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  • urs4 geometry settings

    It is time to change a fiew steering parts and i need to get the geometry done.
    My problem is that with 225 tires after 3 time geometry settings my car tends to change its direction when i get onto tram lines or if the road is bumpy.
    After i bought the car i changed almost everithing on the steering/suspension and i did the geometry "at eye".The trip from my garrage to the geometry garrage was the nicest in my life.I could let steering wheel from my hand on a tram line.After geometry it was exactly like my 100 c4.
    What should be modifyed from stock settings to avoid"copying the road" sinthoms?

  • #2
    Originally posted by pasbogdan View Post
    My problem is that with 225 tires after 3 time geometry settings my car tends to change its direction when i get onto tram lines or if the road is bumpy.
    You might want to consider:

    1. Adding more pre-load into the steering rack (don't add too much pre-load or the steering wheel will not self-centre)



    2. Replacing the steering damper. The PN is 4A0425021. DIY is here:
    http://s-cars.org/postnuke/downloads...mper%20R&R.pdf

    RS2'd 93 UrS4 5 spd sedan
    94 UrS4 V8 6 spd manual avant

    Comment


    • #3
      Thx.The damper is in good shape,tried other,nothing changed.Rack has no play.Only thing is that servotronic seems to work in "city"mode all the time.It is the easyest steering wheel i ever turned.But why with "eye" geometry settings it was great?I asked a friend of mine owner of c3 100's,s4 c4 to try the car with "eye"settings and he also was shocked about how the car handeled.I know a third person owner of s4 who acused the same problem.Something is there.Maybe lot of peoples are not sensing it but it is there.Only a geometry guru should know..
      If you saw marks in asphalt made by big truks on roads where is very hot(they are like rails if you know what i mean) you will understand my problems.Car wants left/right...
      Do not imagine it is incontrolable,but you have to corect to mentain track.Where road is smooth you can let steering wheel free at very high speed and it goes like dream..

      Comment


      • #4
        OE UrS4/S6 alignment specs

        Sorry I don't understand what you mean by " 'eye' geometry settings".

        Toe in/toe out can play a big part in tramlining. Too much toe out = darty = tramlining.

        Also if there is *any* play in the rear control arms, the rear wheels will seem to steer the car.

        Here is the stock OE alignment specs:

        FRONT:
        Camber -1�15' to -0�15' (where the � = degrees)
        Caster +0�15' to +1�35'
        Toe +0�03' to +0�10'
        Turning Angle Diff -1�40' to -0�40'

        Cross Camber -0�30' to +0�30'
        Cross Caster -1�00' to +1�00'
        Total Toe +0�05' to +0�20'

        REAR:
        Camber -0�30' to +0�00'
        Toe +0�00' to +0�10'
        Total Toe +0�00' to +0�20'

        Hope that helps.
        RS2'd 93 UrS4 5 spd sedan
        94 UrS4 V8 6 spd manual avant

        Comment


        • #5
          "eye" means after i changed everything i adsusted geometry without any tools using only my eyes to put it straight.
          Thx for specs.I will print them and see if they are the same as in geometry garage tool database.
          Some settings near margins of specs should help,but i do not know how to do them to solve my problem

          Regards

          Comment


          • #6
            Sorry but even with the best "eyes" you can't do the toe in/toe out accurately enough to avoid tramlining. You need to get your car on a proper 4 wheel alignment machine and have the technician confirm and/or adjust your settings. Note: If the rear control arms are siezed he will either hate you or charge you a lot of money (or both) to get them to move so he can do the 4 wheel alignment. (BTDT).
            RS2'd 93 UrS4 5 spd sedan
            94 UrS4 V8 6 spd manual avant

            Comment


            • #7
              And by rear control arm, I should have called it the track control arm, as shown as Item 1 in this diagram (parts best bought from the dealer - not Chinese junk)

              RS2'd 93 UrS4 5 spd sedan
              94 UrS4 V8 6 spd manual avant

              Comment


              • #8
                Originally posted by UrS4boy View Post
                Sorry but even with the best "eyes" you can't do the toe in/toe out accurately enough to avoid tramlining. You need to get your car on a proper 4 wheel alignment machine and have the technician confirm and/or adjust your settings. Note: If the rear control arms are siezed he will either hate you or charge you a lot of money (or both) to get them to move so he can do the 4 wheel alignment. (BTDT).
                "tramlining" is the english term for my situation?
                I know "eye" will never get you right but i was shocked,and that why i called a friend to ceck the cars feeling.Even when at full turn of wheel and 1 st gear the car did not hooped.I know i did not made good settings,but i did something i would like to approach now...
                I aligned the car several times in several places.It is just not enough..It is not like other cars.Like c6 a6 for example.I know a6 has multi arm suspension and i would understand my car has not.But i drived my car once with some strange settings and it was great and i want them again...

