Bilstein PSS10 Revised Spring Rates
08-29-2018, 04:53 AM
#16
Great thread! I’ve been losing my mind since fitting PSS10’s to my 964 a year ago. Multiple attempts at setup to find something I like and I just can’t get them there. I don’t track the car – back road, mountain runs are what I love. If the tarmac is smooth, I’ve found them to be fantastic, really controlling body roll, dive under brakes and squat when on the throttle. But if the road surface is rough then grip becomes compromised with the car becoming skatey. And for everyday driving around town, the handling is brittle – even at softer settings.
My goal is to eventually fit 18” E88’s but I’d almost given up on that idea, thinking I’d hate the handling.
I was getting to the point of considering selling them and trying a KW V3 or ponying up the big bucks for Ohlins. Strange thing is, it’s always been in the back of my mind that I should consider spring rates but I’d just not really gotten myself over the line with it. I’ve called the local Bilsten distributor today to start the ball rolling – let’s see what the results are. Yup a 964 not 993 but seemingly the same issue.
My goal is to eventually fit 18” E88’s but I’d almost given up on that idea, thinking I’d hate the handling.
I was getting to the point of considering selling them and trying a KW V3 or ponying up the big bucks for Ohlins. Strange thing is, it’s always been in the back of my mind that I should consider spring rates but I’d just not really gotten myself over the line with it. I’ve called the local Bilsten distributor today to start the ball rolling – let’s see what the results are. Yup a 964 not 993 but seemingly the same issue.
08-30-2018, 10:40 AM
#18
thanks for posting the springs rates and part numbers, great information.
what ride height are you using?
my issue with pss10 is using the max collar height on the rears according to bilstein's instructions produces a rear ride height of 115.
not a big problem, just means I have to be careful on steep driveways.
could you post the optional spring rates h&r suggested?
would be interesting to know the range of spring rate change that can be made while keeping the existing pss10 valving.
what ride height are you using?
my issue with pss10 is using the max collar height on the rears according to bilstein's instructions produces a rear ride height of 115.
not a big problem, just means I have to be careful on steep driveways.
could you post the optional spring rates h&r suggested?
would be interesting to know the range of spring rate change that can be made while keeping the existing pss10 valving.
08-30-2018, 01:04 PM
#19
Rennlist Member
Nice work Greg!
Before someone embarks on a similar project with PSS10's I would suggest playing with tires first. There's a good chance you'll get the desired effect without spring changes. The best street ride I found on 18" wheels is the PS2 tires. The worst was the NT01's. Age of tires and pressure played a big role too. Wheel width as well. I don't see stretched out ricer stuff here but I do see people stuffing oversized tires on narrow wheels. Those situations tend to require higher pressures to make tires happy. Conversely stretching out the tires slightly will require slightly less pressure.
FWIW I run 235's on a 9" and 315's on a 12". Pressures are 33 front and 37 rear on PS2's. Quite happy with the ride on PSS9's with that combo.
Before someone embarks on a similar project with PSS10's I would suggest playing with tires first. There's a good chance you'll get the desired effect without spring changes. The best street ride I found on 18" wheels is the PS2 tires. The worst was the NT01's. Age of tires and pressure played a big role too. Wheel width as well. I don't see stretched out ricer stuff here but I do see people stuffing oversized tires on narrow wheels. Those situations tend to require higher pressures to make tires happy. Conversely stretching out the tires slightly will require slightly less pressure.
FWIW I run 235's on a 9" and 315's on a 12". Pressures are 33 front and 37 rear on PS2's. Quite happy with the ride on PSS9's with that combo.
Last edited by MarinS4; 08-31-2018 at 05:51 PM.
08-30-2018, 11:48 PM
#20
Advanced
Thread Starter
Thank you guys for the responses, I have been driving the car a lot this summer and really love how it drives now.
MarinS4 - I agree this was a little drastic. In my case, I was driving around at 30 psi on the lowest shock setting. I wasn't enjoying the ride and the car was squirming around in corners. I like thinking about these things and decided to try this before swapping out the entire suspension.
K722070 here is the best I can do to answer your questions:
What ride height are you using?
My ride height is:
RF 124, LF 122
RR 122, LR 120
Could you post the optional spring rates h&r suggested?
