What pressures for a 255/45R18 103 W XL?

Sim667

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T6 Pro
I’m asking because I’ve never had a vehicle with the non standard wheels before, and on the way back from picking it up I had a TPMS warning, so stopped and inflated all the tyres to the same marked on the pillar. But have realised since this is probably the wrong pressure.
 
Im also on 235/55 18 and run 45psi.

The ideal setting will depend on your preferred driving style, how loaded the van is, the nature the tyres you're using. Try 42-43 as a starting point and adjust slightly either wsy as your tastes require.
 
Currently I’m driving it empty. Eventually it will have an ovano in.

Do you have the same pressures in all 4 tyres?

I’ll probably start off at 42. They’re currently at 56 because that’s just what it said on the pillar but it looks far too high.
 
I'm on 255/45/18 103's currently 48 all round (loaded with winter trip kit), usually run at 46 front 42 rear. I'm always checking for tyre wear from under or over inflation, all good so far 4K miles on this set.
 
I run 45 psi front and rear. I have my Ovano 70 % full with tools. Even tyre wear all round.
 
Right pressures in now and it immediately felt a little gentler on the bumps.

Does anyone know if I can buy the sticker to fit in the doorway, so I’ve got a reference?
 
Right pressures in now and it immediately felt a little gentler on the bumps.

Does anyone know if I can buy the sticker to fit in the doorway, so I’ve got a reference?
Label maker if you have access to one?
 
So following all the posts on pressures I'm now rethinking my 42 all round though that seemed fine on my T5 for 12 years, no abnormal tyre wear at all.

ALL the posted stickers have lower pressure at the back (heavy engine at the front obvs) my van has around 2-300kg in the back day to day.

So if I run 44 front, 38 back (235/55/18 Avon AX7) will I feel any difference? Will it be 'better' in any way I wonder?
 
Lot of over thinking going on I reckon as the tyre itself can make a huge difference let alone tyre size.
Premium car summer tyres of the appropriate load rating are a vast improvement in handling over all season or specifically winter tyres apart from during winter. 🤕
Cheaper tyres aren't necessarily rubbish, I used to be happy with my 255 45 18 HiFlys but in their case the tyre wall was very pliable and felt very much like the Eagles on our car, running them at 42psi gave a decent predictable ride, admittedly they would protest a bit at their limit but that would be when speed matching to hold your lane on the roundabout Grand Prix. :whistle:
Swapping those tyres out finally for a set of Dunlop SportMaxx there was a slight improvement all-round but far less squeals, now on Bridgestone 19" Turanzas after a wheel change and these bad boys are quiet and a bit of a weapon running at 45psi while watching for wear.
Obviously the other thing to allow for is the changing weight of the van, ours is a camper and you'll soon know if your tyres are a bit low with the ride going a bit smeary, too high and you think your power steering has been turned up a notch to city driving mode with the van hunting all over the lane and being very aware of the road camber.:geek:
 
Thanks @Stay Frosty that was helpful, particularly the bit about too high or too low pressures and the different feeling.

I'm now on 44f and 38r, can feel the difference (they'd dropped down to 40) at the front, back feels the same.

Just done 164 miles, mainly motorway on cruise at 60, got 42mpg which I'm very happy with (never seen that before). Recently gone from 20s to 18s so it's partly that, partly steady driving, maybe partly pressure.

And yes, lots of overthinking!
 
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