Rear suspension I have almost no information on.

Rear suspension
Sachs (OEM supplier) list rear struts stroke as 157mm

 

Luke,
My understanding and experience with my 2008 7L in general tells me that first you need to have the VW vehicle specific build data for a particular vehicle, that vehicle data shows the specific components that were used in the build of that vehicle.
Once you have that, you need to look for that vehicles individual Pr-number for the the individual item of interest.

Lets say we are trying to work out what springs were fitted to my actual vehicle.

Looking at my "build data" for suspension related items, an extract from my one shows:

"Pr-numbers
CON.
NO.
NO. ORIGIN FAMILY DESCRIPTION
1 0AB L STV Front stabilizer
2 0E1 L RST Short wheelbase
3 0JD L GKV Weight category front axle weight range 4
4 0KA L KAE Without stickers and badges
5 0NB L SZU Nameplate set in base trim
6 0P0 L AER Rear exhaust tailpipe (standard)
7 0SC L SAU Labels/plates in English
8 0TD L ZFM Front and rear floor mats
9 0VF L BTA Information kit in English
10 0Y2 L KLZ Tropical zones
11 0YB L GKH Weight range 2 installation control only, no requirement forecast
12 1BA L DAE Standard suspension/shock absorption"

which tells me that I have two Pr suspension related items,
#3 = Pr "OJD" and
#12 = Pr "1BA"

to decipher what Pr "OJD" and "1BA" mean we next need to refer to a schematic for this model year, refer

coil spring. anti-roll bar. shock absorbers VW TOUAREG

Parts for unit coil spring. anti-roll bar. shock absorbers VW TOUAREG

www.ilcats.ru

which links the Pr numbers to the actual part number used and the range of year/s used

7L6411105L

coil spring F 7L-7-110 001>> * 2 paint marks white green PR-1BA+0JD, 0JE

2

05.2007 - 05.2010

you will note that it also shows that the coil spring is identified by two paint marks on the coil of white and green, VW identifies the coil used by colour and number of dots painted on the coil, there is no part number stamped, this is a picture taken of my front coil removed to fit aftermarket units

The reason for my long winded post is to demonstrate that it is not easy to determine what coils you have fitted to a particular Touareg, but it is possible to work it out.
Interestingly you do not show 7L6411105L in the part numbers you quoted.
Here are the measurements I took of the actual coil...

	OEM
	Front
Coil OD
Length (Overall)	420​	​
Length (Free ie. Not loaded)
Turns ()	10​	​
Turns (extra)
ID Top	89.5​	​
ID Bottom	59.9​	​
Thickness

Hope some of this information will be of use to you.
TonyB

 

Hi Seafarer. Thank you for your post.
While we would need the part numbers to reference the items we are mentioning, the parts look up rarely provide any real technical information about the part. For example none of the springs I looked up list the actual spring rate.

When looking up dampers, what is the collapsed and extended lengths? This would also give us the working stroke.
What is the motion ratio for the front and back suspension? The suspension design on this vehicle obviously provides for the suspension rate to increase as the wheel compresses. This allows for bottoming resistance. But what is the progression ratio?
What is the total wheel travel on OEM steel suspension and what is it on air suspension?
What is the lengths of the control arms? Most of the ones on the back can be made using straight tubing so it is an easy DIY project.

Thanks,
Luke.

 

All the technical information would be held by the manufacturer, not a chance in the world that VW would release any of their IP information (even if asked nicely).

I fear what you seek will be impossible to find, anyhow at the end of the day what are you trying to achieve?

TonyB

 

Spring rates have been written about a bunch and the consensus is that the best you'll do is an educated guess. Keep in mind also that the spacers change color based on the measurements of each specific spring.

i bypassed all of this with a Cayenne suspension. Just don't ask me the spring rates

 

Jeff. The spring rates could be easily measured off the vehicle.

TonyB. I am aware that the actual technical information is held by VW. How ever that does not mean we can't compile our own, or that there is not information that VW would release to the public.
For example Ford tells you the exact wheel travel for their Ranger Raptor and Raptor F150. Also Mitsubishi published exact wheel travel numbers for their Pajero Evolution and also Pajero models.
If you scour the web you can easily find spring rate, wheel travel, and motion ratio information for common Subarus and Jeeps.

