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      12-21-2014, 01:57 AM   #1
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Ohlins road & track vs Bilstein B12.

There's a wide price gap between these two kits. I'm well aware of Ohlins quality after being involved in snowmobiling for many years. I'm curious if anyone here has had an opportunity to compare these two set ups and could provide me with a little feedback on how the kits differ in ride quality and cornering. My 135 will be used as an occasional DD with periodic rounds of autocross.
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      12-21-2014, 06:55 AM   #2
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B12 are fine for street, but you also autocross and may venture onto the track in time?
Ohlins would future proof it. HPA also offer the Swift spring conversions.

Call Harold HP Autoshop.

For context, I've run B8 with lowering springs on two cars, Konis, Tokico, Tein etc. I currently run B14 PSS on my E87 and am swapping to linear (Swift springs). If I had my time again I would do Ohlins, but with 1M rears and swap out the rear LCA. Use- I live on a mountain and see the track a few days per year.


tl;dr - Buy Onlins R&T with the 1M rear, fit M3 front/rear arms including LCA (camber link). Fit Swift springs.
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      12-26-2014, 12:54 AM   #3
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BMW E9x M3 rear lower camber link kit
135i Vorshalag Camber Plates
Front - E82 135i Ohlins Road & Track, 7" Swift Springs 60N/mm w/ Swift thrust sheets
Rear - E82 1M Ohlins Road & Track, 9" Swift Springs 120N/mm w/ Swift thrust sheets
Ohlins Road & track rear damper adjustment extenders
HP auto-sport rear ride height adjusters

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      12-28-2014, 12:13 AM   #4
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I don't want to come across as a dick but there isn't a comparison between these kits. The B12 kit is a decent replacement for the under-damped stock struts/shocks with slightly higher rate springs. The price is quite attractive at under $1k and you will find they are much better than stock kit.

IMHO the better comparison would be the PSS 10's but they still lack the precision damping and adjustment that Ohlins offer.

I've had the equivalent B12 kit (Bilstein HD's with H&R springs) in another car I've owned and I did like the ride (although slightly bouncy) and performance.

At the end of the day I'm glad I spent the money, because once you ride in a car with the Ohlins R&T setup, you know your money was well spent.

Hope this helps.
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      12-28-2014, 12:15 AM   #5
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Quote:
Originally Posted by PeteA View Post
BMW E9x M3 rear lower camber link kit
135i Vorshalag Camber Plates
Front - E82 135i Ohlins Road & Track, 7" Swift Springs 60N/mm w/ Swift thrust sheets
Rear - E82 1M Ohlins Road & Track, 9" Swift Springs 120N/mm w/ Swift thrust sheets
Ohlins Road & track rear damper adjustment extenders
HP auto-sport rear ride height adjusters

Oh BTW..... this IS the setup hands down
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      12-28-2014, 12:41 AM   #6
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Quote:
Originally Posted by PeteA View Post
BMW E9x M3 rear lower camber link kit
135i Vorshalag Camber Plates
Front - E82 135i Ohlins Road & Track, 7" Swift Springs 60N/mm w/ Swift thrust sheets
Rear - E82 1M Ohlins Road & Track, 9" Swift Springs 120N/mm w/ Swift thrust sheets
Ohlins Road & track rear damper adjustment extenders
HP auto-sport rear ride height adjusters

Really don't need thrust sheets in the rear since the springs don't bind in slow corners......
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      12-28-2014, 01:24 AM   #7
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Quote:
Originally Posted by PeteA View Post
BMW E9x M3 rear lower camber link kit
135i Vorshalag Camber Plates
Front - E82 135i Ohlins Road & Track, 7" Swift Springs 60N/mm w/ Swift thrust sheets
Rear - E82 1M Ohlins Road & Track, 9" Swift Springs 120N/mm w/ Swift thrust sheets
Ohlins Road & track rear damper adjustment extenders
HP auto-sport rear ride height adjusters

A few comments:

1) To run these rear springs you need stiffer rear subframe bushings. I suspect PeteA has M3 rear subframe bushings but hasn't mentioned it. They (or equivalent) really are an essential starting point for any significant suspension upgrade.

