Wheels, brakes, and coilovers - Pt.1 Project Planning

Preface

So I'm developing wheels, brake components, and shocks but doing it the PdV way, which is to say I design, engineer, source, assemble, and ship.  There is no PdV machine shop, no CNC coding in house, no anodizing baths.  I rely on trusted manufacturers from my history in the professional racing market as much as possible to ensure quality whenever possible.

In the case of the wheels, they will not be 100% Made in the USA.  Mostly due to US manufacturers simply costing so much just for the raw material and often requiring minimum order quantities of 50 or more.  A barrier to entry that makes no sense for a one off first prototype and I will never stock and machine in-house.  So if this turns into a significant product line one day and the competitors or trolls don't like what I have to say you can reference this blog and know the truth, I don't care and the product speaks for itself.  So what if the raw material comes from somewhere else in the world when I can send samples off to a lab to periodically verify material properties?  Perhaps there will come a time when I can transition from foreign suppliers and be able to afford 50+ wheels per order.  One can dream but if you search your favorite wheel supplier followed by "bill of lading" you may be surprised at what you find they're ordering.

With that said, as much as possible will be made in the USA which will inevitably mean more design work on my part, higher (and sometimes redundant) expenses, longer lead times, etc.  This whole project is really a tale of two parts, the wheel rim and the wheel center.  The wheel rim requires little engineering and could be from an Asian supplier but I've found a Californian spun forged supplier that seems to make a great product, in a lot of sizes and styles, and has no minimum quantity with reasonable pricing.  The wheel center is a different story I'm going to cover in more detail.

The Plan

With any worthwhile project of some complexity, a plan is needed.  A list of objectives and key results (random book suggestion) will kick off a series of efforts in market research, design, costing, etc.  I'm not going so far as to develop a Gantt chart but writing some things down is certainly necessary.  This blog is part of that effort.

  • 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
    • KR2 - Achieve SAE J2530 certification (USA version of JWL VIA)
    • KR3 - Create an FEA model that accurately represents tire loads and replicates SAE tests
    • 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.
    • KR2 - Align designs and pricing with the PdV brand.
    • KR3 - Expand PdV product line with opportunities that are presented in the wheel development process.
    • KR4 - Expand O1 wheel design to fit 19" and 20" wheels
    • KR5 - Develop 2nd design, a unique 5-spoke.
  • Objective 3 - Copy Obj. 1 & 2 for custom coilovers
    • KR1 - Source cheap rebuildable coilovers, preferably buying only parts instead of full assemblies
    • KR2 - Replace hydraulic components that are critical for performance with my own design.  Benchmark key performance attributes.
    • 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

The PdV brand aligns with my personal feelings toward performance car modifications.  Generally, they should be highly engineered for performance and at a quality level I expect when shipping to a professional race team.  So an expansion of Objective 1 above would be to design the lightest possible wheel for a given design to pass SAE certification with UTQG 200 tread wear tires on a full weight F30.  Lower quality wheels may pass VIA or SAE testing but do so with 400+ tread wear tires.  The higher wear rating usually means stiffer sidewalls which distribute loads better into the wheel and are therefore easier to pass the tests.  I hope my wheels are chosen by serious racers and so I need to cover my ass.  Full weight, 200 tread wear.

Status as of 5/24/2020

In the next post I'm going to get into the actual wheel design and supply chain.  For now, I can share two wheel center designs.  I feel like some added detail and complexity is needed for PdV-01 based on a few other designs I've seen lately and really liked.  The back face is nearly locked in with exception for some minor tweaks from FEA so making a template of the back face to confirm fitment will be the next step.  I'm not yet a big fan of PdV-02 and if its my creation I better be, so we'll see how I can improve that.

PdV-01

PdV-02

Coilovers

Real simple.  I settled on BC Racing.  They have pretty good quality structural parts, they're completely rebuildable, inexpensive, fairly popular already, and they sell components right on their website so I can buy just what I need instead of the whole kit.  I've started reverse engineering a set and designing some of the important hydraulic bits.  Below is a preliminary layout for a rear S60R.  A few length changes and baddabingbaddaboom I'll have a rear F30.

The first issue I'm tackling is the bleed adjuster.  I never ever want a simultaneous compression and rebound adjuster like BC has.  I'd rather have a true single adjustable damper and rebuild if necessary until I'm happy.  So I'm going to be inserting a check valve in my own needle jet assembly (next pic below).  A new needle design to mate with this part will be next on the agenda that will improve the range and linearity of bleed adjustment.

In addition to this I have a few sizing tweaks to make to a lower friction floating piston as well as a high flow and double digressive piston design I've already developed so they'll drop right on to the BC shafts and bodies.

For the lower body caps that come with rubber bushings like the S60R, I'm going to press that out and press in a spherical bearing assembly to match the upper mounts and improve damping hysteresis/response.

Longer term, I'd like to swap out their oversized 18mm rods and shaft bearings to reduce friction and rod force.  Perhaps add a compression adjustable piggyback can.  We'll see how popular this becomes which I know will be highly dependent on my tuning but the target is to be better than KW V2s for less $$$.


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