Does suspension 'warm up'

3t3p · 03-08-2022, 01:32 PM

Don't know if I'm tripping balls but I swear that when the whole car is cold the suspension is not as supple as when I've been on it for a bit and the car is warm? I'd go so far as to say it's a bit longer than the engine takes to warm up.

I thought I noticed this without trying to notice it if that makes sense?!

M Fifty · 03-08-2022, 01:39 PM

Probably the tyres. Select the tyre pressure screen and you'll see it also shows temperature.

Go for a drive and marvel at how the temperature climbs 20C just cruising on the motorway...

Edit: UK temperatures in February. So it starts at 3C, and ends up in the mid 20s.

Connors5453 · 03-08-2022, 01:53 PM

This is absolutely true! Suspension fluid will heat and cool and become more or less viscous. This is why race cars and other high performance applications have external redivides housing for suspension fluid to help keep it cool and prevent air bubbles from forming ruining the performance.

M Fifty · 03-08-2022, 03:23 PM

You have to beat the sh*t out of the suspension 1st - as that's what it's designed to do...

3t3p · 03-10-2022, 02:33 AM

That's what I thought they've got oil in them. Must be an element of what both you say.

rtl32 · 03-19-2022, 06:21 PM

Absolutely. The passing of the fluid through the dampers creates an immense amount of friction that heats it up and affects viscosity, which in turn affects the damping effect. That is why suspension fluid is a science of it's own.

Add in another set of variables to a gas charged system like those found in some mountain bike or motorcycle shocks, and you have the temperature/pressure changes of the gas affecting suspension as well.

Motorcycles have hugely noticeable changes in suspension during their warmup laps.

rtl32 · 03-19-2022, 06:23 PM

Also suspension fluids break down over time which makes it a mystery to me how these cars have non serviceable dampers, and how in the coilover community, nobody stresses getting rebuilds from time to time

HP Autosport · 03-29-2022, 06:15 PM

Quote:

Originally Posted by 3t3p

Don't know if I'm tripping balls but I swear that when the whole car is cold the suspension is not as supple as when I've been on it for a bit and the car is warm? I'd go so far as to say it's a bit longer than the engine takes to warm up.

I thought I noticed this without trying to notice it if that makes sense?!

Yes, there is a such a thing. You aren't the only one experience it. Damper fluid/shock oil can break down, change viscosity, and heat/cold can all affecting damping.

chris719 · 03-29-2022, 09:45 PM

Quote:

Originally Posted by rtl32

Also suspension fluids break down over time which makes it a mystery to me how these cars have non serviceable dampers, and how in the coilover community, nobody stresses getting rebuilds from time to time

Because OEM shocks/struts are considered wear items. They are cheap enough and the fluid may not be standardized.

HP Autosport · 03-29-2022, 09:49 PM

Quote:

Originally Posted by chris719

Because OEM shocks/struts are considered wear items. They are cheap enough and the fluid may not be standardized.

Definitely not the high end synthetic damper fluid we see in Ohlins, MCS, JRZ and such.

stefan · 03-31-2022, 09:01 AM

I can confirm for sure that whatever hydraulic fluid is in the dampers is susceptible to temperature. My car is much stiffer in extreme cold (-25 to -30 deg C) versus warm weather. I think it's cheap fluid. I haven't experienced this on any other BMW prior to this, at least to the extent that it's as noticeable as it is in the M2C. Could be the fact it's paired with stiff springs and cost cutting I guess. Honestly this suspension is terrible. I really hate it but don't want to lower the car.

HP Autosport · 04-11-2022, 05:10 PM

Quote:

Originally Posted by stefan

I can confirm for sure that whatever hydraulic fluid is in the dampers is susceptible to temperature. My car is much stiffer in extreme cold (-25 to -30 deg C) versus warm weather. I think it's cheap fluid. I haven't experienced this on any other BMW prior to this, at least to the extent that it's as noticeable as it is in the M2C. Could be the fact it's paired with stiff springs and cost cutting I guess. Honestly this suspension is terrible. I really hate it but don't want to lower the car.

It also goes for the other direction. When the fluid is too hot damping degradation occurs. The twin tube design is more susceptible to that. KW and Koni are two examples of twin tube campers.

3t3p · 04-29-2022, 11:36 PM

Stock suspension not that bad after M3 brace retrofit and ps4s above 45mph or do really ok.

I appreciate the Bilsteins more and more though, they do so much when you're on it and give you contact patch all the time. Here's hoping they last as are used as OEM for other cars.

Glad I'm not going crazy!

Billy_BMW · 05-07-2022, 06:49 AM

While fluid viscosity in the dampers is susceptible to temperature changes during use, I believe the difference may be more to do with the tyres and rubber compound.

Different tyre compounds behave differently at certain temperatures (think of cold race tyres), and it's often immediately noticeable if you're keyed in, on cold mornings. This isn't just the compound at the contact patch, but the construction and sidewall stiffness.

The tyres are an integral part of the suspension system and differences in tyre sidewall stiffness will translate directly to how the shocks/springs absorb bumps and dips.

