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  • ACOQ 7a : 108 -> 112

    Goal : go from 4x108 to 5x112 bolt pattern on a 1990/91 B3 Coupe quattro (7A-engine)

    I've done some research..., and pretty sure of :
    - the 7A and 3B (S2) share the same wheel-bearing housing :
    . - front (left : 895407257M / right : 895407258M)
    . - rear (left : 893505435B / right : 893505436B)
    - the front calipers are the same (left : 895615123[A] / right : 895615124[A])
    - the front discs have the same dimensions (276X25)
    - the rear calipers are the same (left : 853615423A[X] / right : 853615424A[X])
    - the rear discs have the same dimensions (245x10)
    ( obviously the brake disks has to be replaced but they're relatively low-cost and easy to get. )
    - wheel-base 7A/3B : 2549mm
    - front-track-width 7A/3B : 1455mm
    - rear-track-width 7A/3B : 1437mm
    - rim-offset 7A/3B : ET = 37mm
    - it also seems like number of teeths on drive-shafts (front=38, rear=33) is the same (not sure about rear ABY)

    Given the above is correct I feel pretty sure S2 (3B) hubs would be the simplest solution, straight bolt-on to the 7A, but as they are out of production they are also difficult to find, and those I've found has a price-tag far beyond my wallet....

    I've googled a lot for other solutions and found some useful info, but not enough...
    some mention hubs from URS4/6 (UFO), A4 (B5) both Quattro and non-quattro..., but none giving exact measurements/dimensions (needed for machining).

    The most useful I've found is pictures (at vagparts.2am.fi) of the rear hub for both 7A/3B :

    7A - rear


    3B - rear


    also, I've got a pair of front-hubs from (propably) an UR-UFO :
    ( sorry, not able to read the part # from them .... )



    so,
    I'm looking for :
    - S2 (3B/ABY) front hub dimensions, like on above img's
    - ( 7A front hub dimensions, like on above img's )
    - front hub alternative(s), preferably with dim's as above.
    - rear hub alternative(s), preferably with dim's as above.


    anyone ?

  • #2
    I have a 3B S2 and a 7A 90 quattro and a late 2.8 coupe quattro, I can confirm that the hub parts (bearing carriers) front and rear are the same and interchangable between the 7A and 3B and V6 cars some have slightly larger strutt bolt holes (later cars such as V6 and ABY).

    Basically its all the same except for the actual hubs as you say 5 bolt v 4 bolt, the only other thing to note is the front 4 bolt hubs on the 90 quattros are 4mm thinner than the 4 bolt hubs on the coupe thats how the front wheelbase differs between the 2, hat height on the front discs is different between the 90 and coupe quattros with the 4 bolt hubs they use different discs.

    Source for rear hubs try the B5 A4 or for fronts the C5 100/A6.

    There is a thread on here somewhere with dimensions.

    Comment


    • #3
      Had a look at B5 A4 ( 8D0 407 615 B [D, E] ) for the rear and everything seems to match except for the height, result will be wrong offset

      possible same problem with C5 100/A6 (4A0 407 615 B [D] ) for the front but as I don't have the dim for the original it's impossible to know....

      anyone got the dimensions for the S2 front hub ?

      Comment


      • #4
        Tons of info written on many audi forums.
        For best result you need 2x4A0501653D + 2x8D0501653B

        Comment


        • #5
          B4 V6 front on the left and little bit machined C4 Quattro (non S) rear 4A0501653D on the right.

          1989 Audi 80 Quattro
          1994 Audi 80 Quattro Competition

          Comment


          • #6
            Thnx for feedback !

            the 4A0501653D seems to be hard to get (at reasonable price)

            I've got a couple of hubs like the one on pic #3 in 1's post. Hope to be able to machine them like S2's and keep correct offset.
            But to do that I need the dim of an S2 front hub, or 7A, or mby B4 V6 ?, hasn't checked if its "compatible".
            The measure of most interest is distance measured as ~70,5mm at pic #3 above

            Comment


            • #7
              If C4 quattro hubs are hard to get for you, good luck with sourcing genuine S2 hubs )

              Comment


              • #8
                Are there any hubs for B4 V6 82mm rear axle or S2 avant/sedan hubs only?
                1989 Audi 80 Quattro
                1994 Audi 80 Quattro Competition

                Comment


                • #9
                  Different front hubs can be applied to CV and hubcarrier, same as discussed above. But all of them have larger offset, which will cause brake disk height and wheel offset issues. UrS6 hub 441501653B is the best for that.
                  No simple bolt-on solution except S2 genuine hubs but UrS6 hub with some customization can be a neat solution because many of us usually do rear brake upgrade and use OEM audi wheels with big ET.

