I recently bought a Trek 2.1 and it came with 700x23 100psi tires. I do a lot of road riding, but every once in a while the packed limestone (rails-to-trails) trails are the better option. I've ridden a few times already with no incident, but I would like some input as to whether this is a safe idea?

Side note, I am planning a self-paced century that will utilize almost 50 miles of packed limestone. If 700x23 is not a great idea, what width would you recommend for a limestone/road century?

3 Answers 3


You may want to go up to 700x25s or 700x28s. While you should be okay with 23s, you'll definitely have greater peace of mind with a thicker tire. You may also want to drop the pressure slightly to 80–90psi.

  • Are the 25/28's going to be more sound in terms of flat-resistance or just better handling? Jun 27, 2011 at 15:42
  • Possibly a little of both. You can also opt to get a slightly heavier-duty tire like the Panaracer Ribmo or Specialized Armadillo. There's not really any appreciable difference in rolling resistance for 25s or 28s versus 23s unless you're shaving off every possible second for a race. Jun 27, 2011 at 15:52
  • Last follow-up - what advantage does dropping the psi do for me? Jun 27, 2011 at 15:55
  • 2
    Mostly, this will make it a more comfortable ride, without sacrificing tire reliability. High pressures are great for smoothly-paved roads, as they decrease (to a point) rolling resistance. However, they also make bumps and jolts in the surface much more easily noticeable. By dropping the pressure a little on rough surfaces, you give yourself a somewhat softer "suspension". Jun 27, 2011 at 17:29

I'd say it mainly depends on the smoothness of the surface, and "packed limestone" can run from glass-smooth to too rough for my 35mm tires. And, of course, in terms of punctures a lot depends on the "weight" of your tire as well.

Basically, if your teeth aren't getting shook out of your mouth, and the surface doesn't have a lot of random loose sharp pieces (more likely with stones other than limestone), it's probably OK, unless you're running super-light racing tires.

If you're going to be doing a lot of this in the future, though, you probably want to consider switching to a wider wheel/tire if your frame allows it. And you can probably go up a size with your current wheels, without having to change rims.


Dropping tire pressure adds suspension to your bike. Over little bumps your bike stays in contact with the trail and so you feel more control and get beat up less.

However, on skinny tires you can only drop the pressure a little bit before you risk "bottoming out" and denting your rims or getting a flat tire.

Bigger road tires have a longer way to go before hitting that bottom, so you can get the pressure lower without risk.

Have fun!

  • This post has been flagged buy the community as "Not an Answer". We're looking for answers with more detail that is focused on the original question. Please consider expanding your answer to more clearly and directly answer the questions in the original post
    – Gary.Ray
    Jun 22 at 17:43

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