BC Coilovers?

[baneoh]

I am getting ready to do a complete suspension refresh including new coilovers. This is my DD but I like to drive spirited in the twisties. I have never tracked the car but it's not out of the question, I just don't want anything too stiff. Right now I am running H&R's and they are pretty stiff so I am looking for something a little more compliant, and adjustable dampening is a bonus so I am leaning toward BC BR series.

Budget is a bit of a consideration, but I will spend up till the amount of diminishing returns. $995 for the BC setup is a great deal but I want to hear some of your experiences first. If you can compare the BR vs DS that would be a bonus.

I'll take recommendations for other coilovers also but only if you have driven an E39 with BC's. Otherwise it's subjective. If someone can directly compare the H&R setup with BC that would be amazing.

Also, can someone explain spring rates to me and why I might want to change them?

Thanks.

[seagreen323i]

I have driven a car with bc coilovers and a car with stx coilovers. Those both being the budget options. I went with the stx coils. The bc coils where a bit harsher and I didn't notice any better handeling characteristics because of it. They seemed a tad overdampened. Small imperfections made a big deal but larger ones where fine. The stx are non adjustable and I like that. The manufacturer picked what they thought was best for the chassis. Im not going to go out there and say I could set it up better then any engineer. Stx are also engineered by kw an are effectively kw v1s. I love mine and that car is my daily. I would 100% reccomend them.
Spring rates are basically how stiff the springs are. E39s are a bit heavy so you need a more aggressive spring rate. So in this context spring rate is the force needed to compress the spring 1 inch. If you had a 500 pound spring rate the springs would sag 1 inch when loaded with 500 pounds. If you have a linear spring meaning that the spring rate is constant 1000 pounds would mean 2 inches of sag on the same 500 pound spring. Progressive springs get stiffer the harder they are pressed, this has the benefit of a potentially smoother ride do to a lower initial spring rate with a stiffer spring rate the more the suspension moves to minimize body roll. Progressive springs for comfort, linear for preformance and predictability.

Sent from my SM-G973U using Tapatalk

[BimmrMeUpSnotty]

On the driving of the car with the BCR’s, how do you know if the dampers were properly set right?, springs pre loaded properly? To form that opinion?

[f355spider]

I also have the KW/Suspension Techniques ST-X coilovers. They are a good, reasonable cost production, as stated, similar to the KW Variant 1, but with gold cadmium plated housings instead of SS.
I previously had the Bilstein B14 PSS coilovers, which are very still both in spring rates and damping. I liked the handling, but the internal slider bearings kept wearing out repeatedly in the front struts, causing knocking noises over low speed small road imperfections...super annoying..and it was getting expensive to lay up the car for a week at a time, and send them back for rebuilding every 22k to 24k miles. After the fourth failure around 110k miles, Bilstein threw in the towel and refunded my money. So I got the KW ST-X...they are a great compromise...stiff than oem sport, but not as crazy stiff as the PSS kit.

The BC coilovers are a worthy and popular option. Never ridden in a car with them, so cannot comment, but I know a lot of folks that have them and like them. I'm a snob, I want German.

[BimmrMeUpSnotty]

I'm a snob, I want German.

Well now, that makes sense, that’s why you have a Ferrari, and named yourself so?

[seagreen323i]

On the driving of the car with the BCR’s, how do you know if the dampers were properly set right?, springs pre loaded properly? To form that opinion?

That gentleman whos car i drove had all his work done at a good indy. Im sure they didn't screw it up. I don't see the need for adjustable coilovers for the street just another thing to futz with and feel like its never 100% .

I can also say the st-x coils are durable. Hit a hole hard enough to blow the strut mount out and the coil is just fine.

I never said the bc coils where bad, I just don't particularly like them. They just felt harsher at the limit with no noticeable gain. More prone to harshly rebound in a corner with a dip in the road.
We drove both of our cars down the same road in "mexico" at the limit. We both agreed that while the st-x coils felt a bit softer, they where far more predictable in the body movement department. The bc coils had a tendency to be jarring enough to upset the balance of the car. We screwed with the damper settings to see if that fixed anything. Got kinda slushy after that.

