Talk to me about springs

[duracellttu]

I wanted to start a thread about aftermarket springs. I'm trying to refine my suspension and wanted to know which spring manufactures make quality springs to match with my TCK setup.

Feel free to discuss anything and everything about springs here!

[jager911]

I had TCK and their springs rust out and look like crap. I switched to Eibach, much better powder coating. I have H&R on my 911 and happy with them too. I don't think you can go wrong with either Eibach or H&R.

[duracellttu]

Can somebody confirm the spring sizes for front and rear for my TCK SA setup should I look for 60mm fronts and 2.5” rears?

Also l, do rears need to be barrel shaped or are straight type okay?

[jager911]

I don't have the sizes as I sold my TCK but you can call them for info. The barrel shaped springs are progressive rate where the rate increases or decreases with compression.
The cylindrical shaped springs have rates which are linear throughout their range. The front TCK were linear and the rears progressive, weird!

[mrgizmo04]

Swift and Hyperco are popular and allow you to get custom (off the shelf) rates, lengths, inner diameters, etc to fit your needs.

Most mention Eibach, H&R, etc which are kits specific to our car as lowering springs or parts of coilover kits. If you want to go down flat ride conceot you can customize and go beyond the over sprung front, which most kits do.

[duracellttu]

Swift and Hyperco are popular and allow you to get custom (off the shelf) rates, lengths, inner diameters, etc to fit your needs.

Most mention Eibach, H&R, etc which are kits specific to our car as lowering springs or parts of coilover kits. If you want to go down flat ride conceot you can customize and go beyond the over sprung front, which most kits do.

I’m trying to go down the flat ride road and tune the suspension accordingly. Just trying to learn more about the type of springs to use. I have my target spring rates already figured out.

Just wanting to know if there is any issue with going to non-barrel type springs in the rear. I noticed that Swift doesn’t offer barrel types in that many heights, so I’d likely have to go with 60mm 6” length. Does that sound right?

[mrgizmo04]

I’m trying to go down the flat ride road and tune the suspension accordingly. Just trying to learn more about the type of springs to use. I have my target spring rates already figured out.

Just wanting to know if there is any issue with going to non-barrel type springs in the rear. I noticed that Swift doesn’t offer barrel types in that many heights, so I’d likely have to go with 60mm 6” length. Does that sound right?

I never ran TCK, so I don't know the setup and adjustments it allows. Unloaded length of the spring you need, somewhat depends on the spring rate, since you are adjusting ride height and preload in one. I run Ohlins adjusters in rear and run a 5" 672lbs spring.

Any specific reason you are looking at barrel springs?

[duracellttu]

I never ran TCK, so I don't know the setup and adjustments it allows. Unloaded length of the spring you need, somewhat depends on the spring rate, since you are adjusting ride height and preload in one. I run Ohlins adjusters in rear and run a 5" 672lbs spring.

Any specific reason you are looking at barrel springs?

After doing a little more research, I found the spring sizes on the TCK website. Fronts are 60mm, 7.75" height and rears are 60mm, 6" height. These sizes are listed for all of their spring rates, so I'm going to stick with this, unless there is something else I need to consider.

I was looking for barrel type, because I incorrectly assumed that's what I needed. Looks like linear springs will work in the rear as well. I'm running the RE articulating spring perches so I have some flexibility with the spring height, 5" or 6" will likely work. RE's site says the perches are compatible with either 60mm or 2.25" ID springs.

I'm looking at either Swift or Hyperco springs. Swift offers 60mm, but not 2.25" and Hyperco offers both both. Not sure I can go wrong with either after reading the reviews.

[mrgizmo04]

After doing a little more research, I found the spring sizes on the TCK website. Fronts are 60mm, 7.25" height and rears are 60mm, 6" height. These sizes are listed for all of their spring rates, so I'm going to stick with this, unless there is something else I need to consider.

I was looking for barrel type, because I incorrectly assumed that's what I needed. Looks like linear springs will work in the rear as well. I'm running the RE articulating spring perches so I have some flexibility with the spring height, 5" or 6" will likely work. RE's site says the perches are compatible with either 60mm or 2.25" ID springs.

I'm looking at either Swift or Hyperco springs. Swift offers 60mm, but not 2.25" and Hyperco offers both both. Not sure I can go wrong with either after reading the reviews.

Cant go wrong with either Swift or Hyperco, obviously find ones that fit your inner diameter of the perches.

What are you considering for rates for flat ride?

[duracellttu]

Cant go wrong with either Swift or Hyperco, obviously find ones that fit your inner diameter of the perches.

What are you considering for rates for flat ride?

So I've been on the flat ride spreadsheet a lot lately playing with the numbers. I'm generally in the 300-350# F and 700-750# R range w/ 75% FRC. Right now I'm running TMS front (med) and rear (soft) sways, TCK SA 450# F / 500# R, which is nowhere near flat-ride optimized. Here is my planned suspension setup: TMS front sway (stiff), OEM rear sway, Swift 336# F (1.87 Hz) / 728# R (2.11 Hz) --> 13% ratio-flat ride, 75.2% FRC. This gives me a flat ride road speed of ~83 MPH.

If I keep the 336# F and go down to a Hyperco 700# (2.07 Hz) R spring that will give me a 11% ratio-flat ride, 75.8% FRC, but it bumps the flat ride road speed to 95 MPH. I'm having trouble deciding on what target road speed (or what bounce freq delta between F and R) I should be aiming for. I would think that a road speed I drive most is best (50-90 MPH give or take)??

The Swift site lists very specific spring rates and Hyperco just lists in 50# intervals. Wondering if Hyperco has exact measured data to provide??

Any advice?

