Panaracer Gravel King SK 40 Tires: Getting Rolling

<Back to News Home |

When Panaracer introduced the Gravel King line of tires, it was a curious debut. What with a skinny, treadless design that would barely cut the mustard on most gravel roads, at least those found in the midst of this great nation we call the USA. Then we saw a new, treaded version, but in a relatively skinny 32mm size only. Finally, we have seen a fatter version with a 40mm Gravel King now available to all who ride the crushed rock roads. Not only that, but it is tubeless ready to boot. Let’s take a closer look at the 40mm version of the Panaracer Gravel King SK.

Gravel King
The Panaracer Gravel Kings- Now available in a fat, 40mm size.

When Panaracer introduced the Gravel King line of tires, it was a curious debut. What with a skinny, treadless design that would barely cut the mustard on most gravel roads, at least those found in the midst of this great nation we call the USA. Then we saw a new, treaded version, but in a relatively skinny 32mm size only. Finally, we have seen a fatter version with a 40mm Gravel King now available to all who ride the crushed rock roads. Not only that, but it is tubeless ready to boot. Let’s take a closer look at the 40mm version of the Panaracer Gravel King SK.

Gravel King
The Gravel King SK 40 mounted up easily on the Project Wide Gravel Wheel set.

What It Is: The acronym laden tire is a brand new 2016 model and features Panaracer’s “ZSG Natural Compound” which is a low rolling resistance- “enhanced wear resistance” tread.  The tire has “Anti-Flat Casing Tech”, which, as near as I can tell, is a bead to bead puncture protection belt to ward of cuts and pinch flats. Finally, there is “Advanced Extra Alpha Cord”, which is not listed on their tire tech page, but is likely similar to their tech which enhances casing flexibility for a smoother ride. Claimed weight on the Gravel King SK 40mm tires is 490gm. Our two samples weighed 480gm/510gm, so within reason. By the way, the “TLC” on the hot patch stands for “TubeLess Compatible”. Finally, you may have noted the “SK” at the end of the tire’s name. That stands for “Small Knob” and was tacked on to the Gravel King moniker to indicate that this is a treaded version of the Gravel King series of tires. Other “Gravel Kings”, (can there be more than one “king”?) are file tread, paved road type tires.

Tubeless Performance: Since the Gravel King 40 SK is a tubeless ready tire, I immediately tried it out on our new Project Wide Gravel Wheels, and the Gravel King 40 was a very snug fit. I had to wrestle just a bit to get them on to the WTB KOM i25 rims, which is something I like to see in a tubeless tire- Not loose, not so tight you have to use levers, but just right. One tire set up with a tired, old floor pump while the other needed a boost from my compressor, but I did not have to remove the valve stems to inflate them. The bead on both tires set up completely at sub-30 psi, which is outstanding. All in all, the Gravel King SK on a WTB KOM rim was one of the easiest tires to set up tubeless I have ever tried. Now that is just one rim, obviously, but later into this review/test period I will try these tires on a couple of other rims as well. Then we get a truer picture, but for now, I give this tire very high marks. By the way, it is holding air like a champ. There is nothing to complain about with the Gravel King 40’s in as far as tubeless performance goes up to this point.

Gravel King
The combination of the Gravel King 40 and the Project Wide Gravel Wheels produced a voluminous tire!

Ride Impressions:
The Gravel King 40’s seemed to be a somewhat beefy, thick sidewall tire when I handled them, and the puncture protection the tire has was a concern going in, (remembering the stiffness of the Teravail Cannonball) but while mounting the tires, I could feel that the casings had some give. In fact, after mounting the tires at 40psi, and letting them sit overnight, I could see that they had stretched noticeably. They stretched to the point that I only did one ride with them on my Twin Six Standard Rando before I felt the clearances were an issue with that bike. That bike is rated to handle 42mm tires, so I was a bit surprised by this. That is, until I measured the Gravel King 40’s with a digital calipers. The reading was 43.11mm at the widest point! Okay, so the 25mm inner width KOM rims probably have a little to do with this, but it seems that the Gravel King 40’s will have generous volume and may not even fit on many bikes out there now. I ended up putting the ones I have on my Raleigh Tamland Two, which has super-generous clearances and the tires fit perfectly fine on this bike.

The first rides on the tire were commutes on broken pavement, on dirt, over grassy fields, and on some very rustic gravel road. So far, I have found that the fears of a stiff, unforgiving tire are unfounded. The Gravel King 40, on these rims, can be run at really low pressures and I had them working the best so far at 35psi rear and 32 psi front, which is 10-15 psi lower than I typically can run a 40mm tire and still have good rolling resistance/ride comfort balance. Some of this may be attributed to the thicker, maybe somewhat more robust casing, which would account for the ability to run lower pressure, but the ride feel is very smooth while keeping a very fast rolling performance. Yes, this tire is fast. It crushed everything else I have tested on my roll down test hill, despite this Gravel King being tested in a headwind. I will have to put the Gravel Kings on my HED Ardennes+ wheels before I make a final call here, but I have no doubt the Gravel King 40 is one of the easiest rolling tires I have tested yet. The weight these tires have is felt a bit upon accelerations, but other than that, I have little complaints so far. Speaking of which…..

So Far……The Gravel King SK 40mm tires are making a great first impression with their easy to set up tubeless performance and day to day ability to hold air pressures. The ride feel is cushy, since you can dump a bit more air pressure than usual, and they still remain one of the easiest rolling tires I have yet tried. The only downside is that they stretch a bit after tubeless set up and may not fit many bikes out there. (Ours are 43.11mm wide!) There will be a lot more gravel road riding on these coming up in the future, so stay tuned and I will be back with more on these voluminous monarchs of the tire world soon.  For a Quick Review of these tires done by our contributor, Grannygear, CLICK HERE. For another Quick Review- this time on the narrower, lighter 32mm Gravel King SK tires, CLICK HERE.

