Compatilbe Snow Chains on 2018 Ford F-150 with 275-55-20 Tires

Question:

I have a 2018 Ford F150 with 275/55-20 tires, the compatibility checker and listing all say these chains will work with my truck. I ordered two pairs that are on the way. I obviously should have checked the manual for the truck first, but I was trusting your site. I just read the manual and it says not to use chains on the front tires at all and that Class S chains are required on the rear. Should I just go ahead and use all four? Use just the rear? Or return all of them? Im confused. It looks like there is a lot of clearance in the wheel well.

asked by: Jordan M

Expert Reply:

The use of chains on your 2018 Ford F-150 with 275/55-20 tires is slightly complicated. The tire size isn't one that requires special chains approved by Ford, but Ford does give you some parameters. The Class S parameter is recommended by all manufacturers now days because everyone is concerned about liability based on more limited clearances from the inside sidewall of the tire to the vehicle itself. These margins are shrinking over the years which makes the manufacturer want to pass the liability to others and only recommend the minimal clearance chains that are rated Class S. The Class S means the chains have less than 15 mm clearance required for the chains not to come in contact with the vehicle.

Many manufacturers have further limited their liability by more restrictions that even at times are conflicting with the local laws. The fact is you should measure your clearances to make sure your chains will fit your tire clearances because a lack of clearance can damage your vehicle's ability to operate correctly as well as cause physical damage to the wheel well.

In most cases, trucks don't require Class S. They are typically rear wheel drive so the rear axle is where you want your chains. Some manufacturers restrict even 4WD vehicles to only use chains on the rear axle, but that is due to clearances. Again, if you have clearances that account for all 4 wheels to use chains making sure the turning axle has clearance at all angles, you can use 4 tire chains which will give you the most traction.

expert reply by: Jason S