[casualDIYer]

Anyone using their B6's on stock springs (I have a 2017 340i xDrive)? Initially I thought, are my twin tube OE shocks, built with 1930's technology, getting close to the end of their life? After getting a fine treatment of 'clunk hell' where little, annoying, non-warrantied items contribute to a distracting diving experience and resulted in me swapping out all sorts of minor parts, with the net effect being a quieter clunk (but still a clunk) I've decided it's time to swap the struts.

Looking at my options, reading reviews, and realising the Causual DIYer likes to fix his car twice a year, not twice a month, or week, it seems the Bilstein B6 is a product that would appeal to me. I thought the B12 kit was ideal but after a comment from a significant other that she wasn't too preferential to lowered cars after seeing Lowrider Larry drive by in his ricer, lowered closer to the ground than a street cleaner, spring choices are going to be a delicate, later step. Maybe the F80's springs and bump stops? A 10mm lower spring with the same rubbery performance I now have.

So without touching the springs, and the B6 being an OE replacement, has anyone run them with the stock springs on an xDrive car? Looking over the forums, a lot of B6 users out there, but often on lowering springs. Not clear if any used BMW's wallow wonder springs that come with the car. They probably thought "Why the hell bother?" but alas, if I change the springs now, what excuse will I have to take apart the car next year?

[cfm56d7b]

How many miles does your car have?

Bilstein B6 shocks have been designed to work for OEM springs.

What's your budget for the suspension upgrade? Also - is maintaining OEM suspension height one of the goals?

[gameson]

What’s the lifetime for oem spring?

[cfm56d7b]

Originally Posted by gameson

What’s the lifetime for oem spring?

Depending on road conditions, springs can last anywhere between 60K and 90K miles. Since springs are not expensive, installing 4 new springs with 4 new struts would be worthwhile.

Incidentally, have you considered coilovers?

[gameson]

My strut is almost due for a replacement. I am thinking a new spring and strut but don’t know what to buy.

My max budget is what i would spend on oem as if i am replacing them with another oem when it’s due. I would consider used or new.

The ride i want is closed to oem ride. Not too stiff.

What would you recommend?

Thanks.

[cfm56d7b]

Originally Posted by gameson

My strut is almost due for a replacement. I am thinking a new spring and strut but don’t know what to buy.

My max budget is what i would spend on oem as if i am replacing them with another oem when it’s due. I would consider used or new.

The ride i want is closed to oem ride. Not too stiff.

What would you recommend?

Thanks.

Bilstein B4 shocks would be one of the top choices. These shocks are designed to replace OE shocks with valves operating about 10% firmer.

[gameson]

Originally Posted by cfm56d7b

Bilstein B4 shocks would be one of the top choices. These shocks are designed to replace OE shocks with valves operating about 10% firmer.

B4 shock with B6 strut would cost me close to oem? How’s the ride?

[casualDIYer]

Originally Posted by cfm56d7b

How many miles does your car have?

Bilstein B6 shocks have been designed to work for OEM springs.

What's your budget for the suspension upgrade? Also - is maintaining OEM suspension height one of the goals?

81,000km (roughly 50k miles)
Budget: $1200-1800 before tax. I can do the install so labour isn't a cost I need to incur
Ride Height: No lower than 15mm from current height (I'm on standard springs)

[casualDIYer]

Originally Posted by cfm56d7b

Depending on road conditions, springs can last anywhere between 60K and 90K miles. Since springs are not expensive, installing 4 new springs with 4 new struts would be worthwhile.

Incidentally, have you considered coilovers?

The original goal was KW Street Comforts. The problem? The 8 week estimated wait. I can get the B6s within 2 weeks, and Koni Sports within a week. But I am interested in going for a monotube on this install.

[cfm56d7b]

Originally Posted by casualDIYer

The original goal was KW Street Comforts. The problem? The 8 week estimated wait. I can get the B6s within 2 weeks, and Koni Sports within a week. But I am interested in going for a monotube on this install.

I had KW SC coilovers on my previous car. Definitely worth the wait. Great product.

[casualDIYer]

Originally Posted by cfm56d7b

Bilstein B4 shocks would be one of the top choices. These shocks are designed to replace OE shocks with valves operating about 10% firmer.