Blah blah disclaimer, same tires, same sizes, different rims, he had newer suspension but not sure exactly when it was rebuilt.

Sent from my SM-G973U using Tapatalk

[BimmrMeUpSnotty]

That gentleman whos car i drove had all his work done at a good indy. Im sure they didn't screw it up. I don't see the need for adjustable coilovers for the street just another thing to futz with and feel like its never 100% .



I never said the bc coils where bad, I just don't particularly like them. They just felt harsher at the limit with no noticeable gain. More prone to harshly rebound in a corner with a dip in the road.

You don’t see the need for adjustable coilovers...... Wait, what??? No need for adjustable coilovers.... Then what the hell are you playing around with coilovers for??? !
For the street, you adjust them to the way you want the car to ride, and then see how it rides. Adjust. Some more, as necessary. I guaranty you, a good indy shop will not have the time to properly adjust them, they installed them and moved on to the next job. First, your friend needs to go back, pull each coilover out, check the spring preload. On BCR’s the spring preload is no more than a tad over an eighth of an inch, if it is more, the ride will not be right. No need for adjustments..... This is the whole reason shops do not get to touch my cars, and motorcycles.
You kids get coilovers for, lemme guess..... Oh yeah! Slam it down to the ground! That’s the moment that you became a stancetard. When you fiddled with adjustments, did you do so in small increments? Or just go full retard, willynilly, doing different settings all over the place? When you mess with compression, you will need to adjust the rebound accordingly.

[baneoh]

You don’t see the need for adjustable coilovers...... Wait, what??? No need for adjustable coilovers.... Then what the hell are you playing around with coilovers for??? !
For the street, you adjust them to the way you want the car to ride, and then see how it rides. Adjust. Some more, as necessary. I guaranty you, a good indy shop will not have the time to properly adjust them, they installed them and moved on to the next job. First, your friend needs to go back, pull each coilover out, check the spring preload. On BCR’s the spring preload is no more than a tad over an eighth of an inch, if it is more, the ride will not be right. No need for adjustments..... This is the whole reason shops do not get to touch my cars, and motorcycles.
You kids get coilovers for, lemme guess..... Oh yeah! Slam it down to the ground! That’s the moment that you became a stancetard. When you fiddled with adjustments, did you do so in small increments? Or just go full retard, willynilly, doing different settings all over the place? When you mess with compression, you will need to adjust the rebound accordingly.

I understand what you are trying to say, but your harsh tone and condescending attitude is not going to encourage any sort of constructive conversation. You may be right, but no one likes to be talked down to, especially by someone that can't spell guarantee. I come to this forum for the expertise and constructive suggestions from long time forum members like myself. While I appreciate your experience, your know it all attitude is is incredibly off putting.

- - - Updated - - -

Spring rates are basically how stiff the springs are. E39s are a bit heavy so you need a more aggressive spring rate. So in this context spring rate is the force needed to compress the spring 1 inch. If you had a 500 pound spring rate the springs would sag 1 inch when loaded with 500 pounds. If you have a linear spring meaning that the spring rate is constant 1000 pounds would mean 2 inches of sag on the same 500 pound spring. Progressive springs get stiffer the harder they are pressed, this has the benefit of a potentially smoother ride do to a lower initial spring rate with a stiffer spring rate the more the suspension moves to minimize body roll. Progressive springs for comfort, linear for preformance and predictability.

Sent from my SM-G973U using Tapatalk

Thanks for this explanation.

[baneoh]

I never said the bc coils where bad, I just don't particularly like them. They just felt harsher at the limit with no noticeable gain. More prone to harshly rebound in a corner with a dip in the road.
We drove both of our cars down the same road in "mexico" at the limit. We both agreed that while the st-x coils felt a bit softer, they where far more predictable in the body movement department. The bc coils had a tendency to be jarring enough to upset the balance of the car. We screwed with the damper settings to see if that fixed anything. Got kinda slushy after that.

