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School Bus Auto Chains

Installing auto tire chains on a school bus takes a better part of a day but it’s so worth it! All the service calls I went on to get buses out of a jam during a winter tire spin out was endless. One time a semi truck and trailer spun out on a hill which caused our school bus to start spinning out. Installing chains on a hill is not fun. When the auto chains came in to play there were literally zero incidents. They cost around 1500 dollars and worth every penny.

There are some specs to follow when installing these chains which are manufactured by “Onspot”. Before ordering the chains there are several measurements required to make sure the right set of auto chains are ordered. The distance of the suspension bottom plate from the ground up and the distance to the tire sidewall are just two of the many measurements that have to be submitted to the manufacturer.

These chains come from the U.S so you need to be accurate with the measurements. The 2 chain wheels are colour coded red and blue for right and left side. The instructions are very specific in stating that they have to be installed on their appropriate side of the axle or the chains will not work properly, It’s the way the chains roll under the tire tread when they are actuated that’s important. The design of the chain links make this step important to follow to the letter.

The two air pots which apply the chains are controlled by an electric solenoid actuated by the driver using a simple dash switch, The solenoid energizes the air pressure to operate the chains. The air pots are similar to an air brake chamber used in air brake systems. Once in a while we have to replace the diaphragm on these pots when they wear out from excessive use.

Our fleet runs several auto chain devices mostly on the out of town runs that climb logging roads and run in high elevation areas. I added it up one day the difference of cost if we did not have any auto tire chains. When we go out on a service call it is typically 2 mechanics and a spare bus with the shop pickup. The 1500 dollar cost of the chains gets eaten up quickly with wages, fuel and tow truck charges if required.

That’s the end to my short story on our auto chain program. I would like to see your comment below with your feedback or questions, That’s what the mechanicshub website is all about sharing knowledge and asking questions to our techs in the forum. Check it out if you haven’t already and you’ll see the wealth of knowledge at your fingertips.