Jump to content
roger 04 rt

2017 R1200RT Stability

Recommended Posts

roger 04 rt
Back to my original issue, which I'll now describe as weaving (as opposed to wobbling), meaning that the handle bars don't move but the bike turns left right left right briskly as if I was throwing my weight around. It happened at speeds around 35-40 mph (neutral throttle, never when accelerating) and also at 75+.

 

Originally my front tire was 34-35 psi. (I wasn't smart enough to use the TPM before adjusting and I lost a bit of air.) and the rear tire was 44 psi. Last week I adjusted the front to 39/40 psi and the rear to 42 psi. The tendency toward weaving was better, nearly gone.

 

I've been out riding several move times since, and decided to see what would happen if I lowered the front pressure to 36 psi but ended up at 35. I went for a ride and pushed the bike a bit and now have wear on two-thirds of tread surface. I detected weave only once (in a quick turn) and it was slight.

 

I've ruled out that I'm imagining this, ;) but not fully ruled out that it's just me interfaced to the bike. Is it possible that the tires are behaving differently as I've scrubbed them up?

 

Edit: I have also run the spring preload setting from one rider to two with gear a couple times to make sure it was in the correct position. At full preload (two with gear) but just me (200#) the bike feels a touch less stable.

 

Afternoon Roger

 

I guess we should have asked this earlier-- Is JUST the bike weaving with bars holding still or does it feed back into the handlebars & cause those to move (or you can feel a change in bar resistance in cadence with the weaving)?

 

 

 

With a new bike and so many new sensory inputs occurring I can't say for certain. I'm pretty steady on the controls so I would say if there was any pressure at the handlebars, it was my reaction to the developing weave.

 

As I said above, there were fewer occurrences none/one last ride and lesser amplitude (one small wiggle weave after a curve in the road).

 

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
dirtrider
Back to my original issue, which I'll now describe as weaving (as opposed to wobbling), meaning that the handle bars don't move but the bike turns left right left right briskly as if I was throwing my weight around. It happened at speeds around 35-40 mph (neutral throttle, never when accelerating) and also at 75+.

 

Originally my front tire was 34-35 psi. (I wasn't smart enough to use the TPM before adjusting and I lost a bit of air.) and the rear tire was 44 psi. Last week I adjusted the front to 39/40 psi and the rear to 42 psi. The tendency toward weaving was better, nearly gone.

 

I've been out riding several move times since, and decided to see what would happen if I lowered the front pressure to 36 psi but ended up at 35. I went for a ride and pushed the bike a bit and now have wear on two-thirds of tread surface. I detected weave only once (in a quick turn) and it was slight.

 

I've ruled out that I'm imagining this, ;) but not fully ruled out that it's just me interfaced to the bike. Is it possible that the tires are behaving differently as I've scrubbed them up?

 

Edit: I have also run the spring preload setting from one rider to two with gear a couple times to make sure it was in the correct position. At full preload (two with gear) but just me (200#) the bike feels a touch less stable.

 

Afternoon Roger

 

I guess we should have asked this earlier-- Is JUST the bike weaving with bars holding still or does it feed back into the handlebars & cause those to move (or you can feel a change in bar resistance in cadence with the weaving)?

 

 

 

With a new bike and so many new sensory inputs occurring I can't say for certain. I'm pretty steady on the controls so I would say if there was any pressure at the handlebars, it was my reaction to the developing weave.

 

As I said above, there were fewer occurrences none/one last ride and lesser amplitude (one small wiggle weave after a curve in the road).

 

Afternoon Roger

 

That is starting to sound like your tires are scrubbing in more & you are getting more familiar with the new bike so are getting lighter on the controls.

 

 

Share this post


Link to post
Share on other sites
roger 04 rt

Afternoon DR,

 

If I'd only felt the wiggle/weave on the highway, I might have attributed a lot of it to me and some apprehension and tight grip. But since I drove a 2018 for 10 miles with Metzler Z8s without noticing any unusual handling and since I did notice a pronounced weave of my 2017 with PR4s within a couple miles of riding (and since it was local roads, no traffic and not particularly fast, my grip would have been light), I'm leaning toward the tires at the moment. Honestly, I find it hard to believe that the tires are at the root of this but time will tell.

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
AndyS

Interesting point Roger. I may need to consider changing my tyres VERY early, 'cos I don't particularly like the feel at times with these PR4's. ...if it is the tyres.

Share this post


Link to post
Share on other sites
Red

Just throwing this out there. Could it be road surface. I have highways going every cardinal direction out of my town. When I had a set of tires perform strangely on my automobile, the tire dealer told me only one of the 4 was suitable for testing tire and suspension issues. All 3 others either had groves or ripples that were nearly imperceptible but would affect handling.

Share this post


Link to post
Share on other sites
AndyS

Hi Red, I hear you, but both Roger and myself are experienced motorcyclists who have come from bikes that have handled sweetly on any given road surface with almost any brand of tyre and tyre pressure. Now, on the same road, but with a different bike we are experiencing some interesting issues.

