• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Tire Pressure Monitor

Just be happy you don’t have a Canadian bike. Our pressures display in bars ( no, not the drinking kind). Try and find a pressure gauge on the road anywhere that shows bars!
The answer, of course, is to keep the engine running after you’ve ridden far enough for the display to work and top up the tires until the display shows the correct pressure: it takes a few seconds to stabilize.
 
This is a little off topic but maybe provides a little good info...

Yesterday the front TPM on my K1600GTL guilt working. The bike is several years old so I am pretty sure it is a dead battery. I had a spare. It's a Chinese knock-off but I have read on the K1600 forum that several people are using them. After I installed it I attempted activating it with the GS911. There are two methods. First is to use a special tool to set the sensor to transmit and then use the GS911 to but the bike computer in learn mode. The second method is to manually enter the serial number of the transmitter. Since I don't have the activation tool I used the manual method of putting in the serial number but I could not get the computer to return a confirmation. I read somewhere that the sensor can sometimes be put in transmit mode by inflating the tire to 50 psi and then letting all of the air out. I did this and then used the GS911 to put the bike computer in learn mode. Now neither the front or back monitor is working. My guess is the computer is still in learn mode waiting for a signal from the new sensor. I will take it to the dealership next week and see if they can set it. I will report back after that.

Sent from my XT1254 using Tapatalk
 
I just tried it and it works fine

Did you decompress the zip file first?

There is a file called :Tire Pressure Adjustment.xls inside.
That's the excel file

I can't figure this out. With Excel 2010 on my pc I get a blank page. If I copy it to my ipad it works in excel, numbers and sheets. All three of the spreadsheet options available there.
everything in tried on the PC was blank
No idea why.
Gator
 
This is a little off topic but maybe provides a little good info...

Yesterday the front TPM on my K1600GTL guilt working. The bike is several years old so I am pretty sure it is a dead battery. I had a spare. It's a Chinese knock-off but I have read on the K1600 forum that several people are using them. After I installed it I attempted activating it with the GS911. There are two methods. First is to use a special tool to set the sensor to transmit and then use the GS911 to but the bike computer in learn mode. The second method is to manually enter the serial number of the transmitter. Since I don't have the activation tool I used the manual method of putting in the serial number but I could not get the computer to return a confirmation. I read somewhere that the sensor can sometimes be put in transmit mode by inflating the tire to 50 psi and then letting all of the air out. I did this and then used the GS911 to put the bike computer in learn mode. Now neither the front or back monitor is working. My guess is the computer is still in learn mode waiting for a signal from the new sensor. I will take it to the dealership next week and see if they can set it. I will report back after that.

Sent from my XT1254 using Tapatalk

I'm not aware of the transmit mode you mention, the other two methods work. Your Chinese senors may not have the numbers you need so you need a wake up tool. This one should work fine https://www.amazon.com/VXDAS-EL-50448-Pressure-Monitor-Activation/dp/B072BK693N or find alike.

Jay
 
... chart indicates you should over inflate for temperatures above 68 degrees to get to the recommended cold inflation pressure, unless I am reading them wrong.
What you are meaning to say is correct (increase the cold-tire PSI), but the wording is problematic (overinflate).

All that the chart or Dann's spreadsheet do is identify the adjustment in cold-tire pressure required for different ambient temperatures, as Paul pointed out.

Where a lot of people go completely wrong is thinking that they should put less air in a tire on extremely hot days or when riding with heavy loads. This is wrong. Not only is it wrong, but it is the opposite of what should be done and can easily lead to tire failure. Sometimes catastrophic failure.

Too little air in the tire will increase tire flex which generates more heat on a moving bike than ambient temperature. Too much air (cold-inflation) doesn't allow for sufficient tire flex and therefore generates less heat. The tire will have trouble (in medium ambient temp days) getting up to its optimal operating temperature. In either situation, traction is sacrificed.

Therefore, if one is going to err, it is better to err on the high side of inflation. I've always found that I prefer my tires inflated 1-2 PSI over the manual on newer bikes and 2-4 PSI on the older ones (I suspect that new tire technology is part of that). YMMV
 
I can't figure this out. With Excel 2010 on my pc I get a blank page. If I copy it to my ipad it works in excel, numbers and sheets. All three of the spreadsheet options available there.
everything in tried on the PC was blank
No idea why.
Gator

Your 2010 version of excel is probably too old
 
Crap system

How sad that the computer on this $25K motorcycle which knows air pressure, temperature, and internal tire pressure can’t figure out something that you can do with a spreadsheet. Mine’s off consistently by 5-6 lbs low on both wheels and the dealer told me there is nothing that can be done about that. I seem to recall that the TPMS on my 2010 K1300GT was spot on. If the RT readout was just meant to be a “low pressure” sensor it should have been an idiot light and not some display of bogus numbers. How BMW can say this is OK is beyond me, that's bull$hit.
 