My purpose in this thread was to make a place where information could be gathered and used by those who are in search of it. The Touareg models are now becoming very affordable to purchase and as has been seen in recent years they are becoming more populor for off-road and overland builds. Compiling basic suspension information could make it much easier for people who wish to do builds themselves.
For example. Already from this thread we can see that the maximum front shock stroke that will work standard is around 155-160mm. This is information which I was unable to find before confirming it myself.
I'm sure companies such as Eurowise would have on file the standard wheel travel numbers, shock lengths, and motion ratios as this would be part of them designing the JRZ and Bilstein coilovers for our platform. As this is information only about the standard vehicle it should not be a concern for them if they decided to put the information out in the public. This is where a lot of the information for Jeeps comes from for example. Companies do research to make better products and part of the marketing is releasing the information about the OEM product so they can show how theirs increases travel for example.

When my suspension arrives I will do my best to get all the measurements of standard shocks and measure motion ratios.

Thanks,
Luke.

 

To muddy the waters further, I add my experience with replacing struts assemblies with FCS units from RockAuto.

The first set that arrived was for the front. Before I removed the old units, I measured the number of coils and their diameter.
Then I compared the new to the original and discovered that the new has 2 fewer coils, but the diameter is the same. I don't have the equipment to measure the spring rate.
The original coil springs have 4 marks, 3 green, and 1 blue.
Upon installation of new units, and after it settled, I discovered the front of the Egg sits about 1" (25mm) lower than with original struts.

The findings are HERE

Then I got the rear strut units. Same brand.

The original rear struts I removed from the Egg had coils with one more turn than the new strut units. The overall length of new strut units was 1" (25mm) longer than the original strut, static. The wire diameter of the new coil springs that came with strut assembly was larger by 3% than the original. The original coil springs have 1 green mark.
Upon installation, the rear of my Egg sat about 1/2" (12mm) higher than with the original strut units. The final setup has produced a considerable forward rake.
To compensate for the forward rake, I installed PRG 2 inch lift kit on the front.
After driving the Egg for a couple of hundreds of miles, the suspension has settled to a ZERO rake.

P.S
Comparing the ride between new FCS strut units and busted original struts would not be fair. But one of the major complaints about old suspension was the clunky ride over the speed bumps, which is now gone.

 

Well a small update.
The bushes on this thing really bind up the rear suspension.
I was unable to get any real measurements as the bushes are the limiting factor with the stock steel suspension on a 2007 (MY2008) 7L.
The standard rear coilover is longer than the bushes will allow for droop travel. So you will not get the full shock travel with stock bushes. Seems really strange as I have heard that the air shocks may even be longer than the steel (coil) shocks?

During up travel with the strut removed I did not feel comfortable going further with the bind in the rear bushes. I do not believe I was at what would be full compression of the shock though.

I will need to report back in the future when I switch out the rear control arms for ones with spherical joints.

I will report on the front later too.

P.S. I do wonder if I still have factory bushes and after the 14 or so years they have become HARD which may be limiting their range?

 

Front motion ratio 1.76
Rear motion ratio 1.48

This is from a quick measurement of only about 100mm of wheel travel. Somewhere from where the bushes allow full droop to 100mm up. So not sure on where exactly it is in the total travel range.
The front I imagine is pretty accurate. I will have to confirm when I have new control arms that allow free movement through the entire range.
Rear is probably not very accurate. This is due to the fact that the shock is on such a big angle and the angle changes considerably through out the total travel range.

Also. For those of you with lift spacers or subframe drops/spacers the motion ratio will be slightly different.

I will update with some more accurate measurements when I can.
Hope this can help someone.

 

I got a chance to measure standard steel struts today. Although I did not disassemble the springs and top hat mounts.

I confirmed with a tape measure some figures for the front and rear struts.