[mrgizmo04]

So I've been on the flat ride spreadsheet a lot lately playing with the numbers. I'm generally in the 300-350# F and 700-750# R range w/ 75% FRC. Right now I'm running TMS front (med) and rear (soft) sways, TCK SA 450# F / 500# R, which is nowhere near flat-ride optimized. Here is my planned suspension setup: TMS front sway (stiff), OEM rear sway, Swift 336# F (1.87 Hz) / 728# R (2.11 Hz) --> 13% ratio-flat ride, 75.2% FRC. This gives me a flat ride road speed of ~83 MPH.

If I keep the 336# F and go down to a Hyperco 700# (2.07 Hz) R spring that will give me a 11% ratio-flat ride, 75.8% FRC, but it bumps the flat ride road speed to 95 MPH. I'm having trouble deciding on what target road speed (or what bounce freq delta between F and R) I should be aiming for. I would think that a road speed I drive most is best (50-90 MPH give or take)??

The Swift site lists very specific spring rates and Hyperco just lists in 50# intervals. Wondering if Hyperco has exact measured data to provide??

Any advice?

What do you use the car for the most and where do you drive? Canyons, highway, city? That should tell you what avg speed to try to target.

The larger the delta in frequencies, the more comfortable the ride. Stock is around 20%. I can tell you that going from a pitch to even 5% flat ride feels A LOT better.

Make sure that the front spring you get, especially since you are looking at 300-340# is long enough for you to get to the ride height that you want. I can tell you that if you want the front ride height at 12.75, you will probably be bottoming out and rubbing on inner liner because the spring is just not stiff enough. Running around 13.25-13.5 should be good.

On your FRC%, you are getting a bit too high, but again, depends if you drive canyons, track, etc, and how you like the car to rotate. Over 74-75% gets a bit understeery/pushy, so you might want to move TMS front bar to middle setting instead of shortest/stiffest.

[elbert]

The Swift site lists very specific spring rates and Hyperco just lists in 50# intervals. Wondering if Hyperco has exact measured data to provide??

Swift is "specific" because they are converted from metric to Imperial. Both Swift and Hyperco make quality springs.

[T.J.]

I don't have the sizes as I sold my TCK but you can call them for info. The barrel shaped springs are progressive rate where the rate increases or decreases with compression.
The cylindrical shaped springs have rates which are linear throughout their range. The front TCK were linear and the rears progressive, weird!

After doing a little more research, I found the spring sizes on the TCK website. Fronts are 60mm, 7.75" height and rears are 60mm, 6" height. These sizes are listed for all of their spring rates, so I'm going to stick with this, unless there is something else I need to consider.

I was looking for barrel type, because I incorrectly assumed that's what I needed. Looks like linear springs will work in the rear as well. I'm running the RE articulating spring perches so I have some flexibility with the spring height, 5" or 6" will likely work. RE's site says the perches are compatible with either 60mm or 2.25" ID springs.

I'm looking at either Swift or Hyperco springs. Swift offers 60mm, but not 2.25" and Hyperco offers both both. Not sure I can go wrong with either after reading the reviews.

To clear something up for you guys, barrel type springs can be linear or progressive. The TCK rears are linear.

[Tbonem3]

Barrel linear springs are the best of both worlds. It gives you more travel due to a shorter block height. I know Eibach makes them. Other spring makers sometimes call them High Travel Springs. Worth looking into, at least for the lighter rates where there's fear of bottoming out. GroundControl specs a barrel style Eibach for it's 550lb 6.5" rear spring in its kits.

[duracellttu]

What do you use the car for the most and where do you drive? Canyons, highway, city? That should tell you what avg speed to try to target.

The larger the delta in frequencies, the more comfortable the ride. Stock is around 20%. I can tell you that going from a pitch to even 5% flat ride feels A LOT better.

Make sure that the front spring you get, especially since you are looking at 300-340# is long enough for you to get to the ride height that you want. I can tell you that if you want the front ride height at 12.75, you will probably be bottoming out and rubbing on inner liner because the spring is just not stiff enough. Running around 13.25-13.5 should be good.

On your FRC%, you are getting a bit too high, but again, depends if you drive canyons, track, etc, and how you like the car to rotate. Over 74-75% gets a bit understeery/pushy, so you might want to move TMS front bar to middle setting instead of shortest/stiffest.

Honestly, mostly city/canyon driving with an occasional day at the track from time to time. Stock suspension is set to a 40 MPH target speed w/ 20% flat ride. I would imagine track and city driving would be around 40-50 MPH target, no?? Others had advise around 10% flat ride, but lowering the flat ride % increases the flat ride target speed pretty significantly.

My current springs are 7.75" height, so I was going to get 8", based on the flat ride calculator. 300-350# --> the deflection difference is between 1.0"-0.5". So getting a sightly taller 8" spring will help and I have the flexibility to adjust with in an couple inches with the shock adjustment. My ride height in the front is at 13.5" currently. Might lower slightly, but want to prevent rubbing. Especially since I installing Brembos very soon and will likely need to move to a slightly larger spacer from the 12mm I have on there now.

I was under the impression that for the e46 M3 75% FRC is neutral. Sounds like I want to be just under that? Moving the front bar to medium setting drops the FRC down ~2%, which is a pretty course adjustment. I'm starting to see the appeal of the ground control front sway bar, with infinite adjustment settings...

Here are the leading 5 flat ride options. First two are for reference. Last 5 are all using TMS front sway on stiff and stock rear sway. Any advice?

Swift is "specific" because they are converted from metric to Imperial. Both Swift and Hyperco make quality springs.

Ahh that makes sense. Does Hyperco publishes the technical specs like Swift does?