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#1003083 - 01/02/18 07:08 PM Re: 2017 R1200RT Stability [Re: dirtrider]  
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roger 04 rt Offline
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Originally Posted by dirtrider
Originally Posted by 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, wink 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).

Last edited by roger 04 rt; 01/02/18 07:12 PM.
#1003086 - 01/02/18 07:36 PM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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dirtrider Offline
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Originally Posted by roger 04 rt
Originally Posted by dirtrider
Originally Posted by 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, wink 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.


D.R. ___
Sent from my rotory dial wall phone!
#1003091 - 01/02/18 09:46 PM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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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.

Last edited by roger 04 rt; 01/02/18 09:49 PM.
#1003092 - 01/02/18 11:44 PM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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AndyS Offline
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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.

#1003112 - 01/03/18 07:49 AM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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Red Offline
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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,
"The trouble with internet quotes is that you can never know if they are genuine." -- Julius Caesar
#1003114 - 01/03/18 09:28 AM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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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.

#1003119 - 01/03/18 01:13 PM Re: 2017 R1200RT Stability [Re: Red]  
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roger 04 rt Offline
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Originally Posted by 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.


Red, It seems to me that road surface is a secondary factor since the road surface inputs [u]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!)

Last edited by roger 04 rt; 01/03/18 01:14 PM.
#1003121 - 01/03/18 01:43 PM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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roger 04 rt Offline
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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

[Linked Image]

#1003122 - 01/03/18 02:22 PM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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AndyS Offline
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Hi Roger, it doesn't look any different than any of my tyres.

#1003123 - 01/03/18 02:24 PM Re: 2017 R1200RT Stability [Re: roger 04 rt]  
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roger 04 rt Offline
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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?

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