Speedo seems to be out!!

[D4N13L]

Hello peeps,

I reckon my speedo is out by about 7-10mph, i have plugged the sat nav in and this seems to agree with what i thought.

I am running the standard 15's with 195 55 15 as it came with out of the showroom.

Is there a way of adjusting this other than altering the tyre sizes?

Cheers

Dan

 

[Leopold]

Hello peeps,

I reckon my speedo is out by about 7-10mph, i have plugged the sat nav in and this seems to agree with what i thought.

I am running the standard 15's with 195 55 15 as it came with out of the showroom.

Is there a way of adjusting this other than altering the tyre sizes?

Cheers

Dan

Hello mate,

What speed are you doing? as you will notice that your speedo will be out by around 4-5mph when say you're doing 70ish.. I wouldnt worry about it mate..

Noticed that you are from MK, where abouts mate? as i am from MK also...

Cheers

Lee

 

[Andy_Mk3]

Vauxhalls are bad for over-reading, especially at 70+ .. when my speedo reads 100 sat nav says about 94.. tested this on private land of course but at 70mph on the speedo, satnav says about 66mph

 

[Mr Skint]

mines even worse than that, when im doing 70, im actually doing 63, its well gay

 

[corsa_evn]

im doing 70 on sat nav and speedo is reading nealy 80 !

also my speedo needel seams to bounce !

 

[Vectra-Arctic]

Got the same problem on my Astra Mk3. Speedo undereading by between 5 & 8mph depending on speed. Got 185/70/14's on the car.

 

[Andy_Mk3]

im doing 70 on sat nav and speedo is reading nealy 80 !

also my speedo needel seams to bounce !

Your speedo cable got a kink in it probably!

My speedo bounces off 0 if I brake hard enough

 

[D4N13L]

Cheers for the replies fellas, nothing to worry about then.

Leopold - Giffard Park mate.

 

[Leopold]

Leopold - Giffard Park mate.

Not far from me then i'm in Bradville

 

[KinG^Lee]

if you from MK you should sign up on the central register

My speedo is also out by 10mph little annoying.

 

[MarkGSi]

over time, our odo's will be clocking up loads of miles were not actually doing either!

 

[Brick Driver]

I was wondering what tyres to get for my car and thought they would affect the speedo. When you look at the different sized tyres Vauxhall sold the cars with it's no surprise the speedo's are out. I haven't actually looked so I don't how many different speedo drive gears are available. If they are the same all of the cars will be a bit out.
My car originally had 155/80x13 tyres but a lot come with 175/70x14 or 185/60x14 and when you look at the tyre diameters there is a bit of a difference.
Have a look on here and you can calculate what the differences are.

http://www.carbibles.com/tyre_bible.html

 

[Leopold]

if you from MK you should sign up on the central register

Registered!!!

 

[MarkGSi]

I was wondering what tyres to get for my car and thought they would affect the speedo. When you look at the different sized tyres Vauxhall sold the cars with it's no surprise the speedo's are out. I haven't actually looked so I don't how many different speedo drive gears are available. If they are the same all of the cars will be a bit out.
My car originally had 155/80x13 tyres but a lot come with 175/70x14 or 185/60x14 and when you look at the tyre diameters there is a bit of a difference.
Have a look on here and you can calculate what the differences are.

http://www.carbibles.com/tyre_bible.html

The different diameters/tyre sizes wont make a difference if the rolling circumference work out to be the same.

 

[Brick Driver]

The different diameters/tyre sizes wont make a difference if the rolling circumference work out to be the same.

Hi, yes you are right it's just that some of the sizes that Vauxhall offered standard are different.
I have a parts cd and was just looking at the speedo drives, the gear on the diff and the speedo's themselves. I think all the drive gears have 13 teeth, all the diff gears have 26 teeth. There are a few different speedo versions and these should correct and differences in tyres size.

Has the speedo been changed in the car or non original sized tyres been fitted ?

 

[MarkGSi]

I also think the speedo will read different between new tread depth and on the limit tyres

 

[Brick Driver]

I have in the past rung up a tyre manufacturer to find out what the wheel revs per mile figure is for a particular tyre. I think it's that figure that is written on the speedo on Astras, I know thats the case on Triumphs and Mini's.
Different makes of tyre that are the same size can be different so I suppose a combination of all the wrong things can make quite a big error.
At least it's the right way. I swapped a back axle on my Triumph and forgot about the speedo. Needless to say I got a fine for doing 82 in a 70 limit, made me sort the speedo out though.