Share this post


Link to post
Share on other sites
roger 04 rt
Just throwing this out there. Could it be road surface. I have highways going every cardinal direction out of my town. When I had a set of tires perform strangely on my automobile, the tire dealer told me only one of the 4 was suitable for testing tire and suspension issues. All 3 others either had groves or ripples that were nearly imperceptible but would affect handling.

 

Red, It seems to me that road surface is a secondary factor since the road surface inputs to[/] the bike. In my case, one of the first things I looked at, the first time I got this wiggle/weave event was the road surface. And for a few minutes while I road I wondered whether that was the cause. Because it has happened on several different road surfaces, I don't think it is the primary cause.

 

From my systems background, I am now thinking there are three pieces to the puzzle:

 

--an abrupt glitch to the riding path caused by wind or road

 

--a motorcycle whose stability is underdamped by design (and assisted by a front steering damper)

 

--a factor related to how the tires behave that I will outline in a moment (my tires appear to have been lubricated!)

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
roger 04 rt

Summarizing what's been going on, I've had several stability "events". They haven't happened regularly, I don't seem to be able to cause them to happen, they have diminished in frequency, and they have happened mostly at slow (30-45 mph) riding speeds. They mainly occurred when I am riding down the road, changing a lane or changing sides of lane, or sometimes when a gust of air buffets the bike. The worst occurrence was shortly after I left the dealership. During the last two rides it only happened once (slightly) while coming out of a tight turn. The easiest way for me to describe it that something glitches the bike off line and then it oscillates back and forth 3 or four times before resuming its normal path. I've ridden a 2018 R1200RT with Metzler Z8s for 10 miles and never experienced this.

 

After reading about contamination on tire surfaces, I just went out and had a look at mine and found something very interesting. As I examine the tread from side to side, top of sidewall, across the riding surface to the other top of sidewall I see (photo below) three different "conditions", I'll describe the rear tire but the front is the same, just the dimensions are different:

 

--At the top of the left sidewall, the rubber is dull, dry and smooth. This condition (which is what I would expect) exists for the first 1" above the sidewall.

 

--The next 1/2" has not had road contact and has a shinier (for lack of a better word) slightly gooey something on it. I can see (look carefully at the photo) spatter marks at the boundary indicating that someone wiped a contaminant onto the tire. When I touch it with my finger, the contamination streaks, like a thin sticky grease but it is very hard to mechanically wipe of the tire.

 

--The next 4 1/2" going across the tread is dull, dry and scuffed-up from my riding indicating that this contaminating substance has been scrubbed off by the road.

 

--The 1/2' border on the right of the tire is as the 1/2" border on the left of the tire.

 

--The right sidewall looks the same as the left sidewall (and on the top edge of the rim you can see what feels to me like a different substance).

 

Looking at it, I'd say that something was applied to, got on or otherwise contaminated the surface of the tire. I haven't ridden in the rain, or through any road area that would have applied this residue to the tire and there is none splashed up onto the mud flap.

 

My conclusion is that it was on the tires when I left the dealership and I am wearing it off as I ride and as I push the bank angles. I'm going to contact the dealer and ask what they might have done and then use some detergent and scrub off what I can.

RB

 

Michelin%20PR4%20GT%20Rear.jpg

Share this post


Link to post
Share on other sites
AndyS

Hi Roger, it doesn't look any different than any of my tyres.

Share this post


Link to post
Share on other sites
roger 04 rt

So Andy, are you saying that if you wipe your finger through that shiny boundary layer you get a sticky substance you can smear a bit?

Share this post


Link to post
Share on other sites
AndyS

Hmm, no.

On previous bikes I have the shiny boundary (depending on how and where the bike is being ridden), but can't say it has ever been able to smear it.

Share this post


Link to post
Share on other sites
DJ_Fission

Those look like Michelin PR4s...perhaps that shininess has something to do with the dual-compound construction? I have to say that photo doesn't really look any different from my PR4.

Share this post


Link to post
Share on other sites
Paul De

Hi Rodger,

 

Tire goober you say, that sure isn't normal. Between the smooth surface of a brand new tire and any tire mold release agent (silicon oil, or some type fatty acid compound like erucamide) could cause all kinds of problems until scrubbed off. But that stuff is by design sitting only on the tire surface and the gummy material you say you can smear off may point to some solvent that penetrated and soften the rubber compound which would make the problems persist much longer...maybe even spoil the nature of the rubber compound under prolonged exposure. My guess that unless the tire was sitting in the solvent for a while it really should scrub off with more riding. Maybe try using some Dawn dish soap water and a soft scrub brush to get all that stuff off your tire, rinse and let dry and then see if the issue is gone.

