like the title says i took my RL up to beautiful Mammoth mountain for 4 days for pure epic snowboarding and skiing.
my buddy and i drove up from southern cali. and took about 6 hours. i will start by saying i didn't bring chains and going up i got about 21mpg. and was disappointed. my buddy drove since i worked the night before and so i slept the whole way up. i can only assume he was going 100 passing everyone on highway 395... :x luckly when we hit hwy 203 no chains were needed.

onto the RL: tires were fine in the snow and black ice conditions, she heated up some what quickly when we drove up to the slopes each morning. i was hoping to find an open field covered in snow, so i could try this out: http://www.youtube.com/watch?v=EGxEZ60E-nQ

but knew that it would never happen.

she held up well. only thing that i had a problem with was my tpms went bad the whole time. showing error error, then when i got down and stoped in bishop for gas it went away. it was highlighting all four tires low. also the car will not let you turn the traction control off if the tpms warning sign is on. also the center display and temperature screens were slow to respond in the cold, would take more time then usual to change displays. i also wished that the rear seat opening was bigger. you can not fit a snowboard through, only the skiis will fit.

heading back home, I achieved 25 mpg with crusie control going 80mph. was very happy with that.

she now needs to be washed, espically because she hadn't been for over a month due to the crappy weather "aka" all that rain we hold recieved down here in sourthern california.

yes this post is worthless with out pictures and yes i dont have any. didnt think i was going to write this tread so didnt plan on taking any. on the way home i saw a convey of new bmw's along with the new X1 and the mini countryman all four doors, also a 760 quad exhaust, with the decals covered with black tape on the sides. a few 5 series GTS aswell.

 

not sure what you were epecting for gas mileage going uphill
Also, the tpms warning could have been right. Air pressure goes down in cold conditions. Did you look at the air pressure when the warning came on? By the time you got to Bishop, probably warmed back up enough to shoot above the low warnign threshold.

 

Air pressure changes somewhat with cold temps but unless it was like 0F or colder it should not be enough to cause pressures so low to trigger the TPMS, assuming your "normal" tire inflation is OK and not already borderline on too low. We haven't gotten REALLY cold here yet (only down to about -10C at night which is like 14F) and my pressures have moved at most 2psi from the summer...and yes the nav screen and the MID get noticeably dimmer and slow to respond until the car and interior fully warm up. Will be interesting when it gets below -20C here.

 

no i didnt expect to get greater going uphill, it was more of a joke because i knew my buddy was driving faster than the speed limit going up and would "gun it" when he passed other autos on the hwy.

and i realize air changes with temperature hot/cold, when i left mammoth with the psi @ 23/24 all around and then getting to Bishop which was still at 30F and it jumped to 27/28. not a problem just more of a fact that i felt like stating.

 

I think it has much more effect than that, quoting Tire Tech:
"The rule of thumb is for every 10° Fahrenheit change in air temperature, your tire's inflation pressure will change by about 1 psi (up with higher temperatures and down with lower).

In most parts of North America, the difference between average summer and winter temperatures is about -50° Fahrenheit...which results in a potential loss of about 5 psi as winter's temperatures set in. And a 5 psi loss is enough to sacrifice handling, traction, and durability! "

I noticed this on my trip over the Holidays. Travelled from Bay area to Oregon up through Mt Shasta area. When I was going through the pass and it was sleeting, I checked tire pressure shown in TPMS. Tires were all showing 27/28. Got down to more or less sea level with temp in 50s and Tires were back up to 32/33

So, OPs tires could easily have dropped into warning zone if they were not inflated to 30 psi to start.

 

^^ - oops, want to get reference right, quote is from Tire Tech section at Tire Rack web site

 

This is why i us nitrogen. It doesn't change with temp changes. This is why aviation tires are inflated using nitrogen. All my dealer uses. Some charge extra but even then id pay for the convenience.

 

Unless you deal with a wide range in temperatures/altitudes or race your car professionally, I don't see the point.

 

Your air pressure doesnt change barely at all with nitrogen. Unless you live somewhere the temp spread from season to season is 20 degrees, i guess you wouldnt need to bother with it.

 

What does it cost you? I know your dealer uses it, most don't. Just wondering how they pay for it, higher than market-rate service etc.

 

Nothing for Acura customers. Honda they do but not me because i previously worked there. I also continue to get parts at employee cost...
.

 

Your inflation issue is most likely due to temperature, 1 psi drop for every 10 degrees F, as stated previously.

