Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: JamesV6CDX on 07 June 2008, 20:08:36

Title: Speedo Accuracy
Post by: JamesV6CDX on 07 June 2008, 20:08:36

I'm considering swapping the 15" Wheels currently on the Estate for a set of 16" Elite ones.

Presume this would affect the speedo accuracy etc?

If so, can this be amended with Tech2?

Title: Re: Speedo Accuracy
Post by: TheBoy on 07 June 2008, 20:11:10

Quote

I'm considering swapping the 15" Wheels currently on the Estate for a set of 16" Elite ones.

Presume this would affect the speedo accuracy etc?

If so, can this be amended with Tech2?

If its a mini facelift, we can reprog speedo, and MID needs doing as well.

Title: Re: Speedo Accuracy
Post by: JamesV6CDX on 07 June 2008, 20:41:29

1996 / P

So not mini FL.

What does that mean? :(

Title: Re: Speedo Accuracy
Post by: TheBoy on 07 June 2008, 20:45:27

Quote

1996 / P

So not mini FL.

What does that mean? :(

Replacement instrument cluster

Edit: preminifacelift I think you can get replacement speedo on its own.

Either way, not worth it.

Title: Re: Speedo Accuracy
Post by: JamesV6CDX on 07 June 2008, 20:47:35

Quote

Quote

1996 / P

So not mini FL.

What does that mean? :(

Replacement instrument cluster

Edit: preminifacelift I think you can get replacement speedo on its own.

Either way, not worth it.

I have an instrument cluster from a Elite right here - could I just pop that in then?

Title: Re: Speedo Accuracy
Post by: psychnurse on 07 June 2008, 21:07:56

well you never go over the limit do you James  :)

Title: Re: Speedo Accuracy
Post by: JamesV6CDX on 07 June 2008, 21:09:20

Quote

well you never go over the limit do you James  :)

I would if that poxy smoky underpowered tappy 2.0 prehistoric half engine was capable of it ;D ;D

(I don't envy your 3.0, honest...) ;D

Title: Re: Speedo Accuracy
Post by: Mr Skrunts on 07 June 2008, 21:16:02

Do a heart transplant with the Disco.   ;D ;D

Title: Re: Speedo Accuracy
Post by: Turk on 07 June 2008, 23:33:36

If the wheel diameter is increased, the tyre profile should be decreased. This keeps the rolling radius the same and the speedo will not be affected.
  

Title: Re: Speedo Accuracy
Post by: Mr Skrunts on 07 June 2008, 23:42:55

Here you go James, try comparing tyres with this.

http://www.miata.net/garage/tirecalc.html

Title: Re: Speedo Accuracy
Post by: Mr Skrunts on 07 June 2008, 23:45:08

They seem to be working out the same overall.  The lower profiles is being compensated by the larger rim.

Title: Re: Speedo Accuracy
Post by: TheBoy on 08 June 2008, 09:32:38

Quote

Quote

Quote

1996 / P

So not mini FL.

What does that mean? :(

Replacement instrument cluster

Edit: preminifacelift I think you can get replacement speedo on its own.

Either way, not worth it.

I have an instrument cluster from a Elite right here - could I just pop that in then?

No - the tacho will be marked wrong (different redlines IIRC).

Not sure what the difference is between 205/65R15 and 225/55R16, but I do know that the 225 has a different config on ECUs that use measure true speed than those that use 195/205/235 width tyres.

Title: Re: Speedo Accuracy
Post by: Danny on 08 June 2008, 10:04:35

Quote

I'm considering swapping the 15" Wheels currently on the Estate for a set of 16" Elite ones.

Presume this would affect the speedo accuracy etc?

If so, can this be amended with Tech2?

As Turk said, its the tyre size that should be changed to compensate, and you might find you wont need to

my facelift GLS had those awful 16" alloys similar to the early prefacelift CDX on 225/55/16, I swapped them for facelift elite 17"s on 235/45/17 and the difference was very minimal and well within regulation,

the allowance is something like 2.5% max in either direction, mine was about 1%, I should imagine going from 15 to 16 will be very similar.. alloywheels.com has a tyre calculator too

Title: Re: Speedo Accuracy
Post by: Mr Skrunts on 08 June 2008, 10:12:43

Quote

Here you go James, try comparing tyres with this.

http://www.miata.net/garage/tirecalc.html

According to the above the difference is 1.%

Speedo reads 60 mph and car actually doing 60.6 mph.

With the speedo being set the way it is that means the car will be slighty nearer the true actual speed but I reckon will still be doing under an actual 60 mph.

Title: Re: Speedo Accuracy
Post by: GPar on 08 June 2008, 10:29:19

60 mpg! Gotta get me some of them wheels!

Geoff