8-in-1 Adjustable Barn Door Floor Guide

The base has a slot, and the two nylon rollers reposition along it. Eight documented setups come out of that, varying two things: the spacing between the rollers, which is what suits the guide to your door thickness, and how far the pair sits out from the wall flange, which is what clears your baseboard or trim. The rollers are interchangeable, so either can go on either side. You set it once at install and it stays put. The practical benefit is that you don't need to know either measurement before you order.

Both mount to the wall or baseboard, and neither needs floor drilling or a slot in the door bottom. The difference is adjustability and capacity. The standard wall mounted guide is a fixed bracket with a single roller, sized for doors up to 2-1/4 in — the simpler choice when your door thickness and baseboard depth are standard and already known. The 8-in-1 uses two rollers that reposition along a slotted base and fits doors up to 3-1/2 in, so it's the one to pick for a thicker door, a deeper baseboard, or an install where you haven't confirmed the measurements yet.

In a bypass setup the outer door has to pass the inner door. A bracket-style guide attached to the wall sits in that travel path and blocks it. For bypass, the U Channel wall mounted guide is the right choice — it mounts to the wall but lets doors pass through it.