Nike+ (Nike Plus) calibration issues...

I'm also getting the "This workout cannot be used for calibration" message, when I walk the Nike+ tells me I'm a world class race walker, crediting almost 3 times the distance. Running it credits me less than half my distance.

As far as having the puck in a pouch on you shoe laces, I know many people had problems with this, if the pouch orientation was upside down, so make sure it is oriented the same way it would be in your shoe with swoosh and apple logo on top

same problem here, but i am running actual nike shoes. it worked great for 350 miles, then i think it went down hill when i updates my iphone to OS 3.1. i ran 3.09 miles today according to my garmin, but the nike+ gave me credit for running 1.28 miles. it did give me the option to calibrate, but the highest i could calibrate to was 1.55 miles. it seems to be getting worse everytime i use it. it is pretty much worthless right now. i think they need to do a lot with the nike+.app on the iphone anyway, like uploading workouts directly from the phone instead of threw iTunes, but now that the calibration is SOOOOOO FAR Off it is worthless. i tried to reformat and restore my phone, it did not help at all. i am glad i checked here, because i was just about to buy a new sensor for my Nike shoes.

I've been having similar problems. I can calibrate a walk successfully, but running calibration under-estimates my pace by half. It says I'm running at 18min/mile. I have the sensor inside my show in the little pocket. Has anybody been able to fix this?

I'm having the exact same problems as James. I logged 30 runs in and then all of a sudden the calibration is so far off it's worthless. I did buy a new sensor but that didn't work so I'm convinced it's the application. I also did a format and restore from backup and that didn't work either. I think the backup is restoring the inaccurate calibration data. The answer might be to delete that data file before restoring from backup.

This is very disappointing. Needless to say I think Nike/Apple needs to spend a little time troubleshooting their application.

I have had the exact same issue since I went from the 3.0 to the 3.1.1 and 3.1.2 OS on my 2G iTouch. I have tried in vain to down grade to the 3.0 but when I did the upgrade via iTunes it does not save the earlier versions (that I can find in my /library/application support/. I found some 'old' update flies on the internet that did not work. I tried both my iTouch (3.1.2) and my wife's (3.1.1) and both allowed me to run, but at the end of the run, I could only calibrate the run to a distance equal to or less then the actual distance run based on the nike+ estimate (so my 6.5 mi run was only registered up to 3.5 mi that the software thought I ran). My sensor has been fine or ~ 650 miles and went funny once I updated past OS v 3.0. I hope Apple or Nike read these forums and fix it in the next update because I really love the nike+ app and now feel it is hit or miss as far has how it records the run. After over 600 mi I really found it a great way to track my runs and keep me motivated!

After doing several 'restore' operations I was able to get the nike+ to go from not allowing any increase in the calibration to allowing ~0.5mi. I did the reset one more time and ran today and it allowed a +2.0 mi to the estimate it had so I is seems to be getting better (why I can't say as the restore kept putting the same 3.1.2 OS and all the same apps back on). THis will work as my road and treadmill cadence differ and 2 mi. should allow me to fix the road run tracking.