CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[bmacfrs]

Hi, I have the Tarmac 2s and would like to stiffen the rear slightly. Currently has the 70-170 blue springs. 400# I think. What can I get and where?

[Tatsu333]

The 80-170 spring kit from ST suspensions would be one step up from the stock 70-170's.

[EAGLE5]

Say I want to handle a rough road at fun speeds on semi-custom coilovers, Ohlins DFV with a choice of valving. Stock height or slightly higher.

Road has dips. Bumps. Speed bumps. Mid corner road catastrophes. Single wheel bumps. Double wheel bumps.

Which way do I go?

Springs can be stockish, stiffer, or much stiffer.
Damping can be stockish, stiffer, or much stiffer - adjustable in Ohlins range.
Antiroll bars can be stock, stiffer, or much stiffer - probably adjustable.

I'm thinking stockish spring rates, stiffer damping, and stiffer antiroll bars would mean the car would be on bump stops less, handle bumps better, and not sacrifice ride quality. Might even be better ride quality with better damper quality.

If shocks Ohlins DFV curves are designed for springs of x stiffness, would stiffer antiroll bars recommend getting stiffer damping curves as well, or would the range of adjustment easily handle the transients of stiffer antiroll bars?

Would I be better off with KW V3? Knowing I want stock height or even slightly higher, this seems not as good an option, but the double adjustability might be useful, especially if I want to change spring rates if the first one doesn't work out.

I'm thinking that something like the Ohlins RT off the shelf would be too stiff on spring rate and too stiff on damping, so I'd pay with a brutal ride and maybe even skipping over the bigger bumps, all to get grip on the track I won't ever visit.

Thoughts?

[Tatsu333]

Originally Posted by EAGLE5

Would I be better off with KW V3? Knowing I want stock height or even slightly higher, this seems not as good an option, but the double adjustability might be useful, especially if I want to change spring rates if the first one doesn't work out.

As noted in this post on another thread, I confirmed with KW that you can run their 15mm spring spacers on V3's without over-extending the dampers, which would get ride height to within 5mm of stock, for what it's worth.

[Ohio Enthusiast]

Originally Posted by EAGLE5

I'm thinking stockish spring rates, stiffer damping, and stiffer antiroll bars

I'm far from an expert, but it looks to me that the Twins have settled on the stiff-springs/soft-bars end of the spectrum (vs. other platforms that do embrace soft-springs/stiff-bars). I'm not saying that going with stiff bars is necessarily bad, though.

Final thought - it sounds like you might as well just try stiffer bars and leave the stock suspension as is (or at most replace with 2017+ suspension). Would be much cheaper and you won't be paying money for coilovers that you don't really use. At the very least you could start from stiff bars and see how that works for you before going with coilovers.

[marco_mc22]

Originally Posted by EAGLE5

Say I want to handle a rough road at fun speeds on semi-custom coilovers, Ohlins DFV with a choice of valving. Stock height or slightly higher.

Road has dips. Bumps. Speed bumps. Mid corner road catastrophes. Single wheel bumps. Double wheel bumps.

Which way do I go?

Springs can be stockish, stiffer, or much stiffer.
Damping can be stockish, stiffer, or much stiffer - adjustable in Ohlins range.
Antiroll bars can be stock, stiffer, or much stiffer - probably adjustable.

I'm thinking stockish spring rates, stiffer damping, and stiffer antiroll bars would mean the car would be on bump stops less, handle bumps better, and not sacrifice ride quality. Might even be better ride quality with better damper quality.

If shocks Ohlins DFV curves are designed for springs of x stiffness, would stiffer antiroll bars recommend getting stiffer damping curves as well, or would the range of adjustment easily handle the transients of stiffer antiroll bars?

Would I be better off with KW V3? Knowing I want stock height or even slightly higher, this seems not as good an option, but the double adjustability might be useful, especially if I want to change spring rates if the first one doesn't work out.

