UnderCover Flex Vs UnderCover Ultra Flex

UnderCover Flex hard folding tonneau cover
UnderCover Ultra Flex tonneau cover

UnderCover is a reputable manufacturer of tonneau covers and other vehicle accessories.

It has a wide variety of tonneau covers, ranging from one-piece covers to high-end hard folding ones.

All of them are engineered to keep your gear secure and free from effects of the elements..

Two of its best-selling products are the UnderCover Ultra Flex and Flex. Both of these are high-end hard tri-fold truck bed covers.

Their performance is outstanding and so are their features. The two covers share a lot of features but are also different in some ways.

To help you choose the right one for you, we will discuss some of the differences as well as the similarities.

Below is the summary of the comparison between the two, highlighting the differentiating features.

FeaturesUnderCover FlexUnderCover Ultra Flex
MaterialFiberglass Reinforced panelsAluminum panels
Under Panel MaterialTextured fiberglass-reinforced polymerCarpeted under panel
FinishHigh glossMatte black finish
ProfileLow profileUltra-low profile
Weight capacity300 lb evenly distributed weight400 lb evenly distributed weight
UV resistanceStandard UV resistancePremium UV resistance
Dent/scratch resistanceTop dent and scratch resistanceStandard dent and scratch resistance
Additional accessories NoneFactory LED light strip
Tailgate closing positionWith cover open onlyWith cover open or cloased
Warranty3-year warranty5-year warranty
Starting price$879.00$989.00
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Breakdown of Differences

Construction and top material

UnderCover Flex folding cover
UnderCover Ultra Flex cover: matte black finish

The construction of UnderCover Flex and Ultra Flex is a major comparison point.

The UnderCover Ultra Flex has heavy-duty aluminum panels construction. The UnderCover Flex, on the other hand, has a top-grade fiberglass material and aluminum rails.

Each of the materials has its benefits. The fiberglass material, for instance, is very lightweight and sleek with a glossy finish. This will create a classy and attractive look and feel on your truck.

The aluminum panels are not as lightweight, but they are very strong and durable with an impact resistance property. Ultra Flex has a matte black finish which gives it a cool and stylish appearance.

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Durability and resistance

Weathertight seal

The fiberglass material is very resistant to scratches and dents.

This is one of the main features that attract people to the material as it helps reduce color fading in the sun.

Additionally, it has a standard UV-resistance property that keeps it safe from fading and other UV-related problems.

Similarly, the panels on Ultra Flex are also UV protected, but instead of standard, like UnderCover Flex, it has a premium UV resistance.

This enables it to survive the harmful effects of the UV rays better, allowing it to maintain its color.

Unlike most metals, these aluminum panels are corrosion-resistant, and this is emphasized by the extra coating.

The only issue is, after a while, you might notice a few scratches and dents on the aluminum material on Ultra Flex. But this is never enough to compromise the looks.

The Ultra Flex’s aluminum construction is also distortion resistant which gives it longer durability. While the fiberglass material is also very durable, its resistance to distortion does not measure up to the aluminum’s.

Both UnderCover Ultra Flex and Flex have high resistance to temperature changes. They will not expand or contract with temperature changes. The only difference is, the aluminum panels tends to conduct heat more than the fiberglass material. As a result, it heats up from the sun.

Strength and weight capacity

In terms of strength and weight capacity, the aluminum panels are stronger than the fiberglass material. They are also more impact resistant and can take a thrashing without breaking.

The aluminum panels can thus support more weight on top of them. The UnderCover Flex has a weight capacity of 300 lb of evenly distributed weight while Ultra Flex supports 400 lbs.

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Under panel material

UnderCover Flex Cover fiberglass under panel
Ultra Flex Cover carpeted under panel

Another distinguishing feature is the under panel material.

The UnderCover Ultra Flex has a carpet-like textured under panel material. This keeps your valuables safe against damages like scratches and dings.

It also gives an upscale look and feel, taking your vehicle to the next level.

For the UnderCover Flex folding cover, the under panel material is fiberglass material. This is not as soft or textured as the carpet-like material on UnderCover Ultra Flex.

However, it gives a consistent and seamless look. This creates an OE-like look that will not compromise your looks when driving with the cover open.