Blah blah disclaimer, same tires, same sizes, different rims, he had newer suspension but not sure exactly when it was rebuilt.

Sent from my SM-G973U using Tapatalk

Interesting. I don't want to encourage BimmrMeUpSnotty, but you are the first person to say that about BC's.

I am not stuck on BC's, nor do I need "budget" coilovers, I just observed that as the price gets over $1200 or so, most of those coilovers seem to be for the track. I currently have H&R coilovers and while I don't think they would be considered "budget" they are only $1250 for the set. I don't hate them, but I don't love them either. I have heard many good things about BC for the street and occasional track use, and their price is competitive. Thanks for all the suggestions.

[BimmrMeUpSnotty]

I understand what you are trying to say, but your harsh tone and condescending attitude is not going to encourage any sort of constructive conversation. You may be right, but no one likes to be talked down to, especially by someone that can't spell guarantee. I come to this forum for the expertise and constructive suggestions from long time forum members like myself. While I appreciate your experience, your know it all attitude is is incredibly off putting.

- - - Updated - - -



Thanks for this explanation.

baneoh, that wasn’t harsh, and I really was not talking down to seagreen, he gets me, we joke around a bit, all I am trying to say is, and like you said, you understand, one cannot just come to a conclusion on these types of conversations about a particular brand, or coil over. Hell, race teams go through days of trial and error to hammer down a proper setup,for different tracks, every driver has his own preset expectations too, so a set up for one, is not the same setup for another. Maybe I was harsh, grow thicker skin, sticks and stones may break your bones, my harshness should not hurt you. Bottom line, these types of conclusions is what leads certain companies to the decision of abandonment of support for certain vehicles. Take note, Fortune Auto, and their abandonment of the E39 platform. They got fed up with the diy crowd acting like they knew what they were talking about, not ordering the right spring setups, not dialing in the cars properly, then mouthing off on the boards. Truth is, they will sell you a set for the E39, if they know you, or if you seem to know what you are ordering and not pestering them with a million questions. Too harsh? Well, I was rushing out of the house at the time hitting flush on the can, and hitting the post button on the iPad at the same time.

[baneoh]

baneoh, that wasn’t harsh, and I really was not talking down to seagreen, he gets me, we joke around a bit, all I am trying to say is, and like you said, you understand, one cannot just come to a conclusion on these types of conversations about a particular brand, or coil over. Hell, race teams go through days of trial and error to hammer down a proper setup,for different tracks, every driver has his own preset expectations too, so a set up for one, is not the same setup for another. Maybe I was harsh, grow thicker skin, sticks and stones may break your bones, my harshness should not hurt you. Bottom line, these types of conclusions is what leads certain companies to the decision of abandonment of support for certain vehicles. Take note, Fortune Auto, and their abandonment of the E39 platform. They got fed up with the diy crowd acting like they knew what they were talking about, not ordering the right spring setups, not dialing in the cars properly, then mouthing off on the boards. Truth is, they will sell you a set for the E39, if they know you, or if you seem to know what you are ordering and not pestering them with a million questions. Too harsh? Well, I was rushing out of the house at the time hitting flush on the can, and hitting the post button on the iPad at the same time.

All good. So do you think BC's are a good choice for my application? Or do you have a suggestion or a favorite?

[Jason5driver]

All good. So do you think BC's are a good choice for my application? Or do you have a suggestion or a favorite?