03-08-2022, 01:32 PM	#1
3t3p Major 455 Rep 1,389 Posts Drives: M2 Join Date: May 2018 Location: NZ iTrader: (0)	Does suspension 'warm up' Don't know if I'm tripping balls but I swear that when the whole car is cold the suspension is not as supple as when I've been on it for a bit and the car is warm? I'd go so far as to say it's a bit longer than the engine takes to warm up. I thought I noticed this without trying to notice it if that makes sense?!
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03-08-2022, 01:39 PM	#2
M Fifty Banned 844 Rep 1,962 Posts Drives: M2 & 330CI Join Date: May 2018 Location: The Interweb iTrader: (0)	Probably the tyres. Select the tyre pressure screen and you'll see it also shows temperature. Go for a drive and marvel at how the temperature climbs 20C just cruising on the motorway... Edit: UK temperatures in February. So it starts at 3C, and ends up in the mid 20s.
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03-08-2022, 01:53 PM	#3
Connors5453 Second Lieutenant 467 Rep 291 Posts Drives: 2023 BMW M2 Join Date: May 2019 Location: Bay Area iTrader: (0) Garage List 2023 BMW M2 [9.38]	This is absolutely true! Suspension fluid will heat and cool and become more or less viscous. This is why race cars and other high performance applications have external redivides housing for suspension fluid to help keep it cool and prevent air bubbles from forming ruining the performance.
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03-08-2022, 03:23 PM	#4
M Fifty Banned 844 Rep 1,962 Posts Drives: M2 & 330CI Join Date: May 2018 Location: The Interweb iTrader: (0)	You have to beat the sh*t out of the suspension 1st - as that's what it's designed to do...
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03-10-2022, 02:33 AM	#5
3t3p Major 455 Rep 1,389 Posts Drives: M2 Join Date: May 2018 Location: NZ iTrader: (0)	That's what I thought they've got oil in them. Must be an element of what both you say.
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03-19-2022, 06:21 PM	#6
rtl32 Private First Class 73 Rep 196 Posts Drives: M235i 6MT Join Date: Nov 2020 Location: NJ iTrader: (0)	Absolutely. The passing of the fluid through the dampers creates an immense amount of friction that heats it up and affects viscosity, which in turn affects the damping effect. That is why suspension fluid is a science of it's own. Add in another set of variables to a gas charged system like those found in some mountain bike or motorcycle shocks, and you have the temperature/pressure changes of the gas affecting suspension as well. Motorcycles have hugely noticeable changes in suspension during their warmup laps. __________________ 14' Alpine White M235i 6MT, BM3 Stg2+, VRSF DP-CP-FMIC, Dinan Muffler, GFB DV+, 3.5 bar MAP, Dorch Stg1 HPFP, NGK 97506, BM3 Flexfuel Kit, CDV delete, KW V3, EDC delete, Powerflex Camber LCA bushings, VMR 801 18x8.5/9.5 et45, Conti Extremecontact 235/265 Next step: M2 Competition or Manual Supra MKV build Summer 2022
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03-19-2022, 06:23 PM	#7
rtl32 Private First Class 73 Rep 196 Posts Drives: M235i 6MT Join Date: Nov 2020 Location: NJ iTrader: (0)	Also suspension fluids break down over time which makes it a mystery to me how these cars have non serviceable dampers, and how in the coilover community, nobody stresses getting rebuilds from time to time __________________ 14' Alpine White M235i 6MT, BM3 Stg2+, VRSF DP-CP-FMIC, Dinan Muffler, GFB DV+, 3.5 bar MAP, Dorch Stg1 HPFP, NGK 97506, BM3 Flexfuel Kit, CDV delete, KW V3, EDC delete, Powerflex Camber LCA bushings, VMR 801 18x8.5/9.5 et45, Conti Extremecontact 235/265 Next step: M2 Competition or Manual Supra MKV build Summer 2022
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03-31-2022, 09:01 AM	#11
stefan Brigadier General 2354 Rep 4,254 Posts Drives: M2 Comp Join Date: Feb 2008 Location: North iTrader: (2)	I can confirm for sure that whatever hydraulic fluid is in the dampers is susceptible to temperature. My car is much stiffer in extreme cold (-25 to -30 deg C) versus warm weather. I think it's cheap fluid. I haven't experienced this on any other BMW prior to this, at least to the extent that it's as noticeable as it is in the M2C. Could be the fact it's paired with stiff springs and cost cutting I guess. Honestly this suspension is terrible. I really hate it but don't want to lower the car. __________________ ///M Power
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04-29-2022, 11:36 PM	#13
3t3p Major 455 Rep 1,389 Posts Drives: M2 Join Date: May 2018 Location: NZ iTrader: (0)	Stock suspension not that bad after M3 brace retrofit and ps4s above 45mph or do really ok. I appreciate the Bilsteins more and more though, they do so much when you're on it and give you contact patch all the time. Here's hoping they last as are used as OEM for other cars. Glad I'm not going crazy!
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05-07-2022, 06:49 AM	#14
Billy_BMW Private First Class 54 Rep 139 Posts Drives: BMW M2 Competition Join Date: Feb 2012 Location: UK iTrader: (0)	While fluid viscosity in the dampers is susceptible to temperature changes during use, I believe the difference may be more to do with the tyres and rubber compound. Different tyre compounds behave differently at certain temperatures (think of cold race tyres), and it's often immediately noticeable if you're keyed in, on cold mornings. This isn't just the compound at the contact patch, but the construction and sidewall stiffness. The tyres are an integral part of the suspension system and differences in tyre sidewall stiffness will translate directly to how the shocks/springs absorb bumps and dips.
	Appreciate 0 Quote