gps speedo

[warren57]

When looking at electric speedo's, I see you can use a sending unit or gps.
can anyone offer pros or cons for each?
thanks

[chevynut]

GPS only shows how fast you're traveling on the ground, not how fast your wheels are spinning. You can lose the GPS signal around tall buildings, thick foliage, or even in the mountains. I don't think a GPS speedo can be made to look like an analog gauge, only a digital output, if that matters to you. Personally I'd go with an electric speedo with digital (pulse) input. You can calibrate it to the exact mile. Plus the speedo tells you when your wheels are spinning. :)

[warren57]

That makes sense. Considering the difficulty my Tom Tom plug in gps unit has with keeping a signal, I certainly wouldn't want a speedo that only worked part time!