[ZM2]

Hey guys, I'm finally about to go down the suspension rabbit hole a bit more with front monoballs, rear links, and PSS10 B16's (have been on Dinan HAS & Vorshlag's for some years) for a compliant daily driving setup that can be easily dialed up for the track.

In determining what I'd like my ride height to be after install, I've been reviewing ride height values of various setups, but it seems folks are measuring from the bottom wheel lip to the fender. Altho, my understanding is that ride height should be measured from the hub center to the fender to account for the various wheels sizes (18-20") we all run.

So, I'm curious if anyone has the F&R hub center to fender height values for stock, and maybe some of the more common suspension setups like the MPS?

If you only have the wheel lip to fender values, please state what wheel size you're on, so everyone else can do some quick math if they're on a different wheel diameter.

In my particular case, I'm aiming for 25mm lower than stock in the front & 30mm lower than stock in the rear (slight negative rake for a track setup with better rear weight transfer & traction), but I do not know what the exact hub center to fender measurements should be to achieve that, or the wheel lip to fender measurements if I'm on 18s.

Thanks!

[johnung]

I agree on the chassis height measurement from center of wheel logo straight up to fender lip. That distance never changes regardless of varying wheel/tire sizes.

For consistency, I also try to take measurements with a full tank of gasoline in case 100 lbs of fuel makes a difference.

I’ve also noticed that stock chassis height measurements can vary on left and right so it’s best to measure all four corners rather than assume that left & right are the same.

Hope this helps!

[johnung]

Just curious as to what other setups you considered and how you decided on the B16’s? I have been told some negatives on B16’s on F3x models, mostly that their front spring rates are too high. I’ve also heard some positives about KW, so I’m wondering if you found them worth considering?

[ZM2]

Originally Posted by johnung

Just curious as to what other setups you considered and how you decided on the B16’s? I have been told some negatives on B16’s on F3x models, mostly that their front spring rates are too high. I’ve also heard some positives about KW, so I’m wondering if you found them worth considering?

Mostly the ease of adjustability, spring clearance, and cost.

With the wide wheel/tire setup I run, most coil overs would require jacking up the car, and/or removing a wheel for adjustment, whereas the Bilstein’s can be easily changed via their bottom dial.

Also wanted a setup that wouldn’t require spacers and had stock like spring diameters.

And their cost is about the lowest of the coilover options out there.

Overall, these will be used on the street and ~10 track days a year, and I’ll save the lap times for the race car, so didn’t need an overly complex/costly setup for my needs.

[D.Yooras]

Originally Posted by ZM2

Hey guys, I'm finally about to go down the suspension rabbit hole a bit more with front monoballs, rear links, and PSS10 B16's (have been on Dinan HAS & Vorshlag's for some years) for a compliant daily driving setup that can be easily dialed up for the track.

In determining what I'd like my ride height to be after install, I've been reviewing ride height values of various setups, but it seems folks are measuring from the bottom wheel lip to the fender. Altho, my understanding is that ride height should be measured from the hub center to the fender to account for the various wheels sizes (18-20") we all run.

So, I'm curious if anyone has the F&R hub center to fender height values for stock, and maybe some of the more common suspension setups like the MPS?

If you only have the wheel lip to fender values, please state what wheel size you're on, so everyone else can do some quick math if they're on a different wheel diameter.

In my particular case, I'm aiming for 25mm lower than stock in the front & 30mm lower than stock in the rear (slight negative rake for a track setup with better rear weight transfer & traction), but I do not know what the exact hub center to fender measurements should be to achieve that, or the wheel lip to fender measurements if I'm on 18s.

Thanks!

BMW measures ride heights from the lower rim lip through the axle center, to the fender (Porsche and VW/Audi measure from center of axle and/or chassis points). If you're looking for properly accurate measurements, you're better off finding a control point on the chassis and using that.

Short of that, the center of axle to fender works okay but you have to be diligent about making sure you're holding the measuring top directly perpendicular to the ground. Otherwise, you'll get different numbers because of the angle change of the fender. I personally use rim edge to fender and have a modifier based on rim size because it's easier to line up the measuring tape. For the race car, I use the pinch welds nearest to the wheel because the fenders are not exactly the best reference point anymore.

In regards to your modifications, front monoballs (I'm assuming you're referring to compliance bushings) will make the front end of the car very harsh and will likely make noise which will be especially noticeable on the street. I generally don't recommend them except for purpose built race/track cars for that reason.

If the rear links you're talking about are adjustable toe arms for the rear, be advised the rear suspension (especially the toe arms) are very sensitive to changes. Additionally, the arms have to be EXACTLY the same length as each other, otherwise you will get a different toe curve on each side. If you do end up installing them, the proper way to do it would be to leave the stock eccentric adjuster in and adjust so both arms are the same length. Then you fine tune the toe numbers with the eccentrics to ensure there are no adverse affects to the geometry. If you're talking about spherical rear sway bar mounts, none of this applies.

When it comes to Bilstein vs KW it's pretty cut and dry. Bilstein are monotube (inverted monotube in front which is functionally excellent) and KW are twin tube. Monotube dampers are superior in every way (in regards to design) except for ride quality (even that is debatable) which is due to better wheel control that leads to more force being felt by the chassis. Additionally, Bilstein's tend to last longer before needing to be rebuilt. They do ride more harshly which is generally the biggest complaint.

Short version, price being the same, Bilstein B6 and up are functionally better dampers. That's not to say they have the best tuning out of the box in terms of damping, or spring rate, for every application but they do work better than KW. That said, if ride quality is a critical aspect for you, KW are going to be a better choice.

