Ohlins R&T and Thrust Sheets

Anyone running Swift Thrust Sheets with Ohlins R&T? Any difference before and after? Wondering if any downsides. Don't want to introduce noise in attempts to prevent it...

They're supposed to be used on either end of the spring, but talking with Barry at 3DM seems you can take a hybrid approach with them at the bottom of the front spring and the top of the rear.

There is no downside. A coil spring wants to twist as it is compressed so thrust sheets release the torsional DOF and allow the spring to twist.

The front upper strut mounts and camber plates have a thrust bearing that releases the torsional DOF so technically only thrust sheets are needed at the bottom (it doesn’t hurt anything to add thrust sheets at the top. As for the rear, thrust sheets should be used at the bottom and the top. Below is a drawing from 3DM showing thrust sheets are used at the bottom (items # 2 and 3) and the top (items # 2 and 3).

M3SQRD wrote

There is no downside. A coil spring wants to twist as it is compressed so thrust sheets release the torsional DOF and allow the spring to twist.

The front upper strut mounts and camber plates have a thrust bearing that releases the torsional DOF so technically only thrust sheets are needed at the bottom (it doesn’t hurt anything to add thrust sheets at the top. As for the rear, thrust sheets should be used at the bottom and the top. Below is a drawing from 3DM showing thrust sheets are used at the bottom (items # 2 and 3) and the top (items # 2 and 3).

Yes I've looked at that diagram, but that's assuming the spring is sitting on a metal perch top and bottom, which isn't the case with standard Ohlins R&T.

The factory top hat has roller bearings which will essentially function as a thrust sheet so no issue there, but the rear spring sits on a plastic perch on the bottom. 3DM says thrust sheets are optimal on metal surfaces. Hence why I can only run em on top.

I'm just curious if anyone ran this configuration and had undesirable results like noise or if it alleviated them that were present before.

a5m wrote

Yes I've looked at that diagram, but that's assuming the spring is sitting on a metal perch top and bottom, which isn't the case with standard Ohlins R&T.

The factory top hat has roller bearings which will essentially function as a thrust sheet so no issue there, but the rear spring sits on a plastic perch on the bottom. 3DM says thrust sheets are optimal on metal surfaces. Hence why I can only run em on top.

I'm just curious if anyone ran this configuration and had undesirable results like noise or if it alleviated them that were present before.

Think of the end caps as being generic place holders. Regardless of whether it’s a front strut, front coilover (e.g. na1 NSX, ap1/ap2 s2000), divorced rear spring or a coilover rear spring, the spring still rotates as it is compressed and, therefore, the torsional DOF needs to be released to eliminate stick-slip (or bind-slip). I’ve been using thrust sheets on rear divorced spring setups and front struts for 16 years, and Torrington roller bearings before that. Torrington bearings are a maintenance nightmare because it is not sealed so debris gets into the roller bearings. Thrust sheets don’t have maintenance issues.

I have the sheets on top and bottom of my Ohlins R&T springs, both front and rear. They are cheap and Barry at 3DM told me it would be good when I set up the Ohlins about 3 years ago.

It's been a few thousand miles and several track days and I don't have noise or other weird issues.

andrewmega wrote

I have the sheets on top and bottom of my Ohlins R&T springs, both front and rear. They are cheap and Barry at 3DM told me it would be good when I set up the Ohlins about 3 years ago.

It's been a few thousand miles and several track days and I don't have noise or other weird issues.

I assume you're running linear springs instead of what comes in the kit. That's good to know, should hopefully be no different if running on one end only.

I used thrust sheets on my fronts to try to get rid of a noise I had but they didn't help. Didn't really hurt either. Turns out the noise was from tie rods.

Redd wrote

I used thrust sheets on my fronts to try to get rid of a noise I had but they didn't help. Didn't really hurt either. Turns out the noise was from tie rods.

Interesting, this is the kind of info I was after. What did that noise sound like? I'm getting some noise and trying to narrow it down.

a5m wrote

Interesting, this is the kind of info I was after. What did that noise sound like? I'm getting some noise and trying to narrow it down.

Clicking noise from front suspension during low speed driving (eg parking) especially at full lock.

a5m wrote

Interesting, this is the kind of info I was after. What did that noise sound like? I'm getting some noise and trying to narrow it down.

