Bora 3/8 Wheel Spacers | Precision Truck Wheel Spacers
Our 3/8 inch wheel spacers are precision-CNC machined from aerospace-grade 6061-T6 aluminum for trucks and SUVs requiring minimal clearance adjustment. The 9.5mm thickness provides exactly the spacing needed to clear aftermarket brake calipers, suspension components, or achieve a flush wheel-to-fender stance without the excessive track width of thicker alternatives.
We engineer every Bora spacer with hub-centric fitment and press-in wheel studs rated to OEM torque specifications. The anodized finish resists corrosion in wet climates and winter salt exposure, maintaining structural integrity across the full service life of your vehicle. Each pair ships ready to install with detailed torque specifications and stud replacement instructions.
Specifications for Bora 3/8 inch spacers
Material engineering and load distribution
We machine every Bora 3/8 wheel spacer from billet 6061-T6 aluminum, the same alloy used in aircraft structural components and heavy-duty truck suspension parts. This temper provides tensile strength exceeding 45,000 PSI while maintaining the machinability required for hub-centric bores accurate to within one-thousandth of an inch. The anodizing process creates a hardened oxide layer 25 microns deep, preventing galvanic corrosion when aluminum contacts steel wheel hubs.
The hub-centric design transfers vehicle weight through the machined pilot bore rather than relying solely on wheel studs. This load distribution matches your OEM wheel mounting method, eliminating the vibration issues common with lug-centric aftermarket spacers. Pre-installed Grade 10.9 wheel studs anchor into threaded inserts with thread-locking compound, maintaining clamp load under repeated thermal cycling from brake heat.
Installation requirements and torque specifications
Installing Bora 3/8 wheel spacers requires removing your factory wheels, cleaning the hub face with a wire brush to remove rust scale, then mounting each spacer flush against the hub pilot. We recommend applying anti-seize compound to both the hub face and the spacer’s rear surface to prevent corrosion-welding in winter climates. Torque the spacer’s mounting studs to your vehicle’s factory wheel lug nut specification — typically 100-140 ft-lbs for half-ton trucks.
Extended stud engagement
The 3/8 inch thickness reduces thread engagement between your lug nuts and the spacer’s press-in studs by approximately four threads compared to direct wheel mounting. We design our studs with extended shanks to maintain at least eight full threads of engagement after spacer installation, meeting SAE J1102 standards for lug nut retention. Check stud protrusion with a depth gauge before final torquing — minimum 0.5 inches of exposed thread above the lug nut is required for safe operation.
Clearance applications and fitment scenarios
The 3/8 inch thickness addresses specific clearance challenges where larger spacers would excessively widen your track width. Trucks running factory wheels with aftermarket big-brake kits often need exactly this spacing to clear caliper mounting brackets without moving the tire centerline outboard beyond fender coverage. Lifted trucks with new upper control arms sometimes experience inner tire-to-coilover contact during full suspension compression — a 9.5mm spacer provides the minimal offset adjustment needed without triggering rubbing at the fender lip.
We also see this thickness requested for cosmetic stance corrections when wheels sit slightly recessed from the fender edge. The thicker options like our 1 inch spacers and 1.5 inch spacers deliver more aggressive visual changes, but the 3/8 inch model offers precise control for builders chasing exact measurements rather than dramatic transformation. Measure twice before ordering — excessive spacing voids suspension geometry and accelerates wheel bearing wear.
More Bora wheel spacer thicknesses for custom fitment
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Common questions about our 3/8 inch wheel spacers
Hub-centric wheel spacers like our Bora 3/8 inch model eliminate vibration by transferring vehicle weight through the machined pilot bore rather than the wheel studs. Vibration typically occurs with lug-centric spacers that allow radial play between the hub and wheel. Our CNC-machined pilot bore fits your hub register with 0.002-inch tolerance, maintaining the same centered, vibration-free mounting as your factory wheel configuration.
