Mine is the factory belt 25k and going strong, not a tooth out of place.
You can carry a spare but you have to remove the swing arm to change the belt.
There was a guy on here who was making emergency belts that were more rubbery and tucked up by the motor but you still had to remove the swing arm when you first got it to slip it over the motor gear.
http://electricmotorcycleforum.com/boards/index.php?topic=6597.msg52264#msg52264
The rear wheel catching air seems to be the quickest way to snap one with rocks or other junk getting between the belt and sprocket being a close second.
Thanks for the info. Exactly the info. I wanted. How much hassle is it to remove the swing arm? I wonder if this is a repair that can be done on the side of the road. Doesn't sound like it. But it sounds like you're saying that the new belt can be set up in advance, in case the stock belt breaks. Can that also be done with the stock belt?
I am on unpaved & gravel roads a lot with my DS Zero. Sometimes even in deep sand, such as in Lone Rock Park in Utah, right on the beach of Lake Powell that I was in last week. Also in Cindy Hills near Flagstaff, AZ a couple of weeks ago. Would it be best for me to try to avoid such? I just wonder how common it is for something to break the belt.
When you say the real wheel catching air, do you mean from too much slack in the belt?
Too bad somebody cannot design an emergency belt with a removable link!
BTW, the Zero DS ZF 6.5 is a great bike for these RV trips. It rides itself slowly right up the ramp on my RV hitch. And if not in an RV park, I can use the gas generator to keep the bike charged. But kinda inefficient to use gas to charge an electric bike!
-Don- Cottonwood, AZ