dorkiest, most fun sport ever

Half-cocked · May 5, 2008

You don't need anything but a bare-bones GPS for geocaching, in fact the higher-end models that are intended to give driving directions are all but worthless in this role. Stick with a Garmin eTrex or something similar for geocaching.

Plug the latitude and longitude into Google Maps or Google Earth, and you can see exactly where to park your car, to start your treasure hunt.

DemoDave · May 5, 2008

A little OT but for a while now I was wondering why my GArmin in my car was always showing the speed about 5-7 miles slower than my speedometer. They answered my question in this months Popular Mechanics.

The automobile manufacturers monkey with your speedometer so that it puts more miles on the odometer and causes the warranty to expire quicker. It is set 5%-7% faster on autos and 10% on motorcycles.

alucard0822 · May 5, 2008

DemoDave said:
A little OT but for a while now I was wondering why my GArmin in my car was always showing the speed about 5-7 miles slower than my speedometer. They answered my question in this months Popular Mechanics.

The automobile manufacturers monkey with your speedometer so that it puts more miles on the odometer and causes the warranty to expire quicker. It is set 5%-7% faster on autos and 10% on motorcycles.

The speedometer is also calibrated with brand new tires that are theoretically perfectly round. As tires wear, they become smaller, and turn more revolutions over the same distance, giving a higher speed than actual, tires also compress at the contact patch making the effective rolling circumfrence smaller, for "liability" reasons the speedometer is not calibrated with 50% tread, because it would read low. Motorcycles are calibrated in the same way, and also in a straight line, as the bike leans in turns the round shape of the tire causes the effective diameter to go from small to big, the more dramatic change while turning accounts for the larger degree of error.

I got to be an "expert" witness in a civil trial a few years ago where a guy sued my shop because he got a speeding ticket after he got a new set of tires, and his lawyer was trying to make the case that the speedometer was somehow 15MPH off. When all was said and done, a dyno certification showed his speedo was actually displaying 4 MPH faster than actual, lawsuit dropped, the jerk paid his ticket, and I got the rest of the day off with pay

sorry for the OT, we now return you to your regularly scheduled thread

novus collectus · May 6, 2008

DemoDave said:
A little OT but for a while now I was wondering why my GArmin in my car was always showing the speed about 5-7 miles slower than my speedometer. They answered my question in this months Popular Mechanics.

The automobile manufacturers monkey with your speedometer so that it puts more miles on the odometer and causes the warranty to expire quicker. It is set 5%-7% faster on autos and 10% on motorcycles.

The GPS I think is based on a flat plane. I noticed when driving up hills the GPS speed was less than the ground speed and I assumed it was because to the GPS I was just travelling a mile in a straight line on a map without taking into account the actual distance on the angle of the hill's "hypotenuse".

dorkiest, most fun sport ever

The #1 community for Gun Owners of the Northeast

Member Benefits:

Half-cocked

Senior Meatbag

DemoDave

Banned

alucard0822

For great Justice

novus collectus

Banned

Users who are viewing this thread

Latest posts

Forum statistics

Latest threads

Forum statistics

Share this page