When does your noise occur and what does it sound like? If it’s an intermittent pop or ping sound that’s occurring as you are turning the steering wheel to the left and/or right then it could be the spring repeatably slipping and sticking as the steering wheel is turned. Thrust sheets would likely help to address this type of noise. However, thrust sheets themselves are inherently noise free because it’s a low-friction plastic ring rotating against a SS ring.

Did you buy your R&Ts new? If they’re used, do you know the number of miles on them? There’s a brass bushing that was changed to a different material (I could be getting things mixed up between f8x and e9x M R&Ts) and this change resulted in a new noise as the damper compresses or rebounds.

M3SQRD wrote

When does your noise occur and what does it sound like? If it’s an intermittent pop or ping sound that’s occurring as you are turning the steering wheel to the left and/or right then it could be the spring repeatably slipping and sticking as the steering wheel is turned. Thrust sheets would likely help to address this type of noise. However, thrust sheets themselves are inherently noise free because it’s a low-friction plastic ring rotating against a SS ring.

Did you buy your R&Ts new? If they’re used, do you know the number of miles on them? There’s a brass bushing that was changed to a different material (I could be getting things mixed up between f8x and e9x M R&Ts) and this change resulted in a new noise as the damper compresses or rebounds.

It's a very soft click, and a crunching type sound like glass being crushed that seems to come from the strut towers or where the windshield meets the dash. Happens on the rebound stroke, like going over speed bumps. I think that's due to the inappropriate length of the end links BimmerWorld set me up with. That's a whole another story...

I haven't read about the bushing noise issue, so may be from the F8x platform.

a5m wrote

It's a very soft click, and a crunching type sound like glass being crushed that seems to come from the strut towers or where the windshield meets the dash. Happens on the rebound stroke, like going over speed bumps. I think that's due to the inappropriate length of the end links BimmerWorld set me up with. That's a whole another story...

I haven't read about the bushing noise issue, so may be from the F8x platform.

I’ve never heard of a damper making a crushing glass sound. I’m not saying it’s not coming from the damper but that’s a new one for me. R&Ts can be difficult when it comes to picking proper drop link lengths because you can change the length of the damper between the spring adjuster and the knuckle as well as adjust the spring preload. If you believe the drop links are causing a problem, disconnect one, or both (zip tie the bar to something), and see if the noise/issue is resolved. You didn’t answer my question about whether they were new or used when you first purchased them? Perhaps the dampers need a rebuild?

Ok. The internal bushing material change is a f8x issue.

M3SQRD wrote

I’ve never heard of a damper making a crushing glass sound. I’m not saying it’s not coming from the damper but that’s a new one for me. R&Ts can be difficult when it comes to picking proper drop link lengths because you can change the length of the damper between the spring adjuster and the knuckle as well as adjust the spring preload. If you believe the drop links are causing a problem, disconnect one, or both (zip tie the bar to something), and see if the noise/issue is resolved. You didn’t answer my question about whether they were new or used when you first purchased them? Perhaps the dampers need a rebuild?

Ok. The internal bushing material change is a f8x issue.

Oh sorry, they're used with about 6-8k street only California miles on them. I think they have some time until a rebuild is necessary.

That's another thing I have to figure out with the Ohlins - the shock length. The front seems easy enough to adjust if I want to go lower than the recommended height settings, just 1:1 with how many mm I lower, but not sure if the same applies to the rear since it's a divorced setup. I've read people doing 1.5x the spring adjustment, so 1.5mm shock length for ever 1mm spring length.

I plan to use shaved front top hats and Dinan RSM so that adds an additional measurement to factor in.

a5m wrote

Oh sorry, they're used with about 6-8k street only California miles on them. I think they have some time until a rebuild is necessary.

That's another thing I have to figure out with the Ohlins - the shock length. The front seems easy enough to adjust if I want to go lower than the recommended height settings, just 1:1 with how many mm I lower, but not sure if the same applies to the rear since it's a divorced setup. I've read people doing 1.5x the spring adjustment, so 1.5mm shock length for ever 1mm spring length.

I plan to use shaved front top hats and Dinan RSM so that adds an additional measurement to factor in.

