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What Are Auto Chains On A Semi Truck? (Explained & Solved!)

Automatic tire chains on a semi truck are a safety mechanism designed for icy and snowy road conditions and aids the truck in staying on the road when conditions are harsh.

Some truckers dislike them and some love them.

We’ll explain why these innovative products could save time, money, and lives, whether your considering installing them on your truck or just curious we have the answers.

Here is a quick answer to what Auto Chains on a Semi Truck are:

Auto chains on a semi truck are snow chains that are activated automatically by a switch located inside the cab of the truck. A hydraulic arm extends from underneath the vehicle and flings rotating chains under the tires to help keep its traction and avoid losing control on snow and ice terrain.

onspot auto chains

What are Auto Chains on a Semi Truck?

Auto chains are a set of automatic ice, snow, and mud chains that extend from a small wheel at 60-degree intervals.

They have 1 to 3 chains on each section which are continuously thrown under the tires to gain maximum traction.

The auto chain is mounted to the axle or suspension of the vehicle and is a clever design to help the driver remain in control of the truck during icy and snowy conditions.

It is controlled by a switch located inside the cab of the truck and deploys in less than 2 seconds.

They are effective as long as they make contact between the tire and the road surface.

They are made of steel, polyurethane, rubber, and fabric materials making them highly durable in most conditions.

How do Automatic Chains Work on a Semi?

A switch will be mounted on the driver’s dashboard, once the switch is activated.

The chain wheels are lowered next to each wheel by an arm. The chain wheels then collaborate with the truck’s tires and spin.

The chains are then thrown under the tires to reduce contact with the slippery road surface and acts as traction until the flip of the switch moves them back to their sleeping position.

Check this cool video on Onspot auto chains and how they work:

At what Speed can you Drive with Auto Chains On?

The auto chain manual has a recommended speed limit of 35 mph it is down to the driver’s discretion to drive to this speed if needed or to drive slower whichever is safer.

Although they are designed for the recommended speed for long hauls it is our recommendation that you assess the road conditions and drive according to the speed you feel suits your driving skills.

Driving faster than recommended can cause the system to fail or break therefore rendering it useless in the task of maintaining control over the huge vehicle.

On which Tires are Auto Chains Installed?

On a semi truck the auto chain is installed on the rear axle or suspension to support the rear tires in an effort to prevent sliding and will reduce this by up to 30%.

They will be installed on the drive tires because these are the tires that are connected to the axle and make it easier to line up the air pressure the auto chain kit needs to work.

It is also a better place for the stabilizing of the vehicle itself in the traction control process, spinning would usually occur from the front or the back.

Do Automatic Tire Chains Work in Reverse?

They do work in reverse as they’re not mechanically operated and rely on the spin of the wheel of the truck to keep them moving. When the truck stops they stop spinning.

When in reverse they will spin in the opposite direction, the whole idea is to make it safer and easier for the driver to engage or disengage them.

It would rarely be used in reverse as the truck wouldn’t need to pick up much speed.

However, in reverse, the system will operate safely up to speeds of 5 mph any greater than that and it could break.

Are Auto Chains Good for your Semi Truck?

They are great as long as you stick within the recommended speed limit.

However, if you exceed this limit and the auto chains break off or get caught somewhere they do not belong it won’t be good.

The damage to your truck could be severe and debris could even damage other vehicles around you.

Repairs could go into the thousands. That aside they generally are a truck driver’s savior.

Better with one than without most truckers say and in moments of road signs changing due to road layouts the switch on switch off comes in handy compared to a manual set that would tend to be left on throughout.

Will Auto Chains Damage your Semi Truck Tires?

They can only cause damage to the actual tire if driven on a hard surface or have not been installed properly or come loose.

Check that they have been properly fitted by testing them yourself.

Planning the road ahead. Retracting them when you see the snow, ice or mud has cleared up. This will prevent the chains from coming into contact with a hard surface.

Snow covers a lot of things on the road that we would normally avoid such as a concealed rock. This can damage or loosen the chains.

If you notice they are becoming loose you can either tighten the bolts yourself or visit a qualified mechanic.

Will Auto Chains Work well in Deep Snow?

It is best to avoid deep snow but if you must drive through it, the auto chain system will aid you so long as you keep the momentum of the truck going as the chains rely on the wheels of the truck turning.

If you get into a situation where the truck stops completely the auto chains will become useless in helping you out of the thick snow as they have no motor of their own… so keep it moving and you’ll be just fine.

Are Auto Chains on your Semi Truck Noisy?

Not for the driver as they are set way up in the cab and the chains are underneath at the back.

During snow, you probably wouldn’t hear them at all with ice however you may hear a crunch.

Anyone near the rear end of the truck may hear some noise but this will blend into the crunching sounds of the snow or ice.

On a hard surface, you will also hear some noise with the chains making contact with the ground.

Are Auto Chains better than Manual Snow Chains for Semi Trucks?

Auto snow chains are better for saving time on getting out and putting them on yourself which can take you an hour or more to install they also remove the risk of a collision.

In poor visibility, drivers may not see you installing manual chains and may hit you or your truck but with the flick of a switch all of this goes away and you don’t even have to stop.

Manual chains are a lot cheaper but more time-consuming and hazardous to fit.

What are the Typical Problems Associated with Auto Chains?

There have been reports of the tension system getting stuck or frozen.

They also do not seem to be too effective when working in reverse.

Some drivers reported that the arm lost pressure which somehow caused a punctured tire and damage to the airbag suspension, but these are rare cases and it seems that auto chains are a good product that works great.

Regular maintenance and checks will prevent any inconveniences the product may cause.

If you feel there is a problem take it back to where you purchased it and have them check it out.

How Much do Auto Chains Cost?

The price for an auto chain system starts around $1500 to $2000 and that’s just for the kit.

To have one installed you are looking at an additional $300 to $500.

Pricing for a vehicle with air brakes is around $1900 per drive axle for the kit, freight, and installation and with vehicles, without air brakes the price is $500 more.

The reason it cost more to install in a vehicle with no air brakes is that the system requires air pressure to operate it which would require the installation team to fit a 12 volt electric air compressor kit.

This provides the air onboard to pull and push the arm of the wheel chains.

However, this should be a problem for semi trucks as they operated on an air brake system.

What are the Best Auto Chains for your Semi Trucks?

There are quite a few companies out there that supply automatic chains and all carry the same brands with very similar guidelines which then makes it tough to know what is the best.

Branding isn’t going to matter much here as they’re all made up of the same materials and operate in the same manner, but if you’re going by brand names then some of the top ones are OnSpot, Insta-chain, and RUD.

Happy Trucking!