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[duggs]

Just purchased a nice set of 17" alloys from a Vectra C which I think are 7j with an offset of 41, picking them up tomorrow.

Believe my f/l Elite to be 7.5 with an offset of 39...Is this correct.

It was going to be my intention to put my existing 235/45/17 tyres on them.
Is this possible and is the 2mm difference in the offset going to make much difference and in which way please.

Am rather worried that 235's won't fit on a 7j rim.

[vauxfan2k]

just buy a set of 20mm spacers, will sort it out and make it fill the arches better 

[Kevin Wood]

235s on a 7j rim.. I think 225s are about the limit on a 7j :-/

I'm sure they will physically fit, but the question is how the mismatch will affect the sidewall.

Kevin

[duggs]

Hmmmmmmmmmm.

Might be selling them on again by the looks of things.

Just got some new 235's so not really looking to buy 225's as well. Ho hum !

[eliteomegaman]

Looking at a suggested sizes for the mig is as follows :-

PCD      5x110
OFFSET 35 - 45
BORE     65.1
TYRES   225/50/17

I think, but not sure, that u can put 235/45/17 on 7j rims
but to make sure why don't u fone ur local alloy wheel shop & ask them OR i'm sure some-one from this forum will know 

[Brikhead]

Looking at a suggested sizes for the mig is as follows :-

PCD      5x110
OFFSET 35 - 45
BORE     65.1
TYRES   225/50/17

Suggested by whom?
No Omega came with 225 50 17 tires.

[eliteomegaman]

Looking at a suggested sizes for the mig is as follows :-

PCD      5x110
OFFSET 35 - 45
BORE     65.1
TYRES   225/50/17

Suggested by whom?No Omega came with 225 50 17 tires.

Suggested by Alloy Wheels when changing to new alloys
The question from duggs was that he had some new alloys from a vectra & cud he use 235 instead of 225's

I've found the following from TyreSave:-

Tread     Profile    Wheel       Overall
Width     Height    Diameter   Tyre Diameter

225mm   50%       17ins        25.86ins  657mm

235mm   45%       17ins        25.33ins  643mm

We recommend ±2.5% is the MAXIMUM difference in diameters
Difference in Diameter: percentage = -2.13%  actual = -14mm

So in a nutshell the new size is ok

Hope this helps 

[Mr Skrunts]

Looking at a suggested sizes for the mig is as follows :-

PCD      5x110
OFFSET 35 - 45
BORE     65.1
TYRES   225/50/17

Suggested by whom?No Omega came with 225 50 17 tires.

Suggested by Alloy Wheels when changing to new alloys
The question from duggs was that he had some new alloys from a vectra & cud he use 235 instead of 225's

I've found the following from TyreSave:-

Tread     Profile    Wheel       Overall
Width     Height    Diameter   Tyre Diameter

225mm   50%       17ins        25.86ins  657mm

235mm   45%       17ins        25.33ins  643mm

We recommend ±2.5% is the MAXIMUM difference in diameters
Difference in Diameter: percentage = -2.13%  actual = -14mm

So in a nutshell the new size is ok

Hope this helps 

Plus possibly voiding your insurance in the event of an accident claim. :-/

[eliteomegaman]

Agree Mr Skrunts but when i used to swap alloys for bigger ones i used to phone the insurance company up & tell them (never cost me anymore as long as you are not going from 15'' to 19''!!) and in this case he's only swapping 17's for 17's so should no problemo 

[TheBoy]

Suggested by Alloy Wheels when changing to new alloys
The question from duggs was that he had some new alloys from a vectra & cud he use 235 instead of 225's

Suggest a quick review of our forum guidelines, as posted at top of every section

Tread     Profile    Wheel       Overall
Width     Height    Diameter   Tyre Diameter

225mm   50%       17ins        25.86ins  657mm

235mm   45%       17ins        25.33ins  643mm

We recommend ±2.5% is the MAXIMUM difference in diameters
Difference in Diameter: percentage = -2.13%  actual = -14mm

So in a nutshell the new size is ok
Hope this helps 

Not necessarily - as Kevin Wood points out, what is the effect on the tyre sizewall in trying to fit a wide tyre to such a narrow wheel?

[aaronjb]

Suggested by Alloy Wheels when changing to new alloys
The question from duggs was that he had some new alloys from a vectra & cud he use 235 instead of 225's

Suggest a quick review of our forum guidelines, as posted at top of every section

Tread     Profile    Wheel       Overall
Width     Height    Diameter   Tyre Diameter

225mm   50%       17ins        25.86ins  657mm

235mm   45%       17ins        25.33ins  643mm

We recommend ±2.5% is the MAXIMUM difference in diameters
Difference in Diameter: percentage = -2.13%  actual = -14mm

So in a nutshell the new size is ok
Hope this helps 

Not necessarily - as Kevin Wood points out, what is the effect on the tyre sizewall in trying to fit a wide tyre to such a narrow wheel?

They'd look like a baloon?

FWIW, Toyo state that a 235/50 can be fitted to 6.5-8.5J, 235/45 from 7.5-9J and 235/40 from 8-9.5J .. so whether or not they'll fit properly really depends on the profile of the tyre.

Of course, all manufacturers publish their own data - the above only holds for Toyo, not Bridgestone etc etc, but a tyre shop should be able to advise you (since they have all the data sheets)

Going outside of the tyre manufacturers recommendations could void your insurance in the event of an accident even if you tell them what you've done, since you've fitted something that the tyre manufacturer explicitly says not to..

[duggs]

Well !   They are fitted.   ATS chaps, including a Manager said they should be fine. I asked them, mentioned everything you guys said and they said they'll be fine.

In fairness they look ok, no more bulging than on the original Omega wheels to be honest....although the handling seems a bit better, more precise. Not to mention that they've made a 10 year old car look as modern as a 5 year old one. 

[eliteomegaman]

That's brilliant 

Was hoping it would work cos i was afraid i may have given you duff info & i hate making a t*t of myself 

[duggs]

I WAS rather worried as I take advice and opinions from here very seriously hence i was very upfront with ATS about all the concerns.

As mentioned they said it shouldn't be a problem. When they filled them with air there was quite a "pop" as the tyres settled on the rims. "They ain't coming off them in a hurry" was the comment. "I sure bloody hope not" was my reply.

[2woody]

Three things to look at :-

wheel revs per mile (gearing)
hub height (for handling)
wheel width (for physical fitment)

outside diameter as stated by this company is irrelevant - use only "wheel revs per mile" for the gearing, as the car manufacturer will have done.

standard Omega is 817 wrpm

your proposed size is 804 wrpm

a 1.6% difference, so easily do-able on the gearing front.

Next, look at the handling - so you need to compare the "hub height", or "static laden radius".

standard Omega is 11.2 inches

your proposed size is 11.9 inches

that's going to be borderline for affecting the handling. Placing the hub further off the ground will result in the tyre not rolling over to the correct angle under cornering.

Thirdly, will it actually fit.

Standard Omega tyres (235/45 x 17) are ok for 7.5 to 9 inch rims.

Your proposed size is ok for 6 to 8 inch rims.