25c Gravel Tire (or 25c tires on gravel)
 

Hey there,

I'm looking at doing a local 80 mile ride that is about 50% on dirt road. With as much pavement as there is I was wanting to tackle this on my road bike rather than my MTB (fat bike).

Problem is, I'm pretty much maxed out with 25c tires. I currently ride 25c Gator Hardshell tires and am open to buying a second set if there's something that would handle the dirt a bit better.

Any tire recommendations in that size? Roads will be anywhere from smooth dirt hardpack, to lot's of pea sized gravel.

Thanks!

I've ridden the Katy trail in Missouri quite a few times on just regular road tires. Mostly graded pea gravel.

There's a canal trail around here that I also hit with whatever I have on my bike.

http://www.bikeforums.net/attachment...7&d=1461792529

The canal trail has one steep climb (or descent) which can be a bit hairy going either way. I just don't feel safe for hard braking or sharp turns on the gravel.

Anyway, I suppose a lot would depend on what your roads are like. If it is mostly straight and flat, then I'd just ride your normal tires. If you have a lot of steep hills and tight corners, then maybe consider something else.

I do have one road that I'm wanting to ride that has about 2" to 3" gravel on it, so the road bike is out.

The Schwalbe Marathon Plus 700x25 has a moderate amount of tread. But, I think it would be overkill for a single ride.

I'd suggest Panaracer Gravelking 25c for that. It's supple, comfy, and very adept at fast pavement while providing a light file tread for a little extra grip on loose stuff. I used the 23c on a Lemond road bike for hardpack dirt roads for a couple of years, and quite successfully. I currently have 28c and 32c on two other bikes, because they're great, and affordable, all-'round tires.

Was just looking at those. They look good and at 40 a piece they're not redonkulous.

I should add, the GK is billed as a 26c, but I think on a std (or narrow) width rim, they'd measure 25mm. Actually, I think I have 26c GKs on Mavic ksyrium Equipes downstairs, so I can measure that exactly...

That'd be cool. I'm using cr18s so 18mm internal width.

I hear a lot of talk about pinch flatting with these narrower tires too. I haven't been road biking long but come from a mountain biking background and the idea of pinch flatting a tire blown up to 90 psi is kind of bewildering.

I actually got out and hit about 5 miles of dirt road today just to see what my gators would feel like. I didn't really mind it at all. The biggest concern was flats, every time I'd miss dodging a pointy rock I'd cringe.

As far as comfort goes, I've definitely ridden worse so there are no concerns there.

Really wish I could fit a 28 but think it'd be tighter than I'm comfortable with.

So at this point I'm really considering the gravelkings.

At 80psi, those 26-622 Gravelkings measure out at 25.77mm on the Ksyrium Equipes, which I believe are 13 or 14mm internal, so I'd expect them to be a bit past 26mm on 18mm bsw rims.

Okay, so those'd fit no problem. Thanks for the measurements.

Chaad, how much dirt riding do you supposed you did on the Lemond? There are enough dirt roads around here that don't justify breaking out my MTB that I'd be interested in doing this regularly if I knew my wheels would hold up.

Thanks!

I started doing a group dirt road ride just over a year ago, which really enhanced my focus on it. We go out Tuesday mornings May through November, and we do a dirt route occasionally through the winter, as weather permits. Previous to that, I'd ride a couple of miles of dirt road here and there during road rides, but didn't seek dirt out.

So to answer your question, the Lemond saw dirt roads once a week for 35 miles or so, 7 months out of the year. In other words, not much, really.

The wheelset on that bike is primarily a Velocity Aerohead Race set, from probably about 10 years back; I do 't recall. It's a 32h, offset drilled rear, double butted spoke wheelset with Velocity hubs. It has been a flawless wheelset, and I don't believe it has ever needed adjustment, despite my thundering 220-230lbs mass.

I guess I don't know that dirt road riding is any tougher on wheels than pavement, if only for the fact less traction on a less stable surface mitigates the amount of stress on the wheels. That, and dirt road irregularities like washboard and potholes tend to be more rounded and softer at the transitions than broken pavement.

Nowadays I run 30c tubeless tires on wide-ish rims on a Kinesis Racelight 4S frameset for gravel road work, while the Lemond hangs unused in the basement.

Thanks for the explanation. Very helpful. I think that 35 miles once a week would exceed anything I have in mind so I'm gonna just go for it.

I have a path like that nearby, and I never thought about it when I had a gravel bike and 32c tires. Now that I have 25c road tires, it just freaks me out. I stopped down a few times to look at conditions (it's good for walking and sight seeing too), and paid attention to people's tires. 99% of bikes that I see, even if they have drop bars have at least 32's. I see a lot of partially buried rocks where there's like an inch of pointed, exposed rock.

I frequently ride a short section of crushed gravel trail on 25c tires with no issues, but I definitely slow down and ride as gingerly as possible. The gravel is angular and not very fun to ride on with 25c tires. I can't imagine doing it for more than a few miles. Same bike with 33c knobbies floats over this stuff like it isn't even there.

As someone else said, a lot of this depends on the type of road. Hard-packed dirt or gravel is no problem for 25's. Doing 40 miles of loose gravel, rocks, holes, etc on 25's sounds brutal.

If you're planning on a bunch of similar rides, then you can get your gravel tires.

if it is only a single ride, then either ride your existing tires, or get new tires that you might use elsewhere. For example, the Marathons, while perhaps not the classic gravel tire, they would make generally tough commuter/touring tires.

I picked up a set of Gravelkings today. Whether or not I actually do much gravel riding, they seem like a great tire. They feel as beefy as my Gators and are still relatively smooth.

One nice difference though was how supple the GK's feel compared to the Conti's.

Thanks for all of the replies.

I've done a good amount of off road and gravel riding on my road bike with 25c Gatorskins and even at 90 psi every little bump and rock translates into the frame. A road bike is more capable off road than people think, just not too comfortable for longer distances.

Not all gravel is created equal. Just within Minnesota, the type of gravel used on the road varies greatly and because of the type of rock and grade of gravel can have dramatically different impact on tires. The "gravel" path shown in the photo posted earlier is smoother than any gravel I've ridden on recently. I'm riding 40 mm Clement MSO's which seem to be able to handle anything I've encountered on an actual road.

https://www.compasscycle.com/shop/components/tires/700c/compass-700cx26-cayuse-pass/

and better than gators is Schwalbe Durano plus (much better) but not sure if gators or durano plus handle well on gravel

If it really is pea size gravel at most, I wouldn't even bother with changing tires. When tires are that skinny, a little bit of tread won't make a lot of difference. If I was going to do a lot of gravel regularly on skinny tires, I might get something with a bit of a file tread on it, but otherwise I wouldn't bother.

As mentioned already, "gravel" is such a broad term that it really is down to what these particular roads are like. I've ridden a ton of gravel roads in New England that are perfectly good on slick road tires, some in the South that were bumpy but fine, and still others that were all but unrideable. Meaning not necessarily literally impassable, but requiring enough work that it was just no fun. Like I said, if it's the smooth stuff, I wouldn't even bother swapping out tires.

If you want fatter and you have the width between your stays or fork blades you could do a 650B conversion. Then just pick up some long reach calipers.