After a shortish run shopping, I tried the temperature of the tyres on my GV by hand and found the front tyres were warmer than the rears. I put this down to the weight of engine and transaxle on the front. Also the "bulge" in the tyre sidewalls was noticeable, and always has been, whereas the rears wasn't. Another little thing was the tyre on the nearside (UK) was a little warmer than its oppo. on the other side. I put this down to lopsided engine/transaxle weight at the front.
I've not been happy with that over-distinct "bulge" in the front tyres for a long time now, so I've increased the front pressures to 40lb/sq". I use a Shrader tyre pressure tester, not a petrol station one. This has lightened the steering considerably, removed most of the bulge, and the fuel consumption has reduced, according to the mpg meter, but this has to be verified by the brim-brim method. I don't like altering manufacturer's spec. at all, but so far no effects on braking or handling has been observed. I suppose tyre wear will eventually show what's best.
Any observations on this one?

Leedsman.

 

40lb/sq Is that the same as PSI?
We do BAR on this side of the canal

I have 17" wheels and I experimented which pressure gave best mileage and handling and I came up with 2.8 BAR f+r (=42 PSI)

 

Apologies for old-fashioned Fred Dibnah measurements, yes, 40lb/sq" is 40 PSI.
Noting your improvements at 42 PSI., will try this.

Leedsman.

 

More air = less wet or dry road contact = less CO2 emissions = less road noise = less drag = lighter steering = worse stopping distance = better MPG

- 20% of a vehicle’s fuel consumption is mainly due to rolling resistance
- an ‘A’ instead of ‘F’ class stamped on the tyre could help save you 80 litres of fuel, or £100 quid a year
- an ‘A’ instead of ‘F’ class stamped on the tyre could mean 2 car lengths or 10 meters less on wet stopping distance

Having said all the above I run @ ± + 5psi [look on the door pillar for 'hot' pressure] and have since the hand-crank Ford Pop which had cross-ply's.

 

The ideal pressure depends on choice of tires (and rims) too. Because wider rims = wider tires and thus different ideal PSI.

BTW You might consider Nitrogen filling.
Reporst indicate there are (slight) advantages from nitrogen compared to "regular air"
Like it holds the pressure a little better.

 

hehehe I had to look that up too..

 

When I was a kid (like a million years ago) you could see Fred Dibnahs on every street corner in every northern town. They all wore dark blue boiler-suits that had seen better days and were covered mainly in oil and grease, sometimes paint as well. They all wore cloth caps (also covered in oil and grease) and had a *** (ciggy) hanging out of their mouths, often waiting for the 'pub to open -- oh, and reading a newspaper to see if their horse was a slow one. They all smelled the same too, beer, sweat, tobacco. After-shave? What's that?
But when it came to engineering, they were all pretty sharp. Cars? Easy-peasy for them. Of course there were no microprocessors, or even transistors. The radio in the car had a "vibrator" in it as part of the 250volt supply to the "valves". There were a few jokes about that vibrator later on... Those of you who have classic cars and valve radios will notice a very faint 'buzz' from it upon switch-on and before the valves "warmed-up".
End of nostalgia trip!

Leedsman.

 

Yes I've noticed as well my car cruises easier on 40psi, its like it doesn't need the engine sometimes. When it drags a bit I find a tyre needs topping up.

 

I do a bit of 'naughty' cruising (in the vehicle I mean...) and it certainly "flows" along the road better in neutral with 42PSI in the front tyres. I'm hoping for a 5mpg improvement, fingers XXed.

Leedsman.

 

Did I say 40psi. should have kept quiet. Got a slow rear puncture today, had to blow it up at home. Blow it up at Carlisle one hour/40 odd miles away. then blow it up back home before going out again. Pressure was down to about 10psi, tyre abit squashed.
Did it drag, didn't half, it certainly wouldn't flow along without power.
However got my new tyre fitted to my secondhand alloy courtesy of fleebay and all pumped up awaiting balancing on Monday.
Stock, stock, about time I bought another tyre for stock.