0utlier

1990 s4 auto

I put 21mm spacers on the rear so the wheels don't get so swallowed up by the wheel wells. This looks much better and will suffice until I get around to putting larger wheels on the car.

However, immediately after installing the spacers the RDK is telling me the rear tires are low . I put 50psi in the rears and it still says the tires are low. This wasn't a problem prior to the spacers, so I'm guessing the spacers are blocking a sensor? Does anyone have experience with this situation?

I know I can bypass the RDK, but I hate to do it unless that is the only alternative. Thank you.

Scott G.

Mrmerlin

Hi spacing the wheels out has moved the sensors away from the pick up coils, if you can , try to move the pick up further out to match the wheels and let the air out of your tires 50 psi is waaay to much

0utlier

I didn't look very carefully for any pickup coils. Are those on the wheels or elsewhere? And they can be moved? I just want to get an idea of what I'm looking for.

I put 50 psi for testing purposes just to make sure. I wouldn't run the car with 50 psi. Thanks for looking out for me though.

Vilhuer

PET is little confucing in this matter.

ROW '89 GT had M393 = Club Sport wheels including 17mm spacers and M482 = RDK as standand. '90-91 S4 had RDK yet spacers are not listed for it. Both use same bracket part number for RDK sensor. So either same mounting position works for 0-17mm range or there are in fact more than one bracket type for these two different option combinations.

In any case 21mm moves to area which is not what factory was using. This means custom mounting point is needed to make it ideal.

Vilhuer

Oops, I forgot there are three different rear wheels which were used with RDK.

8x16 ET 52.3 Flat Disc
9x16 ET 60 Club Sport
9x16 ET 52.3 Design 90

All those can have different depth mounting points for sensors. This means one bracket is ok as long as 17mm spacers are always used with those wheels they were intented to be used with. This also means 21mm require 21mm change into hub mounted sensor position to make system work again instead of 4mm.

0utlier

So I guess I'm looking at disabling the RDK then. What is commonly used to jumper pins 13 to 2 on the RDK?

Mrmerlin

Hi if you remove the rear wheel you should find the sensors attached to the rear wheel hub see if they can be moved outwards without hitting the disc this should solve the RDK problem

worf928

FYI: There are also 17" Cup wheels with RDK from '93 GTSs.