Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Doctor Gollum]

32-34psi, all round. Unless camping (crammed to the gunnells, with roofbox as well), in which case, I might take to 38psi.  235/45/17 or 245/30/18


IIRC 225/55/16 should be slightly less. Whacking up pressure wont help with handling (that's suspension), just make it slide about more.

Please read the manual

Unfortunutly I left the manual at home. 

Download the free one from the FAQ section...

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

[Andy A]

32-34psi, all round. Unless camping (crammed to the gunnells, with roofbox as well), in which case, I might take to 38psi.  235/45/17 or 245/30/18


IIRC 225/55/16 should be slightly less. Whacking up pressure wont help with handling (that's suspension), just make it slide about more.

Please read the manual

Unfortunutly I left the manual at home. 

Download the free one from the FAQ section...

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Got the owners manual. 

What make of shocks for the rear are recommended?

[Doctor Gollum]

Personally, Sachs or Genuine...

Starter for 10...

https://www.ebay.co.uk/itm/Sachs-2x-Shock-Absorbers-Dampers-Rear-Pair-Gas-Pressure-105-842/253668814146?fits=Car+Make%3AVauxhall%7CModel%3AOmega&hash=item3b0fd6ed42:g:FmYAAOSwEzJbFVHq

 

[Andy A]

Check the diff mounts and the subframe donuts

The diff mounts are in good shape. How can I tell if the subframe donuts are worn? What do I need to look for?

Thanks for the link Al. 

[Doctor Gollum]

No worries 

The subframe bushes can just about be inspected visually and physically with aid of a pry bar. Parking the car on a kerb will allow sufficient access...

Equally if you press on a bit in the twisties and the back end feels like it is connected by jello, then they are probably toast...

Same test for diff mounts, although the weight transfer off a broken one is sudden and more pronounced, especially in the estate... But best test for these is reverse the car onto ramps and, whilst SUPPORTING not Lifting the diff with a trolley jack, undo ONE diff mount from the chassis... If it drops more than 1/4", is floppy* or simply falls off, then it's toast. Refit and tighten then test the other side

Whilst on ramps look at the donuts... Pop the pry bar between the triangular plate and subframe and try to push the subframe up with the bar... Again if it moves easily or clonks, then the donuts are shot.

*Like Alan Carr in a convent shower rather than a chocolate moose

[Andy A]

No worries 

The subframe bushes can just about be inspected visually and physically with aid of a pry bar. Parking the car on a kerb will allow sufficient access...

Equally if you press on a bit in the twisties and the back end feels like it is connected by jello, then they are probably toast...

Same test for diff mounts, although the weight transfer off a broken one is sudden and more pronounced, especially in the estate... But best test for these is reverse the car onto ramps and, whilst SUPPORTING not Lifting the diff with a trolley jack, undo ONE diff mount from the chassis... If it drops more than 1/4", is floppy* or simply falls off, then it's toast. Refit and tighten then test the other side

Whilst on ramps look at the donuts... Pop the pry bar between the triangular plate and subframe and try to push the subframe up with the bar... Again if it moves easily or clonks, then the donuts are shot.

*Like Alan Carr in a convent shower rather than a chocolate moose

I'll have a good look when I get back in a couple weeks. 

[TheBoy]

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Pumping them up higher won't improve handling, in fact quite the opposite.  However, its a necessary evil to protect the tyre.

[atann]

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Pumping them up higher won't improve handling, in fact quite the opposite.  However, its a necessary evil to protect the tyre.

My CDX has extra load tyres all around. I rarely carry anything & it is normally only me in the car. Have put the fronts to 32psi & the rear to 34psi, as recommended in the thread. Car feels more stable & better traction. Does a higher psi help fuel consumption in urban driving?

[Doctor Gollum]

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Pumping them up higher won't improve handling, in fact quite the opposite.  However, its a necessary evil to protect the tyre.

My CDX has extra load tyres all around. I rarely carry anything & it is normally only me in the car. Have put the fronts to 32psi & the rear to 34psi, as recommended in the thread. Car feels more stable & better traction. Does a higher psi help fuel consumption in urban driving?

Yes. In a word.

At the correct pressures, (full load pressures even more so), the tyre circumference and profile remains more stable, reducing rotational drag. The trade off however at full load pressure, is that unless the car is carrying some weight, the centre of the tread will wear more quickly.

[atann]

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Pumping them up higher won't improve handling, in fact quite the opposite.  However, its a necessary evil to protect the tyre.

My CDX has extra load tyres all around. I rarely carry anything & it is normally only me in the car. Have put the fronts to 32psi & the rear to 34psi, as recommended in the thread. Car feels more stable & better traction. Does a higher psi help fuel consumption in urban driving?

Yes. In a word.

At the correct pressures, (full load pressures even more so), the tyre circumference and profile remains more stable, reducing rotational drag. The trade off however at full load pressure, is that unless the car is carrying some weight, the centre of the tread will wear more quickly.

Thanks for the reply. Am I right in saying the tyres normally wear at the edges first, due too the toe in on Omega’s?

[Doctor Gollum]

Tyres should wear evenly with correct pressure and geometry, however the Omega being a bit lardy will scrub the outside edges of the front tyres in turns if you press on... Fast roundabouts being the biggest cause. 

[TheBoy]

At the correct pressures, (full load pressures even more so), the tyre circumference and profile remains more stable, reducing rotational drag. The trade off however at full load pressure, is that unless the car is carrying some weight, the centre of the tread will wear more quickly. the car is unable to deal with corners in a decent manor.

FTFY.

[TheBoy]

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Pumping them up higher won't improve handling, in fact quite the opposite.  However, its a necessary evil to protect the tyre.

My CDX has extra load tyres all around. I rarely carry anything & it is normally only me in the car. Have put the fronts to 32psi & the rear to 34psi, as recommended in the thread. Car feels more stable & better traction. Does a higher psi help fuel consumption in urban driving?

I would consider swapping those around. 34psi is too high for any Omega at the back, unless carrying weight.

[Doctor Gollum]

Full load for a Desmond saloon is 36/42... Which is significantly higher than 32...

This is your most likely problem, although tired shocks won't help matters...

Pumping them up higher won't improve handling, in fact quite the opposite.  However, its a necessary evil to protect the tyre.

My CDX has extra load tyres all around. I rarely carry anything & it is normally only me in the car. Have put the fronts to 32psi & the rear to 34psi, as recommended in the thread. Car feels more stable & better traction. Does a higher psi help fuel consumption in urban driving?

I would consider swapping those around. 34psi is too high for any Omega at the back, unless carrying weight.

Which begs the question as to why GM bothered to establish optimum pressures and included them in the handbook...

I would wager that 'TB prefers his steering twitchy and his backend slightly squiffy in order to negotiate MK at a minimum speed of 70 mph...' was not on their list of criteria

[GastronomicKleptomaniac]

FWIW on my old Elite I dropped them from 34 to 32 psi, and it instantly stopped bouncing around like a toddler on crack. It was verging on scary with 34. I recommend experimenting with a known accurate gauge and seeing how you get on.