Front strut total length 678mm
Front strut stroke 125mm
Front strut bottom mount width 74mm

Rear strut total length 550mm
Rear strut stroke 157mm
Rear strut bottom mount width 50mm

Because the springs and top hat mounts were not removed I obviously did not actually cycle the shock to check stroke. But I measured from seal housing to where the top of the bump stop sits.
Because these measurements match up (within 1 or 2 millimeters) with what has been found listed online by KYB/Sachs I think it is safe to say that the measurements are correct and it is not necessary disassemble and cycle the shock shaft to confirm.

Please note that all measurements may be off by up to 5mm. For example the front strut bottom mount width should really be measured on the control arm. I noticed on my Intrax shocks that they were approx 1mm wider and pulled in when I tightened the bottom mount bolt.
I will have to confirm whether the front is actually 70mm? or 75mm? as it is not likely it is actually 74mm.

These measurements are also from Center of bottom mounting bolt to the top mounting surface of the top hat mounts. Not including the actual cradles which attach to the body. For example the front cradle which also locates the front upper control arm.

Hopefully this can help people like MidnightTouaregV8 to confirm that they have the correct length struts as he said he had a problem with the rear ones he ordered.

 

Confirmation of wheel travel numbers for a 955 (2002) Porsche Cayenne.

Air suspension
Front 220mm
Rear 249mm

Steel suspension
Front 220mm
Rear 233mm

It appears our Touaregs have identical wheel travel.

 

 

Front lower control arm bushing information for 2007 Touareg V6 TDi. This is a facelift model for those in different countries where the model year is in switch over.

The information is taken from measurements of Polyurethane bushes from Problem Solving Bushings. PSB

Front lower control arm.
Front arm inner rear bushing:
OD 72.62mm
Width 60.40mm

Front arm inner front bushing:
OD 40.90mm
Width 60.40mm

Front arm outer bushing: (aka shock mounting bush)
OD 46.25mm
Width 74mm

 

Some good info here. This inspired me to make some suspension travel measurements when working on my rear suspension. I loosened all the bushings and with the strut removed measured 300mm of travel. taking into account 32" wheels hitting the wheel well, the usable travel is 255mm. I see you reported above 233mm for a 2002 Porsche Cayenne so we are close (I didnt have a strut in place to that probably accounts for the difference. As reported above, the rear strut has 157mm of stroke. There is a rather stout bump stop bushing that takes up ~90mm of that 157mm stroke so there is no way that the suspension has 233mm of travel as reported in the Porsche book. I calculate 99mm of suspension travel before you are on the bump stops I think that 233mm is the theoretical stroke if you were to install a damper with no spring or bump stop. It seems the easiest way to increase suspension travel to reduce the bump stop height. I'm trying to improve my articulation. I removed the swaybars which made a dramatic improvement in articulation and off road performance. I just trimmed 10mm off my bump stop which will give me 15mm more upward travel . I don't tow or carry heavy loads so I'm not concerned about loosing some overload capacity. I think 10mm is conservative and will likely trim this more.

 

I did some more measurements on the rear suspension. The damper has a stroke of 157, under the weight of the car it compresses 67mm of the available 157mm stroke, so 90mm of stroke remains but, the bump stop measures 90mm. So the rear strut is in contact with the bump stop the entire compression stroke! I am very surprised that the rising rate on the rear suspension is governed by a $2 piece of polyurethane. And it really isn't just a bump stop, it is active on all rear suspension compression, not just the last bit. Mountain bikes used to have polyurethane suspension springs, but that was abandoned years ago.

 

Bump...

 

I am sure you can reduce the bump stop / auxiliary spring length at the rear if you want to increase rear travel and articulation off road. However it will affect on road handling and potentially create some very undesirable affects and instability in hard cornering

 

Since I do not have sway bars, I avoid hard cornering . I have never thought of the touareg as a sports car. I think of it as a jeep, that has given up a little off road ability so that it is tolerable on the drive to the off road. I just posted on this on "Lets Talk Bump Stops"

 

Curious, if you can tell us how the FCS struts worked out? Also if you have some insight on the PRG 2 inch lift on the front. Just to confirm you didn't need for the back?

 

The original poster mentioned the fronts were 1" lower, and the rear was 1" higher and the springs had a different number of coils.
I'm not sure why you world even consider putting a FCS strut on you car when you can replace the shock with OE Sachs shocks for just $200 more all around. than the FCS.