Automatic tire chains

Ever wonder what those rotating chains under local school buses are? They are part of an automatic chain system used in snowy weather.

Many school buses in Klamath County are equipped with Onspot chain systems, a set of built in chains that can be released to provide traction on icy roads. The chains look like a small octopus that hangs next to the rear wheels of the bus.

The chains are fixed to the bus’ suspension and when required are engaged by a button on the dashboard, releasing small rubber chain wheels that run along the inside of the back tires of the bus. As the bus accelerates the chain wheel spins and the chain links are thrown underneath the tires to provide traction. If the bus is stationary or slows down, the chains are retracted.

The department of transportation for the Klamath County School District doesn’t use the chains as much as the city district, Klamath County Transportation Supervisor Shawn Snoozy said.

“They don’t do much,” he said. “That’s why we don’t use them.”

Expense, maintenance

In 2000, when the chains came to Klamath Falls, Snoozy said he put them on all the school buses in Gilchrist, but the expense of installation and maintenance cost the transportation department $1,000 a year, per bus.

“You can buy a set of chains for $300 and leave them on for a long time,” he said. “It wasn’t worth it.”

In order for the chains to work, the buses have to be moving. Unlike emergency service vehicles, which might find the chains more useful due to their speed, Snoozy said school buses make frequent stops while driving, including picking up and dropping off children, making the chains redundant.

The chains are designed to provide traction on snow-packed and icy roads and struggle to function in thick snow, Snoozy said. If a bus is stopped at the top of a snowy hill, the chains will stop moving and won’t provide the traction needed to help the bus keep going. They can also become frozen inside the bus if there is snow and ice blowing around on the roads.

Fitted on purchase

The school buses operated by the Klamath Falls City Schools Transportation Department had already been fitted with Onspot chains when they were purchased from another school district, KFCS Director of Transportation Sam McGuire said.

A school bus weighs around 30,000 pounds and most are rear-wheel drive with the engine in the back, McGuire said, which provides more traction in heavy snow as the majority of the weight is in the back of the bus.

Although there are advantages to the chains, such as extra traction when the roads are slippery and buses need a little extra help to stop on a hill, the chains also reduce the speed of the buses, like regular chains, as they are not able to exceed 25 mph, McGuire said.

“They have their place,” he said. “They are not a true wheel chain and when you need real chains, you need real chains.”

Learn more about Onspot chains here: