[thatBimmerBloke]

Need some proper advice guys, hopefully everyone is in a good mood this Friday and ready to impart some knowledge and experience
I'm looking for coilovers for my F32 xDrive. I've narrowed it down to Bilstein B14, KW V1 and KW Street Comfort. Earlier I wanted B12 kit but it's on back-order and similar in price to B14 with no room for height adjustment. I don't want my ride slammed, just want better handling + cornering and at the same time want to get rid of the absurd xDrive wheel gap. Can BMW please stop doing this?

If I go with B14 then I'll probably have it on the highest setting i.e 30mm lower all around which doesn't seem that huge of a drop and should be fine in winters also. However, are B14s too stiff and uncomfortable, does the handling improve considerably, these are the questions holding me back. I've mostly heard positive reviews from many members. JonBk is running these on his F31 and describes them as "more comfortable than the standard passive M-Sport suspension and run flat combo".

On the other hand KW V1 also has great reviews but the rear minimum lowering of 1.4 inches is a bit of a concern, can I use FaRKle! 's shim technique to raise it .4 inch? Or at-least .2 inch? A forum member suggested this but the link wasn't working, not sure what this technique is but I'll trust Farkle with anything related to suspension I called KW, they do have spring spacers for V1, 30mm, which would make the rear adjustable .21 inch to 1.2 inches but they said it will void the coilover warranty, maybe spring spacers aren't good? I just need the rear to be .8 inch to 1.2 inches lower. Also, V1 is about $400 more than B14.

Third option is KW street comfort, lowering range is perfect for both summer and winter, however these might not improve the handling a lot as compared to V1 or B14? Again, $600 more than B14.

johnung

[FaRKle!]

Originally Posted by thatBimmerBloke

On the other hand KW V1 also has great reviews but the rear minimum lowering of 1.4 inches is a bit of a concern, can I use FaRKle! 's shim technique to raise it .4 inch? Or at-least .2 inch? A forum member suggested this but the link wasn't working, not sure what this technique is but I'll trust Farkle with anything related to suspension I called KW, they do have spring spacers for V1, 30mm, which would make the rear adjustable .21 inch to 1.2 inches but they said it will void the coilover warranty, maybe spring spacers aren't good? I just need the rear to be .8 inch to 1.2 inches lower. Also, V1 is about $400 more than B14.

Here's an example of using shims/spacers to raise the rear ride height:

Originally Posted by FaRKle!

I've modified my rear ride height with 0.1" thick kydex spacers/shims placed in/on the upper spring cups. The concept is similar to the spacer/shims Macht Schnell uses.

Here's a pic where you can see the two shims I put on top of the spring cup (there are an additional 3 inside the spring cup, which is why the rubber lip isn't flush with the cup lip).


For the range of lifting you want (an additional .5-.75" at the wheel) you'd need 3-4 0.1" shims. I can make you some for pretty cheap.

Since the KW/Bilsteins already have their own rear height adjusting mechanism you might be a bit more limited in how many shims you can use.

Another option to raise the height is to find out what the spring rate is in the kit you're buying and just buy a longer spring with that same rate. Coilover springs are typically in the $60-$85/each range.

When going to a higher ride height than what the kit normally provides the thing you'll need to check is how much droop travel the damper has before it reaches the end of travel. That means seeing how much further the damper can extend before reaching the end. You don't want to be hitting the end during driving. Typically this isn't too much of an issue though.

[thatBimmerBloke]

Originally Posted by FaRKle!

Here's an example of using shims/spacers to raise the rear ride height:


Since the KW/Bilsteins already have their own rear height adjusting mechanism you might be a bit more limited in how many shims you can use.

Another option to raise the height is to find out what the spring rate is in the kit you're buying and just buy a longer spring with that same rate. Coilover springs are typically in the $60-$85/each range.

When going to a higher ride height than what the kit normally provides the thing you'll need to check is how much droop travel the damper has before it reaches the end of travel. That means seeing how much further the damper can extend before reaching the end. You don't want to be hitting the end during driving. Typically this isn't too much of an issue though.

Thanks! Changing springs doesn't seem like a straight forward process, need to account for a few things. Any suggestions on B14 vs KW V1 vs Street Comfort? Any experience with B!4 in particular?
For KW V1 will adding two .1" ships cause any issues?

[FaRKle!]

Originally Posted by thatBimmerBloke

Thanks! Changing springs doesn't seem like a straight forward process, need to account for a few things. Any suggestions on B14 vs KW V1 vs Street Comfort? Any experience with B!4 in particular?
For KW V1 will adding two .1" ships cause any issues?

Changing springs is literally just swapping one spring out and putting a different one in. The post below says the SC rear spring rate is 100N/mm. So you can go to Hyperco/Swift/Eibach's catalog and look through their coilover springs (I believe the rear springs are 60mm ID) and pick out one with the same spring rate, but longer free length. I like that they kept the front spring rate reasonable on the SC, but would prefer they went up in the rear to 115 N/mm. 115 N/mm isn't terribly far off from 100 N/mm such that the damper wouldn't handle it at all.

Alternatively, you could see what the spring rates come with the F31, F34, and F36 versions of KW's coilovers. Those might already come with rear spring rates that are what I'd prefer, and ride a bit taller because of that.

Originally Posted by daac

Hey guys. I recently emailed kw about spring rates for my car wanted to compare to the v1s. The answers I got is the fronts are progressive and therefore no set spring rate and the rears are linear 575in/lbs. I initially emailed the euro address first and got a different answer. Their response was that they were both linear and the rates are 45 and 100 N/mm. 262 and 571in/lbs. So I'm a little confused now. I confirmed they were both talking about the same kit #1802000U. Also, everything I've read on the forums say they are linear springs. Anyone know first hand about linear or progressive?

I don't have much seat time with KWs, plenty with B14s though. Too high front spring rate, too low rear spring rate. I don't like how they tuned the rear. I personally wouldn't buy a B14 kit without planning on swapping in different spring rates or using it as a donor set for a custom build (which they're excellent donors for).

[thatBimmerBloke]

Originally Posted by FaRKle!

I don't have much seat time with KWs, plenty with B14s though. Too high front spring rate, too low rear spring rate. I don't like how they tuned the rear. I personally wouldn't buy a B14 kit without planning on swapping in different spring rates or using it as a donor set for a custom build (which they're excellent donors for).

How is B14 as compared to stock? Maybe your suspension standards are too high than mine Also do you have any experience with B14 with different springs that seemed like an ideal setup? Or any springs that you would suggest to pair with it?
Thanks.

EDIT: FaRKle! Will the 06-22 or 05-22 or 18-22 springs have different drop if paired with B6 or B8? I can't find the exact numbers for each of these combinations for my car For springs, Eibach suggests 18-22 for my F32 xDrive with 20mm/10mm front/rear drop but I'm not sure if it'll be same if paired with B8 or B6.