 

Just a swag here, but you might ask how the dealer prepared the bike. Did they use some solvating type cleaner to wipe off the exhaust and rims. Some of those so called environmental friendly cleaners could be a culprit as they are based on limonene compounds which are very soluble in rubber. Limonene can turn un-vulcanized rubber into a gummy sticky mess...we call it glue where I work:grin:

Share this post


Link to post
Share on other sites
JamesW

Hi Roger, congrats on the new RT. Do you still have your '04 ? One thing nice is you won't have to concern yourself with fueling issues.

Share this post


Link to post
Share on other sites
roger 04 rt
Hi Roger, congrats on the new RT. Do you still have your '04 ? One thing nice is you won't have to concern yourself with fueling issues.

 

Thanks, I really like this bike! Although the fueling feels quite good, I will do some work on it. First I'll add the AF-XIEDs and later a pair of LC-2s. I'd like to see how it reacts to a few percent more fuel, then I plan to use the LC-2s to map the fueling and see what's what. None of this will happen until later in the spring or summer though until I've got the bike broken in. The one thing I notice is that I'm downshifting more at low RPMs than I had to with the R1150RT (sold) at 8% rich. We'll see how a little fuel effects that.

Share this post


Link to post
Share on other sites
Indy Dave

Roger, not sure if you've seen this from Ax-fied's website:

 

R1200

Use of the BMW AFXIED is no longer recommended for 2014 and later liquid cooled R1200. Field updates to the ECM by BMW Dealers during routine service department visits are creating incompatibility between the ECM and the AFXIED.

 

The field upgrade was something beyond our control, with no know issues prior to the new ECM load occurring in late 2016. With the field upgrade slowly propagating the change, the situation was not discovered until early 2017. This resulted in our de-certification of the R1200 LC models.

 

We are in the process of developing an updated AFXIED for these bikes. Release date to be announced at a future time.

 

There are no known issues with the older air/oil cooled engines.

Share this post


Link to post
Share on other sites
roger 04 rt
Roger, not sure if you've seen this from Ax-fied's website:

 

R1200

Use of the BMW AFXIED is no longer recommended for 2014 and later liquid cooled R1200. Field updates to the ECM by BMW Dealers during routine service department visits are creating incompatibility between the ECM and the AFXIED.

 

The field upgrade was something beyond our control, with no know issues prior to the new ECM load occurring in late 2016. With the field upgrade slowly propagating the change, the situation was not discovered until early 2017. This resulted in our de-certification of the R1200 LC models.

 

We are in the process of developing an updated AFXIED for these bikes. Release date to be announced at a future time.

 

There are no known issues with the older air/oil cooled engines.

Let me hijack myself for a moment ...

 

Yes, I am well aware of that but thanks for bringing it up. I was the pioneer for that project after putting an Innovate Motorsports LC-1 on my R1150RT. The LC-1 worked great but it was too hard to implement for the average rider. I got Nightrider to create an AF-XIED that would be plug 'n play for the entire BMW line of bikes.

 

It's working out pretty well except on the latest model R1200 LC bikes with the latest software. BMW has incorporated a new test of the O2 sensor to try and knock out bad sensors (fueling modifiers) and as a result the AF-XIED causes the BMSX to throw a minor code. For the last several months, I have been helping Steve at Nightrider to develop an add-on module, together with an owner of an LC GSA and LC RT. As of just last week, a new adaptor module to the XIED has passed all its tests on a LC bike and will be headed into production soon.

 

The new adaptor module will be compatible with all existing AF-XIEDs. Nightrider is pretty conservative so I expect they will take several weeks or months to bring it to production.

 

This whole episode reminds me of the Mad Magazine Spy vs Spy cartoon where each spy tries to outdo the other. BMW keeps making its sensor tests more accurate and fueling add-on makers then have to adapt.

 

As of this time, I should be able to get a pair of the Beta Units now that I've got an RTW. I'll run those first but then later switch to LC-2s so that I can log the RTW AFR for the entire map. Actual, on the road AFR, is almost always much different than the inaccurate AFRs you see from Dyno runs. That's why I want to map it myself. If you've got a few nights, ;), here's a link to the research: http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=746671#Post746671.

 

Here's the beta-unit add-on module that gets the AF-XIED to play with the newest RTWs.

AFXIED Addon.jpg

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
roger 04 rt
Hi Roger,

 

Tire goober you say, that sure isn't normal. Between the smooth surface of a brand new tire and any tire mold release agent (silicon oil, or some type fatty acid compound like erucamide) could cause all kinds of problems until scrubbed off. But that stuff is by design sitting only on the tire surface and the gummy material you say you can smear off may point to some solvent that penetrated and soften the rubber compound which would make the problems persist much longer...maybe even spoil the nature of the rubber compound under prolonged exposure. My guess that unless the tire was sitting in the solvent for a while it really should scrub off with more riding. Maybe try using some Dawn dish soap water and a soft scrub brush to get all that stuff off your tire, rinse and let dry and then see if the issue is gone.

