Generally speaking, tubes are very stretchable. In a pinch, you can use almost any tube somewhat smaller than the size of the tire (within reason - I am not sure you could get away with using a 20" kid's bike tube in a 650B wheel). High-quality tubes have more uniform walls and can be stretched more. (I often use 700C tubes intended for 19-28 mm tires in 32 mm tires.)
So for 650B, almost any 26" tube will work, and those are pretty widely available. Most of all, you are unlikely to need more tubes than you carry - wide 650B tires get very, very few flats. I've had only 2 flats on Grand Bois Hetres in more than 20,000 miles on all kinds of roads, from urban commuting in Seattle to gravel roads in the Cascades. Both were on very worn tires... I have had as many flats from faulty tubes on test bikes, so make sure you get high-quality tubes! On big rides, I carry two superlight spare tubes plus a glueless patch kit, but even that appears to be overkill. Still, it's better than having to walk for a day or two – in many places we ride, there is no bike shop within 50 miles, so it doesn't matter which tube I ride. Overall, as 650B is becoming the most popular mountain bike wheel size, you can expect the availability of tubes to increase rapidly. Jan Heine Compass Bicycles Ltd. http://www.compasscycle.com Follow our blog at http://janheine.wordpress.com/ -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/groups/opt_out.
