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Brake disc thickness on RV9a

RicoB

Well Known Member
Patron
I got a question, since I can make it to my hangar for couple of days would anyone know the thickness of the standard RV9a disk rotor?
The reason I ask is because I got my hands on a set of grove calipers (2 pistons) model number 31-2M I was told that it requires a 1/4” disk. I currently have Cleveland/Parker 30-9 but I can’t find any info about what disk thickness it uses 1/4” or 0.182”?
I was hoping to be able to just drop the grove calipers in.
Thanks
 
This might help, maybe not!

My RV7A wheels, tires and brakes:
Cleveland wheel 5.00-5 PN: 40-78B
Brake disk PN: 164-17
Min. thickness 0.167” / 4.242 mm
Rapco brake disk: RA164-01700
Brake puck o-ring AN6227B-23
Brake Pads: Repco 06-00651
Tire: AirHawk 5.00-5 6ply
Tube: Aero Classic Leakguard

You should be able to find the disk thickness on Cleveland’s site.
 
9A disk thickness

I've helped put new tires on our -9A and the brake disks are definitely not 1/4" thick, they are thinner, even accounting for wear.
 
You can easily “upgrade” the standard discs to the thicker ones. Off hand I don’t have the part numbers in front of me but I did it on my -9A. My concerns were overheating and warping the standard discs. Somewhere on the forum is a thread or two that includes part numbers if you are so inclined.
 
You can easily “upgrade” the standard discs to the thicker ones. Off hand I don’t have the part numbers in front of me but I did it on my -9A. My concerns were overheating and warping the standard discs. Somewhere on the forum is a thread or two that includes part numbers if you are so inclined.

I did the Matco high energy upgrade on my 9A a couple of years ago. I believe they are 0.17" minimum thickness rather than 0.13", but don't quote me. I know the OP has different brakes. This is the best single upgrade I've done on the plane, I went from having frequent overheating to the point of having to add lots of power to taxi after a short stop landing, to having plenty of brake and no overheating whatsoever.
 
Last edited:
Yeah I will do the upgrade for sure. I am getting the full grove brake kit from a friend ( calipers, masters, parking valve, ss hoses, except the disks) the system was using DOT4 brake fluid. I will be changing all the O rings over to 5606 Compatible. Not sure about the hoses if I can clean them off and re-use it . At the moment I wasn’t planning on changing it all over yet. I just wanted to install the caliper but seems that I will have to get the thicker disk.
 
Yeah I will do the upgrade for sure. I am getting the full grove brake kit from a friend ( calipers, masters, parking valve, ss hoses, except the disks) the system was using DOT4 brake fluid. I will be changing all the O rings over to 5606 Compatible. Not sure about the hoses if I can clean them off and re-use it . At the moment I wasn’t planning on changing it all over yet. I just wanted to install the caliper but seems that I will have to get the thicker disk.

Just a reminder to consider the effects of additional thickness of the disc. Like caliper spread (add spacers), clearance from disc to pants bracket, and trimming the axle nut. SCARD did a good post about this back pre 2017. Good luck finding it.
 
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