I think this Nitrogen stuff is for the birds.

 

But "it is said" Nitrogen is good in your tires (although we don't know who said that and whether the "sayer" had any of the right credenzas).

 

I am still running the OEM michelins on my 2009 rx and have right at 20k miles on the vehicle. Hoping I can get to 45-50k miles on them. They are nice and quiet so I like them for that, but not so great in the snow here in Colorado.

My next set of tires will be the Continental DWS.

 

I bought the Alenza's and have loved them. No remorse at all. Quiet, great ride and nice and quiet. No complaints at all.

 

I would advise against getting the Continentals, they become extremely noisy, and dont last very long either.

 

Read this article from Popular Mechanics regarding Nitrogen filled tires and draw your own conclusion. Costco offered to fill my new tires with Nitrogen for free. I don't know why I would refuse that.

http://www.popularmechanics.com/cars...stions/4302788

 

nitrogen is a component of air..

 

Just the latest fad bro. Besides, if it`s so great, it sure as hell wouldnt be free! and as sura already mentioned...."its a component of air"

 

What do you recommend then?

 

filmteknik - I have a certified used 06 RX330 and it came with the Bridgestone Dueler Alenza's at ~35K. Unsure how long ago those tires were on the car, if they were new or came OE of the lot but all 5 tires were the Dueler's so I'd assume the later.

I think the loss of MPG you mentioned could be due to the dry weight of the tires. The Michelin's are much lighter than the Bridgestone's, 27 and 33 lbs each respectively. I have to admit they're lasting and are quiet; I'm at ~45K and tires are still good at 5-6/32" of tread. My next tires will either be the Yokohama Parada's or the Continental DWS's.

Willybob - Tirerack gave the Cont. DWS's pretty good reviews; at what mileage did it start to get noisy and how long did it last?

 

Exactly---the air we breath is 78% nitrogen. The benefits of nitrogen in street tire use is -vastly- overstated... mostly by either people selling nitrogen or folks needing to convince themselves it was worth the $ they paid for it.

For free it's worth getting, for money not so much, and since normal air is mostly nitrogen anyway there's no harm at all to "mixing"

A good quote to remember "Nitrogen is a gas and is still affected by changes in ambient temperature (about one psi for every 10° Fahrenheit). Nitrogen filled tires will require pressure be added during the fall/winter months as ambient temperatures and tire pressures drop. Nitrogen is good but can't break the laws of physics.

 

The michelin energy MXV4 tires have almost unananimous complaints about the treadlife on tirerack. Up until March, it looks like they were not giving any warranty on the tread either (now they are). Good to hear from other lexus owners. Thanks for the input. Not sure what I'm going to do yet. Will update when I do.

 

I am happy to report that my buyer's remorse may in fact be premature. Yesterday's fill-up calculated to 20.077 MPG. That was a mix of highway and stop & go. Hope I didn't make a mistake.

What is the true tank capacity on the 2008 RX? I keep reading 17.20 gallons but I put 18.334 into it yesterday. The display still said several miles to go and I know I've driven it on 0 for miles in the past. So I would think there was still a half gallon or more left. I must have the wrong tank size figure as an inflated amount from a cheating pump would have me coming up with a low MPG, not more than expected.

368.1 miles / 18.334 gallons.

BTW, the calculated MPG tracked very closely with the on-board computer. That surprised me.

Steve

 

My brochure lists the fuel tank capacity as 19.4 gal.
In my experience, I have found the MPG calculations on the 3 Lexus cars I have owned to be remarkably accurate. What is not accurate is the gas gauge and the cruising range readouts, which have large margins built in to help you not run out of gas.
The most accurate way to compute mpg is to fill the tank up (and not top off) and set the odo to zero. Then make notes when buying gas in the future, and always fill up in the same manner. Note the gallons purchased from the pump (which is very accurate and monitored by a state or county agency - usually the auditor) and note the miles on the odo, which is also accurate. Reset the odo on each fill up. I did this for a month or so, including highway trips, and each time for each car my manual calculations almost exactly matched the dash readout. I just don't bother with the manual calculations any more. I think my RX gets about 18 in the city and over 20 on the highway, although I don't take it on many long trips (I tend to take the SC430 on longer trips, where the very powerful V-8 gives me 22 fun-filled mpg all the time, probably because it is loafing along at such low rpm; I'm not sure why, as it's a heavier car than the RX.)
As for the gauge, it looks to hit "E" at about 3 gals in the tank, and the cruising range is a good 50 miles too low, but I seldom go below a quarter of a tank, although the yellow fuel light did come on recently, so it's nice to see that the light still works. At that point, I think it took about 17 gals to fill up, so the light gives about a 40 mile warning, which is plenty.
That's my experience with the fuel gauge, lights and readouts, but your mileage may vary.

 

^^ I do the same as you.
I always reset Odo Trip B and at every fill up write down the miles driven on the new receipt before resetting. I then divide the total miles driven with the total miles filled. that gives me a pretty accurate read on mpg I actually drive; which is roughly the same as you, 16-18 city (SF hills) and 20 highway.
Most vehicles it is built in as a safety for when the gauge hits the E there's at least 3 gals "reserve".