2) The Ohlins front struts have internal bump stops that you can't see; however they have a stroke of 89 mm to the bump stop and 109 mm until the bump stop is fully compressed. Swift 7" x 60 N/mm (p/n 65-178-060) springs have a maximum usable stroke of 106 mm and an absolute maximum stroke of 118 mm before they go coil bound. That means that these springs should be installed with minimal preload to prevent them being over-compressed when hard on the bump stop. With 12 mm preload on the springs, they will just go coil bound when the bump stop bottoms out. This is the absolute maximum preload you should consider, but really is too much. Better would be somewhere between 0 and 6 mm. This means that you have very little ability to adjust the front ride height with these springs if you want to keep them properly in the working range. They are the absolute shortest 60 N/mm spring you can use with this strut. The Ohlins 200 mm 60 N/mm spring, or a Swift 8" spring will give you more adjustability, but at the expense of tire to spring clearance. This issue is exactly why it is better to have a strut that adjusts preload and ride height separately (as the 1M/M3 Ohlins front strut does). Unfortunately they don't work with the 135i steering knuckle.
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      12-28-2014, 04:06 AM   #8
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^ Spot on. M3 RSFB are a must. I went solid turner mounts following some deflection in the rear on hard acceleration. (This is bound to happen when the vehicle is punching out over 400ftlbs of torque)

Yep a 1M front end strut would work with the 1M front knuckles. Not sure if many have done this. It would require new brake hats and caliper brackets to suit. I went a 7" front spring for tyre/spring perch clearance. This is quite a bit of it as a result so for that it doesn't have an issue. 8" would ofcourse provide more stroke but at the expense of clearance. Nevertheless, I don't seem to have any issues with the setup at all and I can highly recommended. Harold sent me my kit pre-assembled with Vorshlags and from what I could tell the spring had next to 0 pre-load as it was quite easy to spin the spring by hand. So I didn't touch it.

Ride height is pretty much stock as well. I wouldn't buy Ohlins to slam the car anyway.



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      12-28-2014, 08:33 AM   #9
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^ Your car looks great. In the real world, suspension travel is a wonderful thing.
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      12-28-2014, 09:30 AM   #10
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Good info on springs and preload - but I never understood how to adjsut preload with these struts. I guess it just changes with ride height? Does lower ride height + more pre-load? Any springs you recommend over the Swifts? I wasn't happy with those, so I'm running Eibachs, but I think I need a longer spring (they sent me a 6" spring for free, so I'm using that with a Swift helper spring to make up the difference - will probably switch to a 7" Eibach spring #400 with no helper). Thanks for any insight.

To the OP's original question: look, it's simple. The Bilsteins are decent, and priced accordingly. The Ohlins are quite a bit pricier, but better in every possible way. I ran Bilstein PSS9's (which I liked, but both front struts blew) for a couple years before switching to Ohlins R&T's. They are sublime in comparison. Much more refined. Better for city driving and better on a road course or at autocross. But you definitely pay for the pleasure. You have to do what you can afford. The Bilsteins will definitely be better than stock and add a sportier character to the car, and are fine for track days, etc. Good luck.
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      12-28-2014, 11:31 AM   #11
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Not sure if OP is absolutely set on either-or for these 2 choices, why not consider TC Kline single adjustable coilover kit? Possibly not as good ride quality as the Ohlins, but $500 cheaper for a set. Excellent setup for DD and autox.
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      12-28-2014, 12:03 PM   #12
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Quote:
Originally Posted by Bimmer-Bob View Post
Good info on springs and preload - but I never understood how to adjsut preload with these struts. I guess it just changes with ride height? Does lower ride height + more pre-load? Any springs you recommend over the Swifts? I wasn't happy with those, so I'm running Eibachs, but I think I need a longer spring (they sent me a 6" spring for free, so I'm using that with a Swift helper spring to make up the difference - will probably switch to a 7" Eibach spring #400 with no helper). Thanks for any insight.

To the OP's original question: look, it's simple. The Bilsteins are decent, and priced accordingly. The Ohlins are quite a bit pricier, but better in every possible way. I ran Bilstein PSS9's (which I liked, but both front struts blew) for a couple years before switching to Ohlins R&T's. They are sublime in comparison. Much more refined. Better for city driving and better on a road course or at autocross. But you definitely pay for the pleasure. You have to do what you can afford. The Bilsteins will definitely be better than stock and add a sportier character to the car, and are fine for track days, etc. Good luck.
Yes, as ride height changes you'll effect preload. Basically you match the spring up (length wise) to avoid as much preload as possible.

