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[Anthony in Madrid]

Hi guys...
I'll be in the market for a wheel and tyre upgrade from 15" to 17" Soon.
I'll be lowering my omega 30 mm so if anyone can help me....
I dont want the wheels to be wider than the arch so what numbers am I looking at?
I mean the rim width?
Do I need to consider a spacer or do anything with the nuts?
Also..Will the wheels of a 2001 Omega fit my Mig 1994 2.5 V6???
Cheers in advance.
Ant

[TheBoy]

235/45/17 is standard tyre size, pcd is 110, would have to check the offset for 7.5j

30mm at back is too much. 20mm tops

[Temetsy]

I'd sat it fits with fat tires as well as lo-pro tires. I have lowered mig with 16" alloys and semi slim tires and there is a LOT room between tires and archs. All omegas have 5x110 and 61,5 (IIRC) center hole.

[TheBoy]

All Omegas are identical.

[05omegav6]

To save looking, offset is ET33

If you're looking to 18"s, then 8J, ET33 with either 235/40/18 or 245/40/18 tyres

Some nice five spoke 17s on the Design Edition

[TheBoy]

To save looking, offset is ET33

If you're looking to 18"s, then 8J, ET33 with either 235/40/18 or 245/40/18 tyres

Some nice five spoke 17s on the Design Edition

ET32 ish on 8J wheels. 7.5j will be something like 37...

[05omegav6]

To save looking, offset is ET33

If you're looking to 18"s, then 8J, ET33 with either 235/40/18 or 245/40/18 tyres

Some nice five spoke 17s on the Design Edition

ET32 ish on 8J wheels. 7.5j will be something like 37...

7J16 is ET39

7.5J17 and 8J18 are both ET33

9J18 is ET30

Based on what I have here

[elvin315]

I posted this on the CateraOwners Forum (http://cateraowners.forumotion.com) but you might find some useful info for your Omega regarding wheels & tires, offsets, hud diameter, etc. I made it a few years ago and it might be missing some newer Vauxhall/Opel models but it should point you in the right direction.

The first custom touch many Catera owners make are bigger and wider wheels. Some of you do it to improve handling and give your cars a sportier stance. Others want that custom look only chrome Dubs (20" wheels) can provide. Depending on the width and offset big wheels will fit an unlowered Catera. No guarantees on Dub Deuces (22" wheels) or lowered cars.

Remember, the wider the tire, the lower the aspect ratio. That means a shorter sidewall. To support the weight of the car and keep the rim from contacting the road surface tire makers have to stiffen the sidewalls. That results in a harsh ride. The shorter the sidewall, the rougher the ride. If improved handling is your aim the best compromise between side grip and ride quality would be 17" - 18" wheels. Bigger than that and normal street imperfections will be more noticeable.

Whatever sized wheel you choose, if you want them to fit they must have a 5x110 bolt pattern, a hub diameter of 65.1mm, and, depending on the wheel, a +35mm to +45mm offset. Offset determines the wheel's inner and outer clearances. Follow the link to an explanation of offset and how to measure it. Or you can use the Offset Calculator.

http://www.yokohamatire.com/utcustom.asp
https://www.rsracing.com/tech-wheel.html
http://www.1010tires.com/WheelOffsetCalculator.asp

The Catera shares the same wheels sizes with the following GM cars. Wheels that fit them will fit the Catera. The Opel/Vauxhall wheels will be nearly impossible to find in the US but the rest should be available. Search eBay, the auto recyclers, and the local Pennysavers. I am by no means an expert so please double check the wheels before purchasing. Some cars like the Saturn Ion and Chevy Cobalt use both 4 and 5 bolt patterns depending on trim level. Please report any mistakes, corrections, or additions to this list and I will update it.

