ALT Forged ALTR18 20x9 / 21x12 wheels for C8 Corvette Stingray / Z51
WARRANTY
LIFETIME STRUCTURAL WARRANTY
FITMENT
FITMENT GUARANTEED OR MONEY BACK
Pairs well with
The ALTR18 is unlike anything else in the ALT Forged lineup. Its 5-spoke forged face is wrapped by a separate bolt-on aero lip — a precision-machined outer ring with rectangular cutout windows around the perimeter that gives the wheel an aggressive, layered depth you have to see in person. The face and the aero lip are finished independently, creating a two-tone appearance with maximum visual contrast between the center and the rim. What looks like a high-end 2-piece construction is actually a full forged center with a bolt-on aero ring that screws in cleanly — combining the structural integrity of a monoblock with the visual drama of a split-design wheel. Crafted from 6061-T6 aerospace-grade aluminum using precision forging technology, the ALTR18 delivers a wheel that is lighter and stronger than anything cast or flow-formed, engineered to the 5x120.65 bolt pattern of the C8 Corvette Stingray and Z51 with no modifications required.
| Front Wheels | 20x9 |
| Rear Wheels | 21x12 |
| Bolt Pattern | 5x120.65 |
| Model | ALTR18 |
| Construction | Forged + Bolt-On Aero Lip |
| Material | 6061-T6 Aluminum |
| Finish | Two-Tone — See Finishes tab |
| Center Caps | Accepts OEM Corvette Caps |
| Valve Stems | Not Included |
| Quantity | Set of 4 Wheels |
| Build Time | Approx 6-8 Weeks |
- Bolt-On Aero Lip — Separate Outer Ring with Rectangular Window Cutouts
- Two-Tone Design — Face and Aero Lip Finished Independently
- Full Forged 6061-T6 Aerospace-Grade Aluminum Center
- Stronger and More Durable Than Cast or Flow-Forged Wheels
- Aggressive Layered Depth from Every Viewing Angle
- Maximum Concavity in Every Profile
- Clearance for the Majority of Big Brake Kits on the Market
- Fender-Flush Fitment Engineered for the C8 Stingray / Z51
- Stock TPMS Compatible and Transferable
- Accepts OEM Corvette Center Caps
- Message Us for a Free Custom Render of Your Vehicle
Custom face and aero lip combinations available — message us with your color vision and we will work with you on a custom two-tone spec.
No modifications required. The ALTR18 is engineered specifically for the C8 Corvette Stingray and Z51 with a 5x120.65 bolt pattern and hub-centric mounting dialed in for a clean fender-flush stance. OEM Corvette center caps are accepted and stock TPMS sensors are fully compatible.
Each set is custom-built and finish-matched to your specification. The aero lip assembly process adds time to the standard build, but the result is a wheel that cannot be replicated off the shelf.
Important Notice
- All timelines are estimates and may vary depending on material availability, production scheduling, and international shipping.
- No rush orders or exceptions can be made for upcoming events, car shows, or deadlines.
- Aero lip assembly and two-tone finish matching require additional lead time.
- By placing an order, the customer acknowledges and agrees to this production timeline.
Disclaimer
Product Quality
All wheels we sell are 100% brand new. Each wheel is handcrafted, hand-powder coated, and undergoes quality control to meet U.S. customer standards. Due to the nature of the manufacturing and finishing process, minor imperfections such as microscopic blemishes under the clear coat may occur and are considered normal in the aftermarket wheel industry.
Aero Lip Assembly
The ALTR18 aero lip is attached using precision hardware included with each set. Proper torque specifications must be followed during installation. We recommend professional installation to ensure correct fitment and alignment of the aero lip.
Exchange Policy
In the rare event of a significant defect, such as a visible chip or a noticeable dimple on the face of the wheel (e.g., larger than 1/2 inch), we will gladly offer an exchange. All wheels are covered under the manufacturer's powder coat and structural warranty.
Cancellation Policy
All wheels are custom built to order. Cancellations requested within 7 days of purchase may be eligible for cancellation depending on production status. After 7 days, all orders are considered final and cannot be canceled under any circumstances.
Feedback and Legal
We are a small, family-owned business. If any customer or competitor attempts to misuse feedback systems such as threatening negative feedback to obtain a refund, or leaving false or malicious reviews, we will pursue legal action to the fullest extent permitted by law.
ALT Forged ALTR18 20x9 / 21x12 wheels for C8 Corvette Stingray / Z51
If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.
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Shipping Information
Inventory Items will ship the same day! Forged order have ETA of 5-6 weeks.
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Customer Support
Give us a call at 818-210-8770 or email info@gemmotorsports.com
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Live sale on orders over $2500 + / Use promo code "SAVE200"
FAQs
Please read our FAQs page to find out more.
What is the ETA for Forged wheels?
Most of the forged wheels we offer are custom-built to order for your specific vehicle. Current estimated production time is 5–6 weeks. Certain finishes, such as Chrome, Two-Tone, or Brushed, may require an additional 1–2 weeks for completion.
Your patience ensures a perfect fit and premium quality—thank you for your order!
Will this fit my car?
All of our products come with a **perfect fit guarantee**—if it doesn’t fit, you get your money back!
Can I cancel my order?
All forged wheel purchases are final sale and non-refundable. If you need to cancel a custom order, we can issue store credit for future use.
For in-stock (inventory) wheel orders, cancellations are subject to a 25% restocking fee.
By completing your purchase, you acknowledge and agree to these terms, including waiving the right to file a chargeback.
Thank you for understanding our policy—we’re here to assist with any questions!
Why? Forged wheels are custom-built for your vehicle with custom specs, colors and design, so we can’t resell them. This policy helps us keep prices fair while ensuring quality craftsmanship.
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Why Choose Gem Motorsports?
We’re a family-owned business in the heart of Los Angeles, built on three simple promises: honest customer service, unbeatable deals, and top-tier quality.
Every member of our tight-knit team treats this business like our own—because it is. And it shows. Check out our 5-star ratings across eBay, forums, and review sites. In the aftermarket world, that kind of trust is rare—but for us, it’s just the standard.
Why? Because your satisfaction isn’t just our goal—it’s the only way we know how to do business.