 

Just a swag here, but you might ask how the dealer prepared the bike. Did they use some solvating type cleaner to wipe off the exhaust and rims. Some of those so called environmental friendly cleaners could be a culprit as they are based on limonene compounds which are very soluble in rubber. Limonene can turn un-vulcanized rubber into a gummy sticky mess...we call it glue where I work:grin:

 

I spoke to the dealer, who seems fairly transparent. Here's what he said:

 

--They don't treat the tires, "that's a no no."

--All the new tires they see have some release agent on them and are slick at delivery

--Coating described as waxy, almost like Armor All like. Consistent with what I see.

--Someone left the dealership last week on a new bike and dumped it exiting the parking lot. Fall attributed to slick tires.

--When you just replace one tire, the coating issues aren't so noticeable as on a new bike.

--Their advice is to ride-in the tires with caution. (I don't remember them saying that ;) )

 

The last two Michelin tires I changed were shiny over most of the surface of the tire but not quite like the ones I have now. The coating I've focused on in the photo doesn't cover the whole tire, just the road contact area (yikes) and not even the last inch on either side of center. And the coating I see is a little thicker than I remember on my other tires. ...

 

So that's what I heard. After looking at what's on them a little more I'm going to give them a strong scrub down with detergent and a 3M pad.

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
Red

For what it's worth. I have been advised by dealer and non dealer tire installers to "take it easy" for the first 50 miles or so on new tires until they are scuffed up because out of the box they are slick and will dump you like hard breaking on a wet lawn. People dumping their bike shortly after getting new rubber is not uncommon if they brake, accelerate, or corner aggressively soon after installation. Almost every tire I've owned had, at some time, a similar color/wear profile as the one pictured. Good or bad, the coloration and wear seems to be typical (for me).

Share this post


Link to post
Share on other sites
roger 04 rt

I got out for an hour of tire scrubbing-in a couple days ago and rode for several miles of S-turns at various speeds on a two lane road, banking as far over as I could in the two lanes of space available. The handling felt quick and completely predictable, really very good.

 

On the way home I rode into a blustery headwind and noticed that as I changed sides of my lane, with the bike essentially straight up, there was a sense of a lack of precision. Perhaps this is due to the compound tread construction with a relatively harder center tread, time will tell. Interesting though that there was a feeling of greater precision making aggressive turns than going straight ahead.

 

Regarding tire pressure, I haven't really noticed a big difference between front tire 36 and 39 psi in the handling, just the ride is a bit harsher so I'll stay at 36 as recommended in the manual. Odd that by specifying 36 and 42 as measured by the TPM. that they want higher actual pressure on hot days and lower on cold ones.

 

Dirtrider has suggested that I get 1500 miles or so on the tires which will flatten the center section some and I'm going to take that advice and see where I'm at.

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
marcopolo
...Odd that by specifying 36 and 42 as measured by the TPM. that they want higher actual pressure on hot days and lower on cold ones.

 

...

 

The TPMS compensates for temperature, and the pressures it displays are adjusted to read as if the temperature were 20C (68F). Presumably this also means that the recommended 36/42 PSI are also for tires at 20C. So, if you inflated your tires to those pressures at 68F, and the ambient air temperature reaches 90F, then if you used a gauge to measure the pressure in your tires, it's going to be higher than 36/42, but the TPMS would still show them to be 36/42 (or, at least in a perfect world it would).

Edited by marcopolo

Share this post


Link to post
Share on other sites
roger 04 rt

Marco,

 

That's exactly what I'm saying and in other words, the BMW tire pressure spec is:

 

at 38F ... 33 psi

 

and:

 

at 108F ((88F plus 20F tire rise) ... 40 psi

 

In effect BMW is saying absolute tire pressure doesn't matter that much as long as it's in an acceptable range.

 

This is news to me because I've always set tire pressure to target in the garage, tires cold.

 

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
LAF

And that is correct, cold in the garage to the PSI you want to run.

 

Most of us run 40/42 on our tires.

 

I check before I leave for a ride with a gauge and that is what I run.

 

TPS are ok, but the tire gauge is what I look at and believe.

 

I do no calculations or anything, cold tire, in tire gauge I trust.

 

Share this post


Link to post
Share on other sites
LIRider

The temperature compensation thing makes no sense at all. I want to see the actual pressure in my tires and fully understand that once I heat up the tires by riding that the pressure will show higher than the specified "cold" (current ambient temperature) setting. Why they complicated the crap out of something so simple is beyond me.

Share this post


Link to post
Share on other sites
roger 04 rt

Agreed, that it isn't what I've done for decades. On the other hand, BMW is very specific:

 

The tire pressures are shown adjusted for temperature on the multifunction display and are always relative to the following tire air temperature:

 

68°F(20°C)

 

Tire pressure adjustment

Compare the TPC/RDC value in the multifunction display with the value on the back cover of the Rider's Manual. The difference between the two filling station values must be compensated with the tire inflation pressure tester at the filling station.

