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rear springs
Posted: Tue Jan 09, 2018 4:54 pm
by Dean.s
I know about the bilstein kits but i see different rated springs on the yank sites mainly.
Has anyone built up different shocks and springs? What did you use and what ratings on the springs?
Re: rear springs
Posted: Tue Jan 09, 2018 9:21 pm
by Mr Pharmacist
I used a coil over kit from rebel racing and 180 lb springs for my track set up
Re: rear springs
Posted: Wed Jan 10, 2018 2:49 pm
by 914 KEV
All depends on how you will be using the 914.
If you are using the 914 for touring and general driving the standard spring set is fine.
The higher the spring rating the harder the ride will be and will be a lot less comfortable if you are going to be spend hours travelling in it.
Re: rear springs
Posted: Wed Jan 10, 2018 7:18 pm
by Dean.s
Should have included the use. It will be set up for road use. When you say standard, what is standard now? I think i saw 90lbs springs as standard but offer 110lbs as an improvement but what shocks? Kyb do a set of shocks would these be standard?
Re: rear springs
Posted: Wed Jan 10, 2018 9:17 pm
by Canarydelia
I had KYBs and they were back breakers - awful. Changed to Bilsteins with standard springs last April. Changed the car remarkably - feels like it can corner 10mph quicker, but maintains a compliant ride. Best improvement made to the car bar none, IMHO. Got Bilsteins and springs from Rexbo.
Re: rear springs
Posted: Thu Jan 11, 2018 3:10 pm
by Dean.s
I took one absorber off yesterday and they are kyb white shocks. The only reason i'm replacing is due to leaks on both and the sag on the rear end is more than i would have liked so was looking at springs too.
I have found a supplier of sachs shocks for a very reasonable price, anyone have experience with these?
Re: rear springs
Posted: Thu Jan 11, 2018 4:04 pm
by KAS.750
Dean.s wrote:I took one absorber off yesterday and they are kyb white shocks. The only reason i'm replacing is due to leaks on both and the sag on the rear end is more than i would have liked so was looking at springs too.
I have found a supplier of sachs shocks for a very reasonable price, anyone have experience with these?
Who is the Sachs supplier Dean?
Re: rear springs
Posted: Thu Jan 11, 2018 5:22 pm
by davep
KYB= Kill Your Back
Stock 914/4 springs were pretty weak, I believe about 80 to 90 pounds per inch; colour bands indicate weight group. The 914/6 springs were heavier. As time passes, the springs get weaker; you see the coil start to bow. Probably get the 100+ rate springs, or the progressives.
Re: rear springs
Posted: Thu Jan 11, 2018 6:28 pm
by Dean.s
A quick reply on the shocks, no Sachs/boge both appear as NLA.
They are now chasing kyb and bilstein b6, I hope to hear tomorrow. I'll be able to gauge price and try to negotiate a group buy if enough interest.
My springs are black and the kyb's are rusty white!
Any idea what rating the springs are? And what their length is when off the damper?
The distance from the lip of the rim to the bottom of the wing/fender is 55mm. It is a stock 914 15" steel rim. I'm not sure what the stock stance should be so I'm trying to figure things out. The front have what appear to be green bilsteins and the car sits high up front. It looks like the front adjust ment screw is approximately 1/2 way through, so 50% more adjust either way.
Re: rear springs
Posted: Fri Jan 12, 2018 12:40 am
by 914 KEV
From left to right:
Factory Original 914-4
Spidan 56104 replacement OM spec. spring
Mittelmotor 914-6 aftermarket sports spring
Weltmeister SP100 (100lb) common U.S. repacement spring
Factory 914-4 spring: 479mm long, 105mm outer diameter, 9.5mm thick
Factory 914-6 spring: 473mm long, 106mm outer diameter, 10mm thick
Mittelmotor 914-6 spring: 428mm long, 106mm outer diameter, 10mm thick
Weltmeister SP100 spring: 382mm long, 108mm outer diameter, 11mm thick
As you can see from the list above the replacement springs are shorter than the originals and will also lower the rear.
The Bilstein rear shock absorber has an adjustable spring plate while the Boge original oil shock was fixed.
I have fitted many Spidan springs with Bilstein on 914s as well as the Mittelmotor 914-6 springs and the owners have all said that they have improved the 914s performance as well as not being too hard.
I have also used these on my 914s.
I have removed a few sets of the Weltmeister SP100 springs as many owners have found these are too hard and back breaking.
I know of one 914 owner on here that his spring/shock set up is way too hard for his wife’s back that she won’t get in his 914 and he turns up at 914 events with his wife in a Triumph stag!
And some aftermarket 914 springs are so short that when you jack up the back of the 914 they rattle about!
Below is a photo of the 914-6 factory springs with red marks next to the 914-4 factory springs green marks to show the difference in length between the two.

Re: rear springs
Posted: Fri Jan 12, 2018 11:16 am
by camperco
We use the Mittlemotor 914-6 spring (as in Kev's pictures) on all the 4s. The resultant ride height comes out lower than the GKN spidan springs and the rate is just perfect for road use especially with the Bilstein shock.
The Spidan spring is not actually listed for 914 on the GKN website but its stocked by at least one popular 911 parts outlet. We thinks its too tall and too stiff and you may end up with positive camber on the rear. I got a picture of a car fitted with them that we removed but I've not got into posting pictures.
We have a couple of sets in stock.
Re: rear springs
Posted: Fri Jan 12, 2018 2:42 pm
by middlefour1
I have standard Boge shockers with the Mittlemoter 914/6 springs on my car and am very happy with the ride this gives.
Re: rear springs
Posted: Fri Jan 12, 2018 2:44 pm
by 914 KEV
camperco wrote:The Spidan spring is not actually listed for 914 on the GKN website
Not true Angus, see below. And I have fitted a few and so have a few people on here and found they work fine, just adjust the spring plate to one of the 6 settings.

Re: rear springs
Posted: Fri Jan 12, 2018 5:39 pm
by KAS.750
Dean.s wrote:I took one absorber off yesterday and they are kyb white shocks. The only reason i'm replacing is due to leaks on both and the sag on the rear end is more than i would have liked so was looking at springs too.
I have found a supplier of sachs shocks for a very reasonable price, anyone have experience with these?
Shocks are available from Porsche but they £243.82 each.
Re: rear springs
Posted: Fri Jan 12, 2018 9:39 pm
by 914 KEV
KAS.750 wrote:
Shocks are available from Porsche but they £243.82 each.
Porsche now supply Black Koni Classics in place of the original Boge.