Material guide: What do 210D, PU and PVC mean on a cover?

In short: A cover is not just a cover. What it is made of, how thick the thread is, and how it is made waterproof determine how long it lasts, how well it withstands sun, frost and wind – and what it costs. Here we explain it all in plain language, so you can choose the cover that suits your needs. For a quick overview of what else to look out for, see our guide to finding the perfect cover.

How to read the material description

For all our products, the material is listed under the specifications, e.g. "210D Polyester PU-coated". The description typically consists of up to three parts:

1. The number with D (e.g. 100D, 210D, 300D) – how thick the thread in the fabric is.
2. The material (e.g. polyester, nylon, polyethylene) – what the cover is made of.
3. The coating (e.g. PU-coated, PVC-coated) – the layer that makes the fabric waterproof.

Some covers do not have all three parts. Plastic covers, for example, rarely have a D number because they are not woven from thread in the same way as fabric.

1. What does "D" mean? (Denier)

D stands for denier and describes how thick and strong each thread in the fabric is. The higher the number, the thicker the thread – and the more resistant the fabric is to wear, tears and wind.

Denier	Comparable to	Typical use
70–100D	A thin rain poncho	Lightweight covers, indoor use, transport and shorter periods outdoors
170–210D	A good rain jacket	Standard for outdoor bicycle and MOTORCYCLE covers
300D	The fabric in a sturdy backpack	Cargo bikes, motorcycles and year-round outdoor use
400–600D	A heavy-duty sports bag	Very exposed locations and heavy use

Important: Denier tells you about strength, not waterproofing. A thin cover can certainly keep the rain out – it is simply more vulnerable to tears, wear and strong winds.

If you see "T" instead of "D" (e.g. 170T), it is not the same thing. T indicates how tightly the fabric is woven (number of threads per inch), not how thick the thread is.

2. The materials – what is the cover made of?

PE film (polyethylene film)

A thin plastic film – not woven fabric. The material is waterproof, very light and inexpensive, and the cover can be folded up completely. On the other hand, film does not withstand much wear, becomes stiff in frost and brittle from sunlight over time. It is a budget material best suited to sheltered places and shorter periods.

PEVA

Also a plastic film, similar to a shower curtain. Softer than PE film, but with the same advantages and limitations.

Woven polyethylene (tarpaulin material)

Narrow plastic strips woven together and coated with plastic – the same material as a classic tarpaulin. It is stronger and more tear-resistant than film, waterproof and still inexpensive. It is stiffer and less breathable than fabric, and the plastic ages in sun and frost.

Polypropylene (uncoated) – non-woven fabric

A light, airy "non-woven" material, like a reusable shopping bag. It is not waterproof and is made for indoor use, where it keeps dust and dirt away and lets moisture escape. See our bicycle covers for indoor use.

Polyester – the most commonly used

Woven fabric used to make most mid-range and top-range covers. Polyester is strong, holds its shape, withstands sun better than plastic and does not become stiff in frost. Combined with a good coating, it is the best compromise between price, durability and weight.

If you see the word "Oxford" in the material description, it refers to a particular tight weave of polyester – not a different material.

Ripstop

Ripstop is not a material, but a weaving method: Stronger threads are woven in a small grid pattern. If the fabric gets a small hole, the grid stops it from developing into a long tear. It is used in tents and rainwear, and a small hole can be patched with a tent repair kit.

Nylon

Stronger and softer than polyester at the same denier, and slightly more elastic. Often used in premium covers. Nylon is more expensive and can absorb a little water, which is why it is almost always coated.

Canvas and tarpaulin (tarpaulin fabric)

Heavy, strong materials. Robust and stable in windy conditions, but also heavier to handle.

Spandex/stretch

Elastic fabric that fits closely around the bicycle or motorcycle. Used for indoor covers against dust and scratches, e.g. indoor motorcycle covers.

3. The coating – what makes the cover waterproof

Woven fabric is not waterproof on its own. It only becomes waterproof with a coating.

Coating	Properties
PU (polyurethane)	Soft and flexible, even in the cold. The most common coating on quality covers. Withstands sun well, but slowly wears over the years.
PVC	Very waterproof and inexpensive. Makes the fabric stiffer and heavier and can become brittle in frost.
TPU	Elastic and hard-wearing. Used especially in stretch covers designed to fit closely.
Acrylic	Good UV protection, so the colour and fabric last longer in the sun.
UV-coated	Extra treatment that slows the sun's degradation of the material.
Plastic-coated (coated with plastic)	A plastic layer on woven plastic, as on a tarpaulin. Waterproof, but stiff.
Uncoated (no coating)	No waterproof coating – for indoor use.

