With the spring looming, now is a good time to consider gravel tire selection. The seasonal change is going to mean all sorts of things to riders in all sorts of places, and choosing the right gravel tire is much tougher than people might think. I say that as a reviewer who got tired of reviewing road tires because the top-of-the-line clinchers all became so close in performance. It’s similar with mountain bike tires. There are tire combinations out there that are you can run most anyplace.
But gravel tires? No. Here it pays to choose well and wisely.
Prior to a Grasshopper gravel event, I’ll text with friends and look at weather conditions and any other beta we can get to inform a choice.
For starters, in mud you want to go narrower, not wider, because mud, when it’s not being sticky, is slicker than AstroGlide. So, the issue is getting the tire to sink in the mud so that it can bite into the soil beneath. Also, you want big blocks spaced as far apart as possible. If the blocks are too close together, the space between them will simply pack up with mud. I learned this from watching swamp buggy racing. Hey, I’m a Southerner. In swamp buggy racing, the tires are remarkably narrow relative to the wheels’ diameters.
The next thing I’m going to say may be just as surprising. Most of the time, riders don’t need a tire with a lot of tread. I’ve ridden nearly bald 40mm-wide tires on hardpack dirt and not had any problems with losing traction. And in case anyone is wondering, at a certain point a tire can have so much surface area that it’s traction will begin to drop because there’s not enough weight relative to the surface area, but bicycle tires don’t ever get big enough for that to happen, so wider will always mean more traction.
At this point, I’ve developed a kind of logic tree or flow chart for choosing the right gravel tire, and it looks like this:
- What sort of surface will you be riding on? If it’s muddy, or loose, you’re going to need knobs. If it’s firm, you can go with less tread.
- How much rock is there? If there’s a lot of rock, I suggest going wider to prevent pinch flats. The smoother the course, the narrower a rider can go.
- How comfortable do you want to be, or how much comfort are you willing to give up to be fast? If someone wants to try to stay with a group of quick riders, go narrower, as narrow as you dare. You’d be amazed the stuff I’ve ridden on 25s. If, however, you want more comfort or to reduce the chance of a flat, go wider.
Ultimately, this is a question of competing interests: Riders want optimal traction for the surface they are riding on, and they want as few flats as possible. Those two interests line up rather well. However, riders also want to go as fast as possible and as tires drop in width, they lose rolling resistance up to a point. But it’s important to remember that the narrower the tire, the higher the pressure you need to run; And the higher the tire pressure, the more likely something sharp will puncture the tire.
If you’ve got a solid go-to tire, drop it in the comments and let us know what conditions it thrives in.
You’ve got two of my choices in the pics. I bought a Litespeed Gravel a couple years ago and it came with those Panasonic Gravel King SK, as in the pic with the mini-block tread. You can feel them squirm on pavement but on relatively mild gravel/dirt trails like the Santa Fe Rail Trail (shown here https://labikes.blogspot.com/2020/09/end-of-line.html ) they are fast and sure footed. The 40mm width is overkill for most of the trail but the last couple miles at the south end is very rocky and harsh so a lower pressure wider tire takes some of the hurt off the sit muscles. I have a second set of wheels with the 32 mm Gravel King SS Plus with the center file tread which is a great combo for rides that are part trail and part pavement.
I bought a set of the Xplor MSO’s to put the biggest tire I could find on my old Salsa Cross bike just for grins. Obviously not the lightest set of tires in the world but they are great all around city tires and dirt tires too. They are on the orange Salsa LaCruz in that web page photo. That bike alternates between the MSOs and an old set of Richey 700-32 Speedmax Pros which are probably my favorite off road tire on that bike.
I tried a few gravel tires last year and ended up on Schwalbe all Roads. They may be called overland or something like that now. I put them on at the start of a 1500mile mixed surface tour and rode them all winter for all my rides. They are bomb proof and very long wearing. Other tires I tried either had very flimsy sidewalls or tread that wore down in just a month or so (there was a Rene herse and a vittoria).