Suspension

L

LukeT

New Member
Hi All, I am after a bit of advice - I need to change the front springs/shocks etc on my TDi 75. I have ordered a set of KYB springs, but am struggling to work out which shocks to get - there is so many different options out there and I didn't want to put on a set that are crap or fall apart. I am looking for a pliant (well as much as you ever get on an A2!) ride, so standard spec really.
Also with regards to top mounts is it always wise to change these at the same time? I don't notice any major untowards noise from the front suspension, but the car has done 110000 miles so maybe they'd need doing? Again there are many cheap options out there, but I didn't want to put a set on that fall apart 5000 miles down the road.

Thanks all!
 
Have a read of this:

The Definitive Suspension Parts List

If you're looking to do a complete suspension overhaul, you'll need a collection of miscellaneous parts. The purpose of this thread is to keep an up-to-date list of part numbers. Choose your dampers, springs and drop links and add the following for a complete renewal of the suspension. 6N0 412...
www.a2oc.net

Yes, change everything in one go, bump stops, top mounts, drop links, dust covers - the lot.

Ian
 
Kleynie said:
Have a read of this:

The Definitive Suspension Parts List

If you're looking to do a complete suspension overhaul, you'll need a collection of miscellaneous parts. The purpose of this thread is to keep an up-to-date list of part numbers. Choose your dampers, springs and drop links and add the following for a complete renewal of the suspension. 6N0 412...
www.a2oc.net

Yes, change everything in one go, bump stops, top mounts, drop links, dust covers - the lot.

Ian
Click to expand...
Thanks for the info Ian.
 
LukeT said:
Hi All, I am after a bit of advice - I need to change the front springs/shocks etc on my TDi 75. I have ordered a set of KYB springs, but am struggling to work out which shocks to get - there is so many different options out there and I didn't want to put on a set that are crap or fall apart. I am looking for a pliant (well as much as you ever get on an A2!) ride, so standard spec really.
Also with regards to top mounts is it always wise to change these at the same time? I don't notice any major untowards noise from the front suspension, but the car has done 110000 miles so maybe they'd need doing? Again there are many cheap options out there, but I didn't want to put a set on that fall apart 5000 miles down the road.
Click to expand...
KYB recommends RH1664 front springs for the 1.4TDI. However, their online catalogue shows the RH1664 front springs as having a Thickness 1 of 12mm, which I presume is the wire diameter. This doesn't make sense, as most 1.4TDI front springs have a wire diameter of 11.25mm or 11.5mm. However, the 1.76kg weight would suggest that this spring does in fact have a 11.5mm wire diameter and not the 12mm that KYB claims.

Maybe you could check the specification before fitting. Details such as uncompressed length, weight, number of coil turns (probably about 5.5 coil turns), wire thickness are all useful to know. If the front end, ends up high (as one member found out when he fitted KYB RH1664 to his 1.4TDI), then knowing the specification could help in choosing more suitable front springs next time.

KYB Catalogue - KYB Europe

KYB catalogue - use the electronic catalogue to search for the correct part using vehicle make and model or VIN.
kyb-europe.com kyb-europe.com

KYB RH1664 (KYB's recommend front springs for the 1.4TDI)
Weight1.76 kg
Thickness 112 mm
Outer diameter140 mm
Length330 mm
 
Last edited:
carlston said:
KYB recommends RH1664 front springs for the 1.4TDI. However, their online catalogue shows the RH1664 front springs as having a Thickness 1 of 12mm, which I presume is the wire diameter. This doesn't make sense, as most 1.4TDI front springs have a wire diameter of 11.25mm or 11.5mm. However, the 1.76kg weight would suggest that this spring does in fact have a 11.5mm wire diameter and not the 12mm that KYB claims.

Maybe you could check the specification before fitting. Details such as uncompressed length, weight, number of coil turns (probably about 5.5 coil turns), wire thickness are all useful to know. If the front end, ends up high (as one member found out when he fitted KYB RH1664 to his 1.4TDI), then the specification could help in choosing more suitable front springs next time.

KYB Catalogue - KYB Europe

KYB catalogue - use the electronic catalogue to search for the correct part using vehicle make and model or VIN.
kyb-europe.com kyb-europe.com

KYB RH1664 (KYB's recommend front springs for the 1.4TDI)
Weight1.76 kg
Thickness 112 mm
Outer diameter140 mm
Length330 mm
Click to expand...


Thanks Carlston, I'll check the thickness out before i fit them.
 
Since when does wire thickness have a definite effect on spring rates? The material will be more important. There have also been some scientific measurements done on this elsewhere.

B3 would be my suggestion for standard ride height and similar feel, though I'm really liking the b8 with Eibach...
 
bretti_kivi said:
Since when does wire thickness have a definite effect on spring rates?
Click to expand...

Well it does have some effect on spring rates.

A spring is basically a 'coiled' torsion bar.
Stick a the end of round bar in a vice. Clamp a set of mole grips on the free end and try to twist it.
Increase the bar diameter and it will be harder to twist
Make the bar longer and it will be easier to twist.

Form a spring from the bar. More coils and / or bigger dia coils increase the length of the torsion bar.
Both make the spring 'softer' and reduce the spring rate.
Increasing the bar dia makes the spring 'harder' and increases the spring rate

Material properties do have a massive effect on spring characteristics but are likely to be fairly standard across the range of most car road springs

Cheers Spike

All thanks to my great physics teacher 60 years ago
 
TIL....

That also implies something simple - your coil diameters are going to be just as important as the thickness and length. But also the number of larger coils will be important, not just the size.

So we're back at: you cannot accurately predict the behaviour of a part from its listing in a catalogue. In the spring case, you're not getting the full picture of the size of coils, the number at a larger or smaller size or any other similar details. H&R were denounced for wooden performance back in the day, but I suspect there's minimal difference between those and the Eibachs in technical terms.

I'll also refer back to this: https://www.a2oc.net/community/index.php?threads/re-eibach-springs-for-a2.27924/ which has a bunch of links.
 
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