Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: soupdragon44 on 05 May 2010, 21:02:37

Title: Wheels and Tyres sizes and Speedo readings.....
Post by: soupdragon44 on 05 May 2010, 21:02:37

My Omega has 195/65 x 15's on it and i have just purchased a set of Elite wheels that are 225/55 x 16's, have done a tyre sixe check and according to that the speedo will read 3% fast... would like to know if the speedo is read electrically and will it matter with different sizes on it?? cheers joe

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: cem_devecioglu on 05 May 2010, 21:20:34

can be arranged via tech2

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: soupdragon44 on 06 May 2010, 08:29:04

sorry for sounding thick but what's tech2?

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: Hannah Judes Dad on 06 May 2010, 08:44:56

Quote

sorry for sounding thick but what's tech2?

You are not thick and every question has an answer from the kind folk on here. :y
Tech2 is the vauxhall data reader/writer that is known as the magic box of tricks for solving many problems with Omegas including things like gearbox software updates for the facelift models.I hope that helps.

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: jonnycool on 06 May 2010, 08:47:05

Quote

sorry for sounding thick but what's tech2?

Tech 2 is the computer that Vauxhall dealers use to diagnose faults and communicate with the car's ecu. It's an expensive piece of kit but a few members on this site have them and are far more useful with them than any dealer  :y :y

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: 2woody on 06 May 2010, 09:02:46

205/65 x 15 has 833 wheel revs per mile
225/55 x 16 has 811 wheel revs per mile

that makes 2.7 % difference.

..... and it will lower the reading on your speedometer, but it will still over-read anyway ( ALL car speedometers over-read by a certain amount, by law - just to make you think you're going faster than you really are )

the "new" wheel/tyre package is slightly taller, but not really enough for the handling to suffer.

once fitted, double-check with a sat-nav.

Omega B generates its speed signal through the ABS, using primarily the left-hand rear wheel, but double-checking it with the others.

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: Sixstring on 06 May 2010, 09:54:36

My satnav tells me I am doing EXACTLY 70mph when my speedo reads 76, so shouldn't make that much difference.

(I have the same wheels/tyre sizes as you)

Title: Re: Wheels and Tyres sizes and Speedo readings.....
Post by: soupdragon44 on 06 May 2010, 17:09:09

Thanks chaps,will check with the satnav but will just remember the differnace,
Paid £77:00 for the rims with new budget tyres on from Fleabay and there very tidy indeed. Will be fitting tommorow so hopefully she won't look like Range Rover anymore.....
17" when dosh allows...... :)