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I am soon wanting to buy a full set of ground control coil overs for my 75 e12 and would like input on what spring rates to use.

Any help would be appreciated.

Thanks

Brent

For a car like the E12/E28 for street/occasional track use, they recommend 440 front and 325 rear.

Anything Cheaper than GC out there? I wonder if IE is still doing anything?

JodyStevens wrote:Anything Cheaper than GC out there? I wonder if IE is still doing anything?

I wouldn't give IE my business, they have the worst customer service of any company I have ever dealt with and most of the parts I have bought were sub-par. Just my opinion of coarse.

And their shipping.....

wkohler wrote:For a car like the E12/E28 for street/occasional track use, they recommend 440 front and 325 rear.

Thanks Chris!

wkohler wrote:For a car like the E12/E28 for street/occasional track use, they recommend 440 front and 325 rear.

I like the ratio's but make sure the 440 are long enough. My euro was pretty light and I could still coil bind 450# 7 inch springs.

Note if you have enough compression in front shocks (Bump) you may be ok

I didn't have that problem with my E28. They send 7" springs and with their kit and shortened housings the front adjusters were at the top and the rears at the bottom. On my 528i E28 I'm not going to run their Konis. Either Spax adjustables or Bilsteins. Mostly because I've got all of the other pieces.

bkbimmer wrote:

JodyStevens wrote:Anything Cheaper than GC out there? I wonder if IE is still doing anything?

I wouldn't give IE my business, they have the worst customer service of any company I have ever dealt with and most of the parts I have bought were sub-par. Just my opinion of coarse.

And their shipping.....

I've ordered from them before and did not have any problems. I hear alot of chatter about them being sub-par though.

I live in Canada so shipping is eye-watering no matter what.

I think the question has to be asked...what are your goals?

Personally, for street use I would think 440 is a bit stiff in front and may require custom valved struts to control them. I would tend to stay in the 350 range. I do recall being in an E28 with 400 lb springs and the car felt very solid and firm. However if you want the car very low you will have to go with stiff springs.

I do want to put in the caveat that I have not had experience with coilovers personally so I can't comment on the binding issue that Peter raises. I can see how that could be an issue under very hard use.

Right now I have Motorsport springs with Bilstein Sports and the front end seems to have either too much compression or is hitting on bump stops. It's a little stiff and bouncy. It's possible I have a stiff spring with too much compression.

One other thing I will research is why there are separate part numbers for E12 and E23 Bilstein HDs in front vs. THE SAME part number for E12 and E23 Bilstein Sports. Not sure that makes sense to me. The Sport struts seem to work better on an E23 vs E12.

I do think that rear springs in the 300 range is a good choice. If I recall from the E28 website, Dinan uses 275 lbs in the rear and they feel better than any of the other aftermarket springs which tend to be in the 200-250 range.

That's the thing. I ran 440/400 on my 535is. I was lazy and didn't swap the rear springs, but 6" 600lb springs were ridiculous. Anyway, having run Dinan springs, I think the higher rear spring rate helps a lot.

I think the question has to be asked...what are your goals?

Personally, for street use I would think 440 is a bit stiff in front and may require custom valved struts to control them. I would tend to stay in the 350 range. I do recall being in an E28 with 400 lb springs and the car felt very solid and firm. However if you want the car very low you will have to go with stiff springs.

I do want to put in the caveat that I have not had experience with coilovers personally so I can't comment on the binding issue that Peter raises. I can see how that could be an issue under very hard use.

Right now I have Motorsport springs with Bilstein Sports and the front end seems to have either too much compression or is hitting on bump stops. It's a little stiff and bouncy. It's possible I have a stiff spring with too much compression.

One other thing I will research is why there are separate part numbers for E12 and E23 Bilstein HDs in front vs. THE SAME part number for E12 and E23 Bilstein Sports. Not sure that makes sense to me. The Sport struts seem to work better on an E23 vs E12.

I do think that rear springs in the 300 range is a good choice. If I recall from the E28 website, Dinan uses 275 lbs in the rear and they feel better than any of the other aftermarket springs which tend to be in the 200-250 range.

For someone whom already has the Bilstein Sports installed, what is a good spring length to drop the car to help eliminate the wheel well gap? I already have lowering springs on it now but still have a bit of gap both front and rear (obviously more front than rear). I'm not looking to slam it, just looking to drop the front so there is next to zero gap then the rear relative to the front as to not create a lot of rake (so perhaps tucking just the top of the rear tire tread).

And at that ride height do 440/400 sound decent as mentioned previously?