Let's talk Spring rates

*PICTURE FOR REFERENCE ON Compression

Currently I am on MCS Double Adjustable Shocks

Ground Control Race Camber Plates

Helper Springs with Dividers Both Front and Rear (keeps springs seated when you jack up the car)

Hyperco 600/6" Front Springs
Hyperco 900/7" Rear Springs

Ground Control Rear Height Adjusters

Rear Shock Mounts

Torrington Bearings on the Front Springs (No spring bind when turning the wheel)

BFG R1 285 square slicks
18x10.5 Apex square

Weight of car no driver is 3,091 with 1/4 tank left. Mind you I'm 250lbs.

Now.......
I feel I'm at the limit with pushing my car, what do the pros out there recommend I switch my spring rates to? 750 front and 1050 rear? I'm not on a full rear coil over. The car is rarely driven on the street but she is street legal.

nicksm3 wrote

Hyperco 600/6" Front Springs
Hyperco 900/7" Rear Springs

Ground Control Rear Height Adjusters

Rear Shock Mounts

Torrington Bearings on the Front Springs (No spring bind when turning the wheel)

BFG R1 285 square slicks
18x10.5 Apex square

Weight of car no driver is 3,091 with 1/4 tank left. Mind you I'm 250lbs.

Now.......
I feel I'm at the limit with pushing my car, what do the pros out there recommend I switch my spring rates to? 750 front and 1050 rear? I'm not on a full rear coil over. The car is rarely driven on the street but she is street legal.

I've been down this road a couple years ago. I wrote about it back in mid-2017 across several posts in my build thread. Perhaps something in there is useful to you. Starts with the 2nd-to-last post on page 19:

https://www.m3post.com/forums/showthread.php?t=1158445&page=19

Topic continues on page 20:
https://www.m3post.com/forums/showthread.php?t=1158445&page=20

Originally, I was at 600/800. I went to 750/1000----hated it. Couldn't turn in when entering high speed rounders. Went to 600/1000. Was pretty good. Went to 600/900, really liked it and that's where I am now. (My car weighs 3250 no fuel no driver. I weigh 170lbs)

Bryan Hise from JRZ is very adamant that, on a quality damper, stiff springs are a myth. He claimed a JRZ suspension should feel "plush" (his word). When you go too stiff, you reduce the damper's ability to move freely and make subtle changes with the surface. That was definitely what I experienced. On 750/1000, I felt like the tires were just scraping across the ground when trying to turn in. I lost several mph on high speed rounder turn in.

You say you're at the limit......then I would say, there are better tires out there than an R1. Personally, I think you have the right springs for that suspension and weight of the car. Move up to slicks.

Anyway, don't just take my word for it. I'll repeat what Bryan said to me springs are cheap....there's no harm in trying.

What are your rebound and compression settings? What type of corners are you feeling the car is at the limit?

MCS is very helpful if you give them a call.

dogbone wrote

I've been down this road a couple years ago. I wrote about it back in mid-2017 across several posts in my build thread. Perhaps something in there is useful to you. Starts with the 2nd-to-last post on page 19:

https://www.m3post.com/forums/showthread.php?t=1158445&page=19

Topic continues on page 20:
https://www.m3post.com/forums/showthread.php?t=1158445&page=20

Originally, I was at 600/800. I went to 750/1000----hated it. Couldn't turn in when entering high speed rounders. Went to 600/1000. Was pretty good. Went to 600/900, really liked it and that's where I am now. (My car weighs 3250 no fuel no driver. I weigh 170lbs)

Bryan Hise from JRZ is very adamant that, on a quality damper, stiff springs are a myth. He claimed a JRZ suspension should feel "plush" (his word). When you go too stiff, you reduce the damper's ability to move freely and make subtle changes with the surface. That was definitely what I experienced. On 750/1000, I felt like the tires were just scraping across the ground when trying to turn in. I lost several mph on high speed rounder turn in.

You say you're at the limit......then I would say, there are better tires out there than an R1. Personally, I think you have the right springs for that suspension and weight of the car. Move up to slicks.

Anyway, don't just take my word for it. I'll repeat what Bryan said to me springs are cheap....there's no harm in trying.

Dogbone similar experience I am on AST 5300 true coilover so rear rate is different but eaualivalent of 700/1000 now. AST said I may want to go just a bit softer to 600/900 so the damper can do the work.
Also I just increased my nitrogen pressure from just under 200 to 275 and it made it stiffer almost like more spring but made it rebound faster.

My car is heavier than yours 3,600 lbs w driver. I was going to do full aero but haven’t yet. I think at my weight with full aero 700/1000 may be the way to go but stock aero go down 100 lbs in spring rate.

I think part of why your car is somstiff is you are running 300 psi nitrogen in your shocks.

