A fresh Maxxis Receptor gravel tire.

Back in the good old days of XC yesteryears, Maxxis made a mountain bike tire called the Larsen Oriflamme. It had a nearly smooth diamond pattern across almost the entire tread, then perfectly sized side knobs on the side so that you stood at least a small chance of catching a slide before it was too late. In the right conditions, they were so fast. They were always sketchy. I loved those tires. 

The Maxxis Receptor is basically a gravel-sized Oriflamme. Within Maxxis’ own gravel range it slots in between the road-going Re-Fuse and the well-rounded Rambler. It’s a semi-slick with a good sidewall, fast on packed dirt and gravel and downright terrifying on anything loose or wet. After half a year of testing in dry Colorado, has my Oriflamme love extended to this gravel offering? 

Story Highlights

  • What it is: A gravel tire that excels on hardpack surfaces.
  • Features: Semi-slick, dual-compound tread with EXO sidewall protections
  • Weight: 429 g (claimed); actual 428 g and 439 g for review set.
  • Sizes:700x40mm (tested), 650x47mm
  • Price: US$62 / £45 / €52 per tire
  • Highs: Super fast rolling with just enough side knob to prevent spills and a good sidewall
  • Lows: Good luck on loose or muddy surfaces, you’ll need it.

Tech Details

Maxxis is quite good at finding the right balance of rubber compound (or two rubber compounds, in this case), casing durability, and traction for a particular use case. 

The Receptors get Maxxis’ EXO sidewall protection. It’s a tightly woven fabric – think Kevlar, but not Kevlar – that gets stuck on the sidewalls below the tread, adding cut protection without significant detriment to weight or ride quality. Years of use on the mountain bike side suggests it’s pretty effective stuff. Just a single layer is used on these tires.

The tread itself uses two different compounds, a firmer rubber for the smooth center and another, slightly softer compound for the taller side knobs. 

The tires are Tubeless Ready, as you’d hope for any gravel tire. In Maxxis-speak that just means there’s a bit more rubber on the sidewall so they’re, in theory, airtight without sealant. I only tested them with Stan’s sealant. 

I tested the 700c version, which comes in 40 mm width. The actual measured size was 41mm when mounted to the Easton EC90 AX gravel wheels I used for most of the testing, which have a 24 mm internal width. A second set of tires mounted to Hunt wheels with a 25 mm inner width (shown in the photos here) measured 41.2 mm.

Like someone hit a road tire with a growth ray.

It feels like a supersized road tire

With PSI in the low 30s, the Receptor’s short side knobs usually make no contact with the ground, leaving you to ride exclusively on the essentially slick center of the tire. Unsurprisingly, the feel on pavement and hardpack dirt is basically like a road tire hit with a growth ray. There’s no road buzz, none of the sluggish feeling I associate with more heavily treaded gravel tires. 

That has its benefits and drawbacks of course. This is not a gravel tire for every condition; it has a pretty specific use case. Fall outside that use case and you’ll find yourself tip-toeing, not shredding. Stay where the Receptor is happiest and you’ll be rewarded with a plush ride and, above all, speed. 

Where the Receptor excels

If your rides feature a healthy dose of pavement, some packed dirt roads, maybe the occasional bit of Grade 2 and 3 gravel, a semi-slick like the Receptor is a great option. 

The center tread rolls fast and has just enough grip to stay planted when climbing steep stuff and the Receptor’s side knobs are just tall enough to grab when you really need them, or to give you a chance of saving it if you start to slide. 

I’m a fan of 40mm gravel tires. As long as things aren’t wet or extremely loose, you can get away with quite a lot via low tire pressure and high volume, as the tire is able to effectively wrap around whatever surface you’re on. High volume can do a lot of work in the traction department, work that doesn’t need to be done by slow tread patterns. A bit of rougher gravel thrown in here or there isn’t a major concern when you’ve got enough volume underneath you.

The Receptor is therefore a solid tire for a lot of today’s gravel races, which are often contested on a mix of packed dirt roads and pavement. I wouldn’t run it at Unbound Gravel because it doesn’t have enough tread to prevent cuts on that nasty shale, but for something like Steamboat Gravel it’s a superb option.

Cornering, not so great

If you’re buying a semi-slick for its cornering prowess, you may want to re-assess. But you still do have to get these things around a corner every once in a while. 

