Wheels, brakes, and coilovers - Pt. 5 Brake kit progress!

Wheels, brakes, and coilovers - Pt. 5 Brake kit progress!

Hello 2022!  It's been too long since the last update but it has been a wild year with covid things, house things, and day-job things.  I'm finally getting settled down and focusing on growing PdV again as I prepare to move into a new house with a much better workspace.  Today, I want to catch up on the brake rotor project.  I'll paste the relevant OKRs as we go but the entire updated list is at the bottom.

The brake rotor project is getting bigger and more real so a new Objective 4 has been added to the list.  It's pretty simple, copy Objective 2 (wheel product line) for a new brake rotor line.  I'm particularly excited about this project because of the uniqueness of the product.

The one massive problem I have not been able to overcome yet is getting the Wilwood calipers on the stock BMW MPerformance rotors.  The thickness of the BMW rotors and recommended rotor thickness from Wilwood do not align.  My dream of staged upgrades was dead, until I finally had a simple thought that honestly took way too long to have.  I might be able to include titanium brake pad shims to improve performance and adapt the Wilwood calipers to the thinner BMW rotors.  Eureka!

The math is as simple as it gets.

  1. Wilwood caliper is designed for a rotor width of 1.25 to 1.19" (31.75 - 30.226mm)
  2. BMW F30 rotor width from new to full worn is 30 to 28.4mm per Brembo drawings
  3. To fit the F30 rotor width into the Wilwood design "window" I need to bring the BMW minimum up to the Wilwood minimum by adding a total of (30.226 - 28.4) = 1.826mm.  Round that up to 2 and use a 1mm shim per brake pad.
  4. One last step is to double check its not too wide to assemble with the shims.  The caliper piston gap as shipped physically measures 65.77mm.
    1. 65.77 - 30mm (rotor) - 2x16.5mm (pads) = 2.77.  With two 1mm shims that leaves us with just enough space to install everything and clearances will open up as soon as you start bedding pads.  0.89mm (0.035") Ti sheet is also easy to get for a tiny bit more margin.

The same analysis is done on the rear and even more space is available while needing 1.5mm shims per brake pad to fit the OE rotor to the Wilwood caliper.

As far as I'm aware as of this writing, no one sells everything listed at this price point;

  • Full floating rotors and lightweight aluminum rotor hats
  • Radial mounted lightweight forged calipers
  • Calipers in 20-30 different colors from the factory as well as hard anodized
  • 6/4 piston forged calipers with optional dust boots
  • All of the above while retaining the rear parking brake
  • Titanium brake pad shims
  • Custom braided SS brake lines

Obj-4, KR1 - Develop front and rear full floating rotor kits with a target price under $2,500 per kit.

The work isn't done but enough of it is to say that I am going to achieve this target.  My next step is to get a rear knuckle on the CMM so I can design the caliper bracket.  That's it.

Obj-4, KR2 - Find a brake dyno facility and develop a test plan

I've reached out to a friend that used to work at Performance Friction.  I'm hoping to close this task out very soon.

Obj-4, KR3 - Design it to be upgradeable in stages.

I'm so happy this is going to be possible.  For roughly $2,000 a race ready brake package for all four corners will be available for the first time.  For another roughly $2,000 you can add all four full floating rotors.  That is less than a front only Stoptech STR60 kit and you'll have lower maintenance costs per season.

Here are some pictures for the giggles from a trip up to my day-job where I spent personal time in the inspection lab.

Manual inspection has its place...

f30 floating rotor hat inspection

CMM fun!  Hand measurements have gotten me by but now I've got the good data.

f30 rotor inspection

Playing with the laser marker

f30 rotor laser marking 

Rockwell hardness tester to ensure material specs were met..... they weren't :(

Just for record keeping, the entire list of project objectives is below.

  • Objective 1 - Develop the perfect wheel design (IMO) for my personal car, an Estoril Blue BMW F30
    • Key Result 1 - Square setup, 18x9 ET30, 3-piece, forged rim and wheel center, custom color combo incorporating some version of a dark bronze
      • Design basically done but I want to redesign to hide the hardware.  Also need to remodel it to fit 19" wheels for customer base.
    • KR2 - Achieve SAE J2530 certification (USA version of JWL VIA)
      • Everything is lined up with the testing facility.
    • KR3 - Create an FEA model that accurately represents tire loads and replicates SAE tests
      • All SAE related FEA is done in Solidworks.  Adding a little more to look at extreme braking and understanding wheel stiffness a little better.
      • Before committing to anything I will rerun FEA in Ansys to get a better understanding of bolt loads.
    • KR4 - Run my first laps ever on a road course on my own wheels.
  • Objective 2 - Parlay Objective 1 success into a new product line.
    • KR1 - Address supply chain issues for one off designs.
      • Still working through a few important issues such as finding someone with a vibratory polishing machine that is designed for wheels.  No existing wheel mfgs. want to do it for me as a service.
    • KR2 - Align designs and pricing with the PdV brand.
    • KR3 - Expand PdV product line with opportunities that are presented in the wheel development process.
      • This effort has helped kick off a badass brake kit and maybe drop spindles now that I have the knuckles CMM'd
      • Making these efforts public has created new contract work projects.
    • KR4 - Expand O1 wheel design to fit 19" and 20" wheels
      • Still to do but I'm abandoning 20's because no one really races 20's and that's where I want to take the brand.
    • KR5 - Develop 2nd design, a unique 5-spoke.
      • A design is done but will probably continue to be tweaked for a while.
  • Objective 3 - Copy Obj. 2 for custom coilovers
    • KR1 - Source cheap rebuildable coilovers, preferably buying only parts instead of full assemblies
      • Done.  The BC Racing kit has now been through my custom dyno evaluation with the help of 3dM Motorsport.
    • KR2 - Replace hydraulic components that are critical for performance with my own design.  Benchmark key performance attributes.
      • Some designs are done but may start with Ohlins/Bilstein guts or possibly adapt Penske regressive bits to go way nuts before making bespoke pistons.
    • KR3 - Develop business plan with two options.  1) Rebuild service for new or used kits with PdV components 2) Sell new complete coilover kits already built with PdV components.
      • I think selling just the sealed and tuned cartridge for existing BC customers to swap would be a killer deal...
  • Objective 4 - Copy Obj. 2 for custom brake rotors
    • KR1 - Develop front and rear full floating rotor kits.  Target price under $2,500 per kit.  Rear kit to retain parking brake.
      • Front prototypes have been delivered and inspected.  Rear rotor designs are done.  Pricing is not locked down but is currently $2,420 for the front.
      • Rear knuckle needed for CMM and bracket design.
    • KR2 - Find a brake dyno test facility and develop a test plan, possibly to meet TUV standards.
      • Will close this out when I discuss with my PFC buddy.
    • KR3 - Design the package so that its upgradable from stock brakes in stages.
      • Done!

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