Rough ride

[jkennebeck]

I thought my ride was fine until I had my car in to a service center and they gave me a loaner S. Thought the ride was much smoother in the loaner. DIdn't give it much thought. Next time, in a different loaner the ride was again much smoother. Started searching and found this and the pressure buffeting thread. Unscrewed those just a few minutes ago and test drove and not only is the ride 80% better, the audio (premium) is much more full/bassy. Give it a try! And thanks to the community for posting all this useful knowledge!

 

[sorka]

Unfortunately that's not going to help us pre April 15 P85Ds

 

[jkennebeck]

hmmmm how to tell build date from vin???

 

[dgpcolorado]

hmmmm how to tell build date from vin???

The usual way to determine build date is from the placard in the driver's door frame.

 

[jkennebeck]

i will take a look at mine today after work. not sure when in 2015 mine was built.

 

[sillydriver]

Just read through this thread, which is kind of a mystery to me. My air-suspension P85DL is the same vintage as @sorka 's to within a month and I know I have the early-vintage suspension because of the part number on the front struts. I'm running 21" Pilot Super Sports at 45 psi cold.

I absolutely love the ride, even on rare ventures onto DC urban streets, although most of my driving time is either on I-66 or on well-maintained Northern Virginia country/suburban roads. The suspension is quite stiff but not jarring, and makes the car incredibly sporty for a vehicle that big and heavy. My memory may be playing tricks on me, but it feels as good and tight to the road as both a 911 and an R8 I used to own.

I can tell the spring rates are high because of the high frequency of the brief side-to-side sloshing when I quickly turn off the street into a particular entry way where you hit a ramp upon entry that's a couple inches high (although that could also be due to a stiff front sway bar). But because it takes up to a couple cycles for that slosh to completely settle, I think the damping of the shocks on my car is not excessively high.

I suspect the that what makes the ride of some early P85Ds too harsh is that the damping of the shocks is somehow set too high. Spring rate, whether of air or coil springs or of sway bars, and shock damping are two very different parameters from a physics standpoint. But while I am familiar with the basic physics, I am not an experienced petrolhead and do not know the practicalities of suspension tuning on real cars, or of whether the shock damping is adjustable in the MS. Even so, shock damping is the prime suspect in my view.

 

[sillydriver]

For what it's worth, here is a photo of the part number on the front strut on my P85DL, which I think has a great, if very sporty ride. It would be interesting to see whether those who have P85Ds with the rough ride problem have the same part.

 

[juju]

I own a 2014 P85 on coils. It’s much smoother than my last car (Honda Civic) so I’m very happy. I switched to 21” wheels and noticed a slightly bumpier ride, which was to be expected. Took it to the SC for other issues and got a loaner 2018 100D on air and 19s. It rode much smoother than mine (again, no surprise). Definitely enjoyed the smoothness but my car looks much meaner on the outside

I’m now planning on lowering mine with T Sportline springs. About to get even bumpier! And better looking

 

[Dragetreneren]

I thought my ride was fine until I had my car in to a service center and they gave me a loaner S. Thought the ride was much smoother in the loaner. DIdn't give it much thought. Next time, in a different loaner the ride was again much smoother. Started searching and found this and the pressure buffeting thread. Unscrewed those just a few minutes ago and test drove and not only is the ride 80% better, the audio (premium) is much more full/bassy. Give it a try! And thanks to the community for posting all this useful knowledge!

Can you be so kind and post the guidelines of how this can be done? Thank you so much!

 

[jkennebeck]

Can you be so kind and post the guidelines of how this can be done? Thank you so much!

Start with this thread here (has pictures, should be easy to follow). Hope it helps!
Quick reference to resolving pulsating air issue cause by liftgate

 

[Dragetreneren]

Start with this thread here (has pictures, should be easy to follow). Hope it helps!
Quick reference to resolving pulsating air issue cause by liftgate

Can I kindly ask if that was a correct thread? It seems like it is related to some liftgate problem.

 

[jkennebeck]

Can I kindly ask if that was a correct thread? It seems like it is related to some liftgate problem.

Yes. The liftgate buffeting was cured by following the steps in that thread to reduce the buffeting thus reducing the roughness of the ride. Sounds odd but I guess the gate and glass add up to enough weight to bounce the car a bit. Worked like a charm for me. Ride is much smoother now and the car has a better sound to it. Less outside noise/road noise.