I'm thinking that something like the Ohlins RT off the shelf would be too stiff on spring rate and too stiff on damping, so I'd pay with a brutal ride and maybe even skipping over the bigger bumps, all to get grip on the track I won't ever visit.

Thoughts?

Kw v3 max height using stock springs (40-50nm) is roughly 20mm lower than stock, depending on model and year, restyling models are lower in the front, PP cars are even lower.

Going higher with spacers is possible, without problems, using longer springs is also possible but keep in mind that you're going outside of the recommended range, raising it 10mm is ok but no more otherwise shock could be damaged, they're designed to run lower.

Spring range (as per Kw) is 40-70nm on both axles, going softer or harder is possible but not recommended, dampers cannot be revalved but low speed compression adjustment helps and rebound damping range is wide enough for those springs. They will work.

Ohlins R&T can be used at stock height no problem, even higher. They can be fully customized form gas pressure to damping, monotube design is also stronger and better.
Downside is lack of travel here, soft rates aren't ideal for Ohlins, especially in the rear.

That said, the balance YOU WANT is the KEY and you can achieve that on both soft or stiff setups, having pros and cons on both. You have to try different setups and then decide. Personally after MANY tries my advice is to keep everything under 50nm for road usage, stiffer springs could work with premium and well dialed dampers but then tire choice will be limited + going over 2Hz is just too much for a road car, 1.5-1.8Hz is a good compromise IMO.

I prefer stock sways for road usage, stiffer front for track.

[EAGLE5]

I really wish suspension were more straight forward. At least on the track, things are more figured out for the platform.

[Pat]

I've found the best way to learn about it is through first-hand experience. Go drive as many setups as you can, in as many different environments as you can. It will become more clear to you which is the best for your priorities. Reading about suspension on the Internet is often an exercise in frustration, theory, and inexperienced opinions. Nothing beats real-world experience.

[marco_mc22]

Originally Posted by Pat

I've found the best way to learn about it is through first-hand experience. Go drive as many setups as you can, in as many different environments as you can. It will become more clear to you which is the best for your priorities. Reading about suspension on the Internet is often an exercise in frustration, theory, and inexperienced opinions. Nothing beats real-world experience.

THIS. Best way to learn, only way to build a setup around YOU, without trusting of someone else.

Also, suggest you to invest in a good pyrometer, that’s really helpful.

[Tatsu333]

Originally Posted by marco_mc22

Kw v3 max height using stock springs (40-50nm) is roughly 20mm lower than stock, depending on model and year, restyling models are lower in the front, PP cars are even lower.

Going higher with spacers is possible, without problems, using longer springs is also possible but keep in mind that you're going outside of the recommended range, raising it 10mm is ok but no more otherwise shock could be damaged, they're designed to run lower.

From speaking with KW support directly, you can run their 15mm spring spacers on V3's without issue, which puts max height at 5mm lower than stock. They specifically said no higher than that, though.

[strat61caster]

Agree with Pat.

I've driven and setup; Bilstein B14/B16, custom Bilstein, custom Megan, KW V3
Driven briefly; Ohlins, Tein, and Godspeed.
Ridden; JRZ, MCS

For a 99% street car with 1% sporty/track with a focus on backroads comfort, of what I've driven; KW. I want to try Koni Yellows on otherwise stock suspension, but time and money have not permitted it. I think twin tubes at softer settings are great street shocks that soak up most road imperfections, the KW V3's turn up enough to be fun on track/autox when needed.

The Ohlins stuff I've driven/ridden with is a bit weird, too stiff for the road, too soft for hard driving, but they may not have been setup well for their applications and I may not have experienced best of breed. Enough people swear by them that I won't advise against going for Ohlins, but at $2k buy in plus another ~$1k for a revalve I'd be looking at MCS instead.