72dan wrote

Dogbone similar experience I am on AST 5300 true coilover so rear rate is different but eaualivalent of 700/1000 now. AST said I may want to go just a bit softer to 600/900 so the damper can do the work.
Also I just increased my nitrogen pressure from just under 200 to 275 and it made it stiffer almost like more spring but made it rebound faster.

My car is heavier than yours 3,600 lbs w driver. I was going to do full aero but haven’t yet. I think at my weight with full aero 700/1000 may be the way to go but stock aero go down 100 lbs in spring rate.

I think part of why your car is somstiff is you are running 300 psi nitrogen in your shocks.

I don’t remember if I ever talked about it, but I lowered the nitrogen to 225psi with the stiffer springs——didn’t help.

And fwiw, 300 psi on my JRZ is not harsh or stiff. Casey from Racewerkz Engineering sought me out at the track years ago because he had heard I was running 300 psi and thought it was too stiff. So I took him out on track to feel for himself. After a full session on track at Buttonwillow, he thought it felt great and encouraged me not to change a thing. Because I have my own nitrogen rig, I was able to experiment with different settings at the track. I found that I like more psi.

Over the years, as I have experimented with various setups, I have found that not all conventional wisdoms are universal. You just gotta feel things out on your specific setup. Things like camber, suspension setup, alignment, brake pad config——if I blindly followed generic “wisdom”, my car would be setup differently......and in my opinion worse....The conclusions I have come up with over the years have come from me actually driving things and feeling the results. And believe me, I didn’t always get it right. Sometimes you do things, and they just don’t work out.

dogbone wrote

I don’t remember if I ever talked about it, but I lowered the nitrogen to 225psi with the stiffer springs——didn’t help.

And fwiw, 300 psi on my JRZ is not harsh or stiff. Casey from Racewerkz Engineering sought me out at the track years ago because he had heard I was running 300 psi and thought it was too stiff. So I took him out on track to feel for himself. After a full session on track at Buttonwillow, he thought it felt great and encouraged me not to change a thing. Because I have my own nitrogen rig, I was able to experiment with different settings at the track. I found that I like more psi.

Over the years, as I have experimented with various setups, I have found that not all conventional wisdoms are universal. You just gotta feel things out on your specific setup. Things like camber, suspension setup, alignment, brake pad config——if I blindly followed generic “wisdom”, my car would be setup differently......and in my opinion worse....The conclusions I have come up with over the years have come from me actually driving things and feeling the results. And believe me, I didn’t always get it right. Sometimes you do things, and they just don’t work out.

Don’t know if the AST design is similar to JRZ. When I spoke w AST they said more pressure would make it stiffer somewhat but more like fine tuning, not as much as with changing springs. I found 250-275 ps made the tire stay in contact with the road more. More pressure did make it a little stiffer but Significantly made the shocks rebound faster after compression.
I haven’t gone through the effort of buying slightly softer springs and trying them.

dogbone wrote

nicksm3 wrote

Hyperco 600/6" Front Springs
Hyperco 900/7" Rear Springs

Ground Control Rear Height Adjusters

Rear Shock Mounts

Torrington Bearings on the Front Springs (No spring bind when turning the wheel)

BFG R1 285 square slicks
18x10.5 Apex square

Weight of car no driver is 3,091 with 1/4 tank left. Mind you I'm 250lbs.

Now.......
I feel I'm at the limit with pushing my car, what do the pros out there recommend I switch my spring rates to? 750 front and 1050 rear? I'm not on a full rear coil over. The car is rarely driven on the street but she is street legal.

I've been down this road a couple years ago. I wrote about it back in mid-2017 across several posts in my build thread. Perhaps something in there is useful to you. Starts with the 2nd-to-last post on page 19:

https://www.m3post.com/forums/showthread.php?t=1158445&page=19

Topic continues on page 20:
https://www.m3post.com/forums/showthread.php?t=1158445&page=20

Originally, I was at 600/800. I went to 750/1000----hated it. Couldn't turn in when entering high speed rounders. Went to 600/1000. Was pretty good. Went to 600/900, really liked it and that's where I am now. (My car weighs 3250 no fuel no driver. I weigh 170lbs)

Bryan Hise from JRZ is very adamant that, on a quality damper, stiff springs are a myth. He claimed a JRZ suspension should feel "plush" (his word). When you go too stiff, you reduce the damper's ability to move freely and make subtle changes with the surface. That was definitely what I experienced. On 750/1000, I felt like the tires were just scraping across the ground when trying to turn in. I lost several mph on high speed rounder turn in.

You say you're at the limit......then I would say, there are better tires out there than an R1. Personally, I think you have the right springs for that suspension and weight of the car. Move up to slicks.

