6 Best Custom Mounting Shims For Uneven Dashboard Surfaces

Finding the perfect spot for a navigation screen or phone mount in a van or tiny home cockpit is rarely straightforward. Modern dashboards are a landscape of curves, textured plastics, and awkward slopes that defy standard suction cups. Securing gear effectively requires more than just a strong adhesive; it demands the right shim to bridge the gap between flat mounting hardware and irregular surfaces.

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ProClip Angled Wedge: Best for Pro Mounts

The ProClip Angled Wedge serves as the gold standard for those who prioritize a low-profile, permanent installation. By providing a precise, angled shim, it corrects the steep rake found on many modern vehicle dashboards, ensuring the mount sits perfectly perpendicular to the user. This creates a solid foundation for heavy-duty smartphone cradles without the need for bulky, articulating arms.

This product is the ideal choice for anyone utilizing a custom ProClip vehicle-specific mount that needs to counteract a dashboard’s downward slant. Because it is engineered to integrate seamlessly with existing mounting plates, it avoids the “tacked-on” look of universal solutions. It is not, however, a standalone fix; it requires a vehicle-specific base to function correctly.

Choose this if the vehicle dashboard has a steep, non-adjustable incline that prevents the screen from facing directly toward the driver. It transforms a poor mounting angle into an ergonomic, factory-integrated position. It is the most reliable investment for high-end, dedicated setups.

iBolt BizMount Wedge: Best Universal Solution

When the dashboard surface is slightly textured or rounded, the iBolt BizMount Wedge provides the necessary mechanical advantage to create a stable base. This wedge acts as a spacer that compensates for minor surface irregularities, preventing the “wobble” that inevitably leads to adhesive failure over time. It is particularly effective for heavy-duty mounts that exert significant leverage on the dash surface.

This solution is perfect for those who shift between different mounting locations or want a universal bridge for varied hardware. Its design is utilitarian and rugged, making it well-suited for van conversions and work trucks where vibration is a constant factor. It lacks the aesthetic subtlety of a custom-molded piece, but it makes up for that with sheer versatility.

If the goal is to stabilize a mount on a surface that isn’t perfectly flat, the iBolt wedge is the smartest universal compromise available. It is not the most attractive option, but it provides a rock-solid platform that keeps heavy devices locked in place. It is a workhorse accessory for the pragmatic traveler.

Sugru Mouldable Glue: Best for Awkward Shapes

Sugru is a specialized moldable silicone that bridges the gap when no mechanical shim will fit. Because it starts as a putty, it can be hand-sculpted to fill the specific voids between a flat mounting plate and a deeply curved dashboard surface. Once cured, it creates a custom-fit, semi-flexible support that bonds permanently to the dashboard.

This is the ultimate hack for custom van builds with irregular, fiberglass, or uniquely textured dashboard areas where mass-produced shims simply fail. It excels at filling “negative space” that would otherwise cause a mount to vibrate or snap off under pressure. Users must be aware that once it cures, it is extremely difficult to remove, making this a “measure twice, install once” proposition.

If the surface is highly customized or unusually shaped, look no further than Sugru to solve the geometry problem. It provides a level of structural stability that pre-formed plastic shims cannot match on complex contours. Use this when you are committed to a permanent location and need a bespoke interface.

RAM Level Cup Base: Best for Heavy-Duty Gear

The RAM system is built for the rigors of off-road driving and extreme vibration, and their specialized level-bases serve as the ultimate shim for heavy equipment. These bases allow for minor adjustments to the pitch and yaw of a mounting plate, effectively shimming the mount to ensure it stays level even when the dashboard surface slopes aggressively. They bridge the gap between heavy, high-vibration gear and the mounting surface.

This option is strictly for those running heavy-duty setups like tablets, radio equipment, or dedicated navigation screens. The added weight and structural integrity of a RAM base mean it will handle off-grid environments where lesser mounts would shatter. It is overkill for a standard phone holder, but essential for heavy-duty internal architecture.

Investing in a RAM base is a long-term play for equipment stability. It provides a robust, adjustable interface that makes other shims look flimsy by comparison. If the gear is expensive and the terrain is rough, this is the only reliable choice.

3M VHB Tape Stacks: Best DIY Budget Option

5952 VHB Tape: 2.5cm . x 15 ft. (Black)

For those working with a tight budget or a space where a rigid shim is too bulky, building up layers of 3M VHB (Very High Bond) tape is an effective technique. By layering the tape, you create a dense, slightly compressible shim that absorbs minor surface imperfections while providing extreme adhesion. It is a low-profile way to raise one side of a mount to achieve a better angle.

This method requires patience and cleanliness to ensure each layer of tape bonds to the next without trapping air bubbles. It is ideal for small, light-duty mounting tasks where a plastic wedge would be too prominent. It is not recommended for heavy items that will put excessive shear force on the adhesive bond over time.