Just to add, I believe the Bilstein B4s are twin tube. Does it matter? That would depend on the end goal of the user.

Twin tube shocks, likely due to their low gas pressure, tend to be a little softer but chassis reaction can seem slower. Monotubes, the pressure is considerably higher, so the ride can be a bit stiffer but chassis reaction is more immediate.

Twin tubes use 2 tubes in which oil will pass from one tube to the other. The issue with this design is that a certain volume of oil will not be held in the outer tube, limiting the effect of cooling from outside air. Twin tube performance can degrade during excessive cavitation of the shock. Twin tubes also contain a gasket, not found in monotubes, that can wear over time, meaning the twin tube shock's peak performance degrades over time and use.

Twin tubes tend to be heavier (since they contain two tubes) than monotubes.

Price? Twins are typically, but not always, cheaper than monotubes. Last time I looked, the difference in price between a B4 (twin) and a B6 (mono) is about $200 per shock for fronts, and $100 per shock for rears. Taking a guess, I'd say OE twins, roughly $600, OE fit monos, about a grand.

Note that I am speaking in general terms here regarding shock designs. There is much variation in the basic twin tube design added as a way to overcome the shortcomings of the original.

[Tommi_Mav]

Originally Posted by cfm56d7b

Depending on road conditions, springs can last anywhere between 60K and 90K miles. Since springs are not expensive, installing 4 new springs with 4 new struts would be worthwhile.

Whaaaaat? The lifetime of springs exceeds the life of the car itself. Unless someone wants to change spring rate and height, there's no need to replace springs when you replace struts.

[Jvac]

Originally Posted by casualDIYer

Anyone using their B6's on stock springs (I have a 2017 340i xDrive)? Initially I thought, are my twin tube OE shocks, built with 1930's technology, getting close to the end of their life? After getting a fine treatment of 'clunk hell' where little, annoying, non-warrantied items contribute to a distracting diving experience and resulted in me swapping out all sorts of minor parts, with the net effect being a quieter clunk (but still a clunk) I've decided it's time to swap the struts.

Looking at my options, reading reviews, and realising the Causual DIYer likes to fix his car twice a year, not twice a month, or week, it seems the Bilstein B6 is a product that would appeal to me. I thought the B12 kit was ideal but after a comment from a significant other that she wasn't too preferential to lowered cars after seeing Lowrider Larry drive by in his ricer, lowered closer to the ground than a street cleaner, spring choices are going to be a delicate, later step. Maybe the F80's springs and bump stops? A 10mm lower spring with the same rubbery performance I now have.

So without touching the springs, and the B6 being an OE replacement, has anyone run them with the stock springs on an xDrive car? Looking over the forums, a lot of B6 users out there, but often on lowering springs. Not clear if any used BMW's wallow wonder springs that come with the car. They probably thought "Why the hell bother?" but alas, if I change the springs now, what excuse will I have to take apart the car next year?

Some eibach springs or f80 competition pack maybe? (both are progressive, I believe, so they'll be an improvement over stock). These should lower the car by about 10 mm below the m sport ride height, not too aggressive. You might also consider koni red or yellow shocks in that price range. A lot of folks on here like that combo. I think unless you are tracking the car hard, they will be ok. If you really are pushing it they might not be up to the task. I haven't used them, so just relaying what I read during my own research on suspension upgrades. Search here and you can find for yourself. It seems like a lot of the guys who really modded and pushed these f30 cars have moved on to other platforms and aren't here commenting anymore, but the info is still here.

[Jvac]

Originally Posted by Tommi_Mav

Whaaaaat? The lifetime of springs exceeds the life of the car itself. Unless someone wants to change spring rate and height, there's no need to replace springs when you replace struts.

I never heard of replacing springs as a wear item until I joined this forum. I wonder if we all just over-maintain our cars or there's something unique to the bmw that I haven't discovered yet.

[casualDIYer]

Originally Posted by Jvac

Some eibach springs or f80 competition pack maybe? (both are progressive, I believe, so they'll be an improvement over stock). These should lower the car by about 10 mm below the m sport ride height, not too aggressive. You might also consider koni red or yellow shocks in that price range. A lot of folks on here like that combo. I think unless you are tracking the car hard, they will be ok. If you really are pushing it they might not be up to the task. I haven't used them, so just relaying what I read during my own research on suspension upgrades. Search here and you can find for yourself. It seems like a lot of the guys who really modded and pushed these f30 cars have moved on to other platforms and aren't here commenting anymore, but the info is still here.

