Ohlins R/T Advice Needed

[M-Pilot]

I've posted this thread in the M2 section originally but thought might as well post here too.

I've been running Ohlins R/T on my M2C for about a year now and I'm still confused by couple things in the instructions manual. Additionally, I'm also still experiencing some issues with the ride comfort.

Firstly, I want to ask how the rear ride height is adjusted. According to the image below, the height adjuster is on the strut and spring perch is only for preload:



However, my shop during the install kept telling me that the only way to adjust the ride height was to play with the spring perch. I didn't initially believe it as it contradicts with the manual. However, Brian from Ohlins replied to my email in a similar way:

"The static ride height must be set using the spring adjuster as the shop has performed. Preload, for this situation, is set by the shock length as the shock is what’s maintaining tension on the spring while in full droop.



The height adjuster is not on the shock body. The height adjuster is the spring preload adjuster in this case.



An example of this being true is if you lengthened the shock via the lower gold cup. This would not affect the static height of the car – it would only reduce bump travel of the damper and reduce tension on the spring while in full droop."

If the spring perch is the height adjuster in this case, what does the "height adjuster" on the strut do? Really confused about this issue and it's driving me crazy. In my opinion, installation instructions provided by Ohlins aren't clear at all.

Another thing is the ride quality... I have their recommended spring rates (90 front and 190 rear). Even though they phenomenal at the track, I find the rear to be extremely stiff for street use. I tried using different stiffness (15 to 20 clicks) and still very bouncy/jumpy on bumpy roads. I just someone's comment on how to describe the situation so I'll use the same words... Even on highway, at certain dips or bumps, it launches me out of my seat and I'm not exaggerating. If it's this uncomfortable for the driver, it's usually significantly worse for the passenger. I definitely wouldn't wanna be a rear passenger in my car. I wanted to post about this issue because I have read so many posts on how much better Ohlins is than the stock suspension when it comes to ride quality. Maybe I should switch to 70/160 spring rates.

Anyone else experienced similar problems with Ohlins or does anyone have any recommendations?

[chief1richard]

Originally Posted by M-Pilot

I've posted this thread in the M2 section originally but thought might as well post here too.

I've been running Ohlins R/T on my M2C for about a year now and I'm still confused by couple things in the instructions manual. Additionally, I'm also still experiencing some issues with the ride comfort.

Firstly, I want to ask how the rear ride height is adjusted. According to the image below, the height adjuster is on the strut and spring perch is only for preload:



However, my shop during the install kept telling me that the only way to adjust the ride height was to play with the spring perch. I didn't initially believe it as it contradicts with the manual. However, Brian from Ohlins replied to my email in a similar way:

"The static ride height must be set using the spring adjuster as the shop has performed. Preload, for this situation, is set by the shock length as the shock is what’s maintaining tension on the spring while in full droop.



The height adjuster is not on the shock body. The height adjuster is the spring preload adjuster in this case.



An example of this being true is if you lengthened the shock via the lower gold cup. This would not affect the static height of the car – it would only reduce bump travel of the damper and reduce tension on the spring while in full droop."

If the spring perch is the height adjuster in this case, what does the "height adjuster" on the strut do? Really confused about this issue and it's driving me crazy. In my opinion, installation instructions provided by Ohlins aren't clear at all.

Another thing is the ride quality... I have their recommended spring rates (90 front and 190 rear). Even though they phenomenal at the track, I find the rear to be extremely stiff for street use. I tried using different stiffness (15 to 20 clicks) and still very bouncy/jumpy on bumpy roads. I just someone's comment on how to describe the situation so I'll use the same words... Even on highway, at certain dips or bumps, it launches me out of my seat and I'm not exaggerating. If it's this uncomfortable for the driver, it's usually significantly worse for the passenger. I definitely wouldn't wanna be a rear passenger in my car. I wanted to post about this issue because I have read so many posts on how much better Ohlins is than the stock suspension when it comes to ride quality. Maybe I should switch to 70/160 spring rates.

Anyone else experienced similar problems with Ohlins or does anyone have any recommendations?

Was wondering what the final answer was for adjusting the rear height. I am having a set of these made as we speak. Did you stay with original spring rates?