                  Comment


                  • #10
                    Originally posted by pfi View Post
                    I've got a couple of hubs like the one on pic #3 in 1's post. Hope to be able to machine them like S2's and keep correct offset.
                    You can use UFO hub. It is 1.5mm less offset than S2/B4 one. You can live with this or compensate this difference with proper thickness washer in hubcarrier.
                    With UFO hub you will also face an issue using audis brake discs central hole. The hub has slightly different hump for that.

                    But anyway, all is doable with some tricks, and it was done many times.

                    If you just had a chance to hold all that stuff in hands you would forget about everything except 4A0501653D cause they fit fckn perfect.



                    Comment


                    • #11
                      1.5 mm can be shimmed as You say so that's ok, still not sure if mine are UFO's......,
                      mine are machined to dia ~130,3mm (ref C pic #3) to allow for a standard disc central hole.
                      Not showed on pic #3 : the "hump" for centering the disk is ~68mm and the rim centering is ~57mm

                      If 4A0501653D is a full match it would be preferable but is rare here, and expensive.
                      (4A0 501 653D is cheap and easy to get)

                      still would be nice to have some measurements of original S2 and 4A0501653D .....
                      Last edited by pfi; 24 May 2017, 19:14.

                      Comment


                      • #12
                        Originally posted by M2ki View Post
                        Are there any hubs for B4 V6 82mm rear axle or S2 avant/sedan hubs only?
                        To my knowledge the rear of coupe S2 is all 75mm, B3 and B4

                        Comment


                        • #13
                          Originally posted by pfi View Post
                          If 4A0501653D is a full match it would be preferable but is rare here, and expensive.
                          (4A0 501 653D is cheap and easy to get)

                          still would be nice to have some measurements of original S2 and 4A0501653D .....
                          You are saying 653D is rare and expensive and then easy to get and cheap?
                          Lots of C4 quattros for parts here, I should start hoarding rear hubs together

                          Whats measurements do you need from 653D? After machining it has same measurements as original S2 front.


                          Originally posted by pfi View Post
                          To my knowledge the rear of coupe S2 is all 75mm, B3 and B4
                          You are correct, also all coupes are B3, typ89, the so called "B4 coupe" is just exterior facelift.
                          I was talking about B4 V6 sedan/avant rear axle, they have 82mm bearing housings, like S2 sedan/avant.
                          1989 Audi 80 Quattro
                          1994 Audi 80 Quattro Competition

                          Comment


                          • #14
                            Machined 4A0501653D

                            1989 Audi 80 Quattro
                            1994 Audi 80 Quattro Competition

                            Comment


                            • #15
                              Originally posted by M2ki View Post
                              You are saying 653D is rare and expensive and then easy to get and cheap?.
                              Yeah, little bit quick on copy/paste (doesn't remember what part# I was to paste....) .... :0

                              Originally posted by M2ki View Post
                              Lots of C4 quattros for parts here, I should start hoarding rear hubs together
                              U might got a source for makin' some extra cash

                              Originally posted by M2ki View Post
                              Whats measurements do you need from 653D? After machining it has same measurements as original S2 front.
                              Thanks a lot for picture with measurements !!!!!

                              The ("internal" ?) hub offset is calculated from (pic #3) ref A - ref B
                              For my (pic #3, propably UFO) hub, this gives : 70,5 - 35,5 = 35,0 mm
                              For u'r 4A0501653D it's : 72 - 35 = 37,0 mm
                              So, my hubs needs a 2,0 mm shim beetween the bearing and hub to match S2 offset

                              I also have to machine off (pic #3 ref F/G) so the area with 80mm dia has a height of (minimum) 7 mm ?

                              Originally posted by M2ki View Post
                              You are correct, also all coupes are B3, typ89, the so called "B4 coupe" is just exterior facelift.
                              That's exactly my understanding (and, the B4 facelift started with B3 coupe/cab "B4" front wings.......)

                              Comment

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