Rear Auxillary Springs Installation Guide (for towing and heavy loads)

jakm15

Registered User
I've just fitted some MAD suspension auxillary springs to my 2010 A4 Avant, they are designed to help when towing heavy loads such as a caravan or when you have a loaded up car, bike rack on, roof box or all of the above like we do. They stop the cars rear springs from bottoming out and not absorbing bumps etc, the auxiliary springs aren't supposed to affect the every day driving of the car but come into play when a lot of weight is placed over the back, for us it's for when we are towing the caravan to stop it bottoming out and jiggling around as much when your on rough country lanes.

This guide applies to the A4, A5, Q5 and A6 as it's the same kit for them all.

Fitting them was pretty straight forward, just whip the wheels off and then you wind the bottom part of the aux spring into the original spring until it bottoms out and then push the top part of the aux spring through the coils into the original spring, there's also a bush that sits at the bottom which you put in before anything and then one at the top which I put in once the spring was in, I just used a tyre lever to push the aux spring down and then pop the bush in at the top.

My tips would make sure you wind the spring in exactly as it appears on the photos as it took me a few goes, if your good at those metal Chinese puzzle things you get in crackers you'll find it easy, if your rubbish at them like me it might take you a few goes, just make sure you wind it in on the exact coil it shows on the photos and as far as it shows and it will drop right into the center.

Rear ride height gap before was around 65mm and now it's just short of 95mm so around a 30mm raise, I've not drove it yet so it may settle slightly but I expect the car to handle bumps etc much better when I'm fully loaded or when towing the caravan.

I'll update when I have the caravan etc on the back.
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Pie-eyedpiper

Registered User
Are they any good?
They look a bit of a faff to get in, and what are they like to get out?
Are they vehicle specific? I found a few sets on eBay, but they are all for Peugeot 605 and Nissan Primera.

Has anyone used this type when towing and are they any good?
Just concerned when I fit my lowered springs I might get some bottoming out when towing my caravan.
Screenshot_20200605-174128.png
 

jakm15

Registered User
Are they any good?
They look a bit of a faff to get in, and what are they like to get out?
Are they vehicle specific? I found a few sets on eBay, but they are all for Peugeot 605 and Nissan Primera.

Has anyone used this type when towing and are they any good?
Just concerned when I fit my lowered springs I might get some bottoming out when towing my caravan.
View attachment 204199
It tows nice and level now and they also help when I have a boot and car full.

Easy to fit no issues with that.

They are vehicle specific, go on MAD suspensions site and it asks for car make and model.

The ones you've posted are not as effective as the auxiliary springs and are a bit of a botch.

If you tow a caravan like me I wouldn't lower my car it's a bit backwards.

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Pie-eyedpiper

Registered User
Do you leave them fitted all the time, or take them out after use?
I only tow a couple of times a year, I want my car to look and perform well for the other times too. I believe the type I posted can be removed when not in use.
I have the dire S line suspension at the moment and never bottomed it out (caravan nose weight is 50kg). So with lowered, stiffer suspension I hope not to have issues either.
 

I'm Just Rob.

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Are you 2wd as the Mad ones are not for Quattro or S4 .
 

jakm15

Registered User
Do you leave them fitted all the time, or take them out after use?
I only tow a couple of times a year, I want my car to look and perform well for the other times too. I believe the type I posted can be removed when not in use.
I have the dire S line suspension at the moment and never bottomed it out (caravan nose weight is 50kg). So with lowered, stiffer suspension I hope not to have issues either.
Yeah you leave them in.

That nose weight doesn't sound right at all, a nose weight of 50KG would only be right for a caravan with MTPLM of 850KG which would be micro caravan. The nose weight should be 5 to 7% of the caravans MTPLM so it tows safely.

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Pie-eyedpiper

Registered User
Are you 2wd as the Mad ones are not for Quattro or S4 .

Yes 2wd Rob, but I'm lowering my car, not raising it!
They aren't an option then anyway.


Yeah you leave them in.

That nose weight doesn't sound right at all, a nose weight of 50KG would only be right for a caravan with MTPLM of 850KG which would be micro caravan. The nose weight should be 5 to 7% of the caravans MTPLM so it tows safely.

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No sorry 80kg, it's been a while since I towed last year.

How often do you tow? And how does your car handle when you're not towing?
 

jakm15

Registered User
Yeah 80KG sounds right

Probably 15 times a year I'd say.

It handles no different with no caravan on with the aux springs in, it's an Avant so it's no 911 in terms of handling anyway it feels big and heavy compared to other cars I've had.

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PenttisHSR

Registered User
Has anyone used this type when towing and are they any good?
Just concerned when I fit my lowered springs I might get some bottoming out when towing my caravan.