6-8k miles is 1/4-1/3 of the way to a rebuild at 25k miles. However, on my r56 Cooper S R&Ts, my first rebuild wasn’t until 40k miles.

The divorced spring and damper motion ratios are 0.60 and 0.80, respectively, so for every 1 mm adjustment at the divorced spring location is equal to a 1.33 mm adjustment at the damper location.

M3SQRD wrote

6-8k miles is 1/4-1/3 of the way to a rebuild at 25k miles. However, on my r56 Cooper S R&Ts, my first rebuild wasn’t until 40k miles.

The divorced spring and damper motion ratios are 0.60 and 0.80, respectively, so for every 1 mm adjustment at the divorced spring location is equal to a 1.33 mm adjustment at the damper location.

You're the best Donnie, thank you. Just what I was looking for.

I'll consider these half way through their service life then based on Chicago roads. If I get more that's a bonus.

So seems the hybrid thrust sheet approach is a go. I'll order them up Monday.

a5m wrote

You're the best Donnie, thank you. Just what I was looking for.

I'll consider these half way through their service life then based on Chicago roads. If I get more that's a bonus.

So seems the hybrid thrust sheet approach is a go. I'll order them up Monday.

I’m glad to help

You’ve probably already stated this but what spring rates are you running with the R&Ts? How have you set/measured your rake and how much (forward, I hope) rake are you running?

You should be fine with either thrust sheet approach. You can always install one more pair of thrust sheets per rear divorced spring if you find the spring binding. Also, to eliminate the concern of the steel sheet sitting on a rubber isolator, you could place an additional thin steel ring shim on top of the rubber isolator before installing the thrust steel sheet so it rides on another piece of steel, not rubber.

I’ve been having a thumping/binding feel through the steering wheel after the car goes on a 15+ minute drive. You would only feel the sensation at parking lot speeds. If the car is stationary and I repeatedly turn the steering wheel slightly back and fourth you can feel the bumps/bind, it will go away but come back after the car moves. This is NOT a click/pop/creak.

I had this happen since day one of installing the ohlins RT + millway street camber plates. All parts were brand new so figured it might be the oem sway bar endlinks. Swapped to spl but still having the same issue. Thought it was preload on sway bar but got it balanced properly and even went no endlinks to rule that out. Car has gotten several alignments and I’ve been driving for 6-8k miles and the issue is still present. Car had 20k miles when first installed so I’m assuming the oem parts are all still good…

Does anyone know if the thrust sheets would help? I am also planning to get a shorter/softer spring to try and fix this. Or is there anything else I should be checking?

I do have this install on a f87 but figured it might be a universal problem with ohlins RT

Toroinu wrote

I’ve been having a thumping/binding feel through the steering wheel after the car goes on a 15+ minute drive. You would only feel the sensation at parking lot speeds. If the car is stationary and I repeatedly turn the steering wheel slightly back and fourth you can feel the bumps/bind, it will go away but come back after the car moves. This is NOT a click/pop/creak.

I had this happen since day one of installing the ohlins RT + millway street camber plates. All parts were brand new so figured it might be the oem sway bar endlinks. Swapped to spl but still having the same issue. Thought it was preload on sway bar but got it balanced properly and even went no endlinks to rule that out. Car has gotten several alignments and I’ve been driving for 6-8k miles and the issue is still present. Car had 20k miles when first installed so I’m assuming the oem parts are all still good…

Does anyone know if the thrust sheets would help? I am also planning to get a shorter/softer spring to try and fix this. Or is there anything else I should be checking?

I do have this install on a f87 but figured it might be a universal problem with ohlins RT

Adding them won’t hurt anything but will it address your issue? I’m not sure. Based on your description, it seems your binding issue shows up after a short drive of at least 15 min. What happens if you stop after only a 5 or 10 min drive? Is there no thumping and/or binding feeling as you are sawing the steering wheel to the left and right? Spring binding typically doesn’t have a time component to it - it’s either always there or it’s not there and that’s why I’m not sure thrust sheets will address your issue. However, I personally always recommend to everyone that they should be running Swift thrust sheets because they help the spring to rotate freely as the spring is compressed/extended and they are maintenance free unlike Torrington roller bearings.

