What coilovers for wide tires?

[M43S7RO]

I've read that there are fitment issue's with some coilovers rubbing against the front wheel in some scenarios. I run AD08R 275/30 R19 up front and 295/30 R19 out back and would prefer to keep a wide setup as I love the grip!

I'm currently researching systems and would appreciate input from those with experience as to what the widest tires you have been able to run without the issue above and without modifying the coilover.

I am currently considering KW V2 or Bilstein B16.

TIA.

[SYT_Shadow]

I have two different M3s, one with JRZ and one with MCS

I use 10.5" ET27 wheels all around, sometimes with 275 all around and other times with a staggered 275/295

You'll find the spring perches of both systems (and KW is even worse from reading) are optimally designed to fuck with you. It's just unbelievable!

With a 10" front wheel you can get away with MCS and JRZ with a 5mm spacer which is fine. From reading about KWs, you need a 12mm spacer to do that with. Some people remove the helper spring from the KW CS to improve the clearance.

With a 10.5" wheel, you have two options
1) Use a 5" front spring instead of 6" which moves the stupid perch out of the way
2) Use a 12mm front spacer to clear the perch

If you have never run a 12mm spacer on a 10" ET25 front wheel you're in for a treat, because you look like a stancebro even with -2 negative front camber and it still rubs at times.

In the rear, no system is even close to rubbing regardless of tire size. Your issue is the fronts.

[M43S7RO]

Originally Posted by SYT_Shadow

I have two different M3s, one with JRZ and one with MCS

With a 10.5" wheel, you have two options
1) Use a 5" front spring instead of 6" which moves the stupid perch out of the way
2) Use a 12mm front spacer to clear the perch

If you have never run a 12mm spacer on a 10" ET25 front wheel you're in for a treat, because you look like a stancebro even with -2 negative front camber and it still rubs at times.

In the rear, no system is even close to rubbing regardless of tire size. Your issue is the fronts.

When I initially mounted my 19x10" et22 wheels up front, I tried a 5mm spacer and the wheel protruded WAY too much IMO so I definitely would not do a 12mm spacer to clear a perch. Stancenation is not my thing...

Good info regarding the spring size, much appreciated!

[SYT_Shadow]

Originally Posted by M43S7RO

When I initially mounted my 19x10" et22 wheels up front, I tried a 5mm spacer and the wheel protruded WAY too much IMO so I definitely would not do a 12mm spacer to clear a perch. Stancenation is not my thing...

Good info regarding the spring size, much appreciated!

Not my thing either. I can't stand the look. On the track car it looks kind of purposeful, but someone will mistake it for a stancenation car :'(

As long as you stick to 10" you are more or less ok. I have no idea of the clearance of the B16, although a few people here have them so they should chime in.

The KW needs tons of spacing if you want to clear the 10" front. I fear the B16 will be the same

[slicer]

You can run those tire sizes with any coilovers as long as you have the right wheel size and offset.

Front with 275/30/19 AD08:
9.5 et19 or less, 10 et17 (some run et20 with success) should clear most coil-overs
You will want to run around -2 camber for this fitment


Rear with 295/30/19 AD08:
10.5 et25 or higher (any offset lower than et25 will potentially rub the fender at 10:00 on driver's side. I have run as low as et22 with eibach springs but it did rub on big dips)
11 et25 or higher

Alternatively you can easily swap to a shorter front spring to add clearance. Eibach linear springs are around $175. You are looking at two coilovers options that have progressive springs. A spring swap may not work well in that instance. The good news is that a progressive spring may have less interference with inner clearance because it doesn't use a helper spring which pushes the spring perch lower. The clearance will be dependent on the ride height you choose as that will dictate the placement of the perch on the threaded shock body.

[squartus]

Curious about this as well with the Bilstein B16 damptronic EDC plug and play. Run 275 up front and 315 rear "stock non zcp suspension"
Not alot of feed back on the kit yet other than it handles and rides very well

[M43S7RO]

Are there any drawbacks to a shorter spring? That seems like the most logical solution.

The spring type is one of the considerations I am looking at. From what I have read and understand, I would prefer a linear spring.

[slicer]

Originally Posted by M43S7RO

Are there any drawbacks to a shorter spring? That seems like the most logical solution.

The spring type is one of the considerations I am looking at. From what I have read and understand, I would prefer a linear spring.

Search under KW spring swap. I did a thread on it. I'm not sure of the consequences of installing a linear spring on a shock designed for a progressive. The KW Clubsport uses linear springs. That's the basis of my spring swap solution.