Anyway, don't just take my word for it. I'll repeat what Bryan said to me springs are cheap....there's no harm in trying.

Thank you! I'll look over your past thread.
I do like these R1's granted they aren't a full spec race slick. Best I felt were the Pirelli DH's.
Most importantly I'll give MCS a call or ANZE. After today's event I feel it's time to send my dampers for some rebuilding. Realistically they should be rebuilt every year if you do 10-15 events a year and I have yet to do so (2 years ownership, 2nd hand MCS's)

nicksm3 wrote

Thank you! I'll look over your past thread.
I do like these R1's granted they aren't a full spec race slick. Best I felt were the Pirelli DH's.
Most importantly I'll give MCS a call or ANZE. After today's event I feel it's time to send my dampers for some rebuilding. Realistically they should be rebuilt every year if you do 10-15 events a year and I have yet to do so (2 years ownership, 2nd hand MCS's)

Well, if you’ve driven Pirelli DH (and assuming they weren’t burned out scrubs), then at least you know what’s out there in terms of more tire grip performance. I’ll go out on a limb here and predict that you will not find more grip from the R1 tire with stiffer springs. But again, don’t just take my word for it, try it for yourself.

As far as damper rebuild time intervals, I have not heard of intervals that short for a street/track line of damper. JRZ told me 30k miles, and there was no limitation of track days on that. In 2015, when I pulled the dampers at 30k miles and had them rebuilt, the tech said they were still pristine inside and could have gone another year easily. Up to that point, my car was seeing both street and track duty—-meaning it was seeing rain on freeways, etc. Now my car only does track duty and never sees bad weather—-except when I go off track into the mud, so the miles are building up much more slowly. With these rebuilds, it’s all about the seals. If the seals are holding up, then you’re in good shape. The internals should be fine.

Speaking of internals, if you feel like you need more dedicated Motorsport valving in the dampers, then that’s a different reason for a rebuild.

dogbone wrote

nicksm3 wrote

Thank you! I'll look over your past thread.
I do like these R1's granted they aren't a full spec race slick. Best I felt were the Pirelli DH's.
Most importantly I'll give MCS a call or ANZE. After today's event I feel it's time to send my dampers for some rebuilding. Realistically they should be rebuilt every year if you do 10-15 events a year and I have yet to do so (2 years ownership, 2nd hand MCS's)

Well, if you’ve driven Pirelli DH (and assuming they weren’t burned out scrubs), then at least you know what’s out there in terms of more tire grip performance. I’ll go out on a limb here and predict that you will not find more grip from the R1 tire with stiffer springs. But again, don’t just take my word for it, try it for yourself.

As far as damper rebuild time intervals, I have not heard of intervals that short for a street/track line of damper. JRZ told me 30k miles, and there was no limitation of track days on that. In 2015, when I pulled the dampers at 30k miles and had them rebuilt, the tech said they were still pristine inside and could have gone another year easily. Up to that point, my car was seeing both street and track duty—-meaning it was seeing rain on freeways, etc. Now my car only does track duty and never sees bad weather—-except when I go off track into the mud, so the miles are building up much more slowly. With these rebuilds, it’s all about the seals. If the seals are holding up, then you’re in good shape. The internals should be fine.

Speaking of internals, if you feel like you need more dedicated Motorsport valving in the dampers, then that’s a different reason for a rebuild.

Great info! Thank you.
Called up ANZE and they specifically told me rebuilt every year especially if you do 15-20 HPDE's a year or wheel to wheel aka NASA GTS.

Great thread, actually just posted a spring rate related inquiry in the chat. Good info guys

(looking to move on from the KW clubsport stock springs here)

I understand that the higher spring rate is not the best choice. I have read the book (Vehicle Dynamics and Damping) which was written by the founder of JRZ suspension.

For me on my Motons I am happy with my 800lbs front and 450lbs rear (true coilover). My car is pretty much full weight and I am about 200lbs

Suspension geometry plays a role in the rate you use but seems kind of strange in my opinion when the E46 race cars/some track cars are running higher rates than the e92? Here is a copy of what James Clay said for the E46 M3. Not saying this is the way to choose rates, but makes me think more about using lower rates?


"Agree with a lot of this. Rates are a function of the chassis (and weight), use, tires, some other lesser things, and constrained by the damper.

E46 M3 - 3300#
Ideal track rate (no Aero) 800/900 - 900/1000
Comfortable street rate depends on damper - up to 600/700 with an MCS for my preferences (my DD/test mule/non-track version has these)

Those are a little much for a TCK Koni with standard valving and 4100, but the GC DA can handle that 600/700 or a little more well.

Dampers have the larges effect on feel - that's the reason they cost what they do for good ones and 4 winds of steel in a spring are $300 - invest there and do it once..."