This comment on altitude effects is an aside, because you never used an air pressure gauge to test your tire pressure. Much of the info is from the May 2006 Acura ServiceNews. A later issue also discusses ambient air temperature differences as you experienced.

Interesting what altitude does to TPMS.The TPMS sensors are mounted inside the tires and are designed to measure absolute pressure (the actual pressure inside the tires).

So if you set your tire pressures at Mammoth Mountain base, about 8000 feet the last time I was there you will observe that the tire pressures on the MID will be lower than the tire pressures on your air pressure gauge. TPMS is working just as it should, measuring the actual pressure inside the tires. Your tire pressure gauge is measuring the difference between the pressure in the tires versus atmospheric pressure.

At sea level, the atmospheric pressure is about 14.7 psi. But for every 1,000 feet you climb above sea level, it drops by about 0.5 psi. While not a linear relationship, the rule is close enough.

So Mammoth is 8000 feet above sea level, so .5 x 8 = 4 psi difference, or 10.7 psi atmospheric pressure at Mammoth (which is also why it is harder to breathe, oxygen dissolution into the blood occurs slower at lower pressures). So if your RL front tire pressure was set to factory specified 32 psi at sea level, at Mammoth you would read only 28 psi on the tire pressure gauge, even though the actual pressure in your tires, as measured by TPMS never changed! By the time you get back to sea level, the MID and the tire pressure gauge would match again at 32 psi!

Interesting, huh? Well, I thought so anyway

 

Yeah altitude is the likely culprit here. I live right at sea level (on the coast at the ocean) and trust me, we went from +37C in a heatwave in late August to around -10C now here, and my cold pressures first thing in the morning have moved at most 5psi, going by both the MID and my tire gauge. No nitrogen, just air. So if I had been running low on cold inflation to begin with in the warmer months, pressures prob would have dropped enough to throw the warnings now that it's colder outside.

I have heard from others with TPMS equipped cars (not acuras) that when it gets REALLY cold (-20C and lower) they often get warnings despite pressures being fine, some sensors apparently just don't deal so well with really cold weather. I experienced this myself with a rental SUV (Chev Blazer) two winters ago, cold snap came in quickly and we went from above freezing to around -25C overnight and I suddenly had tire pressure warnings on the dash but all tires were fine.

 

Cool posting. I'd love to drive our RL to Mammoth, but I am a "not getting that winter slush on my car" guy: we have an SUV that's slower, not as fun to drive but carries plenty of gear and scratches just fine. Then, everytime we go up for the summer, it's with bikes. I'm a "not getting that bike rack on my car" guy...

 

Great post. Thanks for sharing.

 

thanks for the posts guys, i was a bet hesitant also about bringing the RL, but wanted to put the SH-AWD to good use. i finally washed her yesterday took before and after pics ill get them up soon enough. she had that frozen-on slush in front of the mudflaps at all fours, just a dirty mess all around haha

 

as for my tire pressure, its currently in the 27/28 range. i'am getting the tires rotated at Americas tires tomorrow. and will make sure that they are properly inflated. noobie question tho: the Acura standard is 32psi correct? so 32psi will be the same for any type of tire you put on? i currently have Hankook Ventus V12 and i'm pretty happy with them, have 5000 miles on so far. did well in the rain the past few months. socal will know.

 

I too have the Hankook V12's in 19" (no room for chains) pressure =32 at 37 degrees, normal =35 goes as high as 37-38 when hot. BTW - I too like the V12's (apprx 20K miles). Ride is a bit rougher but the higher pressure does not roll the outside of the tread.

 

If you read your manual, the recommended pressure is 32F 30 R and I believe 36/35 for high speed driving. So 32/30 should be your cold minimum. If you drive to get it filled, overfill by 4-6 lbs and adjust in the morning when cold. Even one mile of driving is enough to heat up the air in the tires, and since your are underinflated already, you will heat up even faster.

 

Do 35psi of nitrogen. It doesn't change with temp or elevation.

 

Not to make too fine a point on this, while I agree that the absolute pressure inside the tire does not change with elevation, temperature changes, up or down, will change the pressure of any gas inside the tire, whether the gas is so called 100% dry nitrogen, or air (which is 78% nitrogen, of varying humidity).

If you get the dry nitrogen for free (e.g., Costco), go for it. If you have to pay a premium for it, don't bother.

 

thanks for the tips again, because i bought the tires at america's tires you get the free rotation. brought them in, done 35 mins later. first jumped in they were 32front/30rear. went home now left for work and sensors read 38/37psi.

 

Sounds about right for hot tires. Notice a difference in handling and/or ride?