 

So the question is, why have they done it this way? It seems like they've gone to extra effort to make this system temperature compensated.

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
dirtrider
The temperature compensation thing makes no sense at all. I want to see the actual pressure in my tires and fully understand that once I heat up the tires by riding that the pressure will show higher than the specified "cold" (current ambient temperature) setting. Why they complicated the crap out of something so simple is beyond me.

 

Morning LIRider

 

Actually BMW (as well as most auto companies) have simplified it.

 

As it stands now the dash reading is temperature corrected. If it wasn't temperature compensated then BMW would have had to use dual output in-wheel pressure/temperature sensors & add two on-dash tire temperature readouts (or one readout that is complex & switchable) then the rider would be required to do the compensation math for each wheel while riding.

 

Once riding (with the tires warming up), then just knowing (uncompensated) tire pressures is about useless without knowing each TIRE's temperature to go with the pressure reading.

 

When I rode to work last Friday my bike started out in my shop @ about 65°f, I rode out into negative 4°f ambient (4° below 0°f), onto a road surface that was WELL below freezing. By the time I got to work my tires were warm to the touch (so above body temperature anyhow). If the tire pressures were not temperature compensated then I would probably have seen a low tire warning after a mile of riding as my first mile was on frozen ice covered back roads.

 

While I was in the workplace it only got up to +8°f (high for the day) but one side of both tires were in direct sun light (without compensation where should my pressures have read to be correct?)

 

I suppose BMW could have been a little more thoughtful & used more expensive dual channel wheel pressure sensors & a much more complex dash readout that allowed the rider to switch between compensated tire pressure readings & direct tire pressure readings for the 1 presenters that would like that option. Or done like some aftermarket TPS systems & just used ambient temperatures to sort-of guess at tire temperatures for the compensated reading (works OK after sitting all night but not so good while riding).

 

Share this post


Link to post
Share on other sites
LIRider

I'm not sure I follow dirtrider ... if you're tires were set to proper inflation pressure at the current ambient temperature (not your nice warm garage/shop), then why would there have been any issue with low pressure warning? In fact, had you set your tires in that nice warm shop, then indeed you were probably low once you got out on the road and the tires cooled to ambient temperature (before starting to warm up from riding, which should have brought the pressure up above the spec setting). Am I misinterpreting something?

Share this post


Link to post
Share on other sites
JamesW

Hi D.R., -4F?? And riding a motorcycle?? Now that takes dedication. Have you ever had a shock start to leak when going from +65 to -4 ? If I did that about the last thing I would be worried about is my tire pressure but that's me.

 

Share this post


Link to post
Share on other sites
dirtrider
I'm not sure I follow dirtrider ... if you're tires were set to proper inflation pressure at the current ambient temperature (not your nice warm garage/shop), then why would there have been any issue with low pressure warning? In fact, had you set your tires in that nice warm shop, then indeed you were probably low once you got out on the road and the tires cooled to ambient temperature (before starting to warm up from riding, which should have brought the pressure up above the spec setting). Am I misinterpreting something?

 

Afternoon LIRider

 

BMW specified tire pressures (as well as most autos & motorcycles) are based on a nominal cold tire @ 68°f. Most manuals don't mention that as in most cases the ambient temps are not far enough off of 68°f (20°c) to make much difference so adding more confusion to tire checking procedures is not useful & can be confusing for most operators.

 

So lets assume I did the correct thing & (correctly) set my tire pressures in my shop to 32 psi at 68° (or 65°f in my case)-- I now ride the bike out into the -4°f cold. As the tires drop to ambient temps they could lose 7 psi, 32 psi minus 7 psi = 25 psi. 25 psi could be low enough to trip the low tire pressure warning. With the TPS temperature compensation system it all bases back to 68°f so the low tire warning threshold just drops to reflect that.

 

I am an all season rider (within reason) so usually run my tires a few pounds higher in the winter just so I don't bend a rim if I find a hidden square edged pot hole.

 

 

Share this post


Link to post
Share on other sites
dirtrider
Hi D.R., -4F?? And riding a motorcycle?? Now that takes dedication. Have you ever had a shock start to leak when going from +65 to -4 ? If I did that about the last thing I would be worried about is my tire pressure but that's me.

 

Afternoon JamesW

 

No, no shock or seal leaks but in the early days of alloy wheels I had a few lose air pressure due to porosity and/or tire/rim sealing.

 

Actually my biggest problem is a fogging face shield & inability to turn my head very far due to head covering & a neck stuffer. I also have problems with some of the finer controls due to thick heated gloves.

 

I do get a lot of razzing from co-workers about being stupid enough to ride in the cold but those very same co-workers will go north for the weekend & ride snowmobiles all day (or at least from bar to bar) in sub 0°f weather with visibility of ZERO at times.

