[SF335]

I am looking to upgrade the springs and shocks on my 2011 335i M-Sport coupe (~90k mi) and would like your advice. The car is my daily driver but it is driven hard and will see about 10 track days per year. I have tracking experience and do generally prefer my cars on the stiffer side. Currently, to me it feels like I am floating on clouds when taking turns.

Reading the forums (which I did a lot), I see a lot of people suggesting going with B12s or ST XTAs (top of my budget). I would prefer staying away from coilovers, to keep things simpler and more trouble-free, but I am concerned that the B12s might leave me desiring something more stiff, especially when at the track. As far as ride height, I am happy staying a little lower than stock so the B12s are fine in that respect.

For those of you with experience, are the B12s sufficient for occasional track use or do they leave you desiring more stiffness? Are there other spring/shock combos I should consider or does the coilover route seem like the right choice for me?

I will probably do solid rear subframe bushings and front M3 control arms in the near future as well. An LSD would be next on the wish list.

The car has a catless downpipe, exhaust, chargepipe, FMIC, and MHD tune.

Thank you in advance.

[chris@strutmonkey]

From what you describe, the B12 would be perfect. It is definitely firmer than stock and is huge performance upgrade. We recommend getting a complete, fully-assembled kit that provides new strut mounts, spring pads, mounts, perches, bumpstops, etc... that way you replace all your worn parts at one time. Here is a pic of the kit:

Originally Posted by SF335

I am looking to upgrade the springs and shocks on my 2011 335i M-Sport coupe (~90k mi) and would like your advice. The car is my daily driver but it is driven hard and will see about 10 track days per year. I have tracking experience and do generally prefer my cars on the stiffer side. Currently, to me it feels like I am floating on clouds when taking turns.

Reading the forums (which I did a lot), I see a lot of people suggesting going with B12s or ST XTAs (top of my budget). I would prefer staying away from coilovers, to keep things simpler and more trouble-free, but I am concerned that the B12s might leave me desiring something more stiff, especially when at the track. As far as ride height, I am happy staying a little lower than stock so the B12s are fine in that respect.

For those of you with experience, are the B12s sufficient for occasional track use or do they leave you desiring more stiffness? Are there other spring/shock combos I should consider or does the coilover route seem like the right choice for me?

I will probably do solid rear subframe bushings and front M3 control arms in the near future as well. An LSD would be next on the wish list.

The car has a catless downpipe, exhaust, chargepipe, FMIC, and MHD tune.

Thank you in advance.

[SF335]

Thank you Chris.

Does anyone have some input on how the ride (comfort and handling) on the B12s compares to the ST XTAs? I realize the XTAs are adjustable so would the B12s be comparable to the XTAs on let's say a middle setting? Are the spring rates similar?

It would be a crime to put Eibachs on a car that goes anywhere near a track.

Dinan, BMW Performance, Tein, Swift, etc. will likely provide much better results given the amount of track time you hope to see.

[SF335]

Yes, I am concerned that I'd find the B12 setup inadequate at the track.

Regarding the recommendation for "Dinan, BMW Performance, Tein, Swift, etc.", do you suggest getting springs and then matching shocks? If so, can you recommend which spring/shock combos are popular with the tracking crowd?

Is this a better approach than coilovers like the ST XTAs?

Many thanks for the help.

For dampers you're pretty much limited to either Bilstein B8 or Koni Sport. The above springs will work with either, just depends on which style you feel like going with.

Coilovers are a whole other can of worms altogether. Way too many types/spring rates/rate of adjustment/etc. available to go much into detail on any specific unit. If you want coilovers, don't limit yourself to the ST XTAs though. You'll likely find that you can dial in a number of more appropriate options for about the same price; it'll just require a lot more homework to get you where you need to be.

At the end of the day, you need to asses your goals/budget/etc. and the variables will work themselves out in the process.

[mweisdorfer]

Originally Posted by chris@strutmonkey

From what you describe, the B12 would be perfect. It is definitely firmer than stock and is huge performance upgrade. We recommend getting a complete, fully-assembled kit that provides new strut mounts, spring pads, mounts, perches, bumpstops, etc... that way you replace all your worn parts at one time. Here is a pic of the kit:

Attachment 1742507

Don't forget the differential mounts when yo do the subframe bushings.....

[chris@strutmonkey]

If you want a more track oriented set up, get the B8s (or Koni Yellows) with Swift Spec R springs. We can even add Dinan adjustable front camber kits to it.

Originally Posted by SF335

Yes, I am concerned that I'd find the B12 setup inadequate at the track.

Regarding the recommendation for "Dinan, BMW Performance, Tein, Swift, etc.", do you suggest getting springs and then matching shocks? If so, can you recommend which spring/shock combos are popular with the tracking crowd?

