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-   -   2011 335D tire pressure discrepancy? (http://www.bimmerfest.com/forums/showthread.php?t=649738)

Snaggy 10-03-2012 06:24 PM

2011 335D tire pressure discrepancy?
 
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I've got a sport package with 18" wheels and there is a discrepancy on the stickers on my door with regards to tire pressure specs. The white sticker indicates PSI of 35/42 front /rear. The small yellow sticker below it indicates, "for speeds up to 100 mph", 42/51. It seems to me that the yellow sticker might be incorrect since the manual also states 35/42. All my tires are low( significantly so) compared to the white sticker, so I don't know which one to top off to. Searching the forum many guys are going with 36/36.

Thoughts/ suggestions?

Thanks,

Dave

floydarogers 10-03-2012 09:29 PM

The yellow sticker is for speeds *OVER* 100 mph, not below.

Use 35/42.

Snaggy 10-04-2012 04:58 AM

floydarogers: Thanks for the reply. Common sense told me that your statement is correct. I was just confused that the label is confusing since it states:
"use inflation pressure specified ABOVE (they are listed below??) UP to 100 mph only" How would you interpret that? Regardless, i intend on using 35/42.

ChasR 10-04-2012 05:24 AM

Above (toward the roof) the yellow sticker with the statement "Use inflation pressures specified above up to 100 mph only" is a white sticker that states the "normal" inflation pressures. The yellow sticker goes on to state tire pressures for speeds over 100 mph. Seems pretty clear unless you use the text allignment to determine where above is.

Snaggy 10-04-2012 05:35 AM

ChasR: You are absolutely correct!! I am just being pretty dense!! I should have read it more carefully.

Thanks

Axel61 10-04-2012 05:48 AM

currently 34/40 I like to race from time to time

Flyingman 10-04-2012 11:16 AM

I run my Michelin Super Sports (non-RFT) in the 40/42 range.

badgerbob 11-04-2012 06:58 AM

It took me some getting used to, but I have settled on 35/42 as best all around.

F32Fleet 11-05-2012 01:17 PM

I run 32/35 (non sport)

Sent from my MB525 using Bimmer App

badgerbob 01-06-2013 07:16 AM

Has anyone noticed if the tire pressures affect gas mileage on this vehicle? I get pretty much right on 36-37 mpg on the highway, but see some getting 40 mpg plus. Other than speed I am wondering what others have found that may influence mpg.

KeithS 01-06-2013 07:57 AM

Quote:

Originally Posted by badgerbob (Post 7293342)
Has anyone noticed if the tire pressures affect gas mileage on this vehicle? I get pretty much right on 36-37 mpg on the highway, but see some getting 40 mpg plus. Other than speed I am wondering what others have found that may influence mpg.

MANY factors impact MPG
  • Size of tires - bigger tires use more fuel
  • Tire Presssue - more pressure improves MPG but deteroriates ride quality
  • Software version in the DME
  • Ambient Temperature
  • AC use
  • How heavy your right foot is (accelerating faster vs slower)

But acutally I'm not sure about the last one. I have a feeling that with the D if you accelerate up to speed quickly then get into cruise/maintain speed mode sooner, that it uses less fuel than accelerating very slowly delaying getting into the maintain speed mode.

rmorin49 01-06-2013 08:00 AM

Quote:

Originally Posted by badgerbob (Post 7293342)
Has anyone noticed if the tire pressures affect gas mileage on this vehicle? I get pretty much right on 36-37 mpg on the highway, but see some getting 40 mpg plus. Other than speed I am wondering what others have found that may influence mpg.

Terrain is also a big factor. I could get close to 40 mpg with my d on level roads at 65-70 mph. On my daily commute to work at the same speeds, I had to climb 2 "mountains" of about 1000 feet each and could never get more than about 34 mpg.

ChasR 01-06-2013 08:29 AM

Cold starts take a big bite out of fuel mileage as well. My daily commute of 20 miles on a warm engine results in about 36mpg. With a cold start thrown in at each end mileage drops to about 34. Overall average is 33.22, lower than the commute due to traffic in my drives between commutes.

As for accelerating fast vs slow, I believe in a diesel, slow works best. In a gas motor however, accelerating slowly means the engine sucks vacuum against the almost closed throttle plate, decreasing the efficiency. You get better mileage by mimicking diesel throttle function (no throttle plate) by accelerating briskly (opening the throttle plate) and short shifting. Hard to do in an automatic, though that may be why some manufacturers (Hundai come to mind, but not BMW) program in an abrupt throttle tip in, to max mpg on the EPA city cycle. Real world the driver compensates and mileage suffers.

Pasa-d 01-06-2013 09:26 AM

I don't know how much effect it had, but I used that technique in my old Audi S4 (the twin turbo model). For example, leaving a stop light on a 35 mph marked street, I would floor the gas pedal and use the manual shift feature of the tiptronic to work quickly up to 4th or even 5th gear. The acceleration would be brisk, but not law enforcement attracting, with very little noise from either engine or tires (thanks to a stock exhaust system and all wheel drive). As soon as I'd hit the speed of the street I'd back off the throttle and cruise from there. It's a very stealthy way to get rapid acceleration without the attendant "racing noise" of high engine rpms. Still barely managed to eek out 21 mpg on average though.

Of course, I can't use this technique in "the d" without leaving darkies all the way across the intersection!


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