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Originally Posted by a5m
Yea aren't the infamous E88's known for bending? Maybe they're generally beat on more compared to other wheels. Perhaps the multi-piece design's purpose is to make em serviceable.
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Quote:
Originally Posted by jmeenach
I've heard it's common(ish) to bend E88 barrels. No personal experience, though. One of the reasons I didn't buy them. The lead time, cost, and repair combined made me decide it was easier to pay a discounted price to replace a bent Apex.
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E88s are motorsport wheels designed with minimum weight as the priority. Because of that, the barrel is intentionally lighter and structurally weaker than a typical street wheel. It is considered a consumable component, especially in high-load racing environments.
Since they are three-piece wheels, it is usually more cost-effective to rebuild or replace individual components (typically the barrel or lips) instead of buying an entirely new set of forged wheels.
For street use, the E88’s design philosophy carried over into the RT88. The RT88 keeps a similar face but uses a much heavier and stronger BBS LM-style barrel. This adds durability for daily driving, though it does sacrifice some of the weight savings.
Quote:
Originally Posted by a5m
Not sure what the argument is here. Never claimed to be an expert, just stating facts and curious on how various forged wheel manufacturing processes impact their ability to withstand abuse.
Speaking of which, can't wait to put my TE's on.
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Quote:
Originally Posted by M3SQRD
Very simplistic view of how forged wheels are made. The weakest part of any forged wheel is formed the same way. You don’t machine “carve” the barrel and the tire seat/foot on the wheel. Just give Forgeline a call who makes wheels for almost all professional race series.
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You're correct that most forged wheels, even from top-tier brands like Rays, BBS, or Forgeline, typically use a similar barrel-forming process. Generally, manufacturers spin-form the barrel rather than machining it from solid aluminum. This spinning process aligns and elongates the aluminum’s grain structure around the rim, significantly improving strength and fatigue resistance.
For context, my background includes extensive experience in manufacturing carbon fiber components, as well as aftermarket wheels including flow-formed and multi-piece forged wheels. Our wheel manufacturing processes were similar to Enkei's MAT approach, but our designs and structural tests were conducted entirely in-house using specialized software.
When comparing wheel manufacturers, I'll highlight two well-known OEM suppliers: Rays (Volk Racing) and Enkei.
Rays / Volk Racing – Fully Forged Process
Most forged wheel manufacturers, including Rays, start with similar high-quality aluminum billets (typically 6061 alloy). Rays sets itself apart through their specialized forging process:
- Billet Heating
Billets are heated to over 500°C, allowing uniform shaping without introducing unwanted stress.
- Multi-Stage Mold Form Forging
Heated billets undergo proprietary mold forging under extreme pressure (up to 5 tons per square centimeter). This precisely aligns grain structure with the final wheel shape, enhancing strength and durability.
- Shuttle-Type Die Forging (Spokes and Hub)
Rays employs specialized dies pressing from multiple directions to form hollow and U-shaped cross-sections, reducing weight while maintaining structural integrity.
- Barrel Spinning
The rim section is spun while still heated, further aligning grain flow to improve fatigue resistance and strength.
- Machining, Heat Treatment, and Finishing
After forging, wheels undergo precision machining, heat treatment (quenching and tempering), shot peening, and corrosion-resistant coatings.
- Rigorous Quality Control
Every wheel receives thorough inspections using eddy-current and X-ray testing, exceeding standard industry requirements.
In short, Rays' extensive forging and testing processes produce wheels we consider the best (subjectively) because they are light, strong, and durable... and for those reasons make great track wheels.
Enkei – MAT (Most Advanced Technology)
Enkei uses a hybrid approach combining casting and rim spinning known as MAT:
- Casting
Molten aluminum is initially poured into molds to create the basic wheel shape.
- Rim Spinning (MAT)
Only the rim area of the cast wheel is spun and rolled afterward. This strengthens the grain structure specifically in the rim, providing some forged-like benefits without applying it throughout the entire wheel.
- Heat Treatment and Finishing
Wheels then undergo heat treatment, precision machining, and corrosion-resistant finishes.
- Spec-E Testing
Enkei applies rigorous Spec-E testing standards, surpassing typical JWL industry tests, to ensure reliability and performance.
The key distinction is that Enkei's MAT process primarily benefits the rim area. The face, spokes, and hub remain cast, meaning MAT wheels offer significant improvements over fully cast wheels but don’t achieve the full structural benefits of a fully forged wheel.
Most forged wheel makers use the same high-quality 6061 aluminum, so the real differences come from how each brand forges, finishes, and tests its wheels. Rays relies on an intensive multi-stage forging process that aligns grain structure throughout the entire wheel, then backs it up with strict X-ray and eddy-current inspections. The result is maximum strength, low weight, and high fatigue resistance. Enkei’s MAT method casts the wheel first, then spin-forms only the rim section.
For custom wheels (What we did), almost everything starts in CAD: engineers model the face, load it in FEA software, and confirm the design meets required load targets. Once approved, a billet blank goes to a CNC mill, which cuts the face profile. From there:
Two-piece wheel – the machined face and the spun barrel are welded together.
Three-piece wheel – the face, outer lip, and inner barrel are bolted together with seals or gaskets.
Regardless of the configuration, barrels are always spin-formed, not fully machined. Spinning expands the heated aluminum, aligns grain flow around the rim, and delivers better strength and impact resistance than cutting the barrel from solid stock.
TLDR: Wheels are a wear item. Even if they are structurally sound for years, material fatigue will eventually affect them, just like it does with engines. Forged or not, nothing lasts forever. If you track your car, expect to replace wheels at some point. At the end of the day, no matter how fancy your $5K wheels are, a 2-foot deep pothole always wins.