What does "2000 mm" mean (hydrostatic head)?

Some manufacturers specify waterproofing in millimetres of hydrostatic head. The number shows how high a column of water can stand on the fabric before water penetrates it. The higher the number, the more waterproof it is. For comparison, rainwear is typically considered waterproof from around 1500 mm, and for a bicycle cover, 2000 mm is good for typical Danish rain. Read more about the balance between waterproofing and airflow in waterproof vs. breathable bicycle covers.

It is not just the fabric you pay for

Two covers made from the same material can cost very different amounts. The price also depends on:

• Taped seams – the seams are sealed on the inside so water cannot penetrate through the stitching.
• Breathability and ventilation – fabric or air holes that let moisture escape and reduce condensation, keeping rust and mould away. Read more about condensation under the cover.
• Straps, buckles and elastic – keep the cover in place in windy conditions. Wind is the biggest cause of wear and tears. If your cover lacks straps, you can buy securing straps and elastic cords.
• Lock holes/eyelets – so you can lock the cover together with the bicycle or motorcycle.
• Heat-resistant panel – on MOTORCYCLE covers, so you can put the cover on while the exhaust is still warm. See all heat-resistant MOTORCYCLE covers.
• Soft lining – protects paintwork and screens from scratches.
• Fit – a cover sewn for a particular model (e.g. a cargo bike) fits more closely and flaps less than a universal cover. Read why fit is more important than waterproofing.
• Size – a cover for a cargo bike or motorcycle simply requires much more fabric than one for a regular bicycle.

Which price range is right for you?

Level	Typical material	Suitable for
Budget	PE film, PEVA, woven polyethylene or approx. 100D	Sheltered places (carport, bicycle shed), indoor dust protection, shorter periods or as an inexpensive seasonal solution. Not intended to stand exposed to wind and weather all year round.
Mid-range	170–210D polyester with PU or PVC coating, or ripstop polyester	Daily outdoor use. The best choice for most regular bicycles, e-bikes and mopeds. See bicycle covers and e-bike covers.
Premium	300D+ polyester or nylon, PU coating, taped seams, ventilation	Year-round use in exposed places, expensive e-bikes, cargo bikes and motorcycles – where the cover needs to last for many seasons. See cargo bike covers and year-round MOTORCYCLE covers.

A cheap cover is not a bad cover – it is made for a different job. If your bicycle is under a roof and just needs to be kept free of dust and rain splashes, a budget cover is perfectly fine. If it stands exposed on a balcony or in the front garden throughout the winter, you will get the best value by choosing a woven polyester or nylon fabric.

How to make your cover last longer

• Secure it. A cover that flaps in the wind wears out many times faster. Use straps, elastic or a securing strap under the bicycle.
• Avoid sharp edges. Pedals, handlebar ends and luggage racks can wear holes from the inside. A piece of tape or a cloth on the sharpest points helps.
• Let it dry. Do not pack the cover away wet – this can cause mould and odours.
• Reproof it. After a season or two, a waterproofing spray can renew the water repellency of fabric covers. Find waterproofing products under maintenance and care.
• Wash it gently. Use lukewarm water and a soft brush – never a pressure washer or washing machine, as these can damage the coating.

Find more advice in our guide to maintenance and care of your cover.

Frequently asked questions

Is a cover with a higher D number always better?

It is stronger, but also heavier and more expensive. For a regular bicycle, 210D with a good coating is often the best compromise.

Why do not all covers have a D number?

Covers made of plastic film or woven plastic are not measured in denier, and some manufacturers specify hydrostatic head or weaving method instead, e.g. ripstop.

Why is there water under my cover when it is waterproof?

It is usually condensation: moisture from the air and ground that collects on the inside when the temperature drops. Choose a breathable cover or one with ventilation, and avoid sealing it completely at ground level.

Why has my cheap cover become stiff or cracked?

Plastic materials such as PE film, PEVA and woven polyethylene, as well as PVC coatings, become stiff in frost and degrade in sunlight over time. This is a property of the materials and the reason they cost less.

Where can I find the material of a cover?

It is listed under the specifications on each product page at Cykelgarage.dk. If you are unsure about the size, see find the right size.

Read also

• Bicycle cover? What should you choose?
• How to choose a cargo bike cover
• How to choose a motorcycle cover
• Bicycle covers for winter

If you are unsure which cover is right for you, write to us – we are happy to help.