kdm123

Do you guys know what is the best lap timer (GPS based) that there is for the current iPhone?

Has anyone tested the app's lap timing against trackside-beacon timing?

aaronc7

Most popular, especially on iphone/iOS is Harry's LapTimer. Multiple versions with varying amount of features/prices. I use TrackAddict made by HPTuners on Android (it's also on iOS). It's free on Android and on iOS I believe there is a free version without all features and also a paid version.

Phone internal GPS is 1hz and generally won't be super accurate for lap timing, but may be good enough. You can also get a standalone bluetooth GPS receiver that can have 5-20hz refresh rate, that will link to phone and tie into Harry's or any other decent laptimer app. Will be pretty darn accurate at that point.

kdm123

Okay, thank you. I bought Harry's lap timer and a GPS receiver. Gonna test it out this week.

YYZ06

If you haven't done so, check out the Harry's web site. He lists all of the supported peripheral devices (external GPS', OBDII readers etc.).