 

The good about riding in the cold is very little waving to other riders but I do get a lot of thumbs up from car commuters.

 

Share this post


Link to post
Share on other sites
LIRider
I'm not sure I follow dirtrider ... if you're tires were set to proper inflation pressure at the current ambient temperature (not your nice warm garage/shop), then why would there have been any issue with low pressure warning? In fact, had you set your tires in that nice warm shop, then indeed you were probably low once you got out on the road and the tires cooled to ambient temperature (before starting to warm up from riding, which should have brought the pressure up above the spec setting). Am I misinterpreting something?

 

Afternoon LIRider

 

BMW specified tire pressures (as well as most autos & motorcycles) are based on a nominal cold tire @ 68°f. Most manuals don't mention that as in most cases the ambient temps are not far enough off of 68°f (20°c) to make much difference so adding more confusion to tire checking procedures is not useful & can be confusing for most operators.

 

So lets assume I did the correct thing & (correctly) set my tire pressures in my shop to 32 psi at 68° (or 65°f in my case)-- I now ride the bike out into the -4°f cold. As the tires drop to ambient temps they could lose 7 psi, 32 psi minus 7 psi = 25 psi. 25 psi could be low enough to trip the low tire pressure warning. With the TPS temperature compensation system it all bases back to 68°f so the low tire warning threshold just drops to reflect that.

 

I am an all season rider (within reason) so usually run my tires a few pounds higher in the winter just so I don't bend a rim if I find a hidden square edged pot hole.

 

 

I have to say that's news to me and contrary to what I've been doing for the past 40 years. It's also contrary to anything I can find online too:

 

Air Pressure, Temperature Fluctuations

 

Winter vs. Summer Tire Pressure - What is the Proper Inflation?

 

Can you supply any information to back up that claim? I'm not being argumentative, just trying to establish the proper method based on facts (and yes, I know that not everything one reads online is in fact, "a fact").

 

The facts as I know them right now are:

The stated pressure is for the current ambient conditions and not some arbitrary "cold" setting.

 

 

 

 

Share this post


Link to post
Share on other sites
realshelby

I think part of your answer is in your owners manual......

Share this post


Link to post
Share on other sites
realshelby

 

Actually my biggest problem is a fogging face shield & inability to turn my head very far due to head covering & a neck stuffer.

 

 

I have been about ready to do a "product evaluation" on this. I finally found something that keeps visors and glasses from fogging. So far I have tested in upper 40's to 90 degree rain with complete satisfaction. I won't likely get a chance to test in sub 20 degrees, maybe you could?

 

Clarity "DEFOG it" I bought the 5ml bottle and it goes with me on every trip.

 

Edited by realshelby

Share this post


Link to post
Share on other sites
dirtrider
I'm not sure I follow dirtrider ... if you're tires were set to proper inflation pressure at the current ambient temperature (not your nice warm garage/shop), then why would there have been any issue with low pressure warning? In fact, had you set your tires in that nice warm shop, then indeed you were probably low once you got out on the road and the tires cooled to ambient temperature (before starting to warm up from riding, which should have brought the pressure up above the spec setting). Am I misinterpreting something?

 

Afternoon LIRider

 

BMW specified tire pressures (as well as most autos & motorcycles) are based on a nominal cold tire @ 68°f. Most manuals don't mention that as in most cases the ambient temps are not far enough off of 68°f (20°c) to make much difference so adding more confusion to tire checking procedures is not useful & can be confusing for most operators.

 

So lets assume I did the correct thing & (correctly) set my tire pressures in my shop to 32 psi at 68° (or 65°f in my case)-- I now ride the bike out into the -4°f cold. As the tires drop to ambient temps they could lose 7 psi, 32 psi minus 7 psi = 25 psi. 25 psi could be low enough to trip the low tire pressure warning. With the TPS temperature compensation system it all bases back to 68°f so the low tire warning threshold just drops to reflect that.

 

I am an all season rider (within reason) so usually run my tires a few pounds higher in the winter just so I don't bend a rim if I find a hidden square edged pot hole.

 

 

I have to say that's news to me and contrary to what I've been doing for the past 40 years. It's also contrary to anything I can find online too:

 

 

 

Can you supply any information to back up that claim? I'm not being argumentative, just trying to establish the proper method based on facts (and yes, I know that not everything one reads online is in fact, "a fact").

 

The facts as I know them right now are:

The stated pressure is for the current ambient conditions and not some arbitrary "cold" setting.

 

 

 

 

Afternoon LIRider

 

Most if not all tire pressures that I work with daily in engineering (some days many) are based off of a 68°f cold factor. Due to the ideal gas law you just can't (with accuracy anyhow) call any temperature a cold temperature. It needs to be defined (especially when setting safe operating pressures).