H&R did not suggest optional spring rates, they provided this chart and showed me how to find the correct spring fitment for the PSS10's:
http://www.hrsprings.com/applications/60mm_id_springs
I made the choices listed in my original post. Which ended up being one selection down for each spring.
When compared to spring rates of the other after market suspensions attached to this post they seemed reasonable.
.
MarinS4 - I agree this was a little drastic. In my case, I was driving around at 30 psi on the lowest shock setting. I wasn't enjoying the ride and the car was squirming around in corners. I like thinking about these things and decided to try this before swapping out the entire suspension.
K722070 here is the best I can do to answer your questions:
What ride height are you using?
My ride height is:
RF 124, LF 122
RR 122, LR 120
Could you post the optional spring rates h&r suggested?
H&R did not suggest optional spring rates, they provided this chart and showed me how to find the correct spring fitment for the PSS10's:
http://www.hrsprings.com/applications/60mm_id_springs
I made the choices listed in my original post. Which ended up being one selection down for each spring.
When compared to spring rates of the other after market suspensions attached to this post they seemed reasonable.
.
Would be interesting to know the range of spring rate change that can be made while keeping the existing pss10 valving.
No idea how to find this out, and suspect Bilstein would say this valving is only good for original spring rates.
My reasoning on valving was that the PSS10's have 10 settings and I was on the lowest. So there would be enough room to drop spring rates by at least one selection down and still be in this 1 to 10 range.
I lucked out as I have the ride I was hoping for at 6 front / 7 Rear.
Thank You,
Greg
No idea how to find this out, and suspect Bilstein would say this valving is only good for original spring rates.
My reasoning on valving was that the PSS10's have 10 settings and I was on the lowest. So there would be enough room to drop spring rates by at least one selection down and still be in this 1 to 10 range.
I lucked out as I have the ride I was hoping for at 6 front / 7 Rear.
Thank You,
Greg
09-10-2018, 01:42 AM
#21
Rennlist Member
I’m very confused by the fact that the tender springs on the original PSS10’s have a higher spring rate than the main springs. To me this would mean the main spring would have to be fully compressed before the tender would compress. Is this not the case?
09-10-2018, 03:38 AM
#22
Rennlist Member
I found this, helps to make a little more sense as to why the tenders are stiffer than the mains on stock PSS10’s
Helper springs have a nearly zero-rate and the purpose is to prevent the main spring from going slack as full droop is approached (and in going slack, unseating or moving around). They have no effect on ride or handling other than to prevent the main spring from unseating and re-seating suddenly. Helper springs are fully-compressed (coil-bound) at static ride height.
Tender springs typically range from 100 to 200 lb rate and the purpose is to create a dual-rate setup in which the suspension travel includes a lower combined rate (according to the (A X B) / (A + B) = combined spring rate formula) as well as a higher spring rate once the tender spring is fully compressed (at which point the main spring rate takes effect). This results in a more compliant ride than is possible with individual high-rate springs and a greater resistance to roll than is possible with individual low-rate springs. Tender springs are not fully-compressed at static ride height.
Helper springs have a nearly zero-rate and the purpose is to prevent the main spring from going slack as full droop is approached (and in going slack, unseating or moving around). They have no effect on ride or handling other than to prevent the main spring from unseating and re-seating suddenly. Helper springs are fully-compressed (coil-bound) at static ride height.
Tender springs typically range from 100 to 200 lb rate and the purpose is to create a dual-rate setup in which the suspension travel includes a lower combined rate (according to the (A X B) / (A + B) = combined spring rate formula) as well as a higher spring rate once the tender spring is fully compressed (at which point the main spring rate takes effect). This results in a more compliant ride than is possible with individual high-rate springs and a greater resistance to roll than is possible with individual low-rate springs. Tender springs are not fully-compressed at static ride height.
09-10-2018, 11:03 PM
#23
Helper springs have a nearly zero-rate and the purpose is to prevent the main spring from going slack as full droop is approached (and in going slack, unseating or moving around). They have no effect on ride or handling other than to prevent the main spring from unseating and re-seating suddenly. Helper springs are fully-compressed (coil-bound) at static ride height.