Another clip I found of James Clay

You are in that 800/900 - 900/1000 range to me. That being said, we have run even the pro cars on much lighter rates - the 3600# E92 M3 ran on 400/400CO at one point with a lot of shock and bumpstop help. Ultimately, I prefer more spring because while the car may not be wildly faster, it is more reactive, and I can adjust as a driver to things that come up, whether traffic or environmental more quickly.

Certainly softer springs are good when grip is bad (rain), but with the right damper, you don't need to ditch the spring. Higher rates are better when grip is good (Watkins specifically has good pavement and banking/elevation giving a TON of load and grip). And softer springs are better when you have dampers that can't handle more - either by build or general design/capacity - a maxed out damper makes an unhappy car!

Great stuff here!

700/800

i listened to a webinar a while back put on by ross bentley about tuning a car's handling. one of the things they mentioned were spring rubbers. you can place these between your spring coils to alter the spring rate. they don't add ride height and are supposed to add linear spring rate, not progressive.
they are designed to help you find spring rates that work, without swapping springs a ton of times. i haven't used them yet.
https://pitstopusa.com/i-5060772-howe-coil-over-spring-rubber-hard-blue-20-lb-rate.html?ref=category:132502

M3 Number 86 wrote

700/800

Stfu

roastbeef wrote

i listened to a webinar a while back put on by ross bentley about tuning a car's handling. one of the things they mentioned were spring rubbers. you can place these between your spring coils to alter the spring rate. they don't add ride height and are supposed to add linear spring rate, not progressive.
they are designed to help you find spring rates that work, without swapping springs a ton of times. i haven't used them yet.
https://pitstopusa.com/i-5060772-howe-coil-over-spring-rubber-hard-blue-20-lb-rate.html?ref=category:132502

Now this is Interesting !

nicksm3 wrote

Now this is Interesting !

its a great webinar- worth buying just to listen. its with race engineer jeff braun. he stated sometimes when the weather shows a chance of rain, they'll run dampeners with softer spring rates with spring rubbers in place to start the race when it is dry. if it starts raining, they simply yank the spring rubbers to instantly have softer spring rates.

i can't wait to experiment with these once i get coilovers. i'd love to get within about say 50lbs of the desired rate, and use the rubbers to "add spring" for the track, and/or take it out for the street, or another track, or for rain. its easy to say that without any experience with them, but it sounds fun.

roastbeef wrote

nicksm3 wrote

Now this is Interesting !

its a great webinar- worth buying just to listen. its with race engineer jeff braun. he stated sometimes when the weather shows a chance of rain, they'll run dampeners with softer spring rates with spring rubbers in place to start the race when it is dry. if it starts raining, they simply yank the spring rubbers to instantly have softer spring rates.

i can't wait to experiment with these once i get coilovers. i'd love to get within about say 50lbs of the desired rate, and use the rubbers to "add spring" for the track, and/or take it out for the street, or another track, or for rain. its easy to say that without any experience with them, but it sounds fun.

Yea this is great way to get down to the bottom of fine tuning! Thanks for this:)

I worked with KW on a custom 2-way Competition setup. They've setup many E92 M3 race cars over in Europe and have a plethora of information on these cars from testing them with different spring rates and valving setups on their shaker rigs.

Decided to go with 800/570 (coilover). This is slightly softer then they initially recommended and was softened due to track conditions where I live - often bumpy tracks. 570 in a rear coilover is equivalent to 1150 in a traditional divorced setup.
Other features:
-Monotube Front and Rear dampers, with inverted fronts
-Custom length reservoir hoses (short) for better performance
-50mm rear springs for better tire clearance
-EXR valving

Will have the setup on the track for the first time next weekend in a recently finished race car build. I'll report back on how these perform.

Pictures of my actual suspension provided to me by KW:

tsk94 wrote

I worked with KW on a custom 2-way Competition setup. They've setup many E92 M3 race cars over in Europe and have a plethora of information on these cars from testing them with different spring rates and valving setups on their shaker rigs.

Decided to go with 800/570 (coilover). This is slightly softer then they initially recommended and was softened due to track conditions where I live - often bumpy tracks. 570 in a rear coilover is equivalent to 1150 in a traditional divorced setup.
Other features:
-Monotube Front and Rear dampers, with inverted fronts
-Custom length reservoir hoses (short) for better performance
-50mm rear springs for better tire clearance
-EXR valving

Will have the setup on the track for the first time next weekend in a recently finished race car build. I'll report back on how these perform.

Pictures of my actual suspension provided to me by KW:

Oh hell yes! Let's us know 👍🏻

StripclubDJ wrote

M3 Number 86 wrote

700/800

Stfu

Best bro. First lap ever shakedown and my first half sector of buttonwillow was faster than years worth of practice on street tires previously. But it's prob jrz LOL