How sad that the computer on this $25K motorcycle which knows air pressure, temperature, and internal tire pressure can’t figure out something that you can do with a spreadsheet. Mine’s off consistently by 5-6 lbs low on both wheels and the dealer told me there is nothing that can be done about that. I seem to recall that the TPMS on my 2010 K1300GT was spot on. If the RT readout was just meant to be a “low pressure” sensor it should have been an idiot light and not some display of bogus numbers. How BMW can say this is OK is beyond me, that's bull$hit.

My '16's TPMS is completely reliable and correlates well after the tires are road-warmed. Moreover, its temperature-correction appears perfect. Sounds like either something is wrong w/ your specific implementation of TPMS, or your manual gauge is off, or they're both off in opposite directions.
 
Same problem as Bill

Bill, I have the same problem with my 2019 R1250GS, which was the subject of my original post in this thread. I inflate the tires with my "Motion Pro Professional" digital tire pressure gage to spec, and the tire pressure monitor on my bike consistently reads the pressure about one pound lower. Not sure which to trust, the gage or the bike, but I think I will trust the motion pro tire pressure gage and use the pressure monitor on the bike as just a guide. I had the same problem with my 2014 GS.
P.S. I use to live in Highlands Ranch. I retired and moved to Tennessee because the cost of living here is lower. I miss the riding in Colorado, however.
 
Bill, I have the same problem with my 2019 R1250GS, which was the subject of my original post in this thread. I inflate the tires with my "Motion Pro Professional" digital tire pressure gage to spec, and the tire pressure monitor on my bike consistently reads the pressure about one pound lower. Not sure which to trust, the gage or the bike, but I think I will trust the motion pro tire pressure gage and use the pressure monitor on the bike as just a guide. I had the same problem with my 2014 GS.

I think 1 psi lies within the noise level. After all, when BMW says the recommended pressure one-up is X, they have no idea if the rider weighs 160 or 250.
 
And what about altitude?

I live at 9000 ft. And I could easily climb or drop 3000 ft on even a relatively short ride.
Not that I’d consider changing pressure on a single ride, but does altitude impact all these temperature / pressure charts?
 
I live at 9000 ft. And I could easily climb or drop 3000 ft on even a relatively short ride.
Not that I’d consider changing pressure on a single ride, but does altitude impact all these temperature / pressure charts?

No, not in an appreciable way. SCUBA divers actually see this all the time. Their tank has about 3000 psi. The starting pressure varies significantly due to temperature (adding air increases the tank temperature significantly), then the pressure drops as the tank cools. Descending in the water (which is a huge pressure change relative to the atmosphere) does not change the pressure.


Sent from my iPad using Tapatalk
 
I live about 70 feet above sea level in south Georgia. Three separate times, I have gotten messages on my display for tire pressure, and all of these times is when I've gone to the mountains to the north of me. For my recent trip that occurred this past weekend, I set my tire pressures at 36 front, 42 rear, at about 85°F the night before. The next day, at about 2500 feet @75°F in the mountains of NC, I again got the dreaded triangle and it showed an errant message for the rear tire. Switching to that display, the rear tire indicated no pressure, and had hash marks ( -- ) instead. Without shutting off the bike, the message eventually cleared itself, and the tire pressure would once again display. Inevitably during the ride, including when I got back down to lower altitudes, it would sometimes return to the hash marks, but I wouldn't get the error again (it seems like the bike figured out the first instance was bogus, and then chose to ignore all subsequent instances). My bike has always read about 1-2 psi low, but I tend to believe the gauge, rather than the TPMS. Since I intermittently get these hash marks, is it possible that the TPMS for that wheel is going dead? It's a 2016 R1200GSA with 24k on it, so it seems kind of soon for that scenario. I find this to be more of an annoyance than something to fret over, but if I started losing air in the tire, I'm not confident that it would warn me.
 
"is it possible that the TPMS for that wheel is going dead? It's a 2016 R1200GSA with 24k on it"

I had the same situation on my 2016 R1200RS where intermittently the dashes would occur on the front tire readout. In for service had the mechanic check and computer indicated it did this 57 times so needed replacing. Replaced using the extended warranty on the bike and not on issue since.
 
No, not in an appreciable way. SCUBA divers actually see this all the time. Their tank has about 3000 psi. The starting pressure varies significantly due to temperature (adding air increases the tank temperature significantly), then the pressure drops as the tank cools. Descending in the water (which is a huge pressure change relative to the atmosphere) does not change the pressure.


Sent from my iPad using Tapatalk

Inside the SCUBA tank, the pressure doesn't change. Outside of the tank, the Pressure (Psi) varies by (Depth / 2.25) in saltwater. So, the wall stresses in the tank will vary due to differences in internal and external pressures.

For the question of altitude (excluding temperature variations) impact on Ambient Pressure (psi), the pressure variation will be, nominally, proportional to ( Altitude / 1800 ). But again, the tire acts as a pressure vessel, like the scuba tank. If the tire was a wimpy material, like a balloon, the the tire would expand.
 
Back
Top