Kenbi

Went for a 40 mile ride on Saturday, part of which involved getting slightly lost and running into a gravel road for a few miles on probably the wrong tires. It was a bit like playing Galaga trying to dodge holes and larger rocks on skinny tires and I nearly dumped it in some pebbles, but I eventually emerged onto asphalt with the bike unscathed and a new appreciation for the capabilities of 23s.

Jarrett2

Despite what some may have you beleive, road bikes won't explode the second they touch gravel. Well... maybe carbon fiber ones

cyccommute 

Riding gravel on a 23mm tire isn't that bad. It's easier on a wider tire but still doable on a narrow tire. One tip: Momentum is your friend. Don't try to avoid everything. The bike will roll over a lot more than you think and, if you picture is any indication of the type of surface you were riding, it should roll over everything I can see. If you spend too much energy trying to avoid every pebble, you are going to slow down and the ride gets worse as speed decreases which makes you slow down more, which worsens the ride, etc.

Keep your speed up, ride without a death grip on the bars, ride with flexed arms and legs, and try to unload the bike as much as possible. Your legs and arms can absorb a whole lot of the roughness.

TrojanHorse

Crap, that's not bad. I took a wrong turn once and ended up riding almost 10 miles on loose sand that was sometimes packed and sometimes 2-3" deep. THAT sucked... but I made it.

But seriously, why 23? 25 is so much wider.

rbk_3

Last 2 times I rode on gravel I got flats so I avoid them like the plague. Can't bike to my parents house anymore

Jseis 

This solves all those "little"problems.

trailangel

Should've aired down a little.

SpikedLemon

I'm on 25's and don't like when gravel is strewn across the road - let alone riding down a gravel road (which I've done - but not, exactly, happily or without choosing the right path).

deapee

I must say I do enjoy my 25's but gravel still sucks. Why I enjoy my 29er...I just roll over whatever

GravelMN

Just rode some gravel and asphalt on 32s this weekend and have to say they are a perfect compromise for mixed riding. I've ridden 25s and 28s on gravel, while doable I wouldn't say it was as enjoyable as with the slightly wider tires.

ChuckD6421 

This is worthy advice that I second. Especially the loose grip on the bars, and butt light on the saddle. Let the bike steer itself (with gentle guidance).

C.

NoGears

I like my 35's on gravel and they aren't bad on the road. For pure road...no reason to ride a 23 over a 25 or 28. Much better ride and just as fast if not faster on 28's.

Kenbi

Yeah the bike just came with 23s. Maybe I'll bump up to 25s when I wear these out.

Rollfast

You can float the river and plow fields with those.


I've been torturing 'kids' 26" bikes since I was a teenager.

Primitive Don

There is also the issue of what width tires a frame can accommodate. My Trek 560EX can clear 25s, but I doubt it can handle 28s. I have an old Schwinn sports tourer that originally with 700c wheels in place of the old 27", allowing me to run 32 CX tires with small knobs, which are pretty good on gravel (unless the road is washed out) and not bad on the road either. I would like a dedicated gravel bike or touring frame that will handle larger tires, though, since riding gravel is my main interest.

With that said, I have seen some riders on an organized gravel ride with some pretty narrow slick tires, but as a Clyde I would not attempt that.

Jseis 

LOL, It'll float in a mud puddle.

NoGears

Yeah...one of my first road bikes came with 23's. I upgraded to 25's and it was a big difference. Blew one out and had to replace so I made the jump to 28's. I'll never ride on the road again with smaller than a 28 on my bike. I got rid of my road bike and now I have a "gravel" bike that will take 40's or larger. I'm rolling on 35's at the moment but I'm having a second wheel set built so one will have road tires and the other will be gravel tires. I'm going to bump up the road tires to 32's once the 28's I have are worn.

cyccommute 

Perhaps you think that going from a 23mm tire to a 25mm tire is a significant change but I suspect confirmational bias more then any real change. A 25mm tire is 2mm wider than a 23mm tire. That's about the thickness of a dime. In terms of cross-sectional area, it's a circle that is about the size of an 1/8" bearing. In terms of volume, it's about the volume of half a cup of air in the whole tire.

Even going from a 23 to a 28 isn't that a large an increase. I suspect that if we couldn't see the tires, we couldn't tell the difference.

hagak

23 to 28 is not a trivial % increase. That is a 21% increase in width.

