Roll Rings

What is a roll ring?

A roll ring is a self-adjusting chain tensioner made from a tough, flexible polymer ring with sprocket teeth around its outside. Instead of being bolted to the machine like a tension arm or idler sprocket, a roll ring is simply squeezed into an oval shape and placed between the two strands of a roller chain, inside the chain loop. As the ring tries to return to its round shape, it pushes outwards on both strands of the chain, keeping the drive tensioned. As the chain runs, the teeth engage with the chain, so the ring rolls along with it.

Because the roll ring presses on both strands at once, it tensions the drive in either direction of rotation, making it well suited to reversing drives. As the chain wears and stretches, the ring simply expands to take up the slack, keeping the chain tensioned automatically.

A typical roll ring has:

• Flexible polymer ring - a strong, elastic ring that provides the tensioning force
• Sprocket teeth - teeth moulded around the outside of the ring that match the chain pitch
• No bearings or fixings - the ring is held in place by the chain itself

Roll rings are usually described by:

• Chain size - the chain pitch the ring suits, such as 08B, or 1/2 inch pitch
• Number of teeth - such as 26 teeth, which relates to the size of the ring and the range of drives it suits

For example, a 26-tooth 08B roll ring suits 1/2 inch pitch 08B roller chain and has 26 teeth around its outside.

Key features:

• Self-tensioning - automatically takes up slack as the chain stretches
• Tensions both strands - works in both directions, ideal for reversing drives
• No mounting required - no brackets, bolts, or arms needed
• No bearings or lubrication - simple, maintenance-free design
• Absorbs shock and vibration - the flexible ring cushions sudden loads and reduces chain whip
• Quiet running - reduces chain slap and noise
• Quick to fit - squeezed into place between the chain strands in seconds

In simple terms, a roll ring is a flexible toothed ring that sits inside a chain loop and pushes the chain outwards to keep it tight automatically.

Why are roll rings essential?

Roll rings are essential because chains stretch as they wear, and slack chains cause problems such as whipping, noise, jumping teeth, and rapid wear. Traditional tensioners need brackets, mounting points, and space on the machine, which are not always available. Roll rings solve this by tensioning the chain from inside the loop, with no fixings and no need to modify the machine. They are especially useful on reversing drives, where both strands of the chain can become slack.

Their main benefits are:

• Simple installation - no brackets, drilling, or mounting points needed
• Automatic adjustment - keeps the chain tensioned as it stretches
• Works on reversing drives - tensions both strands, so the drive stays tight in either direction
• Reduced maintenance - no bearings, lubrication, or regular adjustment
• Longer chain and sprocket life - correct tension reduces wear
• Smoother, quieter running - reduces chain whip, slap, and vibration
• Space saving - fits inside the chain loop, using no extra space on the machine
• Cost-effective - a low-cost way to improve chain drive performance

Roll rings are used across a wide range of applications, including:

• Light industrial machinery - small and medium chain drives
• Packaging and food machinery - chain drives on production equipment
• Conveyors - roller chain drives on light and medium-duty conveyors
• Agricultural machinery - chain drives on implements and equipment
• Printing and textile machinery - chain drives and mechanisms
• Reversing drives - drives that change direction regularly
• Retrofit applications - improving older drives where there is no room for a tension arm

The main types of roll rings

Roll rings are usually grouped by chain size and number of teeth.

By chain size:

• 06B (3/8 inch pitch) roll rings - for light-duty drives
• 08B (1/2 inch pitch) roll rings - one of the most common sizes for general drives
• 10B (5/8 inch pitch) roll rings - for medium-duty drives
• Larger chain sizes - such as 12B and 16B for heavier drives

By number of teeth:

• Smaller rings - fewer teeth, suited to drives with shorter shaft centres and smaller sprockets
• Larger rings - more teeth, suited to drives with longer shaft centres and larger sprockets

Each roll ring size is designed for a range of drive layouts, so the ring must suit both the chain pitch and the gap between the chain strands.

Related products:

• Tension sprockets - free-running sprockets mounted on tension arms or brackets
• Tension arms - spring-loaded arms that hold tension sprockets or rollers against the chain
• Tension rollers - free-running rollers used to tension belts and chains

How to choose the right roll ring?

Choosing the right roll ring means matching it to the chain and the layout of the drive. Work through these points in order:

• Chain size - choose a roll ring that matches the chain pitch exactly, such as 08B
• Chain standard - check whether the chain is British Standard or ANSI
• Drive layout - measure the shaft centre distance and note the number of teeth on both sprockets, as these determine the space between the chain strands
• Ring size - choose a ring size that suits the drive layout, using the manufacturer’s selection guidance
• Direction of rotation - roll rings are ideal for drives that run in both directions
• Speed and load - check that the roll ring suits the chain speed and load of the drive
• Environment - consider temperature, oil, and chemicals, and check they are compatible with the ring material
• Quality and brand - choose roll rings from reputable suppliers for accurate tooth profiles and consistent tensioning force

How to fit a roll ring

Fitting a roll ring is quick and simple:

• Isolate the drive - switch off and isolate the machine before starting work
• Check the chain - make sure the chain and sprockets are in good condition and aligned
• Squeeze the ring - compress the roll ring into an oval shape by hand
• Place it between the strands - position the ring inside the chain loop, between the two strands, roughly midway between the sprockets
• Engage the teeth - release the ring so its teeth engage with both chain strands
• Check the position - make sure the ring sits squarely in the chain and is not twisted
• Run the drive - turn the drive by hand, then run it and check the ring rolls smoothly with the chain
• Consider guides - in some installations, such as vertical drives or drives with heavy vibration, side guides may help keep the ring in position

FAQ - All you need to know about roll rings

What is a roll ring?

A roll ring is a flexible, toothed polymer ring that sits between the two strands of a roller chain and pushes them apart, keeping the chain tensioned automatically.

How does a roll ring work?

The ring is squeezed into an oval and placed inside the chain loop. As it tries to return to its round shape, it pushes outwards on both strands of the chain, taking up slack.

What do the sizes on a roll ring mean?

Roll rings are described by chain size and number of teeth. For example, a 26-tooth 08B roll ring suits 1/2 inch pitch 08B roller chain.

Can roll rings be used on reversing drives?

Yes. Because a roll ring tensions both strands of the chain, it works in both directions of rotation, making it ideal for reversing drives.

Do roll rings need mounting brackets?

No. Roll rings are held in place by the chain itself, so no brackets, bolts, or arms are needed.

Do roll rings need lubrication?

No. Roll rings have no bearings and do not need lubrication. The chain itself should still be lubricated as normal.

How do I choose the right size roll ring?

Match the ring to the chain pitch, then check the shaft centre distance and sprocket sizes against the manufacturer’s selection guidance to choose the correct number of teeth.

What is the difference between a roll ring and a tension sprocket?

A tension sprocket is a free-running sprocket mounted on a tension arm or bracket, usually tensioning one strand of the chain. A roll ring sits inside the chain loop, tensions both strands, and needs no mounting.

Why does my roll ring keep coming out of the chain?

Common causes include the wrong ring size for the drive, misaligned sprockets, a badly worn chain, or excessive vibration. Check the ring size and alignment, and consider side guides if needed.

When should I replace a roll ring?

Replace it if the teeth are worn, cracked, or damaged, if the ring has lost its springiness, or if it no longer keeps the chain tensioned.