NOTE: The Panaracer Gravel King SK 40mm tires were purchased by Guitar Ted for this test/review. Panaracer did not request, pay for, or bribe us for this review and we will strive to give our honest thoughts and opinions throughout.

Discuss and share your questions or thoughts about gravel bikes, gear, events and anything else on the Riding Gravel Forum


Author: Guitar Ted

Guitar Ted hails from Iowa. Home of over 70,000 miles of gravel and back roads. An inaugural member of the Gravel Cycling Hall of Fame and Co-creator of Trans Iowa in late 2004- Guitar Ted has been at the forefront of the growth of gravel events and riding since then. Creator of Gravel Grinder News in 2008, he produced the premier calendar of gravel and back road events. GT joined forces with Riding Gravel in late 2014.

Related Articles

13 thoughts on “Panaracer Gravel King SK 40 Tires: Getting Rolling

  1. I just put a pair of these on my All-City Macho Man Disc. (They came in a day or so before you announced them on your GTP blog.) So far, my findings are spot-on with yours, but I only have about 50 miles on them at this point. Mostly busted-up chipseal with only a couple miles of gravel. Mine did require a lever to get them onto Stan’s rims (as I’d expect), but it wasn’t a wrestling match to do so.

    When I first mounted them, the profile was almost parabolic in shape, but they seem to have rounded out some since they’ve been mounted.

    The speed/lack of rolling resistance is really nice – especially compared to the bald Happy Mediums (40c) these replaced. I’m still playing with air pressure. Starting at 40psi, now I’m down to 32f/37r (tubeless), but I’m gonna go a tad lower and see how that goes. (I weigh 168lbs + gear.)

    We’ll see how they hold up, but so far, I’m really impressed. And yeah, they are big… mine are over 45mm @ 35psi on Iron Cross rims!

    1. Wow, I’m surprised to hear that those tires are spreading out to 45mm. The Iron Cross rims aren’t even that wide–20mm internal, right? And yet both of your TK40 tires expanded to measure in at 45mm?

      1. We’re hearing the same thing from other Gravel King users. These tires are really much bigger than 40’s. I suspect the 35’s would probably act in a similar manner, but I haven’t tried those……..yet. 🙂

      2. NoTubes / Sun-Ringle’s BST hooks tends to seat tubless tires a lot higher than other tubless standards – which is why you will find that some brands tubless compatible tires wount even seat tubless on BST rims (and why BST is the prefered rim standard to run getho tubless tires).

  2. Where would these fall in line with the MSO’s and Challenge GG’s? I have almost wore out a pair of 40 MSO’s and am looking for a tire that provides a little more confidence in the corners. Thanks GT!

  3. Hmmm……..I wouldn’t put any of these tires on for a boost in cornering. The slight differences in any you have listed wouldn’t be enough to make that big of a difference, if all of them had tubes in them. So, since the Challenge tire isn’t tubeless, I’d toss that one out as a choice, because I would choose tubeless for my tires.

    My choice would be to use the wider Gravel King on a wider rim- if your bike will allow that- and run the pressures lower tubeless. The stability of the Gravel King at low pressure is really pretty good. That said, it isn’t a tire I’d throw into a corner at high speed and think it would stick. Anytime you try to roll through a corner at high speed you are going to drift and have to wrestle with the bike, if you are on the gravel we have here, which is like rolling on marbles. Sharp, jagged edged marbles, but you should get the point.

    If you have more of a decomposed granite/dirt/packed situation, then something like a Happy Medium or the WTB Nano 40 TCS would maybe be better. It all depends on where you live and ride.

    1. Thanks for the quick response! I’m not aggressive in corners at all, I was just wondering if any of these inspired more confidence. You have just confirmed that I just need to embrace the drift no matter what tire I roll with! I live in SE Michigan, so I would describe the gravel similar to what you have.

      My frame does allow for up to 45’s, so I think the Gravel King might be worth a shot. My only concern now is that I have Grail rims and I thought I remember reading somewhere that tubeless ready tires don’t work well on these rims? Weren’t they made to make non-tubeless tires tubeless? Thanks again GT!

      1. Grail rims might be fine, just a bit of a struggle to mount the first time. I think you’ll be okay there. Panaracer isn’t using a a strict UST dimension, as far as I can tell, which wouldn’t play well with Stan’s stuff if they did.

      2. they meassure 41-43mm on non-BST tubeless rims regardless if internal whith is 13, 17 or 25mm.

  4. I’m in Vermont. I just put some on my very old Velomax (pre Easton) wheels. It was an extremely tight fit. I like how they roll but I’m finding not enough traction on 12%+ grades going up and they also pick up a lot of gravel and fling it. It can make quite a racket as it hits the bike frame.

    1. Robert, I can see how this tire would do the gravel flinging thing if you have finer gravel pebbles. Also, you aren’t going to get a lot of traction from this tire on steeps since it lacks the more open tread lugs necessary to grab on to things you are riding over. Have you tried the WTB Nano 40? I would think it would be a better choice from the traction standpoint, at the least. Also, the Bruce Gordon Rock & Road would be a good tire to think about.

  5. I have a Cannondale Topstone with clearance cited at 45. I’m looking at the Panaracer Gravel King SK. It seems the 40s are now advertised as the 43s, which aligns with what most people experience for their volume. Anyone else have a frame/fork cited with similar clearance who have tried these tires? I’d like to go as wide as the frame allows but also do not want any caught debris rubbing on its way through…

Leave a Reply

Your email address will not be published.