If you experience vibration after installing hub-centric spacers, the cause is usually incorrect torque sequence, contaminated hub faces, or mismatched pilot bore dimensions. Clean all mounting surfaces with a wire brush, verify the spacer's hub diameter matches your vehicle specification, and torque lug nuts in a star pattern to manufacturer specifications.
SAE J1102 standards require minimum engagement of at least six full threads between the lug nut and wheel stud for safe operation. Our Bora 3/8 wheel spacers use extended-shank press-in studs that maintain eight to ten threads of engagement after installation, exceeding safety minimums by 30 percent.
The 9.5mm spacer thickness reduces engagement by approximately four threads compared to direct wheel mounting. Measure exposed stud length after installing the spacer but before mounting your wheel — you should see at least 0.5 inches of stud protruding beyond the spacer face. If your factory studs are worn or shortened from previous wheel changes, replace them before installing spacers.
We do not recommend stacking wheel spacers under any circumstances. Each spacer introduces an additional joint in the mounting assembly, doubling the potential failure points and creating excessive lever arm forces on wheel studs. Stacking also compounds any minor manufacturing tolerances, potentially creating runout that causes vibration or uneven tire wear.
If you need more than 3/8 inch of spacing, order a single thicker spacer machined to your required dimension. Our product line includes seven thickness options from 1/4 inch to 2 inches, all engineered as single-piece units with load ratings appropriate for their thickness. A single 3/4 inch spacer is structurally superior to two stacked 3/8 inch spacers in every measurable way.
The Magnuson-Moss Warranty Act prohibits manufacturers from voiding entire vehicle warranties based solely on aftermarket part installation. However, if a dealer can demonstrate that wheel spacers directly caused a specific failure — such as premature wheel bearing wear from excessive track width or suspension damage from altered scrub radius — they may deny coverage for that repair.
Document your spacer installation with photos, torque records, and receipts. The 3/8 inch thickness produces minimal geometry changes compared to thicker spacers, reducing the likelihood of warranty disputes. Consult your dealer before installation if you're concerned about coverage, and consider that many lifted trucks and modified vehicles run wheel spacers without warranty issues.
Torque the spacer's mounting studs to your vehicle's factory wheel lug nut specification, typically 100 to 140 ft-lbs for half-ton trucks and 120 to 175 ft-lbs for three-quarter-ton and one-ton models. Your owner's manual lists the exact value for your year and model. Use a calibrated torque wrench and tighten in a star pattern, making three complete passes with gradually increasing torque.
After the first 50 miles of driving, re-torque all lug nuts to account for initial settling of the mounting surfaces. Check torque again at 500 miles and then every tire rotation interval. The press-in studs on our spacers are installed with thread-locking compound at the factory, so you do not need additional Loctite on the spacer-to-hub connection.
Hub-centric spacers are always the correct choice for street-driven trucks and SUVs. They center the wheel using a machined pilot bore that slides over your hub register, distributing vehicle weight through the hub rather than the wheel studs. This eliminates vibration and maintains factory wheel balance characteristics.
Lug-centric spacers use tapered lug seats for centering and are appropriate only for low-speed off-road vehicles where vibration is acceptable. We manufacture all Bora wheel spacers as hub-centric designs because the performance and safety advantages outweigh any cost savings from universal lug-centric construction. Verify your vehicle's hub pilot diameter before ordering to ensure correct fitment.
The 9.5mm thickness of our 3/8 inch spacers produces negligible changes to suspension geometry, steering response, and fuel consumption. Track width increases by 0.75 inches total (3/8 inch per side), which slightly reduces body roll in corners but does not meaningfully alter handling balance on street-driven trucks.
Fuel economy impact is unmeasurable at this thickness — the added rotational mass is less than one pound per wheel, and aerodynamic changes from the minimal track width increase are insignificant. Thicker spacers in the 1.5 to 2 inch range can increase scrub radius enough to affect steering effort and accelerate tire wear, but the 3/8 inch model operates well within OEM suspension tolerance ranges.