Ultra 6x5.50 wheels cover the 6-lug, 6x5.5-inch (6x139.7 metric) fitment that dominates half-ton trucks, SUVs, and off-road builds. Alongside the wheels themselves, the 6x5.50 grouping includes the hardware that finishes an install cleanly — center caps and hubcentric rings machined for this exact hub-and-bolt layout. Whether you are refreshing a daily-driven pickup or dialing in a trail rig, this is the hub for matching an Ultra design to a 6x5.5 vehicle.
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Why the 6x5.50 fitment matters
The 6x5.5-inch bolt circle is one of the most common truck and SUV patterns on the road, used across a wide range of domestic and import half-tons and body-on-frame SUVs. Because it is so widespread, getting the small details right — hub centering and a properly seated cap — makes the difference between a rattle-free, concentric setup and one that vibrates. Ultra is a truck- and off-road-focused wheel maker, and its accessory line reflects that: hardware is offered specifically drilled and finished for the 6x5.50 layout rather than as a one-size-fits-all afterthought. Pairing the correct hubcentric ring with your wheel ensures the load rides on the hub, not the studs.
Which options are carried
For the 6x5.50 pattern specifically, the finishing hardware leads the way. The center cap is offered in an unusually deep range of colorways — from Gloss Black and Satin Black variations to Chrome Plated, Bronze and Gloss Bronze, plus Matte Grey, Opal, White and machined-face treatments — so you can match the cap to nearly any wheel finish. The Hubcentric Ring is available in finishes including Gloss Black, High Polish, Matte Black and machined variants. These accessories dovetail with Ultra's broader truck lineup, so shop the full Ultra lineup to see the wheels that live on the same trucks.
Wheel models on adjacent 6-lug patterns
Most Ultra truck wheels for these same vehicles are cataloged under the closely related metric callout, 6x139.7. If you are cross-shopping wheels for a 6x5.5 truck, browse designs like the 126BK Warmonger 6, the 237B Gauntlet, the 238B Gauntlet, the 195SB Crusher, and the 178B Mongoose. The 235C Maverick in Chrome Plated is a clean bright option if a polished look is the goal.
Fitment coverage
The 6x5.50 designation is the imperial equivalent of 6x139.7, so the practical fitment overlaps heavily with the Ultra 6x139.7 wheels group — the pattern found on many half-ton pickups and SUVs. If your truck uses a different 6-lug spacing, check the Ultra 6x135 wheels page for the Ford-style pattern. Heavy-duty and dually owners should look at the 8-lug groups instead, including Ultra 8x165.1 wheels, Ultra 8x170 wheels, Ultra 8x180 wheels, and Ultra 8x200 wheels. For lighter vehicles and cars, the 5-lug groups such as Ultra 5x127 wheels, Ultra 5x139.7 wheels, and Ultra 5x114.3 wheels cover the common patterns. By diameter, the truck-friendly sizes run through 16-inch, 17-inch, 18-inch and 20-inch options.
How to choose
Start with your vehicle's exact bolt pattern and hub bore, then confirm the wheel offset and width your suspension and fenders allow. Once the wheel is picked, match the accessory finish: choose a center cap that echoes the wheel's face color, and add a hubcentric ring if the wheel bore is larger than your hub. If you like a stealthy look, lean toward the Satin or Gray finishes; for contrast, a machined or Silver face brightens a dark truck. Every order ships free, and financing is available through Affirm.
Frequently Asked Questions
Is 6x5.50 the same as 6x139.7?
Yes. 6x5.5 inches converts to 6x139.7 mm, so they describe the same 6-lug bolt circle. Ultra truck wheels for these vehicles are largely cataloged under the 6x139.7 callout.
What Ultra parts are offered specifically for 6x5.50?
The center cap and hubcentric ring are offered drilled and finished for the 6x5.50 layout, in a wide range of finishes from Gloss Black to Chrome Plated and Bronze.
Do I need a hubcentric ring?
If the wheel's center bore is larger than your vehicle's hub, a hubcentric ring centers the wheel on the hub for a smoother, vibration-free ride. Ultra offers rings in finishes including Gloss Black, High Polish and Matte Black.