NoGears

I suspect you don't know what you are talking about. The difference is real and apparent. I can tell very much the difference when I test road a bike that was on stock 23's. And then got home and rode my bike that was on 28's. No bias. The difference is actual.

cyccommute 

And a change from 23 to 25 is 18%. So? A small change in a small dimension works out to be a large percentage increase. But it's still a tiny increase in diameter. Going from a 23 to a 28 adds the area of a 1/4" diameter ball bearing for comparison. Do you really think that is such a large change?

First off, what is this "difference" you experience? I have bikes on which I have 23mm tires and bikes that have 32mm tires and bikes that have 2.1" (55mm) tires. Yes, there is a large difference in performance between the 2.1" tires and the 23mm tires. But the advantage in performance fall mostly to the 23mm tires rather than the 55mm tires. And, to be honest, the 32mm tires don't shine all that brightly in terms of performance. The bike that has the fastest and liveliest ride is the one with the 23mm tires...but, then, that's not all because of the tires. The 23mm tire equipped bike is 10 pounds lighter than the other 2 bikes.

There are other factors to consider as well. My 23mm tires are higher quality tires with a higher thread count per inch than most tires. The mountain bike tires are low thread count tires which makes them roll a bit slower along with the knobs. I also have bikes with 32mm tires that are 120 thread/inch count and ones with 40 threads/inch count. The 40 thread/inch tires roll worse than the 120 TPI tires. The TPI has more of an influence than the actual width.

hagak

The percentage increase is the important part. Sure adding 2mm to my 245mm car tires will not make a bit of difference but adding 50mm can certainly be noticeable.

NoGears

Ride quality primarily. There's quite a noticeable difference between 23 and 28 and again going up to 35c. More air volume equals better ride. It also offers the ability to run at slightly lower pressure without having to worry about pinch flats. At my weight on a 23c tire...I had to run the back at 100 psi. On 28's I run at around 80 psi. On 35's I'm rolling at 60 psi. No change in my average speed and in fact...it slightly increased when I went to 28's. 35's despite being a gravel tire didn't drop my average speed or increase the rolling resistance either however that's only measured by my perceived efforts at the same average speed I do on a given route. I don't have a powermeter yet to have actual numbers. But I don't need one to know that the larger (28c) tire improved my ride over the 23c. If there was no difference, why is most of the pro peloton going with 25c tires these days over 23's and some rolling on 28's? These are folks that have their efforts measured down to the watt and where fractions of a second can mean the difference between winning a race and looking for a new team.

Spoonrobot 

You're minimizing the differences.

It's not just the casing size it's also the volume of air the tire holds. The 18% difference in width also corresponds to an 18% increase in air volume. Are you suggesting that difference cannot be felt by a rider?

Every increase in tire size has a corresponding decrease in suitable pressure, which can be felt and is obvious when riding different width tires back to back.

https://janheine.wordpress.com/2013/...limeters-make/

cyccommute 

First, I see no benefit from running lower pressure. As you mentioned, pinch flats can be a problem and I'd rather avoid them by running a pressure that keeps them from happening. I suspect that you are trying to get a more comfortable ride with the marginal suspension that a wider tire offers but, personally, I don't depend on the tire to provide suspension. That's what my legs and arms are for.

As for speed differences, there are far too many variables to take into account to say that the tires have provided you with a drastic difference in your overall speed. For a racer where even marginal differences can be an advantage going to a wider tire...and we aren't talking about them going to a 32mm tire...they get a marginal change in rolling resistance. But rolling resistance is only a small amount of the resistance you have on a bike. At speeds over 9mph, aerodynamic drag becomes far more important and increase geometrically with speed while rolling resistance is linear.

I'm minimizing the differences because they are minimal. I've already addressed that 18% difference in air volume above. It's about 1/2 a cup of extra volume over the whole tire. At the contact patch...which is the only place where increased volume matters..., the increase in air volume is the length of the contact patch times the width of the contact patch times the diameter increase. Let's assume 25mm long, 20mm wide and 2mm tall or 1000 cubic millimeters. That's a huge number, right? Except that 1000 cubic millimeters is equal to 1 milliliter or less than a 1/4th teaspoon for the metrically challenged.

As for being able to decrease the pressure, does a quarter teaspoon of volume really make that much of a difference?