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[flyer 0712]

hi can anybody help me please,i have a 2000 omega 2.2cd..it was fitted with original 225 x 55 x15 wheels and tyres when i got the car i had the camber angle and castor all checked which was found to be all ok...i have now fitted oz 225 x 40 x 18 inch wheels and the car is strange to handle..its as if the car is skating on ice and it jigs from side to side on a uneven surface and even on the motorway trys to stray,,i have 28lb pressure in the tyres and have tried different pressures but not sure what to put in them,,,any ideas what to try please..thanks ray...

[TheBoy]

What are the current camber settings?

Lower profile tyres will highlight incorrect settings.

[alank46]

Hi
28 sounds a bit low to me, I use about 35psi, admittedly in the standard 225/55x16 tyres.

Large diameter low profile tyres like 225/40x18 are notorious for being susceptible to "tram-lining" and that sounds just like what you have.  Some tyre makes/models are worse than others.

It may get better as the tyres wear in, how many miles have you done.

Alan

hi can anybody help me please,i have a 2000 omega 2.2cd..it was fitted with original 225 x 55 x15 wheels and tyres when i got the car i had the camber angle and castor all checked which was found to be all ok...i have now fitted oz 225 x 40 x 18 inch wheels and the car is strange to handle..its as if the car is skating on ice and it jigs from side to side on a uneven surface and even on the motorway trys to stray,,i have 28lb pressure in the tyres and have tried different pressures but not sure what to put in them,,,any ideas what to try please..thanks ray...

[Elite Pete]

Hi Ray and welcome to the forum

What offset are the wheels you fitted?

[Agemo]

Yes even if kept empty your pressures need to be over 30 psi. I agree about the offset too, yours must be wrong.   

[05omegav6]

225 seems a bit narrow for 18". Aren't the 17"s on elites/mv6s 235's? :-/

[Diamond Black Geezer]

225 seems a bit narrow for 18". Aren't the 17"s on elites/mv6s 235's? :-/

yep.

and definitely need more pressure in them that tyres!

[aaronjb]

225 seems a bit narrow for 18". Aren't the 17"s on elites/mv6s 235's? :-/

Whether it's too narrow depends on how wide the wheels are - 225 on a 7J, for example, would be absolutely right.

The Elites etc came with 235s, yes, but I think 7.5J (or are they 8J?) wheels.. and the OP only has a 2.2 so the width isn't needed for the power (oh hush, tunnie, before you say anything )

[05omegav6]

width isn't needed for the power

What wheels would a 2.2 elite have then?

[aaronjb]

width isn't needed for the power

What wheels would a 2.2 elite have then?

Not a clue, but I'm guessing a 2.2 Elite still has less power than a 3.2 Elite .. and anyway, the width of the tyre is still largely irrelevant - as long as it's suitable for the width of the wheel and not massively out of spec (165s on a 4J wheel would be silly, as would 295s on an 11J wheel) - I was, for example, considering 215s on 16's for winter tyres (in another thread)

But what I mean is - you can't say "225s are too narrow for an 18" wheel" without knowing how wide the wheel is, since it could be any size..

Anyway .. I don't mean to preach, and we're (ok, I'm!) dragging this off-topic for the OPs problem, I think.

[05omegav6]

Valid point. It's just I would have expected something along the lines of 245/35/18  :-/.

Also with regards tyre pressures, full load pressures on my estate are 41psi at the front, and 48 psi at the rear, with 225/55/16s fitted.

[aaronjb]

Valid point. It's just I would have expected something along the lines of 245/35/18  :-/.

Also with regards tyre pressures, full load pressures on my estate are 41psi at the front, and 48 psi at the rear, with 225/55/16s fitted.

Ditto - I was just presuming (you know what presumption makes ) the OP had sized the tyres for the wheels ..

You're right though, pressures ought to be much higher - never exceeding the maximum rated pressure when hot, of course (48psi might be getting a bit close depending on the tyre construction - but as the maximum pressure is printed on the tyre, that's easy to stick to  ).

Interesting article on pressures, btw, as an aside: http://www.modified.com/tech/0208scc_tire_pressure_guide/index.html

It suggests dividing the weight of the car (in US lb) by 100 and adding 2 for a starting point tyre pressure if you have no ballpark figures to work from..

[05omegav6]

Aren't presumptions great

I always run my cars at fully loaded pressure as I never know what my load is going to be. One job might be a old dear going to the shops, and the next a family of four going on holiday for 3 weeks... .
Also given what the car is capable of, I make sure that the tyres are suitably rated for both speed and load.

[mrgreen]

on my original documents the tyre configurations are,

205/65R15 on 6jx15ET33
225/55r16 on 7jx17 et39
235/45r17 on 7,5jx17 ET39

which on reading is interesting as the offset makes a difference depending on how wide the tyres are

[mrgreen]

on my original documents the tyre configurations are,

205/65R15 on 6jx15ET33
225/55r16 on 7jx17 et39
235/45r17 on 7,5jx17 ET39

which on reading is interesting as the offset makes a difference depending on how wide the tyres are

seems to me that 225's seem a bit thin on an 18" but as said depends on the width of the rim but i can't imagine them being the same size as the 15