[horsepower_and_hounds]

You adjust the ride height with the spring adjustor on top of rear spring to widen or lessen gap X, car goes up...car goes down. Then you adjust your shock height to match that new height ride height + some preload. The rears are a pain but that is how its done. Some systems have you just adjust the spring perch and expect the shock to cover the full height change (KW). Some give you fully adjustable spring & shock lengths to keep the shocks in their preferred working range (Ohlins/BC Racing).

[M-Pilot]

Originally Posted by chief1richard

Was wondering what the final answer was for adjusting the rear height. I am having a set of these made as we speak. Did you stay with original spring rates?

^ what's said above is correct in terms of rear height adjustment and yes, I had the default springs rates. I sold the car last February though and didn't get to experience with different spring rates etc.

[richf80]

How do you determine what the shock absorber height should be? For example if X is 30mm what would the height of the absorber be?

[horsepower_and_hounds]

That varies from manufacturer to manufacturer

[dvq]

Originally Posted by richf80

How do you determine what the shock absorber height should be? For example if X is 30mm what would the height of the absorber be?

What these coilover/damper manuals never offer is the exact question you just asked — here's what I've figured out — I'm not an expert this is just what I've researched.

1.) So you should start with the damper height they recommend.
2.) Then you can adjust the spring collar to get the ride height you want (in this case you mentioned you wanted x = 30) and put your wheels back on and let the car sit as it normally would.
3.) Take height measurements from a center point on the wheel to the fender as a reference to use later.
4.) Jack the car back up on jack stands , remove the wheel, remove the spring assembly and the bump stop from the car. Leave everything else the same. What you're doing is effectively just removing the spring and bump stop from the system so you can simulate suspension stroke in future steps.
5.) Put the wheel back on and jack up the wheel to the same reference measurement as before. This simulates the ride height you wanted without the spring or bump stop.
6.) From ride height, move the wheel up and down through the car's maximum bump and droop travel (what suspension movement you would see at the extremes of the travel). You'll find that there are limits since the damper has physical limits too. In relation to the static height you should see a 2:1 ratio of bump to droop — meaning 2/3rds of the exposed shock should be for bump and 1/3rd for droop.
7.) If you don't see 2:1 ratio for example almost all of the shock travel is bump, you need to adjust your shock height adjustment until it is.
8.) Put everything back together.

There's also bump stop height to play with but this was specifically for instructions on the shock height.

Video that explains this scrub to 20m40s

https://www.racecrafthq.com/introduc...ment/recording

[Mospeada]

umm you need to have this corner balanced to truly benefit from what you have

[richf80]

Originally Posted by dvq

What these coilover/damper manuals never offer is the exact question you just asked — here's what I've figured out — I'm not an expert this is just what I've researched.

1.) So you should start with the damper height they recommend.
2.) Then you can adjust the spring collar to get the ride height you want (in this case you mentioned you wanted x = 30) and put your wheels back on and let the car sit as it normally would.
3.) Take height measurements from a center point on the wheel to the fender as a reference to use later.
4.) Jack the car back up on jack stands , remove the wheel, remove the spring assembly and the bump stop from the car. Leave everything else the same. What you're doing is effectively just removing the spring and bump stop from the system so you can simulate suspension stroke in future steps.
5.) Put the wheel back on and jack up the wheel to the same reference measurement as before. This simulates the ride height you wanted without the spring or bump stop.
6.) From ride height, move the wheel up and down through the car's maximum bump and droop travel (what suspension movement you would see at the extremes of the travel). You'll find that there are limits since the damper has physical limits too. In relation to the static height you should see a 2:1 ratio of bump to droop — meaning 2/3rds of the exposed shock should be for bump and 1/3rd for droop.
7.) If you don't see 2:1 ratio for example almost all of the shock travel is bump, you need to adjust your shock height adjustment until it is.
8.) Put everything back together.

There's also bump stop height to play with but this was specifically for instructions on the shock height.

Video that explains this scrub to 20m40s

https://www.racecrafthq.com/introduc...ment/recording

This is great information. Thank you so much!

[M-Pilot]

Originally Posted by Mospeada

umm you need to have this corner balanced to truly benefit from what you have

Assuming you're referring to me as the OP, thanks captain obvious but the car was corner balanced since day 1 of the Ohlins install.