speedo reading fast

[Bongo Boozer]

Just a quick question,
My bongo has have the speedo face changed to MPH but the it still clocks up in KPH.
I have borrowed a sat nav and this shows (as an example 70MPH on the clock but 65MPH on the sat nav).

1, Can I alter this
2, Am I putting more milage (Kilometers) on the clock because of this?


Cheers
Steve M

[waycar8]

dont think you can alter it, but its common on most bongos to have the face cover and it reading 5mph out

[daveblueozzie]

At least you will not be done for speeding if it reads 70 on the dials and your only doing 65.

[trevd01]

7.5% fast?

Many cars have that sort of speedo error, so it's not necessarily anything to do with the mph face, or even anything Bongo-specific.

[maxheadroom]

Bongo Boozer,
do you have standard size wheels fitted as have non standard size wheels can also effect the speedo.

[haydn callow]

mine has the same setup and reads exactly spot on with a sat nav.
So, there!!

[missfixit70]

If the tyre sizes are correct & the face has been replaced, the needle may have been taken off & replaced incorrectly, in which case it will have no bearing on the mileage. If it bothers you that much, you can unscrew the surround, drop the steering wheel adjustment down, pull it forward, unclip the clear plastic screen & prise the needle off with a spoon, levering it on one of the metal stub bits, difficult bit is getting it bac on accurately in the right place.
Yours isn't that far out, mine was just over 15% out, personally wouldn't bother doing anything about the error on yours.

[madmile]

To be honest a 5mph difference at 70ish is perfectly acceptable. It is illegal to underead even a little bit, so you should be fine.
It is reasonably easy to correct it a bit should you wish (may need a few attempts and use a sat nav).
I dont think it makes a difference to the odometer as I substantially corrected one recently for the speed reading and checked over a 100km trip against sat nav and there was no real difference. I had put larger wheels on and was convinced the odometer would be out as a result.

[Bongo Boozer]

Thanks for the feedback

I will leave it as is and not worry anymore

steve

[bournemouthken]

My speedo was reading 30 -sat nav said about 23, I wondered why there were ques of traffic behind me, at 70 my sat nav said about 64 - so, I took the speedo consul out, removed the perspex cover, and then took off the speedo needle, this I did by using a pair of electical wire strippers, simular to a pair of pliers but with sort of two forks on the end, as you close the strippers togeather they pull on the needle, so that it is lifted off the shaft, be careful that you when you do this you excert upwards pressure on the speedo needle evenly, not prised off one side or the other say with a screwdriver. I refitted the consul minus perspex cover and speedo needle
Then I went for a drive and watched so that the sat nav reading was at a constant 60 mph, this is the tricky bit, I then placed the speedo needle back onto the shaft vey lightly so that it was bang on 60mph, then I compared readings at 70, 50, 40 etc and when satisfied that it was reading exactly the same as the sat nav, I pressed the needle fully home back onto the shaft, I double checked again and then refitted the perspex cover. To this day it matches the sat nav exactly and I have driven through countless speed camers at exactly the stated speed without getting flashed at.
Hope this helps you out...................

[Lovejoy]

This is all very odd, as I have the same 'problem' but thought I had pinned it down to a satnav error rather than a speedo error.

My Bongo speedo was showing, say, 60mph when the Tom Tom was reading 54 or 55mph.

My initial thought was that it was something to do with the Bongo speedo, as we had the face plate changed. But couldn't work out why it should be out by that much.

So, we took two vehicles out, the Bongo and my Combo Van, and I followed the Bongo in the van up the A30. I was in touch with Mrs Lovejoy by mobile phone (hands free of course).

When she reached certain indicated speeds (40, 50, 60 & 70) on the Bongo speedo she would hold it there and tell me. Keeping a steady distance behind, my Combo speedo was reading the same speed. Stoopidly we didn't take the Tom Tom during this test.

But happy that the Bongo speedo was reading the same as the van we went home.

A few days later we were in the Freelander with the Tom Tom, and guess what - we noticed the same thing. The Tom Tom was indicating a speed some 5-7 mph lower than the Freelander speedo. Hmmmm

Last week-end I went with a friend to Oxford in his Focus, and took the SatNav with us as we didn't know where we were going. Again, the TomTom was indicating less than the speedo.

So I believe this proves that it is the satnav which is not showing an accurate mph, having been tried in 3 different vehicles.

Interestingly, when we first got the Tom Tom it used to match the speedo reading spot on. But now it seems it is out by up to 10%.

We have upgraded the tom tom software over the summer from Tom Tom's web site, but other than that nothing has changed.

I would be interested to know if others experiencing the same problem are using Tom Tom's, and if so which version of the software they are using

[Bica]

I have found the same with a Tom Tom using it in my previous Astra, my current Proton and also the Bongo. In all cases the sat nav was registering approx 5MPH less than the speedo readings.

This is a Tom Tom Go that uses SD cards rather than the newer ones that have a hard drive.

I think it is a conspiracy between two pieces of digital equipment

Tom Tom lures you into a false sense of security so that road side camera can get you

[Mr Halibut]

Speedo's should never read under the speed but should be within 4kmh + 10% over the speed (this is what the manufacturers are aiming for). I had to put a manual check into a rolling road to pass some Hong Kong stipulation that all production vehicles must be blah blah blah etc. Not that it matters because the drivers probably just say YES because its less hassle.

[Lovejoy]

I have found the same with a Tom Tom using it in my previous Astra, my current Proton and also the Bongo.....

Interesting, that seems to back up what I have found. Mine is a Tom Tom One with an SD card and a software upgrade to V1.21, Boot 5.05 Map v605.0

It's too much of a coincidence that so may vehicles have inaccurate speedos when measured against a satnav device. You have tested 3 vehicles and I have tested 3, all against a TomTom (different versions but software will be similar) and all 6 vehicles have inaccurate speedos ?

I don't believe that. It has to be a satnav issue.

I just ignore the satnav speed indicator now (not that I took much notice of it before). After all, I bought the device to tell me where to go not to tell me how fast I am getting there
The most useful reading on the TomTom is the ETA, which seems to remain accurate throughtout even the longest journey.

[smartmonkey]

I always believe the sat nav because it is self calibrating. Virtually all cars will read between 3 and 6 mph fast at 60mph. This makes motorists feel better and keeps the manufacturers out of court. I have three sat navs and they are all within 1mph or each other. The Bongo is the only car I have had with an acurate speedo because the needle was put in the right place when the bezel was changed. Police cars have to have recalibrated speedos before they are put into use and they are then checked regularly. Speedos are also subject to the vagaries of tyre size/wear/pressure and production tolerances.