Are generic ebay tubes sufficient? Here's what i'm looking at:
http://cgi.ebay.com/ebaymotors/GR-13-14-15-Universal-Tire-Inner-Tube-13-14-15_W0QQcmdZViewItemQQ_trksidZp1713Q2em153Q2el1262QQcategoryZ33746QQihZ001QQitemZ110170348703
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