I would consider KW V2's, KW V1's / ST's, and Ground Control's coil-overs (Koni sports with Eibach springs) .

https://www.ecstuning.com/b-kw-suspe...2/15220008~kw/

https://www.ecstuning.com/b-kw-suspe...1/10220008~kw/

https://groundcontrolstore.com/colle...oilover-system

ISC coil-overs are similar to BC's but have a lifetime warranty supposedly .
https://www.ecstuning.com/b-isc-susp.../b001-1-c~isc/

[BimmrMeUpSnotty]

I was happy with them on my 540, it took me a while fiddling with settings, then got a set of Swift springs and the ride was much better than the stock BCR springs that came with the kit, the 10K springs were a a tad soft, i got a very slightly used set for one of my wagons, I will be installing them into the green one after the paint job it will be getting in about a month They have the stock 10K springs on them, I’ll fiddle with those for a bit, then get Swift 12K springs eventually. For the wagons, only the fronts are coil overs, the rears, the springs go on the rear arms, and the shocks set the height, go in the stock BMW placement connecting the arm to the body. I have full access to a Hunter alignment machine, so that’s not an issue.
For what it’s worth, I will do a rare thing, and apologize for being Snotty..... wait, nah, forget it I am Snotty, and Seegreen needs to chime back in, I feel the need to harass him some more about muttering about wishing he didn’t need to adjust coilovers..... The hell is wrong with that kid?

- - - Updated - - -

Speaking of Fortune Auto coilovers for the E39, I can get you set up with a brand new set for the 540 sedans, pm me for info on it, I can get them all day long.

[Jason5driver]

I was happy with them on my 540, it took me a while fiddling with settings, then got a set of Swift springs and the ride was much better than the stock BCR springs that came with the kit, the 10K springs were a a tad soft, i got a very slightly used set for one of my wagons, I will be installing them into the green one after the paint job it will be getting in about a month They have the stock 10K springs on them, I’ll fiddle with those for a bit, then get Swift 12K springs eventually. For the wagons, only the fronts are coil overs, the rears, the springs go on the rear arms, and the shocks set the height, go in the stock BMW placement connecting the arm to the body. I have full access to a Hunter alignment machine, so that’s not an issue.
For what it’s worth, I will do a rare thing, and apologize for being Snotty..... wait, nah, forget it I am Snotty, and Seegreen needs to chime back in, I feel the need to harass him some more about muttering about wishing he didn’t need to adjust coilovers..... The hell is wrong with that kid?

- - - Updated - - -

Speaking of Fortune Auto coilovers for the E39, I can get you set up with a brand new set for the 540 sedans, pm me for info on it, I can get them all day long.

All the original springs on BC’s , Fortune , etc. are ALL GARBAGE .
The springs need to be replaced with either Hyperco , Swift , or Eibach springs .
I am pretty positive that can NOT get new Fortune coil-overs .

[BimmrMeUpSnotty]

All the original springs on BC’s , Fortune , etc. are ALL GARBAGE .
The springs need to be replaced with either Hyperco , Swift , or Eibach springs .
I am pretty positive that can NOT get new Fortune coil-overs .

I am 1000% sure you are wrong about not getting new Fortune Auto kits for E39’s. I have one set brand new in a box, and I can order more, it just will not be labelled accordingly, like I said pm me for info if interested.

[baneoh]

I was happy with them on my 540, it took me a while fiddling with settings, then got a set of Swift springs and the ride was much better than the stock BCR springs that came with the kit, the 10K springs were a a tad soft, i got a very slightly used set for one of my wagons, I will be installing them into the green one after the paint job it will be getting in about a month They have the stock 10K springs on them, I’ll fiddle with those for a bit, then get Swift 12K springs eventually. For the wagons, only the fronts are coil overs, the rears, the springs go on the rear arms, and the shocks set the height, go in the stock BMW placement connecting the arm to the body. I have full access to a Hunter alignment machine, so that’s not an issue.
For what it’s worth, I will do a rare thing, and apologize for being Snotty..... wait, nah, forget it I am Snotty, and Seegreen needs to chime back in, I feel the need to harass him some more about muttering about wishing he didn’t need to adjust coilovers..... The hell is wrong with that kid?

- - - Updated - - -

Speaking of Fortune Auto coilovers for the E39, I can get you set up with a brand new set for the 540 sedans, pm me for info on it, I can get them all day long.