I fitted the Grayston ones a few years ago and they are still there. Primitive, easy to fit, but they do the job fine as far as I am concerned. I have a Thule towbar-mounted bike rack and with three bikes on and three people in the car loaded up for a two week self-catering holiday in France including bedding etc. etc (+ beer & wine on the way back!) they keep the back of the car supported. Used to look terrible sat flat on it's ar$e.

When I first fitted the rubber donuts the car sat slightly higher at the back and the rear suspension obviously stiffer. I am used to it now, but at first I could definitely tell the difference with the rear being harder and slightly unsettled. I liked this as it turned in better and removed some of the factory understeer.

The donuts need to be a snug fit with the car off the ground or they would fall out. So when it's back on the ground they are being compressed/raising the car. In effect removing one coil from the spring. In your case, it would be relatively easy to remove them when not towing your caravan to return the car to lowered.
 

Pie-eyedpiper

Registered User
I fitted the Grayston ones a few years ago and they are still there. Primitive, easy to fit, but they do the job fine as far as I am concerned. I have a Thule towbar-mounted bike rack and with three bikes on and three people in the car loaded up for a two week self-catering holiday in France including bedding etc. etc (+ beer & wine on the way back!) they keep the back of the car supported. Used to look terrible sat flat on it's ar$e.

When I first fitted the rubber donuts the car sat slightly higher at the back and the rear suspension obviously stiffer. I am used to it now, but at first I could definitely tell the difference with the rear being harder and slightly unsettled. I liked this as it turned in better and removed some of the factory understeer.

The donuts need to be a snug fit with the car off the ground or they would fall out. So when it's back on the ground they are being compressed/raising the car. In effect removing one coil from the spring. In your case, it would be relatively easy to remove them when not towing your caravan to return the car to lowered.

That's great thank you. Just what I was hoping.
I'm fitting a Bilstein B12 kit soon, so being able to remove them (and easily) when not needed is a must.
I have a Thule 3 bike rack too, so will be handy when that's mounted.
 

PenttisHSR

Registered User
That's great thank you. Just what I was hoping.
I'm fitting a Bilstein B12 kit soon, so being able to remove them (and easily) when not needed is a must.
I have a Thule 3 bike rack too, so will be handy when that's mounted.
I had a pair on my B5 S4 previously also, so I've been using them for several years. They were not listed in the Grayston catalogue but all you need to do is jack the car up and measure the gaps in the coils, then buy the nearest fit. I had to get thicker ones for the B8 or I would have swapped them over! Plenty of neat washing-up liquid helps with sliding them in. Looked down upon as a bodge, but they do the job effectively. I never removed mine, I think the weight of the towbar partly compensated for the extra height gain. I fitted Bilsteins on the B5.
 

Pie-eyedpiper

Registered User
I think that they're a far more convenient and neater solution than the other extra pair of springs that the guy at the beginning put in. If you leave them in or take them out, they're cheaper and as effective.
 

jakm15

Registered User
I think that they're a far more convenient and neater solution than the other extra pair of springs that the guy at the beginning put in. If you leave them in or take them out, they're cheaper and as effective.
They are definitely not as effective, I've tried the spring inserts and they give a much harsher ride. They also basically make several coils rendered useless and put the extra strain on the other coils possibly leading to springs snapping.

If your going to do it, do it right don't botch it with the inserts.

The inserts are basically a can't be ***** fitting and can't be ***** spending approach.

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Pie-eyedpiper

Registered User
They are definitely not as effective, I've tried the spring inserts and they give a much harsher ride. They also basically make several coils rendered useless and put the extra strain on the other coils possibly leading to springs snapping.

If your going to do it, do it right don't botch it with the inserts.

The inserts are basically a can't be ***** fitting and can't be ***** spending approach.

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Can't be any harsher than the S line ride is now, surely.
I tow a couple of times a year. I don't want my car looking and handling like a jacked up hot rod for the rest of the time. I want something I can remove easily.
 

PenttisHSR

Registered User
They are definitely not as effective, I've tried the spring inserts and they give a much harsher ride. They also basically make several coils rendered useless and put the extra strain on the other coils possibly leading to springs snapping

Only one coil is "temporarily removed" rather than "rendered useless". In effect the length of wire making up the coil spring is shortened and therefore stiffer, less compliant for the same length/height of spring.
Yes the ride is harsher because it's a fixed (harder) spring rate rather than the variable harder rate of the extra spring professional solution. As I said, I found the turn-in better, even though at first I was not too happy with the feeling of the rear.
The bottom line is that Pie-eyedpiper can relatively easily fit and remove them when he is towing and a fixed uprate to the spring is required to take the weight of the caravan and luggage. It is a bit of a "botch" but it does work and it is hidden from view.
 
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