"The simple truth is that side knobs don’t help with cornering traction"

The correct answer appears to be one of GravelKing SS, GravelKing SK, GravelKing EXT or GravelKing Slick… Which one though??

100% this.

For most of my gravel riding, we are on hard pack with loose “kitty litter” across the top. A slick is the absolute worst choice…I thought it would be the best and I was wrong. I tried several different option of slicks / minimal tread and all were sketchy as hell in the corners. When I put on a set of knobbies (Goodyear Connector Ultimates) all was right in the world.

Last year at SBT, I ran Pathfinder pro 38’s…wonderful tire for SBT, horrible on my “home” gravel. But I am also considering running slicks this year for SBT. For that course, I think they would be a great choice.

To state categorically that side knobs are not needed in gravel is, IMO, indicative of someone who is 1) posting clickbait; 2) has a limited view of what is “gravel” ; 3) is trying to make a marketing case for a hole in their product portfolio…or all of the above.

6 Likes

If you want your mind blown on what you thought you knew about traction, watch the line up of a world cup CX race. Many ride slicks on tracks you would never guess.

4 Likes

It’s counterintuitive, but the point being made is pretty clear. When you have something like kitty litter over hardpack, or reasonably deep chunky stuff - what happens is that the gravel is either held in place or deflected away from your tyre. Either way, the platform for pressure is, eventually, rock. And no amount of knobs are going to actually create an impression on the rock.

It isn’t like mud or soft ground (or, frankly, snow) - in these circumstances the knobs carve a physical slot inside of which the knob can apply pressure (and so achieve an amount of friction) both down onto the now hardened ground and laterally against the “walls” of the slot. See: your tyre tracks in soft ground.

2 Likes

sounds like a clickbait-y article. the RH Journal is full of bro science and clickbait for example showing with a roll down test that knobby tyres don’t roll that much slower than slick tyres. I run RH 44mm Slicks myself and like them. Would I run them in mud, snow or loamy surfaces? No.

Jan says himself in another article: “Knobs help with traction in mud, snow and whenever they can dig into a relatively firm surface. On loose gravel, rocks slide on other rocks, and tread makes little or no difference.”

Sounds a bit more nuanced than such a blanket statement.

2 Likes

As noted above, IME, slicks on “kitty litter” are the worst choice. It is like riding in micro-marbles. Knobs give somewhere for the kitty litter to go, leaving the knobs to get traction on the hard pack below.

4 Likes

Yea I mean in circumstances like that, the gravel is kinda giving you a way to ride on something other than gravel…if the knobs are able to reach a second level in the surface.

In loose gravel, I’ve alway thought this to be true. Side knobs or not, nothing is grabbing if what is underneath is is rolling and sliding. Now, if you are on somewhat packed dirt, I believe they are helpful.

1 Like

Depending on mud yes 2020 Mid south Payon McElveen won on a slick and that was a full mud fest. Dutch beach racing they’re mostly on slicks too. A good sticky tire compound and proper pressure and you can get away with a lot less tread. Most gravel roads aren’t soft enough that the knobs will bite. If your doing some under biking and thrashing the bike down more mtb trails where its softer ground they will help.

1 Like

I stand by my initial statement. If the surface moves under the tires, knobs dont help. If a knob can penetrate the surface, knobs help. Those really are the core concepts…not necessarily gravel vs snow vs whatever. It’s also why some knobs are amazing on a surface, and others are horrible.

Tightly packed knobs are BAD in mud, while widely spaced ones are good. Rubber knobs bad on ice, while metal spikes good. But it all goes back to the same question - is the know penetrating the surface and, and the surface is staying there.

1 Like

Have you ridden a mountain bike before? Your statement flies in the face of what every mountain biker knows. Nobody uses slicks on a mountain bike. Even if the surface moves there is still some amount of grip and reaction force.

1 Like

Sure, but I dont think you get more with knobs.

I’ve done a small bit of mountain biking…most of my experience is cyclocross. Could you give me an example of mountainbiking you’re referring to?

I will say the one circumstance I can imagine, is loose gravel on top of a very hard, flat gravel road, which I’ve seen a couple times mountain biking. Some mtb tire have really really big knobs…I have to assume they’re digging down to make contact with the surface below the gravel. So they’re not on a surface that is sliding around anymore.

Again…like there’s a lot of nuance here, especially in these situations where you have a loose surface on top of a firm on. In that situation, assuming a big knob would reach the second surface, and a small one would not, large knobs would give the best traction, slicks would be medium, and small knobs would give the worst traction IMO.

My favorite tire on many surfaces is a semi slick, specifically because the cornering knobs make the tire handle more predictably. If you have gravel over a hard surface, then the side knobs make it harder for the gravel to slide out from under your tire. The challenge chicane profile is the bomb-diggity. If only it had a longer wear life and didn’t puncture easily. Bikes handle best with bike body separation, so hitting the cornering knobs doesn’t require you to lean over like a moto gp racer. I wish I could look that cool though.

1 Like

Most top euro CX pros use file treads in sand (e.g Koksijde, Zonhoven). Knobs make it too grippy and would need legs like Forstermann to push through.

3 Likes

I did a very muddy/gravel race this weekend. When it’s dry, the course usually presents as light sand over hard. I opted for the Pathfinder 38s vs. a knobbier tire since there’s also a lot of tarmac road between gravel sectors. I definitely think that was the way to go for this particular ride. My choice was influenced by the podcast when Keegan talked about using a big file tread tire for a wet, muddy race he did (I think he was talking about Unbound? Not sure) I’m honestly impressed by how clean my bike was after compared to the other competitors. I have to think the Pathfinders shed the mud instead of it being stuck in those knobs and flinging around.

I really think the type and % of gravel needs to be defined before making sweeping judgments on tires.

Yep that’s definitely a thing. Looking at a lot of gravel tires makes me think they’re designed by marketing teams honestly lol. Not a slick or file tread…not large enough knobs or enough spacing between them to do much besides carry half the road around with you on your tires :joy:

I’ve got a set of Vittoria grave tires pretty similar to the pathfinder…I like them. Basically a file tread with light knobs on the sides. Quick rolling in the middle, enough knobs to give a bit of grip on soft dirt, but nowhere for mud to pack in.

If you’ve ever ridden behind someone with the Gravelking SKs, you’ve likely been pelted by all the pebbles and rocks they fling.

I’m pretty sure I will run a center file tread with very light knobs on the sides (a la the Pathfinder) for most of my future riding. That style just makes sense for most of my rides and given that many gravel races involve a fair amount of tarmac, I’ll take the free speed. During my race this weekend, I rode with a guy who had some wider, knobbier tires, and every single descent, gravel or tarmac, I rolled right past him while coasting.

2 Likes

Yea the SK was actually the tire I had in mind. I dont really get what the point is of the small knobs in the middle. It’s almost like they designed a tire specifically to roll poorly on asphalt, yet still pick up mud :joy:

I mean I could be wrong of course. But I dont get the theory behind a tire like that.

3 Likes

The real question for me though…is whether I’m ballsy enough to try a file tread in CX this year. Most races are pretty dry…and when we have a wet rave it tends to stay wet for a while, so I doubt I’d be in a rut of swapping tubeless tires every week.

A “gravel” spin for me locally is a mix of fire road, trail, tarmac, mud, fields, open mountain. Pretty much anything. Regardless of the science, can’t say I’ve looked back from switching from GravelKing SK to more knobbly Hutchinson Tundra.

1 Like