Ohlins changed the material of an internal bushing from brass to plastic when f8x R&T dampers were first released. Is your rear spring rate 230 N/mm (original f8x release) or 190 N/mm (original f87 release, revised f8x)? Your issue could be an internal damper issue which could have a time component associated with it (i.e., it needs heat from a minimum 15 min drive before the binding feeling starts). Ohlins would reinstall the brass bushing in f8x dampers and the binding noise/feeling would no longer be there. I believe starting with the release of the f87 kit, Ohlins reverted back to the brass bushing.

Lastly, the binding feeling could be coming from the Millway camber plate thrust bushing. The time component isn’t typically but maybe your setup needs a little heat before the steering wheel input results in a binding condition. Unfortunately, there’s no easy way to test whether it’s the camber plate. You could try spraying a small amount of a dry film lubricant around the perimeter of the spring OD where it contacts the Millway camber plate. If the noise and/or feeling is reduced then it likely could be the camber plate. At least you’ve potentially eliminated the front drop links as being a possible variables. To completely eliminate the drop links (the Ohlins primary ride height adjustment may be fighting with the preload/secondary height adjustment), disconnect the drop links and zip tie the sway bar at one end only to prevent it from swinging down.

Addressing suspension noises are a pain in the ass and can be extremely difficult to solve. Most of us have had to deal with suspension noises and/or feeling at some point so we understand the frustration. I hope you find the cause of your issue sooner rather than later!

Thanks for the detailed response!

I believe my stock rate is 90/190 so sounds like it’s the revised version?

As for the millway camber plates, it reuses the OEM thrust bearings. The car had 20k miles unless that went bad after the install.

At this point I’m just debating if I should start fresh with a new set of coilovers as the diagnosis and replacement part with labor can add up close to a new kit..

Toroinu wrote

Thanks for the detailed response!

I believe my stock rate is 90/190 so sounds like it’s the revised version?

As for the millway camber plates, it reuses the OEM thrust bearings. The car had 20k miles unless that went bad after the install.

At this point I’m just debating if I should start fresh with a new set of coilovers as the diagnosis and replacement part with labor can add up close to a new kit..

Yeah, you have the revised dampers. The oem thrust bearing is pretty durable so I doubt it’s your issue.

If you started fresh, would you stick with the R&Ts or try something else? Although more expensive, the Nitron R1 or MCS 1WNR are both great options. Staying with the R&Ts, the 3DM custom options would be a nice change with a different spec R&T from the Ohlins R&T OTS damper.

M3SQRD wrote

Yeah, you have the revised dampers. The oem thrust bearing is pretty durable so I doubt it’s your issue.

If you started fresh, would you stick with the R&Ts or try something else? Although more expensive, the Nitron R1 or MCS 1WNR are both great options. Staying with the R&Ts, the 3DM custom options would be a nice change with a different spec R&T from the Ohlins R&T OTS damper.

I was initially thinking about sending the struts to get it looked at with the bearings but if that is highly unlikely to be an issue, I might try the thrust sheets and maybe softer springs to see if the problem fixes itself while reassembling.

Can it be tie rods by chance?

How are the mcs 1wnr? I’m mainly street with some backroad driving. Someone in my area is selling a lightly used kit with eibach springs

Toroinu wrote

I was initially thinking about sending the struts to get it looked at with the bearings but if that is highly unlikely to be an issue, I might try the thrust sheets and maybe softer springs to see if the problem fixes itself while reassembling.

Can it be tie rods by chance?

How are the mcs 1wnr? I’m mainly street with some backroad driving. Someone in my area is selling a lightly used kit with eibach springs

What’s the mileage on your R&Ts? Dampers can start to develop noises as they accumulate mileage or approach the rebuild interval.

Adding thrust sheets is a relatively inexpensive option (labor is where the cost is unless you can do the work yourself) and one I would definitely try before starting over with a new setup.

The tie rods could be the culprit but they’d make the same noise with the car idling from a cold start or after a one hour drive. The time component is what makes identifying your cause difficult.

The 1WNR is an excellent street damper especially with street spring rates. However, they still have nice street manners with dedicated track spring rates. It has a wide range of damping so you can have a comfortable street setup and a responsive track setup. I’m a huge MCS fan but I try to provide unbiased posts when it comes to dampers. Do you know the number of miles and the spring rates on the used 1WNR?