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View Full Version : How to upgrade to 390mm rotors



UrS6
July 22nd, 2015, 17:40
I'm not making a case here for why you should upgrade to the larger rotors. It probably slightly improves the braking but could be hard to rationalize if you have to pay full price for the rotors. I just happened to get some 390mm rotors from a newer RS6 for very little money and figured i'd give it a shot. I contacted Unit20 for the parts as I know they make a kit and never got an response. Before you start, run something more than 1/2" thick between your wheel and caliper to ensure you have enough space with your wheels. My factory 5 spoke 19" wheels fit fine. I doubt 18" wheels will fit.

Here's what you need. My total cost with shipping (not including rotors which were $250 each shipped) was about $60:

2 pieces 1-1/4" X 1/2" X 1' flat bar from McMaster Carr http://www.mcmaster.com/#8910k933/=y5xpyv
4 Caliper Bolts from ECS Tuning http://www.ecstuning.com/ES1508991/
(http://www.ecstuning.com/ES1508991/)
Trace the existing caliper bracket--where it mates to the caliper--onto the bar and cut to length. I used a 4-1/2" cut off wheel. Shape the ends of the bar to fit the contour of the bracket if you want it to look nice. I used a grinder, followed by a belt sander, wire brush and then a buffing wheel. Clamp the bracket to the bar and, using a transfer punch, mark one hole of the bracket. Drill the hole on a drill press starting small and working up to the appropriate size. I forget my final size hole but I did it about .015 over to compensate for expansion. Bolt the bracket on to the bar and mark the other hole with the punch. Drill that hole. Chamfer the holes. I then assured there was no ridge with a belt sander. Finish the spacers as you wish to prevent corrosion. I just did paint but am working on another set that will be zinc coated and then finished with a black chromate process. Everything bolts up, torque the bolts to 62 lbs. and blue locktite it all.

hahnmgh63
July 23rd, 2015, 06:56
Nice job, take a few pics when you get the chance.

v8a6
July 25th, 2015, 02:09
Nice! Any pics?

If more RS6 390mm rotors are available, please PM me with the details, as I need a set.

Thanks!