The side knobs on the Receptor are well off to the side and are short. They’re also spaced quite widely. That’s good for rolling along in a straight line as they stay out of the way, but it also means that you have to really lean the tire over to get it to bite. As you lean, there’s a lot of slick real estate to cover before the dirt finally comes in contact with the raised tread. That can be unnerving. 

You have to drive these tires. By that I mean they aren’t going to hook up and whip you around loose corners on their own; you need to be willing to get the bike leaned over, potentially tap a bit of rear brake to bring the back end around. 

If you often ride wet, muddy trails or very loose gravel, the Receptor is useless. This is where you need tread, and the Receptor has none. Look elsewhere. 

This brings me to…. 

Your two tires don’t need to match

My favorite Receptor setup is to only use one of them, on the rear. I’ve matched that rear tire with a couple of different front options – a Donnelly MSO, a Maxxis Rambler, a Goodyear Connector, all near 40mm. The unifying theme with all three of those is they have actual tread across the center of the tire’s profile. 

Tread is good for turning, and you turn with the front wheel. If you lose the rear tire in a corner, you can correct it. If you lose the front, you’re going down. Most mountain bikers run different tires front and rear because your front and rear tires do different things – gravel should be the same. 

There are instances in which a pair of Receptors is great. Those instances involve lots of pavement or super packed dirt and maybe a finish line – if I want to go real fast, perfect. But for everyday riding, something with more tread up front will add a lot of joy with a minimal increase in rolling resistance. 

Look at those wee cornering knobs, aren’t they cute?

Durability

There isn’t much tread to wear down, which is a good thing and a bad thing. The good thing is even once the center of the tire begins to smooth out, the straight-line grip is not significantly affected. The bad news is eventually you’re going to wear through because there isn’t much rubber there. Six months of riding (probably 400 km total on pavement and gravel) resulted in minor wear to the center tread, while the side knobs were still relatively sharp.

The casing durability is excellent. EXO works. I put a small slice in a sidewall that was pluggable relatively early in the testing process by bashing into a square-edged rock at high speed, an impact that would kill most tires. I fixed it with a Dynaplug and then rode it for another 300 km or so, and the cut didn’t continue to grow.

How do they compare to similar tires?

The nearest competitor is probably the Gravel King SS, another slick-centered tire with minor side knobs (actually one continuous side knob). The two options are roughly the same price (USD$60 vs USD$62) and are both tubeless, fast, and sketchy if you try to corner on anything loose. Weights are similar too – the SS is available in a 38mm at 410 g and a 43mm at 480 g, vs the Receptor in a 40mm at 430 g. 

From a traction, cornering, and speed perspective the two are similar. The SS has a solid side “knob,” which is zero help with pedaling traction but works well enough in corners. The widely spaced side knobs of the Receptor offer a hint more traction on loose climbs (I actually found myself leaning the bike excessively to get them to hook up when I really needed rear-wheel traction) but neither excels.

The primary differentiator is in cut protection. The Receptor is a bit burlier and seems less cut-prone. That EXO sidewall, a tech borrowed from Maxxis’ hugely popular mountain bike tires, really does work. I purposefully bashed the Receptors around on sharp, rocky trails here in the Rocky Mountains and was impressed by how well they held up. The SS, which is almost a race-day tire, can’t keep up on the durability front. 

Panaracer does make a burlier version of the SS called the SS+, which has bead-to-bead cut protection via a material they call ProTite. I haven’t used the SS+ yet but it’s probably a better option if you’ll find yourself on larger, Grade 4 or 5 gravel on occasion. 

There are a few other options that come to mind as well. Vittoria’s Tirreno is heavier at just over 500 grams but is another tire that’s tough to flat and rolls incredibly fast. The side knobs are even less effective than the Receptor though. 

The Specialized Pathfinder has a completely slick narrow center tread and drops into a larger tread pattern closer to the center of the tire, lending better traction when the bike isn’t leaned all the way over. That’s going to make the bike feel more confident for riders who aren’t super comfortable on loose surfaces. 

Final thoughts

The breadth of tire options we now have for gravel riding is fantastic, but as that breadth has increased so have we seen tires begin to truly specialize. The Receptor is one of those. If you ride your gravel bike on surfaces that are neither wet nor particularly loose, you’ll love them. The sidewall protection is phenomenal, the weight is good, rolling resistance is superb, and they seat tubeless easily on most rims. Just don’t take them outside their comfort zone for too long. 

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