Hi all
I've been thinking since I bought my EK in December that most everyone else on the road is speeding while I'm sitting in the left lane enjoying the cruise at the speed limit; however, yesterday I went through a speed check point on the Hume Hwy when I was doing 68 which I believed was the correct speed (110Kms) yet the sign displayed 96. Maybe my speedo is inaccurate. Is it possible to verify this and get it fixed?
Cheers
Paul
speedo Q's
Hey Paul,
You will find speedo error caused by the tyre size. I am unsure of the height of the standard tyre as fitted from the factory, but having seen your car I know that the tyre height you have now will be slightly less than the original. As most 13" radial tryes don't have the sidewall height of the old cross plies. You can get devices which act as reducers or in your case increase the speed shown, but I have no idea of cost..
Or somone else on here can tell us the height of the original tyre and the closest sized radial?
My last EK ran 14" tyres and the speedo wasn't to far out at all.....
You will find speedo error caused by the tyre size. I am unsure of the height of the standard tyre as fitted from the factory, but having seen your car I know that the tyre height you have now will be slightly less than the original. As most 13" radial tryes don't have the sidewall height of the old cross plies. You can get devices which act as reducers or in your case increase the speed shown, but I have no idea of cost..
Or somone else on here can tell us the height of the original tyre and the closest sized radial?
My last EK ran 14" tyres and the speedo wasn't to far out at all.....
Speed and Style........... One day I'll get the speed bit.
The original olympic air rides on my FB ute are 620mm high measuring from the ground to the top of the tyre . Any tyre place should be able to match up an equivalent sized tyre - if you have 13s and low profile tyres you may need a corrector box made up ?
I started with nothing and still have most of it left.
Foundation member #61 of FB/EK Holden club of W.A.
Foundation member #61 of FB/EK Holden club of W.A.
Paul, go to FE/FC Holden Forum.On main page click on "Technical Board".Go to page 4 and find post called "Diff Ratios".Scroll down to reply 3 and there are a few websites with calculators there to find all types of gear calculations.Thanks to Craig Alderson at FE/FC/ Forum for these links to gear calculators.
I think the one you are after is the first link
www.wallaceracing.com/gearcalc1.php
The sites are American.
One of my EK Holden's still has the original crossplys near new condition and from memory the wheel diameter is 24 inches or so (I can check later and give dia if required).
Measure your current tyre dia and the original factory tyre dia (24 in crossplies) and the mph speed you need correcting (say 60 mph) and it will work out the actual mph in real terms as opposed to what your speedo is reading.It will give you the indicated speedo error.
For example, If your original tyres were 24 inch and your new tyres are 22 inch then at 60 mph your speedo error would be 5 mph.
Hope this helps.
Terry.
I think the one you are after is the first link
www.wallaceracing.com/gearcalc1.php
The sites are American.
One of my EK Holden's still has the original crossplys near new condition and from memory the wheel diameter is 24 inches or so (I can check later and give dia if required).
Measure your current tyre dia and the original factory tyre dia (24 in crossplies) and the mph speed you need correcting (say 60 mph) and it will work out the actual mph in real terms as opposed to what your speedo is reading.It will give you the indicated speedo error.
For example, If your original tyres were 24 inch and your new tyres are 22 inch then at 60 mph your speedo error would be 5 mph.
Hope this helps.
Terry.
I can't think what to write here so this will do.