I have a bar stem life proof iPhone mount. I manage a restaurant so I have to be able to see and answer phone calls. My cycling computer is basically right next to it. Sometimes my iPhone max speeds were way off (56mph) I wish. Anyway do they interfere the computer is an echo f2 not wireless. Thanks for you help guys.

-Harry

Seems unlikely that they'd interfere, but about the only way to be sure is to try it out and see. I have an old Garmin GPS-V that always loses reception when on the dash in my daughter's car when the car radio is tuned to somewhere in the AM 540 - 580 kHz range. That's not anywhere near the GPS frequency, nor would the radio's local osc. freq. be in the right range, but something clearly causes a problem.

It's not uncommon for GPS-based max. speeds to be off sometimes. Lots of things can momentarily give GPS readings that are off a little (a switch in which satellite signals are being used, one or more satellite signals blocked from direct line-of-sight to a bounced signal, etc.). It generally recovers quickly so the odometer and average speeds aren't affected much, but a momentary glitch can give you an unrealistic max. speed.

Thanks dude

+1 if your bike computer is set up correctly, it will be more accurate than the GPS. Even when GPS is functioning perfectly, it cuts corners. How much, depends on device, settings and conditions. Usually the difference is so small it doesn't really matter.

Wireless bike comps can show unrealistic max speeds too, for different reasons.

--J