How to put on tire chains, and how chain installers work

Pull fully off the road to the right, fit chains to the drive wheels, drive a short distance and re-tighten, then hold 25 or 30 mph as posted until the End Chain Control sign. Installers at checkpoints are independent contractors: get a receipt. Today's chain controls are shown above.

Before the season

• Buy chains that fit. Chains are sized to the tire, so read the size off the sidewall (for example 235/55R19) and buy a set that lists it. Cars with tight wheel wells need low-profile chains or cable chains; the owner's manual says which type your car allows and which axle they go on.
• Practice once in the driveway. Fitting chains for the first time in the dark, in slush, with traffic passing is how people end up with a chain wrapped around a brake line. Ten minutes at home makes the roadside version routine.
• Pack the kit. Gloves, a kneeling mat or a piece of cardboard, a headlamp, and a plastic bag for the wet chains afterwards.
• Keep the chains in the car all winter. Under R-1 and R-2 even an exempt 4WD or AWD vehicle must carry them, and the checkpoint can ask to see them.

At the checkpoint, step by step

1. Pull all the way off the pavement to the right. Chain control areas have wide shoulders and turnouts for this; there is usually about a mile between the "Chains Required" sign and the checkpoint. Never stop in a traffic lane, and do not install on the left shoulder.
2. Hazard lights on, engine off, parking brake on.
3. Find the drive wheels. Front for a front-wheel-drive car, rear for rear-wheel drive, and the axle your manual specifies for AWD and 4WD.
4. Drape the chain over the top of the tire with the hooks facing away from the sidewall, tuck it behind, and connect the inside fastener first, then the outside one. Pull the cross-chains straight so none are twisted.
5. Tighten and add the tensioner if your set has one.
6. Drive 50 to 100 feet and stop to re-tighten. Chains settle onto the tire in the first few turns and almost always need a second pull.
7. Drive at 25 or 30 mph, as posted. Faster than that breaks chains and dents fenders. Avoid spinning the wheels and hard braking, and listen: a loose chain slapping the wheel well means stop and re-tighten.

Cables versus chains

Cable chains are lighter, easier to fit and need less clearance, which is why many newer cars specify them. They count as traction devices under California's rules and get you through the checkpoint. Link chains grip better in deep snow and last longer, especially on bare patches. Either way, use the type your manufacturer allows: some vehicles are damaged by conventional chains, and Caltrans does not exempt a car because chains do not fit it. If your manual says no chains at all, find the approved alternative before the season.

Chain installers

At the busy checkpoints on I-80 and US-50 you will find chain installers working the shoulder during storms. A few things to know:

• They are independent contractors, not Caltrans or CHP employees, and they are permitted by Caltrans to work there.
• Get a receipt and note the installer's badge number. Both help if there is a problem later.
• Installers may not sell or rent chains. You must bring your own set, in the right size.
• Many also work the far end of the control area to remove chains.
• Not every checkpoint has installers. SR-88, US-395 and the Yosemite approaches often have none, so be able to do it yourself.

Taking chains off

Drive past the "End Chain Control" sign to a designated pull-out before removing them; the control area ends where Caltrans says it does, not where the pavement first looks dry. Do not drive on bare pavement at speed with chains on: it wears them out in miles and can break a cross-chain. Rinse and dry the chains before storing them, and check for stretched or broken links before the next storm.

Trailers

Vehicles towing trailers must have chains on one drive axle, and trailers with brakes need chains on at least one axle. Truck-only codes on I-80 (TS, TTA, TH) are explained in the Donner Pass guide.

Before you go

The live strip above shows today's controls on I-80 and US-50; the I-80 and US-50 pages show every checkpoint, refreshed every 3 minutes. Caltrans QuickMap (quickmap.dot.ca.gov) and 1-800-427-7623 are the official sources. Requirements change without notice, and whatever you drive, always carry chains. Chains for AWD, 4WD and snow tires explains when you are exempt from putting them on.