Spedo probs - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

ArT1sT · 06-27-2004, 23:13

On my EF i got 234/45 17's and im pretty sure my spedo is outta wack ever since i put em on... also for some reason i can get the digital spedo up on the odo reading thingy and that shows me a different speed to the spedo too...
any way of correcting my spedo

Dellboy999 · 06-28-2004, 00:01

what was on it originally

ArT1sT · 06-28-2004, 02:10

umm 215/60 15 rims were the orignals

jonbays · 06-30-2004, 23:03

Wouldn't the EF have come with 205/65R15? Is this an Fairmont or Ghia and EF1 or EFII?

If so your speedo will be correct if you swap to 235/45R17 as they have the same rolling radius. If it did come with 215/60R16 then the speedo would read 3% fast ie 100kmh would only be 97kmh. Not really a problem. but you could change speedo drive gears to fix it.

Let me know what the car came out of the factory with and I can work out the difference to waht you have now.

ArT1sT · 07-01-2004, 03:29

215/60 15's were the factory rims... its a EF II fairmont

normell · 07-01-2004, 04:00

Try http://forums.fordmods.com/phpBB2/documents.php?doc=30

jonbays · 07-01-2004, 04:10

EF II Fairmonts a good model to get.

I don't think you can buy 215/60R15 tyres??

From new Ford sold them with 15' wheels and 205/65R15 tyres.
There was a very popular 16" wheel option ( XR6 ) which came with 225/50R16 tyres.

Either way changing to 235/45R17 tyres does change the speedo reading by 4/5 of F*** ALL.

By good design or strange coincidence there is less than 1/2 a percent difference in rolling radius between 205/65R15, 225/50R16 and 235/45R17 tyres so your speedo isn't affected by the different wheels and tyres much at all.

normell · 07-01-2004, 05:33

From 215/60/15 to 235/45/17 the difference is 0.67% so when your speedo is showing 60 actual 60.402, 100 actual 100.67 110 actual 110.737, so not worth worrying about

ArT1sT · 07-01-2004, 18:38

hmm
must be something else then.... caus i sware my spedo is outta wack by about 4 - 5 kms

thanks for all your help guys

Dellboy999 · 07-01-2004, 19:11

I thought all Ford speedo's had a built in margin of 4-5kms towards the top end, is it fast or slow, I mean are doing 100 and people say you are doing 95 or the other way around.