Tender springs typically range from 100 to 200 lb rate and the purpose is to create a dual-rate setup in which the suspension travel includes a lower combined rate (according to the (A X B) / (A + B) = combined spring rate formula) as well as a higher spring rate once the tender spring is fully compressed (at which point the main spring rate takes effect). This results in a more compliant ride than is possible with individual high-rate springs and a greater resistance to roll than is possible with individual low-rate springs. Tender springs are not fully-compressed at static ride height.
Tender springs typically range from 100 to 200 lb rate and the purpose is to create a dual-rate setup in which the suspension travel includes a lower combined rate (according to the (A X B) / (A + B) = combined spring rate formula) as well as a higher spring rate once the tender spring is fully compressed (at which point the main spring rate takes effect). This results in a more compliant ride than is possible with individual high-rate springs and a greater resistance to roll than is possible with individual low-rate springs. Tender springs are not fully-compressed at static ride height.
08-03-2019, 10:39 AM
#24
Advanced
[QUOTE=GregR;15256018]Thank you guys for the responses, I have been driving the car a lot this summer and really love how it drives now.
MarinS4 - I agree this was a little drastic. In my case, I was driving around at 30 psi on the lowest shock setting. I wasn't enjoying the ride and the car was squirming around in corners. I like thinking about these things and decided to try this before swapping out the entire suspension.
K722070 here is the best I can do to answer your questions:
What ride height are you using?
My ride height is:
RF 124, LF 122
RR 122, LR 120
Could you post the optional spring rates h&r suggested?
H&R did not suggest optional spring rates, they provided this chart and showed me how to find the correct spring fitment for the PSS10's:
http://www.hrsprings.com/applications/60mm_id_springs
I made the choices listed in my original post. Which ended up being one selection down for each spring.
When compared to spring rates of the other after market suspensions attached to this post they seemed reasonable.
.
I came across this great thread and wanted to ask if you had any updates now a year later? I have a 95 C4 with carrera III 18 rims and debating whether to go with the coilover Bilstein set up or the Koni's with stock springs. It read like you really found that sweet spot! My intentions for the car mimic yours with minimal track days, mostly daily city drives and some long drives. Any further thoughts would be greatly appreciated. Thx!
MarinS4 - I agree this was a little drastic. In my case, I was driving around at 30 psi on the lowest shock setting. I wasn't enjoying the ride and the car was squirming around in corners. I like thinking about these things and decided to try this before swapping out the entire suspension.
K722070 here is the best I can do to answer your questions:
What ride height are you using?
My ride height is:
RF 124, LF 122
RR 122, LR 120
Could you post the optional spring rates h&r suggested?
H&R did not suggest optional spring rates, they provided this chart and showed me how to find the correct spring fitment for the PSS10's:
http://www.hrsprings.com/applications/60mm_id_springs
I made the choices listed in my original post. Which ended up being one selection down for each spring.
When compared to spring rates of the other after market suspensions attached to this post they seemed reasonable.
.
Would be interesting to know the range of spring rate change that can be made while keeping the existing pss10 valving.
No idea how to find this out, and suspect Bilstein would say this valving is only good for original spring rates.
My reasoning on valving was that the PSS10's have 10 settings and I was on the lowest. So there would be enough room to drop spring rates by at least one selection down and still be in this 1 to 10 range.
I lucked out as I have the ride I was hoping for at 6 front / 7 Rear.
Thank You,
Greg
Hi GregNo idea how to find this out, and suspect Bilstein would say this valving is only good for original spring rates.
My reasoning on valving was that the PSS10's have 10 settings and I was on the lowest. So there would be enough room to drop spring rates by at least one selection down and still be in this 1 to 10 range.
I lucked out as I have the ride I was hoping for at 6 front / 7 Rear.
Thank You,
Greg
I came across this great thread and wanted to ask if you had any updates now a year later? I have a 95 C4 with carrera III 18 rims and debating whether to go with the coilover Bilstein set up or the Koni's with stock springs. It read like you really found that sweet spot! My intentions for the car mimic yours with minimal track days, mostly daily city drives and some long drives. Any further thoughts would be greatly appreciated. Thx!
08-07-2019, 11:42 AM
#25
Advanced
Thank you guys for the responses, I have been driving the car a lot this summer and really love how it drives now.
