Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Andy A on 02 September 2018, 19:59:18
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What tyre pressure do you put in your extra load tyres mine are 225/55 R16?
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41 front, 48 rears as per manual :y
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32 psi front and 34psi in the rears under normal usage.
Tracking is set up as per WIM and I have lovely even wear across all 4 tyres.
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41 front, 48 rears as per manual :y
That's to say if likely to be fully loaded ;)
Normal is 34/41iirc :y
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I came up the motorway with 32 in front and 32 in rear using 225/55 R16 XL Rainsport 3's. 2 people in front, boot and back seats loaded up with stuff and the car was pulling and bouncing all over the road on bends at 70 mph. Not relaxed driving at all.
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Sounds low, but could be a suspension issue highlighted by the low pressures... Put to max load pressures as above repeat and report back ;)
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I came up the motorway with 32 in front and 32 in rear using 225/55 R16 XL Rainsport 3's. 2 people in front, boot and back seats loaded up with stuff and the car was pulling and bouncing all over the road on bends at 70 mph. Not relaxed driving at all.
Too low for that much weight.
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I came up the motorway with 32 in front and 32 in rear using 225/55 R16 XL Rainsport 3's. 2 people in front, boot and back seats loaded up with stuff and the car was pulling and bouncing all over the road on bends at 70 mph. Not relaxed driving at all.
Tired springs and shocks would do that. They deteriorate gradually, so you acclimate to them. An unusual load is often enough to make their poor performance more obvious. Fitting four new springs to my car at 190k miles made a massive improvement to the comfort, handling and stance.
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Got new springs on back around 5 months ago @ 128K miles. Will up the Tyre pressures and report back but won't have another full load for 2 weeks. Will report back then.
Thanks for all your advice. :y
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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.
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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.
Unless you've got so much sh*t in the back that the tyres look almost flat. In which case you should have hired a van. I er, don't speak from experience, of course (twice) because overloading a car is illegal and dangerous.
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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.
;D
Please read the manual ;)
Specifically pages 227/228. Irmscher wheels came new with a data sheet regarding tyre sizes and pressures ;)
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So its looking like a suspension problem on the back. Last year I had the old springs on but had to change the pair because one was found broken on the mot.So I got the garage to change both rear springs.
Carrying the same weight as last year but had different tyres on the back and did not have this problem.
I wounder if the new springs aren't beefy enough or the shocks need changing. :-\ Any advice?
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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.
;D
Please read the manual ;)
Unfortunutly I left the manual at home. :-[
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Check the diff mounts and the subframe donuts
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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.
;D
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... ;)
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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.
;D
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. :y
What make of shocks for the rear are recommended?
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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
:y
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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. :y
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No worries :y
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 ;)
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No worries :y
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. :y
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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.
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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?
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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.
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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?
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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. :y
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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.
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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.
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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 ::)
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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.
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33 in the back
32 in the front on my estate with a gas tank in the wheel well.
Rises the 34 in the back if carrying any real load.
Can confirm it drove straight and true and a steady 80 plus a little bit :-X last weekend
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Which begs the question as to why GM bothered to establish optimum pressures and included them in the handbook... ???
The optimal (although all cars vary, as do tyres, so worth experiementing) is the normal load. The high load/high speed is to reduce chances of tyre failure due to the extra stress, rather than "optimal" ;)
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And "high speed" generally refers to over 100mph, so not a worry with Blighty's maximum 70mph limit. So just the load....