thanks for the quick reply guys. thats just the kinda thing i was thinking about. just go at my own pace as long as i can manage it without pushing to much. but 4 hours riding a day, every day i would of thought would not be a safe way to treat your heart. its just a pump after all and may break if you give it to much work maybe??? also i was planning to take onboard extra carbs but you guys don't think it's necessary? i read somewhere that if the body is working without enough fuel on regular basis it will consume the next available enery source which is muscle and fat (mostly fat obviously but a percentage of muscle all the same which increases the less conventional enery you have). so i think the next purchase will be a spare tube and maybe a smaller pump i can attach to the frame.