If you have 35 inch tires you need them. The Viair 400P is the best personal tire pump I have ever owned. If you own a Smart or a Prius, stop reading. This isn't the pump for you. As a past owner of both of these machines, I can attest that this pump is almost as big as them. However, if you have a large truck or other vehicle with large tires, buy it now. As the proud mother of a 2018 Ford Raptor, I can't imagine inflating my tires with a small air pump that plugs into the cigarette lighter. Yes, this pump is heavy. Yes, you have to assemble and disassemble it to put it in and take it out of your bag, but it's easy and runs smoothly and quickly. It has a lever to attach it to the tire, a nice big sensor and it works on demand so when you squeeze the lever it delivers air. 10/10 Bores my friends with stories about air compressors.