                Do you have any link to some profesionists in geometry settings?I will also need some info for my cq settings if i will be ebble to participate in rallying.

                Thank you,

                Comment


                • #9
                  Originally posted by pasbogdan View Post
                  "tramlining" is the english term for my situation?
                  Yes, as in the car seems to have a mind of its own steering-wise, following grooves in the pavement from trucks, etc. just like it was a tram running on the steel rails of a tram line.

                  RS2'd 93 UrS4 5 spd sedan
                  94 UrS4 V8 6 spd manual avant

                  Comment


                  • #10
                    http://homepage.ntlworld.com/robert....tramlining.pdf
                    First result on google search.If you know what to look for
                    Will investigate more and post a result.

                    Regards,
                    Edit:
                    So caster angle may not be ok.On our cars this can be adjusted to + caster by getting the stabiliser bar to front.But seems not possible.
                    Or the inferior arm much more to front on the stab.bar.
                    The stabilisation bar shoul be machined a little to let the bush and plate to go forward.Or from the upper part of the shock but this requires custom plate with caster adjusting option.
                    Last edited by pasbogdan; 10 March 2012, 16:38.

                    Comment


                    • #11
                      You can do a lot to eliminate tramlining through the suggestions that I gave previously (e.g. toe in/out, rack preload, new steering damper, etc.) as well as tire air pressure, tire width, sidewall stiffness, etc. Caster is normally not adjustable with the C4. You can try to make it even by making sure that the subframe is square to the centerline of the car.

                      If you still wanted to adjust caster (and camber), you could buy custom top plates from shops such as 2Bennett Racing. http://2bennett.com/body_camber.plates.html. Just remember, like the Mercedes cars that have a LOT of caster (making them very stable on the Autobahn), more caster = more camber changes when you turn the wheel.

                      Last edited by UrS4boy; 10 March 2012, 17:14.
                      RS2'd 93 UrS4 5 spd sedan
                      94 UrS4 V8 6 spd manual avant

                      Comment


                      • #12
                        Generally increased castor generates welcome dynamic camber changes though, counteracting the positive camber gain of a mcpherson set-up

                        Don't forget that with a load of new suspension parts, particularly bushes far more of the "road" is felt through the steering as less is absorbed by slack in the suspension. Dave's suggestions about tweaking the rack pre-load are good, interestingly I have found no change from fitting a brand new steering damper over not having one fitted at all. The tyre scrub radius and tyre width will also worsen the "tramlining" effect.
                        Panthero Coupé quattro 20vt
                        Indigo ABY coupé
                        Imola B6 S4 Avant

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                        • #13
                          JFYI

                          http://www.theprojectpad.com/viewtopic.php?f=27&t=225

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                          • #14
                            i have done a lot of things and adjusted so many things on my car.it seems the car is inherited
                            tramlining.especially when the car was running through ybhe uneven
                            road.i need to grab the wheel pretty tight.wheel alignment within the spec too.
                            trued a couple set of the brand new tyres still didnt help.new rebuilt steering rack,suspension,steering
                            dampener etc.adjust a preload nut helps a bit but not significantly improved.i would
                            say it 's only i hate in my car.i dont know if too much compression/rebound on shock abs caused this.
                            i have driven one urs4 last week.the car didnt have servotronic.that car is much better handling
                            than mine.
                            one of a few I5 from Asia.

                            Comment


                            • #15
                              I think a lot of the "trammeling" could come from wheel offset. These cars were designed to run approximately 30 to 45mm of wheel offset. The use of wheel spacers, wider tires & wheels changes that figure in an adverse manner.
                              Chris
                              "Nulla tenaci invia est via"

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