I bought these as a gravel-specific tubless tire for my go-anywhere bike. They were a very loose fit onto a set of 700c Velocity Dyad rims that I've run tubeless for years. I couldn't get them to seat at all. I finally gave up and threw tubes in them for now. I like the tire profile and have ridden them over a variety of terrain. I'm really not happy that I can't run them tubeless.
These tires came spec'd on a gravelcross bike I recently bought. Put some serious gravel miles on them training for the Dirty Kanza 200. They are light, roll well on both pavement and gravel, and seat well when running them tubeless. I did have a pinch flat 67 miles into the 206 mile DK but I don't know that any tire would have held up to the big hit the rear tire took when I hit an expected wash out after bombing down a hill. Put a tube in and finished the race with no other tire issues. If I were to note any cons it would be the somewhat thin sidewalls, but that's a trade off I'll take for the weight savings on the tire. Bought a new tire from WBW at a great price to replace the rear tire that I just couldn't get to hold air after my best effort at patching the multiples holes caused by the pinch flat.
I used these tires at the Lost and Found race with great success. It is billed as a gravel grinder but had sections of rutted out jeep roads and dirt ranch roads. There were also many rocky washed out areas from the hard winter in Northern California Sierra. The Ramblers handled everything with no flats and no burping . Setting up tubeless was also difficult on my DT Swiss rims so I put in a tube for 24 hours and then carefully took off one bead to remove the tube. Had to use a compressor but they finally inflated and held air without sealant overnight.
I highly recommend this tire if you have some patience and a air compressor.
One of my local gravel routes was recently refreshed with lots of new gravel, which meant a change from my normal file treads to a mini-knob. I decided on a Rambler (700x40).
I've mounted tubeless tires before. I have a 60 gallon air compression and a Prestaflator. I always soap the beads and pull the valve cores when mounting. I generally have no problem mounting tubeless tires with this set up. I'm usually done in a few minutes.
I spent significant time one evening trying to mount these tires on 2 different wheelsets (HED Belgium and Stan's Grails, both with Stan's valves). No luck. Finally had to give up. Second try the next day I figured out what was going on. This tire, when on the rim but not seated, turns into a circle in cross section, with the beads sitting against each other in the center groove of the rim. This partially block the value and the air wasn't getting between the beads. Eventually I had to back the nut off the valve body so that I could push the value up between the beads. Then, with 60 psi blasts from the Prestaflator and repeated whacking of the tire I got them to seat. Even with the valve pushed into the tire it was still harder to get these to seat than any other tire I've mounted.
They held air overnight without sealant. The next day I was able to deflate and pull the value core without unseating the beads to add sealant. Took them on a 75 mile ride, 50 of gravel (dirt, mud, loose over hard, just plain deep). Very steep loose climbs, 35mph loose descents - tire worked great overall.
I understand why the reviews like this tire. In practice it works really well.
It appears that Maxxis has addressed one of the complaints concerning mounting of the Rambler. Out of the box the rambler has an open U shape making it easier to set up tubeless. I was expecting a struggle but the tire popped on easily in contrast to the first tire from 2016. Thanks Maxxis for the improvement to this already great tire.