As you increase ride height, you compress the spring. The lower you go (you're spinning down the perch, the less tension there will be.
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      12-28-2014, 12:53 PM   #13
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Quote:
Originally Posted by Kgolf31 View Post
Yes, as ride height changes you'll effect preload. Basically you match the spring up (length wise) to avoid as much preload as possible.

As you increase ride height, you compress the spring. The lower you go (you're spinning down the perch, the less tension there will be.
Thanks, that makes sense.
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      12-28-2014, 02:06 PM   #14
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Quote:
Originally Posted by Bimmer-Bob View Post
Any springs you recommend over the Swifts? I wasn't happy with those, so I'm running Eibachs, but I think I need a longer spring (they sent me a 6" spring for free, so I'm using that with a Swift helper spring to make up the difference - will probably switch to a 7" Eibach spring #400 with no helper). Thanks for any insight.
Kgolf31 has it right of course, but to answer the above parts of your question:

- Swifts generally have a bit more usable stroke in any given length and spring rate than other springs, which is a good thing if you are using short springs. In fact Swift gets out of a 6" spring what Eibach gets out of a 7" spring of the same rate. I am sold on Swift.

- Your 6" springs are way too short. Regardless of preload, you are in danger of coil binding them. The helper springs just make the stack height work but have no effect other than that. You don't mention what spring rate you are using, but if 400 lb/in the spring only has 91 mm stroke so you will never hit your bump stop before coil binding. Any stiffer 6" Eibach spring is even worse. Incidentally, you have to track down an Eibach Global catalog to get this info. We in North America apparently can't handle it, so it isn't in the North American catalog last time I checked.

- A 7" x 400 lb/in gets you 106 mm stroke, which is marginal. From a suspension travel point of view you would be better off with either a 6" x 60 N/mm or 7" x 60 N/mm Swift spring.
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      12-28-2014, 02:08 PM   #15
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Quote:
Originally Posted by fe1rx View Post
Kgolf31 has it right of course, but to answer the above parts of your question:

- Swifts generally have a bit more usable stroke in any given length and spring rate than other springs, which is a good thing if you are using short springs. In fact Swift gets out of a 6" spring what Eibach gets out of a 7" spring of the same rate. I am sold on Swift.

- Your 6" springs are way too short. Regardless of preload, you are in danger of coil binding them. The helper springs just make the stack height work but have no effect other than that. You don't mention what spring rate you are using, but if 400 lb/in the spring only has 91 mm stroke so you will never hit your bump stop before coil binding. Any stiffer 6" Eibach spring is even worse. Incidentally, you have to track down an Eibach Global catalog to get this info. We in North America apparently can't handle it, so it isn't in the North American catalog last time I checked.

- A 7" x 400 lb/in gets you 106 mm stroke, which is marginal. From a suspension travel point of view you would be better off with either a 6" x 60 N/mm or 7" x 60 N/mm Swift spring.
Thanks for the detailed info!
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      12-28-2014, 05:26 PM   #16
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Fe1rx is a suspension guru, you should check out his Ohlins setup thread. I just visually inspected my struts and springs, said "Yep looks about right" and bolted it all in. lol
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      12-28-2014, 06:06 PM   #17
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Quote:
Originally Posted by fe1rx View Post
- A 7" x 400 lb/in gets you 106 mm stroke, which is marginal. From a suspension travel point of view you would be better off with either a 6" x 60 N/mm or 7" x 60 N/mm Swift spring.
I'm a little confused by this - 60 N/mm? Or 60 N/m? Either way, this seems way too stiff. I have a couple Swift 7" springs in 392 ib/in - that's pretty stiff for the front, from what I understand - but that's only 44 N/m. And if you want to talk N/mm, well, then it's over 44,000 N/mm! So either I'm converting wrong (possibly) or there is a typo in your post. I'm thinking you meant 60 N/m, which would be 531 lb/in. Still seems too stiff to me for the front.

Do you feel otherwise?
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      12-28-2014, 11:22 PM   #18
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Originally Posted by Bimmer-Bob View Post
Do you feel otherwise?
Yes, I do. There is a short answer, and this isn't it.