UnderCover Ultra Flex Cover

Both covers mount flush with the truck bed to give a sleek and aerodynamic appearance.

But, from the name, Ultra Flex has an extremely ultra-low profile that lies more flush and seamless with the bed rails.

The UnderCover Flex on the other hand has a regular low profile design, but it still provides an aerodynamic appearance.

Low profiles are important because they create sleeker appearances and they hardly compromise your factory look.

They also help improve gas mileage, since they reduce wind drag.

Both covers can qualify for low profiles, but if you want an extremely low profile then Ultra Flex should be your number one choice.

Water resistance

While no tonneau cover is completely waterproof, both the UnderCover Ultra Flex and Flex covers are highly water-resistant.

They have rubber seals all around them to block out water and all the other weather and road elements. The tailgate also has a seal for better protection.

They also have bed rail mounting systems. This system channels water into the drainage tubes which then carry the water out of the vehicle.

With this, your truck bed cover will remain dry, but in case of heavy rainfall, only a few drops of rain will get into the truck bed.

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Both the UnderCover Ultra Flex and Flex Tonneau Covers lock with the tailgate. They do not have separate locks, instead, they have deadbolt locking rails. When latched, the rails will interlock with each other.

Paired with a lockable tailgate, this will offer maximum security. No one will be able to access your truck bed unless they have your tailgate keys.

This locking mechanism is great since it saves you the stress of a rusted lock. You will also not have to carry around different keys for your tailgate and the cover.

Dual-action tailgate

When it comes to closing and opening the tailgate, the UnderCover Ultra Flex Tonneau Cover has an edge.

This is because it has a dual-action tailgate seal. With this design, you can open and close the tailgate when the tonneau cover is closed or open.

This ensures convenience as well as ease of operation.

UnderCover Flex Tonneau Cover, on the other hand, lacks the dual-action tailgate feature.

Because of this, you can only close the tailgate when the last panel of the tonneau cover is open.

Being hard folding, both Ultra Flex and Flex can fold into different positions to offer bed access. With the prop rods, you will be able to ride with them without experiencing any wind noise.

Compatibility with other accessories

Both of these tonneau covers install inside the truck bed rails. This gives space as well as leaves the stake hole pockets open. With this, you are able to install a utility rack as well as other accessories.

Included accessories

UnderCover ultra flex led light

A truck bed cover can operate on its own without any additional accessories.

But these additional accessories can enhance the cover’s ease of operation as well as your experience using it.

The UnderCover Flex does not come with any extra accessories, but UnderCover Flex comes with a factory LED light strip.

This will illuminate your entire truck bed, allowing you to access your cargo more easily even when it’s dark.

Installation and removal

Installing both of these truck bed covers is rather easy and will take around 20 minutes. Neither of them requires drilling, except when installing the drainage system.

ultra flex and flex installation

They also allow for one-person installation since they are not very heavy, especially the UnderCover Flex truck bed cover.

Each of the covers has a clamp-on system and this only requires tightening, then boom! you’ll have it installed on your vehicle and ready to use.

Both covers can fold to different positions to give you access to your cargo.

But in case you need 100% access, the covers have a quick release system.

This will allow you to remove the bed cover within a few minutes without any tools necessary.

Made in the USA

Both truck bed covers are made in the USA and backed by a manufacturer’s warranty.

The difference is the length of the warranties- a 5-year warranty for Ultra Flex vs a 3-year warranty for UnderCover Flex Bed Cover. The warranties cover both the main material and the rails.

Which one is for you?

For maximum protection against wannabe thieves and road and weather elements, a hard folding tonneau cover is the way to go.

UnderCover Ultra Flex and Flex are one of the most sought after truck bed covers. The covers have similar performance with a few construction differences.

The Ultra Flex, having a full aluminum construction offers more strength and durability, hence the higher price. The UnderCover Flex also stands out with its top resistance to scratches and dents as well as its lightweight.

You can never go wrong with either of the covers. However, if you want to try out other options on your truck, BAK has the BAKFlip line, consisting of MX4, F1, G2 among others.

They have almost similar construction and will keep your cargo just as secure. All BAK covers are made in the USA.

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