For setting up anything; spring rates drive compliance, full stop. A 400#/7k kit is too stiff for backroads on this chassis imho, my progressive spring Bilsteins were right on the limit I think, I wouldn't want to go any stiffer in the rear. Yes damping matters, but the spring is the driving force in how the car will absorb the road. 3k-6k linear rate springs would be my range, and softer the better imho, which is why I want to try stock springs on Koni Yellows. Dampers should be compliant, I gave up on trying to be a curve guru, find someone who knows their shit and trust them (presuming they've done what you want before, if you're an R&D case be prepared to have it not come out perfect) or just take what's off the shelf.

[CSG Mike]

Originally Posted by strat61caster

Agree with Pat.

I've driven and setup; Bilstein B14/B16, custom Bilstein, custom Megan, KW V3
Driven briefly; Ohlins, Tein, and Godspeed.
Ridden; JRZ, MCS

For a 99% street car with 1% sporty/track with a focus on backroads comfort, of what I've driven; KW. I want to try Koni Yellows on otherwise stock suspension, but time and money have not permitted it. I think twin tubes at softer settings are great street shocks that soak up most road imperfections, the KW V3's turn up enough to be fun on track/autox when needed.

The Ohlins stuff I've driven/ridden with is a bit weird, too stiff for the road, too soft for hard driving, but they may not have been setup well for their applications and I may not have experienced best of breed. Enough people swear by them that I won't advise against going for Ohlins, but at $2k buy in plus another ~$1k for a revalve I'd be looking at MCS instead.

For setting up anything; spring rates drive compliance, full stop. A 400#/7k kit is too stiff for backroads on this chassis imho, my progressive spring Bilsteins were right on the limit I think, I wouldn't want to go any stiffer in the rear. Yes damping matters, but the spring is the driving force in how the car will absorb the road. 3k-6k linear rate springs would be my range, and softer the better imho, which is why I want to try stock springs on Koni Yellows. Dampers should be compliant, I gave up on trying to be a curve guru, find someone who knows their shit and trust them (presuming they've done what you want before, if you're an R&D case be prepared to have it not come out perfect) or just take what's off the shelf.

The damping matters more than you think.

The 8kg upcoming CSG damper rides overall even smoother than the 6kg square CSG Spec Flex A, which rides smoother than stock.

[Scargod]

Originally Posted by strat61caster

Agree with Pat....

For setting up anything; spring rates drive compliance, full stop. A 400#/7k kit is too stiff for backroads on this chassis imho, my progressive spring Bilsteins were right on the limit I think, I wouldn't want to go any stiffer in the rear. Yes damping matters, but the spring is the driving force in how the car will absorb the road. 3k-6k linear rate springs would be my range, and softer the better imho, ...

I'm running 7K springs with digressive valved shocks. I like it for an all-purpose compromise that's far better than stock! I crank up the shocks for the track. On the street it feels tight and turns like it's on rails.The wife thinks it's a bit harsh, on full soft, but she's used to her 440ix.
It's hard to imagine that "The 8kg upcoming CSG damper rides overall even smoother than the 6kg square CSG Spec Flex A, which rides smoother than stock." is realistic.

[marco_mc22]

Originally Posted by Scargod

I'm running 7K springs with digressive valved shocks. I like it for an all-purpose compromise that's far better than stock! I crank up the shocks for the track. On the street it feels tight and turns like it's on rails.The wife thinks it's a bit harsh, on full soft, but she's used to her 440ix.
It's hard to imagine that "The 8kg upcoming CSG damper rides overall even smoother than the 6kg square CSG Spec Flex A, which rides smoother than stock." is realistic.

“Road has dips. Bumps. Speed bumps. Mid corner road catastrophes. Single wheel bumps. Double wheel bumps”

It’s realistic but it’s not the point, using 8kg springs (>2Hz) on a car driven 99% of the time in the streets/backroads/canyons with street tires or even winter ones depending on the season doesn’t make any sense IMO. The same great damper we’re talking about would control softer springs without problems, taking care of the backroads/canyon part simply stiffening the damping and allowing you to use a wider range of tires.