Lastly, if you have no installed a big front sway bar or sway bars, you'll want to put that on your short list. The 24mm (BMW calls it a 24.5mm because there is .25mm of paint on it) stock sway bar is ridiculously undersized for this car, it needs a minimum of a 28mm or larger.

[ZM2]

Originally Posted by D.Yooras

BMW measures ride heights from the lower rim lip through the axle center, to the fender (Porsche and VW/Audi measure from center of axle and/or chassis points). If you're looking for properly accurate measurements, you're better off finding a control point on the chassis and using that.

Short of that, the center of axle to fender works okay but you have to be diligent about making sure you're holding the measuring top directly perpendicular to the ground. Otherwise, you'll get different numbers because of the angle change of the fender. I personally use rim edge to fender and have a modifier based on rim size because it's easier to line up the measuring tape. For the race car, I use the pinch welds nearest to the wheel because the fenders are not exactly the best reference point anymore.

In regards to your modifications, front monoballs (I'm assuming you're referring to compliance bushings) will make the front end of the car very harsh and will likely make noise which will be especially noticeable on the street. I generally don't recommend them except for purpose built race/track cars for that reason.

If the rear links you're talking about are adjustable toe arms for the rear, be advised the rear suspension (especially the toe arms) are very sensitive to changes. Additionally, the arms have to be EXACTLY the same length as each other, otherwise you will get a different toe curve on each side. If you do end up installing them, the proper way to do it would be to leave the stock eccentric adjuster in and adjust so both arms are the same length. Then you fine tune the toe numbers with the eccentrics to ensure there are no adverse affects to the geometry. If you're talking about spherical rear sway bar mounts, none of this applies.

When it comes to Bilstein vs KW it's pretty cut and dry. Bilstein are monotube (inverted monotube in front which is functionally excellent) and KW are twin tube. Monotube dampers are superior in every way (in regards to design) except for ride quality (even that is debatable) which is due to better wheel control that leads to more force being felt by the chassis. Additionally, Bilstein's tend to last longer before needing to be rebuilt. They do ride more harshly which is generally the biggest complaint.

Short version, price being the same, Bilstein B6 and up are functionally better dampers. That's not to say they have the best tuning out of the box in terms of damping, or spring rate, for every application but they do work better than KW. That said, if ride quality is a critical aspect for you, KW are going to be a better choice.

Lastly, if you have no installed a big front sway bar or sway bars, you'll want to put that on your short list. The 24mm (BMW calls it a 24.5mm because there is .25mm of paint on it) stock sway bar is ridiculously undersized for this car, it needs a minimum of a 28mm or larger.

Haven’t heard folks complain about these or the Dinan version: https://www.bimmerworld.com/Front-Up...-M2-M3-M4.html

Haven’t heard complaints about these either. Have only heard complaints about SPL parts. https://www.dinancars.com/products/s...arts/D280-0015

Good to know about the Bilstein’s.

Will wait on the sway bar until I try this setup on track. The issue I have is my city roads are poor and a stiffer bar will create a significantly stiffer ride when hitting bumps on one side or the other on uneven pavement/bumps. I’ve been trying to find an adjustable bar with the softest setting close to the stock front bar, but haven’t seen that data floating around.

Good points regarding ride height. So, who knows the stock ride height values on the OEM 19” wheels as measured by BMW?

[D.Yooras]

Originally Posted by ZM2

Haven’t heard folks complain about these or the Dinan version: https://www.bimmerworld.com/Front-Up...-M2-M3-M4.html

Haven’t heard complaints about these either. Have only heard complaints about SPL parts. https://www.dinancars.com/products/s...arts/D280-0015

Good to know about the Bilstein’s.

Will wait on the sway bar until I try this setup on track. The issue I have is my city roads are poor and a stiffer bar will create a significantly stiffer ride when hitting bumps on one side or the other on uneven pavement/bumps. I’ve been trying to find an adjustable bar with the softest setting close to the stock front bar, but haven’t seen that data floating around.

Good points regarding ride height. So, who knows the stock ride height values on the OEM 19” wheels as measured by BMW?

Stock heights with 19" factory wheels are 612mm/615mm F/R respectively (622mm front if it has the rough road package).

A bigger front bar doesn't have too big of an effect on ride quality when going from a 24mm to a 30mm, but even so the effect on NVH is going to be far less than spherical compliance bushings. The vibration from bad road surface quality is far greater with sphericals. That said, if you have your heart setting on going spherical, having caster adjustability built in makes for a good tuning aid.

On the sway bar aspect, generally (and I mean very generally) if you find a sway bar with 3 hole adjustable ends, the middle hole is usually the same arm length as stock. Meaning, if you had a 24mm bar stock, bought an upgrade bar that was a 26mm the middle holes would be a like-for-like upgrade (going from 24mm to 26mm) and the softest hole setting would be around the same effect as a 25mm bar.

Sway bar stiffest based on same dimensions as stock bar except thickness:
24mm(100%)(236.1 lbs/in)
25mm(118%)
26mm(138%)
27mm(160%)
28mm(185%)
29mm(213%)
30mm(244%)(576.5 lbs/in)

General rule of thumb on BMW chassis upgrades in terms of bang for the buck:

1st: Proper alignment (even stock these cars are very sensitive to alignment settings)
3rd: Negative camber and/or front sway bar
4th: Coilovers
5th: Wheel/Tire package (track setup, square or staggered)
6th: Further tuning aids like adjustable compliance bushings (for caster) adjustment, bump steer kits, front lower arms, etc

Of course these can be done in whatever order, but when it comes to value for money that path tends to generate the best ROI.

[Carrera2RS]

I am 600F, 595 R I also dong like a heavy front vs rear drop