Originally Posted by
Marcus_Ti
Depends on where and how you ride.
Up here, lots of rollers that you can only charge half way up with momentum from a previous roller. So you're in your 50x23 or 50x25 at a reasonable cadence, and want one more gear stepping down you'd double shift (and Campag or Di2 IIRC multishift in back) to say a 34x16 or a 34x17. Something I do many times on a daily basis.
The alternative without either double shifting (or multishifting)..is either grinding in a sub-optimal gearing/cadence, or needing to do 1 left hand shift and 5 right hand shifts which takes a good bit longer.
I didn't say you COULDN'T double shift when you had to, I said it was undesirable (okay maybe just LESS desirable) to do it. I meant it is harder than single shifting, and you wouldn't choose to do it if it could be avoided. You don't do it just to get to the next gear ratio only to come back to the original ring and then back and forth. I am not trying to discredit your riding technique, only to point out that programmed, electronic shifting can make moving smoothly up the gear ratios from one to the next closest a non issue.