more readily and more progressively, but i can't 'lean' on the rear of the car as much I used to be able to.

Suspension is always a compromise and TBH I'm on the fence whether I prefer the handling of the car with the 20mm rear bar or the 16mm.

I still have some options to experiment with in terms of equal or unequal front/rear damper settings to see what changes they make.
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      06-12-2020, 09:54 AM   #21
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Big thanks to FaRKle dvc & watsey as always! You guys are awesome and have saved the rest of us countless hours of experimenting and money by contributing to these threads.
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      06-12-2020, 11:48 AM   #22
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Quote:
Originally Posted by Jvac View Post
Big thanks to FaRKle dvc & watsey as always! You guys are awesome and have saved the rest of us countless hours of experimenting and money by contributing to these threads.
You're welcome Jvac

Suspension is hugely subjective, but hopefully some of the insights are useful.

Happy to share my experiences, good and not so good.
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