Stick to VHB tape stacks for lightweight tasks where simplicity and low weight are the priorities. When applied correctly on a cleaned surface, it is surprisingly durable and discreet. It is the go-to solution for minimalist cockpit designs.

Scosche MagicMount Surface: Best for MagSafe

The Scosche MagicMount series often includes specialized base plates designed to handle the nuances of curved dashboard surfaces. These shims are optimized to work with magnetic mounting plates, providing a flat plane for the magnet to attach while compensating for the contour of the dash underneath. It is a targeted solution for those who want the convenience of magnetic mounting without sacrificing structural support.

This is the right choice for the MagSafe user who wants a modern, clean look but lacks a flat spot to stick the magnetic puck. These bases are typically low-profile and aesthetically neutral, blending well with the black plastic common in most vehicle interiors. They are not intended for heavy, non-magnetic devices, so do not attempt to use them for tablets or laptops.

If the priority is a quick-attach magnetic system on a curved dashboard, the Scosche approach is the most refined option. It bridges the gap between modern technology and older dashboard design limitations. It is the best balance of function and style for the everyday driver.

How to Pick the Right Shim for Your Setup

Selecting the right shim depends on two factors: the material of your dashboard and the weight of the device you are mounting. For textured soft-touch plastics, prioritize an adhesive-based shim like VHB tape or Sugru, as mechanical clips will struggle to find a grip. For hard, non-porous surfaces, rigid plastic wedges or mechanical spacers are superior.

Always account for the weight of the device when choosing a shim height. A taller shim increases the “lever arm” of the mount, which significantly increases the stress placed on the primary adhesive. If the device is heavy, keep the shim as low-profile as possible to reduce the torque acting on the bond.

Avoid overthinking the aesthetics initially; functionality and longevity must take priority in a mobile environment. A mount that falls off after three hours of driving is a far greater frustration than a shim that is slightly visible. Start with the most secure mechanical fit possible, then move to adhesive shims only when geometry forces the issue.

Shim Materials: Putty vs. Plastic vs. Rubber

Each shim material serves a specific purpose in vibration management. Rigid plastic shims are excellent for maintaining a strict, unchanging angle, but they do not absorb road vibrations and can potentially damage the dashboard surface if tightened too much. They are best used in stationary, high-vibration-free environments.

Rubber and silicone shims, including moldable putties like Sugru, are superior for off-road or van-life applications. They possess inherent dampening qualities that absorb high-frequency road vibrations, protecting both the dash and the device. These materials also conform better to textured surfaces, creating a more airtight bond than rigid plastic alternatives.

When choosing, evaluate the primary environment of the vehicle. If you are regularly driving on washboard roads or corrugated paths, soft or moldable materials are essential. If your setup is intended for long-haul highway travel, the precision of rigid plastic shims will offer better ergonomics.

Safe Install Tips for a Rock-Solid Mount

The longevity of any mount is 90% preparation and 10% the product itself. Before applying any adhesive shim, clean the mounting site with 70% isopropyl alcohol to remove all traces of interior cleaners, oils, and dust. A single fingerprint can lead to an adhesive failure in the heat of a summer day.

Always ensure both the dashboard and the shim have reached room temperature before installation. If the dash is freezing cold or baking in the sun, the adhesive bond will be compromised from the start. Once placed, apply consistent pressure for at least 30 seconds to allow the adhesive to reach an initial, secure grip.

After installation, resist the urge to attach the device immediately. Most industrial adhesives require 24 hours to reach full bonding strength. Allowing the shim to set undisturbed ensures it will withstand the mechanical stresses of driving later on.

Removing Mounts Without Damaging Your Dash

Removing a bonded shim or mount requires heat and patience to avoid pulling off the dashboard’s finish. Use a hair dryer on a medium heat setting to soften the adhesive layer, warming the plastic evenly until it becomes pliable. Never use a high-heat setting, as it can warp thin dashboard materials or melt soft-touch coatings.

Once the adhesive is softened, use a piece of fishing line or dental floss in a slow, sawing motion to slice through the tape or foam behind the shim. This prevents you from having to pry the shim directly off the surface, which is the most common cause of dashboard tearing. Work slowly, allowing the heat to continue doing the heavy lifting.

After the mount is removed, any remaining adhesive residue should be removed with a citrus-based adhesive remover or a soft microfiber cloth and gentle friction. Never use harsh solvents like acetone or paint thinner, as these will permanently strip the color and texture from your dashboard. Patience during the removal phase is just as important as during the initial installation.

With the right shim, you can turn any irregular dashboard into a reliable, ergonomic foundation for your gear. Whether you opt for a custom wedge or a custom-molded putty, the key is matching the solution to your unique vehicle geometry. Once installed with care, these small additions will keep your navigation and essential devices secure on the roughest of roads.