I am preparing to ride the Katy Trail, 240 miles of crushed limestone. I currently have 32mm tires on my bike. How much benefit would installing 38mm tires provide? I am currently riding a Sirrus with Axis 4.0 disk wheels, the 38's according to other posts will fit.

Split the difference and get some Schwalbe Mondial 35c tires. That's what's going on my Traverse this week. I ride pavement and some packed sand/crushed shell type trails here in FL.

I ride 32mm tires on a touring frame on terrain far rougher than any trail I have encountered made from crushed limestone. I have at times wished for fatter tires to get through rougher sections, but certainly not on a rail-trail. The exception is if it has been a very wet season and the limestone trail is soft, as a fatter tire will tend to float better rather than cut a groove while you ride, and thus roll with less effort.

I do a Katy Trail end-to-end ride every year. I run 700x32 tires at 65-70 psi. I weigh 215 lbs plus my touring bike adds another 30 lbs. I've never felt the need for anything wider.

You wouldn't happen to be doing this year's Missouri DNR Katy Trail Ride? If so, look for me on a green Windsor Tourist.

Thanks for your reply, one thing less to worry about. I am going to be riding with my brother in September or October.

Where about in KC are you? I am out in Independence, ride the little blue trace trail

I'm on the Kansas side of the line and most often ride Tomahawk Creek and Indian Creek Trails. Weather permiting I ride my mountain bike at Shawnee Mission Park and Lawrence River Trails.

cool, a few of my co-workers are trying to get a ride setup for Saturday on tomahawk, weather permiting