Seems I am going to find out how good those Koni Sports are. KW Streets are 8 weeks+ for availability. I can get 1 of 4 required Bilstein B6 within a week then wait 4-5 weeks for the other 3. Konis are 1 week. My patience for the BMW provided clunk-miester shocks has run out. Koni it is. Perhaps twin tube will be fine. I learned KW is a twin as well and those shocks are rated highly.

[Tommi_Mav]

Just curious....How the hell there's only one B6???
At least, there should be two of them, since you usually buy them in pairs!

Anyway, go on with your choice. Hope you enjoy them.

[FaRKle!]

Originally Posted by Tommi_Mav

Just curious....How the hell there's only one B6???
At least, there should be two of them, since you usually buy them in pairs!

Anyway, go on with your choice. Hope you enjoy them.

I've bought a single shock before (and it was a B6). Sometimes one gets damaged so you only need one.

[casualDIYer]

Originally Posted by Tommi_Mav

Just curious....How the hell there's only one B6???
At least, there should be two of them, since you usually buy them in pairs!

Anyway, go on with your choice. Hope you enjoy them.

In general, for performance parts, even online retailers don't keep a lot of stock around. Imagine an online shop buys 40 sets of shocks, then 2 months later, an updated part comes out. Sale time.

As for the Konis as a choice, I have experience with them in the past on my e46. Even in the early 2000s the shocks seemed decent and I expect the experience will be the same this time around as well. The only negative I can see is the setting of the rebound on the rear shocks. I wish Koni had used a 'click' system found on competing makes rather than than the 'touchy-feely' method of setting a cam, after wrestling a piston rod into it's max compressed position. Maybe figuring out a way to set the rears consistently can be a project.

[Tommi_Mav]

Originally Posted by FaRKle!

I've bought a single shock before (and it was a B6). Sometimes one gets damaged so you only need one.

That's wrong policy. Even if one shock is damaged, the right thing to do is to replace both shocks on the same axle, so there's even wear on them.

[FaRKle!]

Originally Posted by Tommi_Mav

That's wrong policy. Even if one shock is damaged, the right thing to do is to replace both shocks on the same axle, so there's even wear on them.

You assume too much...

[Tommi_Mav]

Originally Posted by FaRKle!

You assume too much...

Please, feel free to elaborate then....so we don´t assume!

[casualDIYer]

Originally Posted by Tommi_Mav

That's wrong policy. Even if one shock is damaged, the right thing to do is to replace both shocks on the same axle, so there's even wear on them.

I've heard this as well but it seems the car manufactures have a much different approach. If a shock absorber fails under warranty, the manufacturer does not replace any non-broken shocks. They replace only the broken one. The same goes for brake calipers, control arms, sway bar end links, tie rods, spark plugs, fuel injectors, headlights, tail lights, etc. It would be literally impossible for any two parts on a car to perform identically after they go into extended use. Parts are considered 'working' if they fall into a range of acceptable performance. Once a part falls out of that range, the part is considered 'defective'. 'Feels the same' isn't an objective measure of performance.

Consider this, a car starts off with 4 new shocks at the factory. Customer gets car, then hits a pot hole 3 weeks later. Does the customer now back up and drive each wheel into the pot hole, at the same speed, to make sure all 4 shocks are the same? Does the customer count the number of left and right turns to make sure each side of the car is used equally? Do customers commit to never gaining or losing weight and have a strict rule that passengers must weigh the same as they? After years of use, none of the 4 is going be identical, but the performance of the 4 should fall within an acceptable range.

As an owner, I don't care whether one or two or 4 shocks are replaced in a warranty repair. I just want the car to return to acceptable use. If one shock is swapped and the car now leans heavily to one side, that's not acceptable repair and the maker has to rectify that. So, the maker of the car is interested in parts that maintain a level of acceptable performance during the warranty period to avoid excessive replacement cost.

I believe the 'replacement the pair' idea comes from idea that if one is broken the other may break soon so why not save yourself additional labour cost and hassle and perform preventative maintenance now. If one were to argue for identical performance, I'd say swap all 4 then. Don't front and back need balance too?