How accurate are those iPhone speedometer apps?

[thxcuz]

Just wondering. I used map my ride earlier today and it said my top speed was 16mph. I downloaded an app and I topped at 24mph.
Not sure which is right. I would like to think I was going faster than 16 but with my dinky kit, who knows.

One more thing
I'm going faster on half choke than full. My engine was sitting for several months and I haven't gotten a fresh mix in it yet. Do you think my carb is gunked up?

Ok I lied...on final thing

St. Louis folks. I saw a bunch of you riding on Broadway last Sunday. Is there a group? Good looking bikes!

 

[racie35]

Most GPS apps are right on

 

[bairdco]

i've used a few gps speedo aps that were right on. tested them in cars and they matched the speedos.

 

[Easy Rider]

I use B.icycle and it seems to be pretty accurate. Shows a map of the route you rode, avg and max speed even allitude you've climbed. Only thing that was way off was the calories I burned. haha

 

[thxcuz]

I was using an app called speed box (it was free)
Map my ride is good for distance and stuff but its more for the spandex crowd.
Sure seemed I was going faster than 16.

 

[Pilotgeek]

It's not really a matter of the app so much as it is of the accuracy of the GPS in your phone. Make sure it gets a full signal lock before using. I use mine as a reference to test how far speedometers are miscalibrated.