Link to my thread-

http://www.m3post.com/forums/showthr...Kw+spring+swap

[SYT_Shadow]

Slicer, the thing is, 275 on a 9.5 'can' be done, but it's not optimal. The sidewall will be all bulgy which will be no bueno for steering precision!

If you want 275 you absolutely want a 10" tire, especially up front where stretch is desirable for steering spiritual creaminess

[slicer]

Originally Posted by SYT_Shadow

Slicer, the thing is, 275 on a 9.5 'can' be done, but it's not optimal. The sidewall will be all bulgy which will be no bueno for steering precision!

If you want 275 you absolutely want a 10" tire, especially up front where stretch is desirable for steering spiritual creaminess

A 275/30/19 on a 9.5" wheel is completely acceptable (as is 10" as you suggested). Plus the AD08 has stiff sidewalls. I'm not saying that a 10" won't improve some aspects but that tire will not feel "wobbly" on a 9.5" wheel. The manufacturer spec lists the rim width range as 9" to 10". The measured rim width is 9.5". In other words the tire manufacturer's measurements are all based on the tire getting installed on a 9.5" rim. Compare that to a 275/35/18 tire and your point starts to have more weight. The rim width range is 9" to 11" due to the taller (and more stretchable) sidewall. The 275/35 is still measured on a 9.5" wide wheel. In other words, I would be more motivated to pair a 275/35 series with a 10" wheel than a 275/30.

[SYT_Shadow]

Originally Posted by slicer

A 275/30/19 on a 9.5" wheel is completely acceptable (as is 10" as you suggested). Plus the AD08 has stiff sidewalls. I'm not saying that a 10" won't improve some aspects but that tire will not feel "wobbly" on a 9.5" wheel. The manufacturer spec lists the rim width range as 9" to 10". The measured rim width is 9.5". In other words the tire manufacturer's measurements are all based on the tire getting installed on a 9.5" rim. Compare that to a 275/35/18 tire and your point starts to have more weight. The rim width range is 9" to 11" due to the taller (and more stretchable) sidewall. The 275/35 is still measured on a 9.5" wide wheel. In other words, I would be more motivated to pair a 275/35 series with a 10" wheel than a 275/30.

Yes, I'm familiar with the rim width measurement concept, however, the Tirerack website also goes on to suggest 'use the widest wheel the tire allows'.

It is also true the ad08 has really stiff sidewalls to negate most of the issue, but on the steering end of the car is where I would always err to the widest possible wheel

Cheers

[squartus]

Originally Posted by slicer

A 275/30/19 on a 9.5" wheel is completely acceptable (as is 10" as you suggested). Plus the AD08 has stiff sidewalls. I'm not saying that a 10" won't improve some aspects but that tire will not feel "wobbly" on a 9.5" wheel. The manufacturer spec lists the rim width range as 9" to 10". The measured rim width is 9.5". In other words the tire manufacturer's measurements are all based on the tire getting installed on a 9.5" rim. Compare that to a 275/35/18 tire and your point starts to have more weight. The rim width range is 9" to 11" due to the taller (and more stretchable) sidewall. The 275/35 is still measured on a 9.5" wide wheel. In other words, I would be more motivated to pair a 275/35 series with a 10" wheel than a 275/30.

Yea while you may gain a bit with 10inch 9.5 works pretty well up front, just went with 9.5 for flexibility.
9.5 wheel with 275/35/18s, fits pretty flush. And I think the BFgoodrich g-Force Rival S do run a bit wide.

[M43S7RO]

I reached out to KW for comment regarding swapping to a linear spring on their progressive spring systems and received this response:

"Thank you for contacting KW Automotive,
Yes, if our kit comes with progressive springs, then the damper was designed to work with thatr spring.
Also the connection/fitment won't work. The linear and progressive springs are not tha same size bottom and top."

Hopefully others will chime in with their experiences with other brands. I would prefer not to go through spring swaps or helper spring removal. I also want to keep at least the 10" wheel up front in order to experiment with 285s r18 up front at some point.

Thank you for the info regarding the Eibach spring fix for the KWs. I've saved the part numbers for the 90nmm and 110nmm springs should I go that route.

Search under KW spring swap. I did a thread on it. I'm not sure of the consequences of installing a linear spring on a shock designed for a progressive. The KW Clubsport uses linear springs. That's the basis of my spring swap solution.

Link to my thread-

http://www.m3post.com/forums/showthr...Kw+spring+swap