Is this a better approach than coilovers like the ST XTAs?

Many thanks for the help.

[alpineweissm]

I too skimmed the same options you are, but ultimately went with the XTA's when they went on a sale. I don't regret spending the extra money. I also have M3 control arms front and back. I've done a few track days with this setup and it's been a huge difference. Turns flat, car stays planted. But the street driving is where it made an even bigger difference. No more bottoming out, and smoother ride.

If you're in the Bay Area, hopefully I'll see you out at the track this year!

[SF335]

Originally Posted by chris@strutmonkey

If you want a more track oriented set up, get the B8s (or Koni Yellows) with Swift Spec R springs. We can even add Dinan adjustable front camber kits to it.

Attachment 1743684

Thanks for the recommendation. Do you know the spring rate on those springs and how much lower they would be than I am currently with the M-Sport package?

I would prefer spring rates in the vicinity of F:300-350#/R:600-700#. Also, if I don't have height adjustment, then I would like to drop the car just a bit below where it is now with the M-Sport package but not too much more. Also, would these spring rates match these shocks or would it be over-sprung?

Many thanks for the help.

[bbnks2]

Originally Posted by SF335

Thanks for the recommendation. Do you know the spring rate on those springs and how much lower they would be than I am currently with the M-Sport package?

I would prefer spring rates in the vicinity of F:300-350#/R:600-700#. Also, if I don't have height adjustment, then I would like to drop the car just a bit below where it is now with the M-Sport package but not too much more. Also, would these spring rates match these shocks or would it be over-sprung?

Many thanks for the help.

YCW is a good outlet for custom swift springs in any size/rate you want. That's the only way you'll get a modest drop and significantly stiffer springs. It won't be an easy task trying to figure out the correct length of the spring though... This is why adjustable coil-overs are so great even though no one seems to make a good set for our cars and the cars limitations...

[chris@strutmonkey]

1. The Swifts are about 225/600.
2. Drop is about 1", slightly less in rear. Your car on worn suspension is probably already "lowered" a half inch, so perhaps another half inch.
3. Springs are great with both B8s and Koni Yellows

Originally Posted by SF335

Thanks for the recommendation. Do you know the spring rate on those springs and how much lower they would be than I am currently with the M-Sport package?

I would prefer spring rates in the vicinity of F:300-350#/R:600-700#. Also, if I don't have height adjustment, then I would like to drop the car just a bit below where it is now with the M-Sport package but not too much more. Also, would these spring rates match these shocks or would it be over-sprung?

Many thanks for the help.

[Mavus]

Originally Posted by SF335

I am looking to upgrade the springs and shocks on my 2011 335i M-Sport coupe (~90k mi) and would like your advice. The car is my daily driver but it is driven hard and will see about 10 track days per year. I have tracking experience and do generally prefer my cars on the stiffer side. Currently, to me it feels like I am floating on clouds when taking turns.

Reading the forums (which I did a lot), I see a lot of people suggesting going with B12s or ST XTAs (top of my budget). I would prefer staying away from coilovers, to keep things simpler and more trouble-free, but I am concerned that the B12s might leave me desiring something more stiff, especially when at the track. As far as ride height, I am happy staying a little lower than stock so the B12s are fine in that respect.

For those of you with experience, are the B12s sufficient for occasional track use or do they leave you desiring more stiffness? Are there other spring/shock combos I should consider or does the coilover route seem like the right choice for me?

I will probably do solid rear subframe bushings and front M3 control arms in the near future as well. An LSD would be next on the wish list.

The car has a catless downpipe, exhaust, chargepipe, FMIC, and MHD tune.

Thank you in advance.

Based on the description of the car usage in the future you will need a better quality c/o. I would highly recommend TC Kline either s/a or d/a.

I had stock sport, bmw perf kit, JRZ RS1 and just installed TC Kline d/a two mo ago. Simply put words cannot describe how good they are. You will need 400/600 springs or similar for dual street/track duty. The car carries so much speed around corners it is unreal yet it never gets upset and it is completely comfortable. It feels just slightly firmer than stock sport yet the damping is much better. And this is just the street setting recommended by them. It is pure magic!

GL!

[SF335]

Originally Posted by Smooth 330i

Based on the description of the car usage in the future you will need a better quality c/o. I would highly recommend TC Kline either s/a or d/a.

I had stock sport, bmw perf kit, JRZ RS1 and just installed TC Kline d/a two mo ago. Simply put words cannot describe how good they are. You will need 400/600 springs or similar for dual street/track duty. The car carries so much speed around corners it is unreal yet it never gets upset and it is completely comfortable. It feels just slightly firmer than stock sport yet the damping is much better. And this is just the street setting recommended by them. It is pure magic!

GL!

