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I have a German version of the 2014 RX 450h F Sport. On the door pillar is the sticker indicating proper tire pressure. It's a little confusing and I though perhaps others here may understand it. I have 235 55 19 101V rated tires...so looking at the sticker it appears there are three suggested set ups for the tire pressure. One appears to be for driving over 160 Km per hour as being 2.6 bar in the front and 2.9 bar in the rear. For driving under 160 Km per hour is 2.3 bar all around all four tires. The third one appears to be for driving in the eco mode up to 160 Km per hour is 2.5 bar for all 4 tires. Is my interpretation seemingly correct?
Your interpretation is correct. The higher pressure will minimize the heat buildup in the tire which is a tire's enemy at very high speeds, so good for 160kph+. Higher pressure is also more fuel efficient as there is less flexing in the tire during rotation (and why its good for minimizing heat build up at high speed) which is why the higher pressure it recommended for ECO driving. The lower pressure for slower speeds is mainly for comfort factor. The lower pressure absorbs bumps better, making for softer ride.
In North America, since we don't have highways with certain portions having uncontrolled speeds like in Germany, I believe from memory we only have 2 recommendations: 33 for comfort driving and 35 for highway driving. I typically run my 19" tires at 36 to 37 (2.5) all the time for best economy even though I would only very rarely drive at most up to 130kph.
I keep the 19-inch tires on my wife's 2015 RX350 at 33 to 34 psi. The ride is relatively comfortable and the treadwear longevity is quite acceptable at that pressure.
Wow MellonC00...that seems low in the rear given the extra weight from the batteries. Perhaps, as it appears you're a test driver, that tire mileage is of no concern? I used to run my LS with 37 in the front and 35 in the rear, but it didn't have the weight in the rear half of the car.
The internal combustion engine still weighs more than the batteries. So, it understeers big time. Sometime when I go around the exit/entry ramp at a rather fast clip, it seems like my front end is going into the ditch........(it doesn't do really do that but the sway of the car combined with the understeer makes this into an activity Mrs. MellonC does not approve of)
08-11-19, 05:07 AM
Help with Tire Pressure for 2014 450h F Sport