I have never heard of Fortune springs. I have heard the Swift spring upgrade is a good one to do on BC's. Would the KW V2's be similar? Thanks for suggesting 12K springs. I never thought about it. Honestly I need to make a purchase soon and with all the info I am getting, I am tempted to just have my one bad H&R rebuilt and do a lot more research. IDK. I need to make a decision soon. What is the cost of the Fortune setup you seem to like so much? Or do you prefer BC with Swift springs?

- - - Updated - - -

I would consider KW V2's, KW V1's / ST's, and Ground Control's coil-overs (Koni sports with Eibach springs) .

https://www.ecstuning.com/b-kw-suspe...2/15220008~kw/

https://www.ecstuning.com/b-kw-suspe...1/10220008~kw/

https://groundcontrolstore.com/colle...oilover-system

ISC coil-overs are similar to BC's but have a lifetime warranty supposedly .
https://www.ecstuning.com/b-isc-susp.../b001-1-c~isc/

Those VW V2's look tempting. I can only find the Ground Control kit for the M5. Have you ran the VW V2's? Can you compare them to BC's? Or BC's with swift springs because that's what everyone seems to like.

[baneoh]

Here's something I haven't considered. Will my wheel setup make a difference?? I am currently running BBS RC300/301 with 275/35/18 in the rear and 255/35/18 in the front. Now I am reading that some wheel setups have a hard time clearing top mounts on some of these?? The more I read, the more I am tempted to stay with H&R just for simplicity. I wouldn;t

[Barrman]

Since the OP asked for driving impressions of BC coil overs. I wish to share mine without getting involved in the dispute.

I bought my 525 Touring with 185k miles and a salvage title for hail damage. It wasn’t until I started working on it that I realized it had also had some kind of front end damage. The passenger side strut tower was actually bent toward the engine some. You get what you pay for.

However, to make the alignment right, ride height correct and the car handle as close to my Miata as possible. BC coilovers with the camber plates was the only option I could find to fit my needs at any price. I installed them almost 2 years and 30k miles ago.

It took a while to get all 4 corners at the ride height I wanted. But, once there they have maintained it. Setting the shock rate took more time. I seemed to be going from the front bouncing and the back steady to the opposite. I did all new suspension and steering parts at the same time as the coil over install. Combined with pilot sport tires the car eats bumps without noise, drama or harshness. Yet lets me throw it into corners with confidence. No, it isn’t a Miata but at twice the weight almost it never will be.

Compared to the $1700 Xida coil overs on my Miata the BC coil overs are a bargain to me with the same or better ride/handling ratio. I am very pleased with them and am recommending them.

[baneoh]

I am 1000% sure you are wrong about not getting new Fortune Auto kits for E39’s. I have one set brand new in a box, and I can order more, it just will not be labelled accordingly, like I said pm me for info if interested.

I called Fortune and they told me they can't make the kit for the E39 anymore. If you can somehow get one out of them, or you want to sell yours let me know. They look like the best bang for your buck. I like the KW and Bilstein kits too, but they don't come with top hats/camber plates. So the extra expense will be substantial. The fortune kit's look to be around $1300 with the top hats, if only I could convince them...

Apparently there is a lot more to know about coilovers than I thought. I am not trying to race my 540i, but I do like the twisties. I think I want to splurge on a higher end setup, but $2000 is a bit more than I want to spend. Not a deal breaker, but if I could find something good for $1200-1500 I would be stoked.

[philly98540]

Just to add some to this thread that may be of use. If you have 275's up front they will not fit on many brand coil overs since the lower spring perch is too low and the tire will hit it. I went with the GC for the M5 due to this and could not be happier. Its a pricey kit, but Jay at GC has developed this kit pretty good. My ride is tight but not harsh now. Sorta between a stock M5 and an E92 M3.

[baneoh]

Just to add some to this thread that may be of use. If you have 275's up front they will not fit on many brand coil overs since the lower spring perch is too low and the tire will hit it. I went with the GC for the M5 due to this and could not be happier. Its a pricey kit, but Jay at GC has developed this kit pretty good. My ride is tight but not harsh now. Sorta between a stock M5 and an E92 M3.