MarinS4 - I agree this was a little drastic. In my case, I was driving around at 30 psi on the lowest shock setting. I wasn't enjoying the ride and the car was squirming around in corners. I like thinking about these things and decided to try this before swapping out the entire suspension.
K722070 here is the best I can do to answer your questions:
What ride height are you using?
My ride height is:
RF 124, LF 122
RR 122, LR 120
Could you post the optional spring rates h&r suggested?
H&R did not suggest optional spring rates, they provided this chart and showed me how to find the correct spring fitment for the PSS10's:
http://www.hrsprings.com/applications/60mm_id_springs
I made the choices listed in my original post. Which ended up being one selection down for each spring.
When compared to spring rates of the other after market suspensions attached to this post they seemed reasonable.
.
MarinS4 - I agree this was a little drastic. In my case, I was driving around at 30 psi on the lowest shock setting. I wasn't enjoying the ride and the car was squirming around in corners. I like thinking about these things and decided to try this before swapping out the entire suspension.
K722070 here is the best I can do to answer your questions:
What ride height are you using?
My ride height is:
RF 124, LF 122
RR 122, LR 120
Could you post the optional spring rates h&r suggested?
H&R did not suggest optional spring rates, they provided this chart and showed me how to find the correct spring fitment for the PSS10's:
http://www.hrsprings.com/applications/60mm_id_springs
I made the choices listed in my original post. Which ended up being one selection down for each spring.
When compared to spring rates of the other after market suspensions attached to this post they seemed reasonable.
.
Would be interesting to know the range of spring rate change that can be made while keeping the existing pss10 valving.
No idea how to find this out, and suspect Bilstein would say this valving is only good for original spring rates.
My reasoning on valving was that the PSS10's have 10 settings and I was on the lowest. So there would be enough room to drop spring rates by at least one selection down and still be in this 1 to 10 range.
I lucked out as I have the ride I was hoping for at 6 front / 7 Rear.
Thank You,
Greg
No idea how to find this out, and suspect Bilstein would say this valving is only good for original spring rates.
My reasoning on valving was that the PSS10's have 10 settings and I was on the lowest. So there would be enough room to drop spring rates by at least one selection down and still be in this 1 to 10 range.
I lucked out as I have the ride I was hoping for at 6 front / 7 Rear.
Thank You,
Greg
My last inquiry came imbedded strangely so thought Id ask once more. Sorry if its a duplicate.
I came across this great thread and wanted to ask if you had any updates now a year later? It read like you found that sweet spot! My intentions for the car mimic yours with minimal track days, mostly daily city drives and some long drives. Any further thoughts would be greatly appreciated.
Thx!
08-11-2019, 09:42 PM
#26
Hi Greg
My last inquiry came imbedded strangely so thought Id ask once more. Sorry if its a duplicate.
I came across this great thread and wanted to ask if you had any updates now a year later? It read like you found that sweet spot! My intentions for the car mimic yours with minimal track days, mostly daily city drives and some long drives. Any further thoughts would be greatly appreciated.
Thx!
My last inquiry came imbedded strangely so thought Id ask once more. Sorry if its a duplicate.
I came across this great thread and wanted to ask if you had any updates now a year later? It read like you found that sweet spot! My intentions for the car mimic yours with minimal track days, mostly daily city drives and some long drives. Any further thoughts would be greatly appreciated.
Thx!
For me it hasn’t helped the compliance in the way I’d hoped. It has allowed me to dial up the compression front and rear but honestly, small bump compliance, grip over sketchy surfaces remains disappointing. It is very difficult to achieve a a balance between control of the car through corners and g outs with enough compliance to keep the tyres happily in touch with the road. It’s not like it’s bad to drive, it just doesn’t feel like the damping is particularly sophisiticated. Perhaps that’s a reality of the 964 chassis that the chocks can’t overcome but, in saying that, I can’t imagine Singers are bouncing across every patch of poor tarmac they come across.
I’m not spending any more on setup at this stage. I’ll wait until I can swallow the idea of spending what I’ll need to spend on Ohlins (or perhaps JRZ).
08-12-2019, 10:16 AM
#27
Banned
PSS10's Tender Spring rate Softened
Interesting read.
I am in the midst of a refresh > Suspension > RS A Arms etc with Upgraded Bushings.
My next consideration Wheels and Tires newer Suspension or Refresh to digressive re-valving.
