Do 90 20V front springs fit 55mm rear strut?

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  • TekTac
    S2Forum Tinkerer
    • Jan 2020
    • 6
    • Country: Finland

    #1

    Do 90 20V front springs fit 55mm rear strut?

    Hi all!

    I think I need some help from someone with knowledge of the stock suspension setup of small chassis Audis.


    So I have a B3 Audi 90 20V and my suspension setup consists of:

    FRONT: Stock strut (50mm?), Bilstein B4 shocks, "Supersport" lowering springs (they are old and from 55mm struts)

    REAR: 55mm strut, "Supersport" shocks & lowering springs


    I've driven two winters with 205/45R17 Falkens and they are absolut rubbish. I'm going to fit 205/50R17 for next winter, which are basically the biggest tires that fit rolling in there. I need to get the rear end of the car higher so the tires don't rub the fenders like crazy.

    SO I have a set of new stock KYB front springs for 90 20V. Does anyone know is it possible to fit them to my current rear struts? So basically I'm asking is there major differences other than spring rates between the front and rear springs (OR struts). Also there is the difference that the new springs are for the 50mm stock strut. That shouldn't be an issue..?

    Yeah I know, pretty unusual suspension questions, but I hope somebody has played with them enough to shed some light
    1989 90 quattro NM
  • Mikes2
    S2Forum Extremist
    • Jul 2003
    • 1704
    • Country: Scotland

    #2
    Front and rear springs have a different number of coils. Might I suggest that 205/50 17 tyres are completely the wrong size for a B3 and if you fix that, you won't need to bother with spring changes. For winter use you should have 15" wheels
    Mike

    http://www.s2-audi.co.uk

    Comment

    • Lago Blue
      S2Forum Maniac
      • Jul 2009
      • 843
      • Country: Canada

      #3
      Tek,

      I concur with Mike's advice above. This suggests one resist the temptation to use cartoonish low-profile tires (consider that F1 cars seem to manage pretty well without such), especially in the winter, the tire footprint (contact-patch) is wider and more abrupt than stock sizes making loss of traction easier in poorer weather. Further, speed-rated (greater than or equal to V) tires cannot be soft enough for decent grip even in perfectly clear winter weather. Tall and skinny (65 or at least 60 series) like what you see on a functional rally car works much better, cheaper and the best in the world may be your very own street winter Hakka's. Any 17's will no doubt be alloy and much more easily cracked than steel if you do slide into something solid, all air then escapes; and it may be a long cool walk home.

      The wheel offset you are considering may also be wrong if those tires rub.

      To gauge the differences between front and rear spring rate, note that the front axle carries about twice as much as the rear. It may be that without other changes, adding that much extra stiffness to the rear axle (and raising the rear end) may make the car very easy to spin, as in too easy.

      You are correct in that the Strut OD makes no difference to spring fitment.

      Comment

      • psiconauta911
        S2Forum Maniac
        • Oct 2007
        • 613
        • Country: Portugal

        #4
        Agree with the above except the 90 20V as a 50:50 weight distribution so I "guess" the springs might be not so diferent.

        Comment

        • TekTac
          S2Forum Tinkerer
          • Jan 2020
          • 6
          • Country: Finland

          #5
          Yeah I kind of have it the wrong way now. ​​​ My summer tires are the original 15x6 ET37 alloys with 195/65 tires. And the winter steelies are 17x7.5 ET29.
          I just love the fitment with those 17's. In my opinion 50 isn't that low profile. Okay, maybe it's on the edge. For a B3

          I think I'm going to buy 195/60 friction tires for the 15's nevertheless. I got some experience now with the 17's and I can tell you they act pretty dangerously at winter. Especially driving terrible Finnish roads.The 45 profile Falkens are hard AF. Also if you let your hands off the wheel for 2 seconds, the car will - depending on the road surface - dart at random direction. And last but not least, they rub the rear fenders if there is somebody else in the car with me.
          Btw I test fitted the winter tires on the front this morning just to have a look and I'm not even sure anymore would a 50 profile tire be able to turn without issues.

          Agree with the above except the 90 20V as a 50:50 weight distribution so I "guess" the springs might be not so diferent.
          My car has a 50/50 weight ratio?? Doesn't feel even close to that..

          Anyway thanks for your input with the springs gentlemen
          1989 90 quattro NM

          Comment

          • Lago Blue
            S2Forum Maniac
            • Jul 2009
            • 843
            • Country: Canada

            #6
            Psiconauta,

            I'm not convinced that the 20v sedan has a 50/50 weight distribution either, as it is either 50 or 60 kgs lighter than the Coupe, and that would mean:

            a) The Coupe is tail heavy (because the front half of each is pretty much identical), yes I know the hatch is heavy but;
            b) The rear Coupe springs would have to be heavier than the fronts (that and its' front to rear weight distribution is listed as 58 / 42); and
            c) There would have to be something substantial, aft of the rear axle to counteract the 5 cylinder steel block ahead of the front axle; which (using the front axle as a fulcrum) also tends to lift the rear axle due to that engine overhang. I just don't see much back there that could do that.

            However perhaps you can convince me otherwise?

            Audiurquattrodiagram.jpg?resize=768%2C433&ssl=1.jpg

            Comment

            • _ShurikeN
              S2Forum Maniac
              • Mar 2010
              • 733
              • Country: Russian Federation

              #7
              Front springs technically fit typ89 quattro rear end, not sure you will be satisfied with ride height and stiffness.
              Last edited by _ShurikeN; 4 August 2023, 12:13.

              Comment

              • psiconauta911
                S2Forum Maniac
                • Oct 2007
                • 613
                • Country: Portugal

                #8
                Originally posted by Lago Blue
                Psiconauta,

                I'm not convinced that the 20v sedan has a 50/50 weight distribution either, as it is either 50 or 60 kgs lighter than the Coupe, and that would mean:

                a) The Coupe is tail heavy (because the front half of each is pretty much identical), yes I know the hatch is heavy but;
                b) The rear Coupe springs would have to be heavier than the fronts (that and its' front to rear weight distribution is listed as 58 / 42); and
                c) There would have to be something substantial, aft of the rear axle to counteract the 5 cylinder steel block ahead of the front axle; which (using the front axle as a fulcrum) also tends to lift the rear axle due to that engine overhang. I just don't see much back there that could do that.

                However perhaps you can convince me otherwise?

                Audiurquattrodiagram.jpg?resize=768%2C433&ssl=1.jpg
                I´m probably wrong, got it from the web!

                Comment

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