Thanks. I was looking at the Ground Control kit. $2000 is a bit over budget but they do come with the top hats/camber plates which can add $400-600 so really not much more than the Bilstein PSS9 kit... I have 255 in the front and 275 in the rear. I'm running spacers on the front too IIRC.

Also since GC only makes a kit for the M5, would I have to call them and get a different spring rate for the front due to the lower mass of the M62 in the 540i?

[danb1979]

I've run all sorts of cars on BC coilovers, including a previous E38; I've run x3 E39s on D2 coilovers (the same as BCs) and other cars on KW & Nitron coilovers

Bang for buck; the BC/D2 coilovers are right up there; they work superbly...

But as said above; they have to be fitted a) properly, b.) pre-load set properly and c) ideally with a fast-road set up/tracking & alignment in mind too...

Doing that will guarantee the best ride and handling for the car; but the damping rate needs to be faffed with, a lot, to suss out what's best for the car for every day road driving and then for any spirited road/track driving, IMO

ALL other suspension components and current wheel/tyre (tire) set up & offsets need to be taken into consideration too... Fitting coilovers will only highlight any issues that might not be presenting themselves currently...

But, for every day road driving, I still stand by that the likes of Bilstein/Sachs Sport spec shocks and Eibach/H&R lowering springs work superbly; partnered with ARB upgrades; they can work superbly!

Unless you want/need the full adjustability of damping rate and ride height; then springs/shocks will suit most requirements...

Just my tuppenceworth

[philly98540]

Thanks. I was looking at the Ground Control kit. $2000 is a bit over budget but they do come with the top hats/camber plates which can add $400-600 so really not much more than the Bilstein PSS9 kit... I have 255 in the front and 275 in the rear. I'm running spacers on the front too IIRC.

Also since GC only makes a kit for the M5, would I have to call them and get a different spring rate for the front due to the lower mass of the M62 in the 540i?

I have it on my 540. But I have the supercharger/intercooler stuff up front, so likely close to M5 weight. Jay worked with me to select spring lengths and stiffness to set it up for my ride. He will alter springs to suit you. He has shelves full of various springs. It is a bit pricey though, but yeah if you add up the camber plates its in the ballpark of the competition. I set my front camber at around -1.2 degrees for street use and like it there.

[Jason5driver]

I am 1000% sure you are wrong about not getting new Fortune Auto kits for E39’s. I have one set brand new in a box, and I can order more, it just will not be labelled accordingly, like I said pm me for info if interested.

The Fortune coil-overs you are getting are not from Fortune then. lol.

[Jason5driver]

I have never heard of Fortune springs.
I have heard the Swift spring upgrade is a good one to do on BC's.
Would the KW V2's be similar? Thanks for suggesting 12K springs.
I never thought about it. Honestly I need to make a purchase soon and with all the info I am getting, I am tempted to just have my one bad H&R rebuilt and do a lot more research. IDK.
I need to make a decision soon.
What is the cost of the Fortune setup you seem to like so much? Or do you prefer BC with Swift springs?

Those VW V2's look tempting. I can only find the Ground Control kit for the M5. Have you ran the VW V2's? Can you compare them to BC's? Or BC's with swift springs because that's what everyone seems to like.

You can NOT get the H&R coil-overs rebuilt .
If you are dead-set on getting BC's (or similar) then you should NOT get the springs that come with the coil-overs.
You can "upgrade" them by adding / including the coil-overs with Swift springs, but the coil-overs will cost more .

Also, Feal Suspension has coil-overs as well :
https://fealsuspensionstore.com/feal...-5-series-e39/

I don't think I have ever heard a bad complaint about the KW V2's .

I have driven in an E39 540i with BC coil-overs , totally slammed, and I was pretty impressed , and that was with the standard garbage springs , 8k fronts and 6k rears .