The damnable thing about these units is the difference between mass and force (aka weight), which we use interchangeably, usually without appreciating the difference.

Mass:

1 kg = 2.204 lbm (where to avoid confusion, lbm means pounds mass)

Force = Mass x Acceleration. In this context Acceleration is acceleration due to gravity, i.e. "1 g"

A = 1 g = 9.81 m/s^2 = 32.2 ft/s^2

In common practice 1 lbm "weighs" 1 lbf (pounds force), which is to say 1 lbm exerts a downward force on a scale of 1 lbf.

In metric, the unit for Force is Newton (N) and,

F = M x A = 1 kg x 9.81 m/s^2 = 9.81 kg.m/s^2 = 9.81 N

Now 1 kg is 2.204 lbm, so:

1 lbf = (9.81 kg.m/s^2)/(2.204) = 4.451 kg.m/s^2 = 4.451 N

There are 25.4 mm in an inch so:

1 lbf/in = 4.451 N/in = (4.451 N/in) / (25.4 mm/in) = 0.1752 N/mm

Therefore,

60 N/mm = (60 / 0.1752) lbf/in = 342 lbf/in

To add to the confusion, sometimes metric units are bastardized and springs are expressed in terms of kg/mm. Because 9.81 is very close to 10, a 60 N/mm spring is sometimes called a 6 kg/mm spring (but it isn't really).

Sorry for the long answer, but a 400 lbf/in spring is actually a 70 N/mm spring, so going to 60 N/mm would actually be a bit softer than your current 400 lbf/in spring.
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      12-29-2014, 12:07 AM   #19
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Quote:
Originally Posted by fe1rx View Post
Kgolf31 has it right of course, but to answer the above parts of your question:

- Swifts generally have a bit more usable stroke in any given length and spring rate than other springs, which is a good thing if you are using short springs. In fact Swift gets out of a 6" spring what Eibach gets out of a 7" spring of the same rate. I am sold on Swift.

- Your 6" springs are way too short. Regardless of preload, you are in danger of coil binding them. The helper springs just make the stack height work but have no effect other than that. You don't mention what spring rate you are using, but if 400 lb/in the spring only has 91 mm stroke so you will never hit your bump stop before coil binding. Any stiffer 6" Eibach spring is even worse. Incidentally, you have to track down an Eibach Global catalog to get this info. We in North America apparently can't handle it, so it isn't in the North American catalog last time I checked.

- A 7" x 400 lb/in gets you 106 mm stroke, which is marginal. From a suspension travel point of view you would be better off with either a 6" x 60 N/mm or 7" x 60 N/mm Swift spring.
What's typical stroke length on a stock?
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      12-29-2014, 12:32 AM   #20
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Quote:
Originally Posted by Kgolf31 View Post
What's typical stroke length on a stock?
On a front strut? If the damper is not inverted and you can see the shaft, measure the length of exposed shaft with the strut extended and the bump stop installed and add half the height of the bump stop and that should be a pretty good estimate.

On our cars I am going to guess that 100 mm is typical total front strut stroke, so if you want to fully benefit from your bump stop, you need at least this much stroke in your spring, plus whatever preload you put in the spring.

If you intend to use a 6" spring you are right on the limit of this so actually measuring your strut stroke and getting the data for your spring would be a good idea.
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      12-29-2014, 12:38 AM   #21
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Quote:
Originally Posted by fe1rx
Quote:
Originally Posted by Kgolf31 View Post
What's typical stroke length on a stock?
On a front strut? If the damper is not inverted and you can see the shaft, measure the length of exposed shaft with the strut extended and the bump stop installed and add half the height of the bump stop and that should be a pretty good estimate.

On our cars I am going to guess that 100 mm is typical total front strut stroke, so if you want to fully benefit from your bump stop, you need at least this much stroke in your spring, plus whatever preload you put in the spring.

If you intend to use a 6" spring you are right on the limit of this so actually measuring your strut stroke and getting the data for your spring would be a good idea.
I'll take some measurements.

I'm running 6.5" up front on VVS Springs
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      12-29-2014, 02:12 AM   #22
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Lots of stuff. Ohlins sound good.
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