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[duggs]

I MIGHT have made a balls up...for which I need some advice please.
I've spent weeks looking for the right set and think I've cocked up.

I've just purchased, ebay, some brand new alloy wheels with brand new tyres. They came from a Astra, are 16" and I believe them to be 110x5 which should fit my Omega CD.....BUT..they have 205x55 tyres, mine currently being 205x65. The bore is fine at 65.1 also it would appear.

So my questions are:  Will they look odd and what are the ramifications of using a FWD Astra's alloys on an Omega.

They ARE Vauxhall issued...NOT after market.

[Dazzler]

The offset is different on FWD cars compared to RWD cars, so the wheels will sit to far into the wheelarch and look odd.

[Danny]

they should ideally have 225/55 on 16s

i dont know how the wheels differ on a front wheel drive to a rear wheel drive, as long as the fitment is correct and they're on the right tyre size

omega will take ET 35-45

[duggs]

"The offset is different on FWD cars compared to RWD cars, so the wheels will sit to far into the wheelarch and look odd."

OOOOOOO bugger !  How much further in are we talking about..mm's or an inch ?

I assume I could get spacers BUT I'm not sure its worth the bother..Perhaps I should sell them on...?

[Dazzler]

At least an inch or so, i would say.

[The Doctor]

At least an inch or so, i would say.

Over estimating there a bit, the FWD are usually -45ET on the newer astra's My omega wheels are -39ET, so thats 6mm not 25mm.
Worst case would be 49-35 et, only 14mm. Still a long way off an inch out.

Duggs, your incorrect tyre sizes will in effect alter you gear ratio, making for quicker acceleration and lower top end speed (very marginally) it will also cause your speedo to over-read by a few percent. Your car will handle slightly better due to the lower profile of the tyres, but ride will be a little more harsh as a flip side to that.

Just replace all 4 tyres with the correct size when they wear out, and hold the speedo just over the mph mark instead of just under.

[Dazzler]

At least an inch or so, i would say.

Over estimating there a bit, the FWD are usually -45ET on the newer astra's My omega wheels are -39ET, so thats 6mm not 25mm.
Worst case would be 49-35 et, only 14mm. Still a long way off an inch out.

Duggs, your incorrect tyre sizes will in effect alter you gear ratio, making for quicker acceleration and lower top end speed (very marginally) it will also cause your speedo to over-read by a few percent. Your car will handle slightly better due to the lower profile of the tyres, but ride will be a little more harsh as a flip side to that.

Just replace all 4 tyres with the correct size when they wear out, and hold the speedo just over the mph mark instead of just under.

Bad guess
Sorry.
I was right about the offset though

[The Doctor]

better to err on the side of caution  

[duggs]

Doctor !   Thank you SOOOOOOOOOOOOOO much for the info, I feel a lot happier now. I THINK the wheel width is 6.5 instead of the normal 7 and yet the tyres are the same size...Spooky ?

[tomoco]

Hi Duggs, You have to consider another very important thing about the offset on FWD wheels when fitting to RWD cars . Because the wheel itselt sits deeper into the wheel arch of your car "IT COULD CATCH AND RUB AGAINST PARTS". for example the BRAKE CALIPER HOSE or even the SUSPENSION PARTS when on full lock. Jack up the car, put it on axle stands put the steering on full lock (both ways) and while rotating the wheels check very carefully!!!!!

hope this helps
Mark

[duggs]

Well !   I've done some "online" investigating and it appears the new ones are 37ET opposed to the originals which are 39ET.

So I assume that they'll sit further in by 2mm. Hopefully that will be hardly noticeable.....

Will wider tyres, say 225's sit on 6.5 rims ?

[The Doctor]

Well !   I've done some "online" investigating and it appears the new ones are 37ET opposed to the originals which are 39ET.

So I assume that they'll sit further in by 2mm. Hopefully that will be hardly noticeable.....

The ET will be stamped on the back of each wheel, probably on a spoke. 2mm will not make any difference. Even 5mm will definatly not matter. 235 tyres are okay on an omega, at 30mm wider than a 205, thats 15mm extra width each side of the tyre, and thats still okay. So 5mm difference certainly wont be an issue.

Will wider tyres, say 225's sit on 6.5 rims ?

No. Rims can take a few sizes, 3 ish, perfect size, one under (tyre sidewalls will look stretched on, alloys easier to curb) and one over (tyres will look a bit fat and buldged at the edges)

6.5" probably 215's max, 7inch is fine for  225's, but 235's should really be on 7.5". You CAN fit tyres on and it'll drive fine.. but they are designed in a certain way.. stick with it.

[duggs]

To be honest, courtesy of Ebay, I actually purchased brand new tyres and alloy wheels, cheaper than a set of tyres on there own would have cost...SO next time around perhaps I'll try again and get 17 or perhaps 18's..short term..the new 16" will have to do..

[IanM]

I think Astras would be quite a bit lighter than Omegas, might be worth checking the load rating on the tyes you have fitted, they should be as specified by Vauxhall. Otherwise you could invalidate your insurance, worth a quick look.

[duggs]

Good point Ian.

I've been told they are Bridgestones as fitted new by Vauxhall.
The chap uprated the wheels and tyres as soon as he got the car so the ones I've got from him have touched the road yet...

Will they be ok ?