 

[Dragetreneren]

I have an early p85d the 4th in Canada. I didn't get to test drive that model before purchase. It was punishingly stiff. Dangerously so. I was afraid to hurt people by driving on ordinary roads. I was stopped by police for driving too slowly. They probabIy suspected drunk driving. I don't drink, my back hurt. I previously drove Volvos which are not Cadys but ride well. A friend said it rode like an empty garbage truck and from then on my friends referred to it as the electric garbage truck. I complained at the SC with no results. Which is what the SC does best. They said you had to have that stiffness to handle the HP. I told them a Lambo doesn't ride this bad. I deflated tires which helped a little. I went on a factory tour a few months later. I asked to drive a regular 85. They determined I had a P85D and asked me why. Just for comparison. It rode well and didn't hurt. They asked how I liked my P85D, I said the worst ride I had ever had, my back ached all day after a 10 minute ride to work on roads I had traveled for decades in Volvos without noticing.
Upon my return much to my surprise they called me to replace my suspension at no charge. It took months to accomplish but was a big improvement. I suspect I was not the only one they did this for. Of course they no longer offer a car this stiff. I think they just made a mistake. I am an engineer and had measured G force in preparation for a lawyers letter and found it extraordinarily high as much as 7X compared to other cars. I didn't have to proceed because they fixed it. Never the less I love the car and pickup a replacement P100D tomorrow.

Hi It seems like you are not alone with whit roughness. Would you be able to post a reference to the toll that helped you measure G force? Thank you!

 

[Dana4261]

I bought a used early 2013 P85 this spring and been struggling with rough ride. I have air suspension and 19” rims. Cracks in roads are rough and loud boom noise resonates in car. I’ve tried the things in the forum with no real change. When I test drove the car with my gf and sales guy (big guy) we were like wow this is the quietest most comfortable car ever. When I drove it home a few days later i noticed it rough and been hating the ride since. Anyways, I’ve been stalking the forum and have a theory I’m going to test out. The car needs weight in it to ride softer?!?! Anyone try this?! Here’s a random link talking about load cars ride softer, so it helps support my theory. I’ll test this weekend. Experiencing harsh rides when driving without a load? | Pacbrake

 

[welbach]

Problem might be the rear shocks with PN 1015620-03-C, the 1015620-03-B are smooth, i don´t know if the later 1015620-03-D are too. the 1015620-03-C are hard, causing the hatch buffeting.
I tested a 2016 pre FL 85D with a very loose hatch and there was no booming, it had the 1015620-03-B, nice ride
Mine is a 90D, one of the first Facelifts, hast the 1015620-03-C and the ride is very harsh.
Front shocks seem okay.
greets from Austria

 

[welbach]

I found a 1015620-03-B shock in California and another one here in Europe.
After swapping, the rough ride is gone.

 

[philip295]

Is this any use? I wonder if variation in caster angle could explain the difference between cars... KPI – Kinematic wheel centre recession – Suspension Designer

 

[Welbach1]

nearly all on coil and 19.


Dec 2016 90D Coil 19 Zoll hart pilotSteve
Ende 2016 60D Coil 19 Zoll hart JPRiver front#F4-EE5-K999-W0 162470234; REAR #F4-EE5-K763-W0 162310669
Dec 2016 60D Coil hart Deans
Dec 30 2016 90D Coil 19 Zoll hart Joe F
July 2016 75D ??? ???? hart bucksport
Ende 2015 85D Air 19 Zoll hart, Kdmn neue Dämpfer bekommen jetzt gut
Dec 2016 60D Coil ???? hart, Marty Manners
???????? 60D ??? ???? hart, JRMW
März 2015 P85D+ Air ??? hart, sorka
Dec 2016 75D Coil 19 Zoll hart, jaimed
??? 2017 90D Air ??? hart, dragoljub
??? ??? 85D Coil ?? hart, MileHighMotoring
Anfang 2013 P85 Air 19 Zoll hart booming, Dana4216

 

[philip295]

nearly all on coil and 19.


Dec 2016 90D Coil 19 Zoll hart pilotSteve
Ende 2016 60D Coil 19 Zoll hart JPRiver front#F4-EE5-K999-W0 162470234; REAR #F4-EE5-K763-W0 162310669
Dec 2016 60D Coil hart Deans
Dec 30 2016 90D Coil 19 Zoll hart Joe F
July 2016 75D ??? ???? hart bucksport
Ende 2015 85D Air 19 Zoll hart, Kdmn neue Dämpfer bekommen jetzt gut
Dec 2016 60D Coil ???? hart, Marty Manners
???????? 60D ??? ???? hart, JRMW
März 2015 P85D+ Air ??? hart, sorka
Dec 2016 75D Coil 19 Zoll hart, jaimed
??? 2017 90D Air ??? hart, dragoljub
??? ??? 85D Coil ?? hart, MileHighMotoring
Anfang 2013 P85 Air 19 Zoll hart booming, Dana4216

Mine is 19" coil, 85. I found adjusting the front wheels to toe in reduced the front to back pitching motion. It was slightly toe out before. I'll try adjusting caster when I can measure it accurately.

 

[Welbach1]

Mine is 19" coil, 85. I found adjusting the front wheels to toe in reduced the front to back pitching motion. It was slightly toe out before. I'll try adjusting caster when I can measure it accurately.

RWD on Coils?