Thanks GL! It would be hard to go with anything else after that beautiful description

I am very much leaning towards getting the TC Kline s/a. I am not concerned about being too stiff but the stiffest they have for the rear is 700#, so I'll probably go 400#/700#. I'd go stiffer but am limited with the rear springs and the front wheel spring rate is already quite a bit higher than the rear with 400#/700# so wouldn't go stiffer up front without the rear. Do you know if there are options for stiffer springs in the rear and would you want to go stiffer than 400#/700#?

Can you please tell me what else you've done with the suspension to make it perform? e.g., how about the sways, I am thinking of this 28mm/15mm setup from ECS: https://www.ecstuning.com/b-eibach-p...-kit/2085.320/

[Mavus]

Originally Posted by SF335

Thanks GL! It would be hard to go with anything else after that beautiful description

I am very much leaning towards getting the TC Kline s/a. I am not concerned about being too stiff but the stiffest they have for the rear is 700#, so I'll probably go 400#/700#. I'd go stiffer but am limited with the rear springs and the front wheel spring rate is already quite a bit higher than the rear with 400#/700# so wouldn't go stiffer up front without the rear. Do you know if there are options for stiffer springs in the rear and would you want to go stiffer than 400#/700#?

Can you please tell me what else you've done with the suspension to make it perform? e.g., how about the sways, I am thinking of this 28mm/15mm setup from ECS: https://www.ecstuning.com/b-eibach-p...-kit/2085.320/

I have stock sport rear sway and bmw perf front sway. I had front 500 springs with jrz but it was too stiff. The car would hop when pushed and TC Kline recommended to go with 400. I have 650r and 400f and love it.

I wouldn't touch your sways until you talk to TC Kline. Tell them what you want to do and they will provide their recommendation. That is what I did and wow were they right.

Also have jrz camber plates and m3 arms. The car is the driving machine.

[mike082802]

you ditched the jrz for the tckline?

[Cloud9blue]

Originally Posted by Smooth 330i

I have stock sport rear sway and bmw perf front sway. I had front 500 springs with jrz but it was too stiff. The car would hop when pushed and TC Kline recommended to go with 400. I have 650r and 400f and love it.

I wouldn't touch your sways until you talk to TC Kline. Tell them what you want to do and they will provide their recommendation. That is what I did and wow were they right.

Also have jrz camber plates and m3 arms. The car is the driving machine.

would like to hear your opinion of the JRZ in comparison to the TCK DA, thanks in advance!

[Mavus]

Originally Posted by Cloud9blue

would like to hear your opinion of the JRZ in comparison to the TCK DA, thanks in advance!

I can only compare street driving until I track TCK DA. The JRZ perform very well on track but my opinion is they do not have sufficient damping for street. You feel every single little imperfection on the road and pothole impact ripples through chassis on the lowest setting. The TCK DA damping is much better, it absorbs road imperfections like they are not there and if you go over a duct (which I avoid as much as possible) there is no ripple through the chassis. I did not test their softest setting yet.

On the track though there is no drama with JRZ, very stable at high speed, rebounds almost instantly and there is minimal dive under hard braking. Changing direction is an instant event, very precise without upsetting the car. If you want to go deep into the corner go right ahead no problem. Heavy braking downhill - sure go ahead. Going through chicane there is instant response when changing direction with minimal roll. It is stable and you can feel the limit before the car snaps. The TCK so far feels very good in spirited driving but dare I say it appears the car has better grip in front. Changing direction quickly is non event and it feels very stable. So far no regrets.

Another thing is JRZ performance deteriorates after 15K mi and the damping gets even worse. At 25K mi they need rebuild unlike TCK DA. I am curious to see how TCK perform over time but there are folks that put on more than 50K mi without issue. Hope this helps and I owe you track comparison in the spring/summer.

[Captain Canuck]

Would you mind posting a pic of your wheel gap with the TC Kline's?

[Cloud9blue]

Originally Posted by Captain Canuck

Would you mind posting a pic of your wheel gap with the TC Kline's?

this is mine on the highest setting up front with 400lb/in spring.



tires are 265/35r18 front, 275/35r18 rear

[Biginboca]

Originally Posted by Cloud9blue

tires are 265/35r18 front, 275/35r18 rear

What size rim, offset, and camber are you running to get the 265 up front?

[Cloud9blue]

Originally Posted by Biginboca

What size rim, offset, and camber are you running to get the 265 up front?

18x9 et30 if i remembered that correctly. those are apex wheels, so check with them. super strong, looks great, and priced reasonably too.

I am running around -3.5 degree up front, with vorshlag plates. the tires do rub on the top fender liner a bit when suspension is hitting the bumpstops. i am actually putting in some reinforcement plates on top of the camber plate right now to increase the stack height by 1/4" or so to get rid of that rub. plus the car is a little low for the shitty streets I have here even at max height...