Make/Model Model Years Pattern Offset/mm Hub/mm OPEL/VAUXHALL Astra 5 Stud 1998 - 2003 5x110 35 - 45 65.1 Astra Coupe after 1998 5x110 35 - 45 65.1 Corsa 1.7 CDTi after 2003 5x110 45 65.1 Omega after 1994 5x110 35 - 38 65.1 Vectra/Sigrum after 2002 5x110 35 - 38 65.1 Zafira after 1998 5x110 35 - 45 65.1 SAAB 9-3 2002 - on 5x110 37 - 38 65.1 900/9-3 1992 - 2002 5x110 37 - 49 65.1 9-5 1998 - on 5x110 40 65.1 SATURN Aura 2007 - on 5x110 35 - 45 65.1 Astra 2008 - on 5x110 35 - 45 65.1 Ion Redline * 2004 - 2007 5x110 35 - 45 65.1 L Series 2000 - 2005 5x110 35 - 45 65.1 Sky 2007 - on 5x110 55 65.1 CHEVROLET Cobalt ** 2007 - on 5x110 35 - 45 65.1 HHR 2005 - on 5x110 35 - 45 65.1 Malibu 2004 - on 5x110 35 - 45 65.1 PONTIAC G5 *** 2005 - on 5x110 35 - 45 65.1 G6 2005 - on 5x110 35 - 45 65.1 Solstice 2006 - on 5x110 ?? 65.1

* - Redline only
** - all models except the LS and LT1         
*** - GT only

Elvin

[05omegav6]

The Pontiac G6 has a bolt pattern of 5x120

[elvin315]

From the TireRack site:

Pontiac G6
Offset: 40mm
Backspacing: 5.79"
Bolt Pattern: 5-110
Rec. Tire Size:225/50-17

[05omegav6]

Not my day today

Got confuddled with the G8

[chrisgixer]

Not my day today

Got confuddled with the G8

Does Al need a new Anorak?

[Anthony in Madrid]

235/45/17 is standard tyre size, pcd is 110, would have to check the offset for 7.5j

30mm at back is too much. 20mm tops

Hi thanks for the reply...
Appreciate it....
When you say check "offset" for 7.5...
What does that mean exactly?
Sorry for the lack of knowledge 
Cheers
Ant

[05omegav6]

Question answered in replies #4 and #6

[elvin315]

The offset is the distance from the mounting surface (where the wheel meets the brake disc hat) and the center line of the wheel, usually measured in mm.

[Anthony in Madrid]

235/45/17 is standard tyre size, pcd is 110, would have to check the offset for 7.5j

30mm at back is too much. 20mm tops

If I do 20 mm drop at the back..better to do a 20mm at the front too right?

[chrisgixer]

235/45/17 is standard tyre size, pcd is 110, would have to check the offset for 7.5j

30mm at back is too much. 20mm tops

If I do 20 mm drop at the back..better to do a 20mm at the front too right?

No not necessarily there is a tolerance, but the reality for most is buying a set will give 15mm or 30mm drop. There is also a line of thinking that suggests a lower front gives better turn in and cancels some under steer.

The thing with the rear is to note that the settings are not achievable at more than 20mm drop. So either buy 30mm drop springs and fit a 10mm pad under the rears. Or buy 30mm fronts only, and fit (or keep the original) standard or lsc rear gm springs.

Also bear in mind, a substantial load on the rear will also compromise the rear settings and hence accelerate tyre wear so you need a bit of a buffer on the rear ride height, unless you have level control of course.

[Anthony in Madrid]

To save looking, offset is ET33

If you're looking to 18"s, then 8J, ET33 with either 235/40/18 or 245/40/18 tyres

Some nice five spoke 17s on the Design Edition

Hi again 
... Need to be educated... What does the "ET" stand for/mean?
Also what year did the Design Edition come out because here in Spain for sure it wasn't called that 
And thanks to everyone for the help...Really appreciate you taking the time to answer my questions.

Ant

[Anthony in Madrid]

If I do 20 mm drop at the back..better to do a 20mm at the front too right?
[/quote]

No not necessarily there is a tolerance, but the reality for most is buying a set will give 15mm or 30mm drop. There is also a line of thinking that suggests a lower front gives better turn in and cancels some under steer.

The thing with the rear is to note that the settings are not achievable at more than 20mm drop. So either buy 30mm drop springs and fit a 10mm pad under the rears. Or buy 30mm fronts only, and fit (or keep the original) standard or lsc rear gm springs.

