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Mammoth 12 Hole Satin Black 6-Lug Wheel; 20x9; -6mm Offset (19-25 Sierra 1500)Find parts that fit my vehicle
Item S579316G19
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Our Price
$229.99 each / $919.96 Set of 4
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Sierra 1500 Complete Wheel & Tire Packages
Product Information
Description, Q&A, Specs & Installation
Features & Specs
| Brand | Mammoth |
| Wheel Model | 12 Hole |
| Wheel Size | 20x9 |
| Wheel Diameter | 20 Inch |
| Wheel Width | 9 Inches |
| Wheel Stance | Aggressive |
| Wheel Offset | -6mm |
| Wheel Backspacing | 4.764 Inch, 121mm |
| Wheel Style | Simulated Beadlock |
| Wheel Color | Black, Black Chrome |
| Wheel Finish | Matte |
| Wheel Material | Aluminum |
| Wheel Placement | Front or Rear |
| Wheel Bolt Pattern | 6 x 139.7mm (6 x 5.5-Inch) |
Description
Mammoth Wheels 12 Hole Style Wheel. Mammoth's 12 Hole Style Wheel features D shaped windows of alternating size around the face and simulated bead lock bolt accents around the circumference of the lip. A Mammoth center cap is included. This Mammoth 12 Hole Style Wheel is perfectly suited for both street and off-road applications.
Satin Black Finish. This Mammoth Wheel is completed in a high quality black finish for an aggressive appearance that will make others green with envy. For added protection and good looks, this Wheel features a durable, satin clear coat that is tough enough to stand up against the hazards of everyday driving - including road chips and pitting.
One-Piece Cast Aluminum Construction. Mammoths One-Piece aluminum Wheels are manufactured using gravity casting. Gravity casting is the process of pouring a molten aluminum alloy into a wheel mold or form utilizing the earth's own gravity to help fill the mold. The result is a strong, durable wheel that has the same good looks as a more expensive wheel, at a fraction of the price.
Application. This Mammoth 12 Hole Satin Black 6-Lug Wheel; 20x9; -6mm Offset is designed to fit 2019-2025 GMC Sierra 1500 models. Sold individually.
- Replacement Center Cap – SKU U18861-XT
Mammoth S197645
CA Residents: 
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
Installation & What's in the Box
What's in the Box
- (1) Wheel
- (1) Center Cap
4.8
Reviews of Mammoth Wheel Products (500+)
Reviews of Mammoth Wheel products have an average rating of 4.8 out of 5
Feb 3, 2025
Review shared from Mammoth 2-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2021 AT4 - Davidc1
2 inch spacers
This product looks amazing! Rides great and cleans up the truck a lot! The offset it’s absolutely amazing!
Aug 9, 2024
Review shared from Mammoth 1.50-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2024 Elevation - PlainJane
GREAT PRICE & WELL MADE
I've long considered BORA spacers the standard in quality. I've ran spacers on three previous trucks with nearly 400k combined miles. All w/o issue. I'm confident these spacers are of the same quality!
May 8, 2024
Review shared from Mammoth 2-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2021 SLT - RandyRa
Great Product
Truck looks great now. Easy and fast to install. Did need more threadlocker but had some extra from other project.
Jan 22, 2024
Review shared from Mammoth 1.50-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2021 AT4 - WilsAT4
Great fit
Needs to space wheels out after leveling to keep from hitting UCA’s with larger tires. No problems with figment or vibration.
Dec 28, 2023
Review shared from Mammoth 1.50-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2023 - TJerz
TWO?!
Sold as a set of TWO spacers? That should be in the Title of the item *facepalm.. Didn't think to check the quantity because who would only get two?
Dec 15, 2023
Review shared from Mammoth 2-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2023 AT4X - Jay7503
Just the Right Amount of Peak
Easy install. Looks great on the truck. Couple of things to mention. One of the thread lock containers was cracked so arrived dried out. The lug nuts that came are not the hardest metal. I rounded the corners on one while torquing them. There was no documentation for torque values so I went with the GMC recommendation for my truck. Hopefully I don’t have to change a tire anytime soon.
Nov 18, 2023
Review shared from Mammoth 2-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2022 Elevation - Gabexfrndz
Would not recommend for stock tires
I bought these spacers to give my truck a meaner stance and when I tried to do the installation I found out that these spacers are not meant for factory wheels (even though the product says it works with factory wheels) The spacer was not sitting flush or sinking into my wheel due to the center ring being too big for my wheel thus leaving a pretty big uneven gap between the spacer and wheel. I called the American truck’s customer service and they said that these spacers are more for after market wheels and would not work with the factory wheels. Good look from what I’ve seen on trucks similar to mine but not good for those who have stock wheels.
Jun 5, 2023
Review shared from Mammoth 1.50-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2023 AT4X - JoshAT4X
Perfect fit and look!
These 1.5" spacers give my stock wheels the perfect stance and look I was going for!
Feb 8, 2023
Review shared from Mammoth 2-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2021 SLT - mk4335
Looks Great but too wide for my front 2" lift
Great quality and looks. But they pushed my tire out too far and it hits the back outside corner of the wheel well. Even with a 2" leveling kit. Had to return. I think 1" will work and 1.5" will still be too much.
Feb 6, 2023
Review shared from Mammoth 1.50-Inch Billet 6-Lug Wheel Spacers (99-25 Sierra 1500)
2021 AT4 - Fellers
Beefy
Mounting was a breeze! Money well spent! Looks awesome!
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Wheel & Tire Fitments For 0-0 Sierra 1500 with 20x9 -6mm Wheels
