Speed reading out

ColinBate · Occasional Visitor Joined: Aug 24, 2005 Posts: 2

I have an Ipaq hx2110 & TT5.01 & speed is showing 4/5 miles lower than my speedo any body else seen this problem. Which is the most acurate I assume GPS would be??

Regards
Colin Bate

CJackel492 · Regular Visitor Joined: Mar 15, 2005 Posts: 210

hyjacks · Occasional Visitor Joined: Jul 07, 2005 Posts: 29

at 100 mph my speedo acording to the gps is 10 mph out. does anybody know which is the most acurate?

Skippy · Posted: Fri Aug 26, 2005 11:28 am Post subject:

This has been discussed many times on the forum. 8O Here's the answer:

If you are travelling at a constant speed for several seconds on a flat road and in a straight line, with a good satelite fix then the GPS will typically give a speed reading which is accurate to 0.1 MPH

If your speed is changing then the speed indicated by the GPS will lag behind reality.

If you are going around a corner or up/down hill then the GPS will read slightly slow.

A car speedo will typically read 0-10% fast to allow for manufacturing tolerances, tyre wear, different brands/types of tyre etc.
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Gone fishing!

Andyd32 · Posted: Fri Aug 26, 2005 11:56 am Post subject:

futuresbright · Posted: Fri Aug 26, 2005 10:26 pm Post subject:

I would say that ttm speed reading is very accurate,it is your car speedo that is out.
I am saying this because i am a hgv driver and my wagon has just been in for its 2 yearly tachograph and speedo check,which by law has to be spot on.
when travelling now i cannot see any difference in the speeds shown both on the needle and display of ttm.
I am using the original ttm silver receiver.

BarMuda · Occasional Visitor Joined: Mar 04, 2005 Posts: 30

I have a friend in the police force and he informs me that Speedos are set at 10% less than the speed you are doing, as is quite common knowledge.

MrT · Posted: Sat Aug 27, 2005 6:59 am Post subject:

Speedos can be set at an error of upto 10% overreading but the overreading is only there as a tolerance of error in manufacture and it has to be so that they overead. Most quality cars will not overread by 10% with new tyres.

You also have to remember that on a car the wheel diameter will vary by 12mm between new and severly worn tyres which will effect the accuracy of speed.

I am not impressed by the size of the font of the speed reading on TT5 when compared to TT3. On TT3 without navigation the speed was the large middle font where the distance to the next junction was shown and also very large on the overspeed screen. On TT5 it is tiny and you have to concentrate rather than glance to read it.

brob108 · Occasional Visitor Joined: Jun 02, 2005 Posts: 36

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