My car currently has HD's & Super Sports which we agree has tough sidewall running on 18's OEM Turbo LW - NB 97 Coupe
WE have a car designed on 17 inch Cup II's.
If not mistaken all the concerns with ride quality mostly based on running 18's except GregR fall runs on Cup II with Michelin A/S and MarinS4 on PS2 - 18's.
I am in the camp of Marin S4.
Wondering if going with a softer sidewall say the Conti Extreme Contact or Yokohama's? on 17 inch Cup II would change the ride to a reasonable level for the city? Any thoughts? Anyone tried this?
TJ
I am in the midst of a refresh > Suspension > RS A Arms etc with Upgraded Bushings.
My next consideration Wheels and Tires newer Suspension or Refresh to digressive re-valving.
My car currently has HD's & Super Sports which we agree has tough sidewall running on 18's OEM Turbo LW - NB 97 Coupe
WE have a car designed on 17 inch Cup II's.
If not mistaken all the concerns with ride quality mostly based on running 18's except GregR fall runs on Cup II with Michelin A/S and MarinS4 on PS2 - 18's.
I am in the camp of Marin S4.
Wondering if going with a softer sidewall say the Conti Extreme Contact or Yokohama's? on 17 inch Cup II would change the ride to a reasonable level for the city? Any thoughts? Anyone tried this?
TJ
Last edited by TJ993; 08-12-2019 at 10:26 AM. Reason: typo
08-12-2019, 10:09 PM
#28
Advanced
Thread Starter
So a year after reducing the spring rates on main and tender springs I still very much like the setup. This is a street car, so it solves the problem I was going after. Which was a much smoother ride (more comfortable, less jarring). I had planned to do an autocross, but haven't done that yet. I have driven quite a bit of back roads here in Washington state and feel the car handles well in that situation. I was on a particular crappy road a few months ago and I could feel the bumps. It certainly is not a soft setup, but, a lot is less choppy then when I had the original springs.
I can run both sets of rims and tires and this setup works well. As TJ993 mentioned, possible softer side wall tire would help on the original springs.
The one thing to keep in mind is that I wanted to save my original investment in the PSS10's. I feel I have done that and am personally happy. Now if I was starting from scratch I would probably drive a few other options with the hope of choosing a standard setup that is on the market.
I can run both sets of rims and tires and this setup works well. As TJ993 mentioned, possible softer side wall tire would help on the original springs.
The one thing to keep in mind is that I wanted to save my original investment in the PSS10's. I feel I have done that and am personally happy. Now if I was starting from scratch I would probably drive a few other options with the hope of choosing a standard setup that is on the market.
08-13-2019, 08:10 PM
#29
So a year after reducing the spring rates on main and tender springs I still very much like the setup. This is a street car, so it solves the problem I was going after. Which was a much smoother ride (more comfortable, less jarring). I had planned to do an autocross, but haven't done that yet. I have driven quite a bit of back roads here in Washington state and feel the car handles well in that situation. I was on a particular crappy road a few months ago and I could feel the bumps. It certainly is not a soft setup, but, a lot is less choppy then when I had the original springs.
I can run both sets of rims and tires and this setup works well. As TJ993 mentioned, possible softer side wall tire would help on the original springs.
The one thing to keep in mind is that I wanted to save my original investment in the PSS10's. I feel I have done that and am personally happy. Now if I was starting from scratch I would probably drive a few other options with the hope of choosing a standard setup that is on the market.
I can run both sets of rims and tires and this setup works well. As TJ993 mentioned, possible softer side wall tire would help on the original springs.
The one thing to keep in mind is that I wanted to save my original investment in the PSS10's. I feel I have done that and am personally happy. Now if I was starting from scratch I would probably drive a few other options with the hope of choosing a standard setup that is on the market.
11-03-2019, 03:39 PM
#30
Rennlist Member
Reading through this thread again I think I'll have pone more go at saving that original investment. I changed only the main springs - still not sure I get the whole stacked spring idea but the advice I had through my local Bilstein specialists was that the helper spring is compressed anyway so doesn't really play as significant a role. Sounds as though this isn't quite right. So I'll replace the tender springs now and am considering new bushings all around as well. Will report back...
did you replace tenders and what did you find? Interested in similar
bill