 

While the BMW manual says a cold tire they don't define what a cold tire is that could be anywhere form a -25°f or a +112°f & still be an overnight cold soak. They also don't expect a rider to stop & allow their tires to cool to a cold tire the get re-air'd to the ambient as they ride from a desert area to a very cold high mountain area.

 

Nothing wrong with using the overnight cold ambient temps for base tire setting as long as that temperature is reasonably close to 68°f (48°f to 88°f will get you within 2 lbs so usually close enough for most riders & most conditions.

 

You need to look in the riders manual as under the general tire pressures area, there they just call out cold tire (no temperature definition or fudge factor). Seeing as EVERY 10°f in cold-tire-temperature-change changes the tire pressures about 1 pound you would thing think that if BMW was really concerned that they would specify a nominal cold tire temperature range or give a conversion chart. They don't for the same reason that the company that I work for is very hesitant to use different front & rear tire pressures on general consumer vehicles as most regular drivers get very confused by the split numbers (we do use split pressures on some now but it is a big fight to get that to be written in the owners manuals)

 

Most riders that ride hard (not just think they ride hard) have a good idea of the tire pressures that work for their tire type, bike, & riding style as well as temperature ranges so they usually use their own cold tire temperature offsets.

 

BMW if very contradictory in their riders manual as in the general tire pressure section they just say COLD TIRES. (non defined)

 

But later in the same manual they have a very specific tire pressure & tire filling chart with an explanation on how to use the RDS system to obtain corrected tire pressures (the RDC system IS corrected back to 68°f (20°c).

 

If you use the riders manual & a pressure gauge to fill to 34 psi at 90°f cold tire (think desert areas), or use 45°f cold tire (think upper Midwest in late fall) then your pressures will be way off per the RDC system & RDC procedures.

 

One of the nice things about using the RDC system to (at least check/verify the pressures) is that it IS corrected back to 68°f (20°c). It might not be totally accurate to tenths of a pound but at least it is ALWAYS apples to apples so no matter the temperatures the tires will be well within safe & correct pressure ranges. (without temperature compensation if a rider fills a tire at 0°f to suggested cold pressure then gets on the freeway at 90mph for a couple of hours his tires will be well above max safe operating pressures).

 

wIigNNU.jpg

 

Share this post


Link to post
Share on other sites
roger 04 rt

That's very clear DR.

 

So here in FL I set my tires to 36.3 in the garage at 68F, go out on a 98F day, ride at 80 and heat the tires another 50 degrees (my car tire pressures go up about 5 psi at that speed) and my actual tire pressure will be 44.3 psi but the display will still indicate 36.

Share this post


Link to post
Share on other sites
terryofperry

"One of the nice things about using the RDC system to (at least check/verify the pressures) is that it IS corrected back to 68°f (20°c). It might not be totally accurate to tenths of a pound but at least it is ALWAYS apples to apples so no matter the temperatures the tires will be well within safe & correct pressure ranges. (without temperature compensation if a rider fills a tire at 0°f to suggested cold pressure then gets on the freeway at 90mph for a couple of hours his tires will be well above max safe operating pressures)."

 

What is the max safe operating pressure?

 

Thanks.

 

Terry

Edited by terryofperry

Share this post


Link to post
Share on other sites
roger 04 rt

Hey Terry,

When I saw your question, I thought “that's easy, I'll go read the sidewall.” All I can find on either front or back is a max load spec at a certain pressure. That pressure is 42 psi COLD on each tire. The front load is 520# and the rear is 805#.

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
TJRL
That's very clear DR.

 

So here in FL I set my tires to 36.3 in the garage at 68F, go out on a 98F day, ride at 80 and heat the tires another 50 degrees (my car tire pressures go up about 5 psi at that speed) and my actual tire pressure will be 44.3 psi but the display will still indicate 36.

 

No, I do not think that is how it works. If I fill my tyres up (after an overnight rest in the garage) to the pressures indicated in the manual or perhaps a few PSI above, when I start my ride the display shows the pressures exactly as I filled them. Then as the ride progresses both tyre pressures are shown to increase a few PSI. The next day the display shows the pressures as they were filled the day before.

 

 

 

Share this post


Link to post
Share on other sites
roger 04 rt

I ran the D-ESA calibration using the GS-911. It runs the rear shock spring pre load adjustment to both extremes to figure out where it is. Since doing that the bike is steadier, even up to 90 in heavy traffic, with truck wake, where it had been squeamish. It's not perfectly steady in the buffeting but not bad.

 

Has anyone else tried running the cal?

Edited by roger 04 rt

Share this post


Link to post
Share on other sites
Boxflyer

Hi Roger,

I have used the GS-911 w/WIFI on my 2016 RT for several resets/adaptations with excellent results:

1) Engine (BMS-X)-- 9 Function Tests

2) Engine (BMS-X)-- 5 Adaptation Values

3) ABS (XABS)-- Pump actuation and ABS Bleed

4) Satellite Body Controller (XSFA)-- Calibrate Windscreen

5) Semi-Active Suspension Controller (XSAF)-- Calibrate Travel Sensor

6) Ignition Lock/ Immobilizer (XEWS)-- Learn New Key Fob

7) Tyre Pressure Monitor (XRDC)-- Program/Learn New Sensor (Unsuccessful)

 

Most of the modules restes are pretty benign, but the transmission relearn, fuel mix/idle control, and suspension calibrate travel were perceived in "seat of the pants" improvements.

