Temperature read out on speedometer

[tkeneklis]

Greetings everyone. I have a 2003 Z-4 2.5 convertible. I am still driving it in Wisconsin (no snow yet!) and when I leave the garage I get a signal on the speedometer gauge like +37 o F . What's it mean and why don't I get a constant temperature read out when I am driving.

[Nate4641]

It's a warning that below 37*F there is a chance on ice on the road. It should beep at you and flash that, then go back to normal. The garage is also probably warmer than outside so once you get driving the thermometer starts reading colder. It's an old system so it wont instantly change the displayed temp, it takes time.

[Twixboy]

Yup it's a warning system that's on every BMW. Even that E30 in your post gave this warning. The Germans determined 37 degrees is the temperature that ice starts to form on the roads, so now we get the annoying chime every time we drive a BMW in the winter.

[deemo319]

Twixboy and Nate4641 are both correct, but I will add that it also includes the driver be cognizant and vigilant since water freezes at 32 degrees it actually freezes on bridges and overpasses at 37 degrees because they are suspended and have cold on all four side.

So pay attention going over those two as stated because there can be ice or frost there.

Be on the lookout in the morning and directly after sunset as the temps drop, so don't relax at bridges and highway overpasses by any means.

I lived in Minnesota for a very long time and had three BMW's while I lived there so I know exactly what's it's like during winter driving in the upper Midwest.

[Huz-Z]

The warning also tells you that at these low temperatures, the rubber compound in your summer tires is providing inferior grip, particularly when compared to the rubber formulations used in a winter tire. So, even if there is no ice on the road at all, you should be more vigilant as the tires are not as sticky as they would be in warmer weather.

[HankDKrank]

Mine did it the other day and thanks to this forum I knew exactly what was up. Kinda cool.

[Twixboy]

Originally Posted by Huz-Z

The warning also tells you that at these low temperatures, the rubber compound in your summer tires is providing inferior grip, particularly when compared to the rubber formulations used in a winter tire. So, even if there is no ice on the road at all, you should be more vigilant as the tires are not as sticky as they would be in warmer weather.

Great information, I forgot about that one. This morning it was 23 degrees when I left for work so I decided to leave the Z4 in the garage because I was scared my summer tires wouldn't get enough grip.

[JCF]

Originally Posted by HankDKrank

Mine did it the other day and thanks to this forum I knew exactly what was up. Kinda cool.

Kinda cool??? BOOOOO


It STILL freaks me out every time it does it.

[StickMon]

I like it.
When I drive in the Mojave in the winter the temperature can change 15 degrees in just a few miles.
Nice to get a heads-up on when to go to "big-toe" mode.

[wdb]

Originally Posted by HankDKrank

Mine did it the other day and thanks to this forum I knew exactly what was up. Kinda cool.

I agree that it was cool that I knew what it was the first time it happened because of this forum. I also agree that the warning itself is, while understandable from a Teutonic perspective, nevertheless annoying as hell.

[pungo]

I find it both startling and annoying so I disabled it by coded it so it doesn't chime, it just blinks the temperature on the dash.

[Finnegan]

Originally Posted by StickMon

I like it.
When I drive in the Mojave in the winter the temperature can change 15 degrees in just a few miles.
Nice to get a heads-up on when to go to "big-toe" mode.

Attachment 1327373

Lol on "big toe".

Cold temps and summer tires are not to be considered lightly. I've seen some pretty scary stuff as a result of running with extreme summer rubber in colder temps (30-40f). They turn into hockey pucks.

Traction on street legal R comps like Michelin Sport Cups are rocks below 45 degrees and the rubber can actually crack and destroy the tire if moved. Those tires are not to be moved below 40-45 degrees.

[Efthreeoh]

It might help to be a bit more accurate here. The +37 deg. F is a warning that ice could still be on the road even though the air temperature is above freezing.

[StickMon]