Trip odometer reading

[Pal]

Some of you may have seen my mileage thread, I didn't want to confuse anything by posting in there, the thing is my trip odometer don't seem to read right.

When I filled up last time I set the second trip to 0, I have since done four trips to work, which is a 64 miles round trip (confirmed on my old bike, the car and bing maps). Now after these four trips I would have expected the trip meter to read 256 miles, but instead it reads 238.

Has anyone else had this?

I will check the front tyre size is correct as that could put the reading out.

Incidentally this makes my mileage even more impressive 

[fazersharp]

I would have expected the trip meter to read 256 miles, but instead it reads 238.

  Thats just because the bike is quicker

[darrsi]

Some of you may have seen my mileage thread, I didn't want to confuse anything by posting in there, the thing is my trip odometer don't seem to read right.

When I filled up last time I set the second trip to 0, I have since done four trips to work, which is a 64 miles round trip (confirmed on my old bike, the car and bing maps). Now after these four trips I would have expected the trip meter to read 256 miles, but instead it reads 238.

Has anyone else had this?

I will check the front tyre size is correct as that could put the reading out.

Incidentally this makes my mileage even more impressive 

It won't be anything to do with the tyre.

[schlumpf]

That is about 7% low, very strange. Looks as if your tyre is larger than expected. The circumference should be 1840mm. You could simply measure the real value.
The speed sensor gives 4 ticks per rotation. Any failure, or wrong sensor type, would give a much larger deviation.
Last thing I could think of would be that the speed signals are electrically marginal and a few get lost from time to time.

[Yamazer-92]

When I go to Wales with my dad we both set our trips at the start of the ride and also the start of each day. Every time, mine reads about 5% or so less than his however mine is always closer to the google maps estimated distance so we thought his was over reading?

[tweetytek]

Mine does this although I only noticed after  250 mile trip to the in-laws. Error was about 3% not the 7% like yours which sounds quite a margin. I put it down to an old bike, old wiring, old ECU, old speed sensor - on my 2000 FZS. Doesnt bother me really, I mean we're talking about 7.5 miles out of 250. My daily commute is 26 miles round trip so that 0.78 miles error. Not worth bothering with - for me.

[Pal]

It won't be anything to do with the tyre.

If the tyre is the wrong aspect ratio it will be taller, therefore the circumference will  be more giving a wrong reading for a given amount of revolutions of the wheel.
Simple science.

[unfazed]

A 110/80 or 120/70 tyre would easily throw the clock out that much as both have a bigger circumference then the 110/70

[darrsi]

It won't be anything to do with the tyre.

If the tyre is the wrong aspect ratio it will be taller, therefore the circumference will  be more giving a wrong reading for a given amount of revolutions of the wheel.
Simple science.

You could always give us a clue as to what tyre you're using?

[Pal]

I think this might not help