The ABS module for bleeding the brakes is very worthwhile...I don't know how effective my previous brake bleeding was in the "post Wizzy Brake" era without this!

I have an extra set of rims that I keep swapping out fresh rubber with, and was not able to use the GS-911 to either enter the Serial Numbers or do an adaptive relearn with... both rims were automatically recognized by the bike within 5 miles of riding though.

I was also not successful with this TPMS relearn on my previous K1600GT, but they also were picked up by the bike after a short ride.

 

Just as a note, I try to run my tire pressures at F=40 and R=42 psi all the time...rain or dry, hot or cold, slab or mixed gravel. I've increased the stable feel, and reduced some of the cupping in the front this way.

 

Standing by to assist with anything else...

 

 

Share this post


Link to post
Share on other sites
Boxflyer

Oh, a couple of other things I feel affect the stability of the Wethead RT's...

 

1) I changed the windscreen to the AeroFlow RTW Tall. I'm 6'2 and ride with the seat in the high position, (plus I have a custom Laam seat with an extra 3/4" padding) and this really reduced the buffeting I was getting on either side of my helmet and shoulders. I only have the screen up off the lower stops about an inch, and still have about an inch that my line of vision is above the top edge.

2) I bought the 28L top case. Compared to having no top case, or my 49L BMW top case, this provides the smoothest ride. I get more slipstream back draft with no top case (and no pillion) and feel lots more side pressure, both drawing in, and pushing off from passing trucks with the larger 49L case on...but there are times when you live with it because that's the way you want/need to be configured.

Share this post


Link to post
Share on other sites
NoelCP
That's very clear DR.

 

So here in FL I set my tires to 36.3 in the garage at 68F, go out on a 98F day, ride at 80 and heat the tires another 50 degrees (my car tire pressures go up about 5 psi at that speed) and my actual tire pressure will be 44.3 psi but the display will still indicate 36.

 

I like to adjust tire pressure so that it reads whatever I want it to read on the TPC readout. Consequently, it's always sitting on 39F/42R until it loses a bit slowly over time.. When adding air I'll rough it in a bit over my typical 39F/42R w/ a good gauge following the usual temperature compensation logic of +/- 1psi for every 10 degrees F below or above 68F. Then after being out on the road a while on my first stop will bleed of a bit if it is displaying a little high, for example 40/43, I'll bleed a little air off and can usually get it spot on on the first try taking care not to take out too much.. When you read between the lines in the manual on TPC it seems clear they think you can trust their system certainly more than the gas station's pump gauge, and that can apply to any other gauge for all practical purposes. There is no specification published as to how accurate BMW TPC is, but as I say BMW feels good enough about to tell you to rely on it enough to adjust pressure to the displayed output. It's remarkably stable though: On June 5, 2016 we were riding past Las Vegas OTW to St. George UT in 112F temp for hours uphill, and the displayed pressure stayed exactly the same for the entire ride after leaving Big Pine, CA at maybe 45F or something I forget now. That's pretty impressive in my book.

 

Edited by NoelCP

Share this post


Link to post
Share on other sites
roger 04 rt

Last week I rode about 250 miles up and back for my 600 mile service. The highway (I 75) was mostly North/South and the wind was strongly out of the East @ 25, gusting 35-40 MPH, plus lots of tractor/trailers running between 65 and 80 MPH. Of about 5 hours of riding, 4 hours was on my R1200RTW and 1 hour was on a friend's 2017 Harley Road Glide, while he rode mine. In those conditions, the Harley had the steadier ride--you felt the buffets but the bike felt solid on it's course. I also had the bike ridden by the dealership owner, he and my friend both felt the difference was that the RTW is a lighter, faster steering bike. The dealer also went over all the front end suspension, checking for tightness.

 

On the way back, I changed from One-Up SOFT suspension to One-Up HARD suspension and found that I liked the handling at highway speeds/with gusts better in the HARD setting. The next day, with the wind conditions still the same I tried several other suspension conditions and found that (for instance) the Two-Up setting handled less solidly than One-Up with just me aboard. I'll try similar conditions with no cases as soon as I can.

 

Although I've focused on this issue (which I would now describe as the RTW not liking to be abruptly knocked off course) for a while, I really like the RTW, it does so many things well and is otherwise a pleasure to ride--particularly the gear-shift Pro assist. I'm left with one question, could a tire change (to Metzler or Pirelli) affect handling, in the gusty conditions at highway speeds?

Edited by roger 04 rt

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×