Thanks for the interesting discussion that shines a light on tire size.
I'm currently using Conti Touring tires with a flat bead and a grooved (side?) Size 700x32. My rims are WTB 22?, Tiagra hubs, that came stock when I bought the bike in 2007.
I'm interested in exploring the idea, or buying a new set of wheels, so I can ride my Volpe (cycle cross) bike on dirt roads that can be slippery when wet. I'm interested in exploring some tea field farmer roads. My idea is to have a second set of wheels I can simply swap out for riding off road in a size like 700x38.
If it matters: My brakes are Cane Creek cantilever. My STI shifters are Tiagra triple with front crank sizes 28,38,48.
What are your thoughts on this? Is it better to buy a mountain bike for this purpose? (I doubt I will do any single track here.)
1. You need wheels, tires, tubes, rim strips, cassette, and skewers to be the most convenient. The cost of everything can add up.
2. Make sure that your "off-road" tires clear everything - fenders, seat stays, chain stays, and fork. This should not be a big problem for the Volpe. You should have room for at least 35mm without fenders, and surely 28mm with fenders.
3. Try and get a rid width near what you have now, or you will have to make brake and/or pad adjustments when you swap wheels.
Plan correctly, and swapping wheels will be a 90 second affair.
learn ISO 5775 measurements as it makes everything easier.
622 (ISO) is 700c (French) and 28 Zoll (German)
23-622 is what I ride on my FGSS
57-559 is what I ride on my MTB
once you know those, you can communicate with everyone and never make a mistake as they're always stamped directly on the tire.
meyers66, it depends on your riding. I also happen to have a Bianchi Volpe. I have 32mm tires on it and also fenders. I haven't tested to see what width I can put on, but I suspect I could put on at least 35mm tires while keeping the fenders. With the fenders off, I could probably put even wider tires. My Volpe is from the mid 90's, so the geometry has probably changed a bit, but not necessarily the tire width tolerance.
Changing your wheels makes things convenient, but I'm pretty adept at changing tires, and I wouldn't bother with that expense. I'd prefer to get another bike. It's more fun.
I don't have an off road bike. One of these days, I'll get around to it. In the fall, I took a long trail ride with a bunch of guys. Some had road bikes, and some had off road bikes. All of them had wider tires than I did. I guess that means I'm OK with off road riding with a road bike and road tires. I could have done it with narrower tires, but I wouldn't have wanted to. This was on the Old Croton Aqueduct trail in NY state.