I don't know about the Tundra, but some new pickups don't have enough clearance under the front fenders to use tire chains. If you drive where they're needed, you'd better check it out.
Good point RC.
The fender wells have plenty of clearance. On this generation of Tundra, the clearance issue seems to be the upper A-arm and sidewall. The owner's manual says to use chains only on the rear. However, I use chains on all four tires.
With 275/65-18 tires I have just enough room for SCC cables. I've had awesome luck with their cable chains on multiple vehicles, but admit that there are times when I'd prefer to use V-bar chains. No problem on the rear, but the front would be an issue.
If I went 275/70-18, I think the sidewall bulge would be closer to the upper A-arm which would decrease clearance further. I could be wrong though. Maybe they'd fit better.
