POLL Bilstein B4 vs Bilstein B12

[inkey$]

I'm confused!

Looking at suspension upgrades for my 2.8 and originally earmarked a set of B4's with Eibach Pro Springs to refresh and lower the car by 30mm. But the B12 Pro kit includes springs and is cheaper.

I want the car to be lower than OEM but not to the detriment of ride quality. I understand there will be some compromise here, but I'm talking about the odd bump vs. bone shaking. Don't want coilovers and I dont want to spend over £500.

if you have either setup, what would you recommend?

 

[andyglym]

I have the B12 kit on mine, had it a few years now. The ride is obviously harsher than standard but not to the detriment of the ride. It works for me.

 

[inkey$]

I have the B12 kit on mine, had it a few years now. The ride is obviously harsher than standard but not to the detriment of the ride. It works for me.

That sounds like the description I was after. Do you have any pics?

 

[andyglym]

That sounds like the description I was after. Do you have any pics?

 

[inkey$]

Thanks. Back end looks quite low in that first shot. Is it under load - angle of the driveway etc?

 

[andyglym]

Thanks. Back end looks quite low in that first shot. Is it under load - angle of the driveway etc?

Not under load, must just be the way it's parked.

 

[mrscalex]

So you're asking B4 or B6 shocks? The B12 kit has B6 shocks and Eibach Pro springs. Although some suppliers and even Bilstein sometimes refer to B6 shocks as B8s for marketing purposes. See this thread - https://zroadster.org/threads/the-great-bilstein-b6-or-b8-mystery.27863/.

So the springs are a constant in your question.

B4s are the standard replacement. B6s/B12 kit are the uprated/go faster replacement.

 

[mrscalex]

As well as ride quality you also need to consider if you are prepared to take the occasional scrape on the underside. Becuase of this I stick with -15mm BMW Sport springs which are a very good compromise. I suspect Eibach springs marketed as -30mm are closer to -40mm.

Also note these drops are off the zero point of a standard car. If you start with Sport springs the drop will not be 30mm it will be 15mm.

 

[Lee]

Not under load, must just be the way it's parked.

Saggy beam bushes

 

[andyglym]

Saggy beam bushes

All renewed when I had the rear end taken out so hope not as that would be bad

 

[Lee]

All renewed when I had the rear end taken out so hope not as that would be bad

Might just want some thicker spring pads. Some lowering kits do this.

 

[andyglym]

Might just want some thicker spring pads. Some lowering kits do this.

Right O, cheers. I'll look into it. Any particular make/size etc you'd recommend?

 

[Lee]

Right O, cheers. I'll look into it. Any particular make/size etc you'd recommend?

Grab a pair of 10mm pads from BMW I don’t think they’re expensive. They come in various sizes. I tend to keep a few in stock and play to get the height at the back right

 

[andyglym]

Grab a pair of 10mm pads from BMW I don’t think they’re expensive. They come in various sizes. I tend to keep a few in stock and play to get the height at the back right

Top man and Cheers

 

[inkey$]

As well as ride quality you also need to consider if you are prepared to take the occasional scrape on the underside. Becuase of this I stick with -15mm BMW Sport springs which are a very good compromise. I suspect Eibach springs marketed as -30mm are closer to -40mm.

Also note these drops are off the zero point of a standard car. If you start with Sport springs the drop will not be 30mm it will be 15mm.

Thanks for the link. Really useful read. Yes, the B6[B12] with Eibach -30mm looked like good value and it feels like I have enough drop height to play with. You think -15mm would be the better choice?

I actually had a set of B4's and 30mm lowering springs a couple of years ago that I subsequently sold to Mario! That was my default choice to begin with again, but then I saw the B12 kits was under £500.

All I want is to fill the arches better with my 17 inch wheels (incl. spacers) and not compromise too much on ride.

 

[inkey$]

This is why I think it could handle 30-40mm.

 

[mrscalex]

A standard suspension really does sit a bit high doesn’t it. But you’d be surprised how just -15mm Sport springs change the look.

 

[inkey$]

A standard suspension really does sit a bit high doesn’t it. But you’d be surprised how just -15mm Sport springs change the look.

I’ve kind of decided the -15mm are for me. Do you happen to know where I can get a set or part numbers?
Would these just work fine on standard shocks/B4’s?

 

[Antm72]

You can not buy sports springs anywhere i believe -30 is your only option.

I run bilsteins and -40 Apex if you go -30 and its too low just fit a bigger spring pad stock is 5mm they do 7.5 10,15, and 20mm so you can dial it in

 

[inkey$]

You can not buy sports springs anywhere i believe -30 is your only option.
View attachment 141313
I run bilsteins and -40 Apex if you go -30 and its too low just fit a bigger spring pad stock is 5mm they do 7.5 10,15, and 20mm so you can dial it in

Good info. So if I went Bilstein Pro Kit with the -30mm springs and added 10mm spring pads, that might be about right for the pothole roads? Would it be the same size pads all around and where is the best place to get them from?