Also bear in mind, a substantial load on the rear will also compromise the rear settings and hence accelerate tyre wear so you need a bit of a buffer on the rear ride height, unless you have level control of course.
[/quote]

Thanks for the advice...Will the car be tilting forward a lot if I choose 30 mm at the front and not touch the rear springs?
I'm actually looking for my car to sit similar to this:
Do you think those are 17's in the pic?
Cheers Ant

[chrisgixer]

Looks?

Doesn't come into it as far as I'm concerned.

[05omegav6]

ET is wheel offset. Eg ET 33 means that the hub face is 33mm outward of the wheel centre line

Design Edition was 2001/02, might be Germany only

Wheels in pic are 8J18 'Penta' wheels from Astra G/H and Zafira B.
They have an offset of 42 so ideally you would need spacers of 9-12mm to correct this. Using spacers will also require longer wheel bolts.

Hth

[Varche]

Anthony

You are in luck mate, more of that in a moment.

One thing you will have to think about is how you will get the car through its annual ITV (MOT) here in Spain with any non standard wheels. I know you see folk driving around with non standard but I have a strong suspicion they are in the trade or put their standard wheels back on for the ITV each year. Plus wider rims and bigger diameter and lowering contribute to a much poorer ride.

Now the really good news. I have been holding onto six genuine Omega Elite rims for another Spanish based forum member. He no longer requires them. They all have tyres but only two have good tread. The others I would describe as just legal. I have two sets of different centre caps for them . They are homologated for use on an Omega in Spain and are a straight swap. Homologated means they are listed as options in the Opel handbook.

Spring change at the front? Does that affect the suspension camber, castor etc settings? No WIM over here to set up correctly that I have ever been able to find so front tyre wear might become a serious issue? Omegas weren't big sellers here so not much expertise.

They are 7J X 16 inch diameter. Normal homologated tyre fitment is 225x55R16 95V (or W for 3litre). Good news is the tyres are quite reasonable price over here. Tyre size and rating is an ITV check item and needs to match your logbook.

You could have all six (giving you a spare too) for very reasonable money and I have a host of useful parts(items of Elite trim, badges, centre console, self dipping mirror and so on that I would throw in to a good home. Mrs Varche wants me to clear stuff out. Easy scenic run down from Valencia

Pictures on car here http://www.omegaowners.com/forum/index.php?topic=45487.msg687020#msg687020

If you are interested PM me for details and close up photos.

[TheBoy]

To save looking, offset is ET33

If you're looking to 18"s, then 8J, ET33 with either 235/40/18 or 245/40/18 tyres

Some nice five spoke 17s on the Design Edition

ET32 ish on 8J wheels. 7.5j will be something like 37...

7J16 is ET39

7.5J17 and 8J18 are both ET33

9J18 is ET30

Based on what I have here

Where are you getting that, as I'd expect a 7.5 and 8J to be about 6mm different on the ET. As an 8J is 32...

[05omegav6]

7J16ET39 I have two in the garage (CD 5spokes)

7.5J17ET33 both MV6 and Elite wheels, have had/have both

8J18ET33 Irmscher Stilas fitted to the estate

8J/9J18ET30 Irmscher SportStars (Omega fitment) as per Gixers

[chrisgixer]

7J16ET39 I have two in the garage (CD 5spokes)

7.5J17ET33 both MV6 and Elite wheels, have had/have both

8J18ET33 Irmscher Stilas fitted to the estate

8J/9J18ET30 Irmscher SportStars (Omega fitment) as per Gixers

8J18ET38Irmscher sports stars (Vectra Fitment) on the mv8. For now.

[Mr Gav]

8J18ET38Irmscher sports stars (Vectra Fitment) on the mv8. For now.

Bit early to be putting wheels on it 

[X30XE]

Does anyone happen to know how much the 17" Elite alloy weighs perchance?

[chrisgixer]

8J18ET38Irmscher sports stars (Vectra Fitment) on the mv8. For now.

Bit early to be putting wheels on it 

Yeah it is. But I need something to hold it up on the ramps.