Road Cycling - chain falling off and shifting problems

I just got a new Cannondale R700 triple. Everything was great, until last week (about 3 weeks after I got it), the chain started falling off the front middle sprocket and down to the smallest one. This happens when I am going uphill. I know this combination causes the chain to cross over a fairly wide area. Is this typical of a triple? Are there certain combinations that I should avoid given that it is a triple? Did I make a mistake getting the triple? I got it because I am new and thought I might need the extra gears for big hills.

Your bike shop should have given you a free tune-up or two when you bought your bike.New bikes usually need checked after the first week and then a month or so later.Take it back there and I'd say if they will adjust it for free.Sounds to me that you may have it shifted to go into the small chainring but it's taking a while to drop?Triples are great, just sometimes they don't go into granny easily under a load.

It should not do it assuming you shifted properly.The cable tension is possibly too great.There is derailer adjustment help at www.parktool.com or take it back to delaer.Get a maintenae book too.

Sounds like your cable has stretched, as they usually do when new. If you can't get it back to the shop for a tune up it's an easy adjustment. This depends on your shifter type, but most have a little adjustment knob right where the cable leaves the shifter. Give it about one crank at a time and test until it's back to good again. The bike shop can do more adjustments if needed but this should do the trick. Or, if this doesn't make it perfect, read the instructions and adjust the low and high setting on your derailure. By the way, where's the spell checker on this thang???

Forgive the confuson but I just got back from a grueling hot mountian bike ride with my son...