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J

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Discussion Starter #1
I have a '01 ST4, bought used about a year ago, and wonder if this symptom is typical of the ST line or Ducati in general. While applying front brake when leaned over it wants to sit up. My old beemer airhead never did that, being more neutral in that regard, but complaining in other ways. I wonder if the height is set up correctly. Any input?
 

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I think that it is as much a tire issue as a bike issue. I know that when I changed from Avon tires to Metz. my bike is not very sensitive about standing up if you even look at the break lever. Maybe someone can chime in about the rake/ trail that may effect this condition.
 

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Ummm... I'm not sure how to suggest this...

The ST4 behaves like a bike should.. If you apply the brakes mid corner 99% of bikes will stand up... they just DO.. If you really HAVE to brake IN a corner.. you can apply a little rear.. it won't stand up but you run the risk of high siding..

Please tell me WHY you are braking IN the corner..

Also please read and re-read Keith Code's Twist of the wrist.. then Twist of the wrist II.. then read them both again.



Mal
 

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Jim, Was your BMW an anti-dive type suspension? I know my old air-head BMW would stand up under braking too. I would say that this is a normal part of a motorcycles operation. As Butch said, tires have an effect on the degree, as do the suspension set-up parameters and the motorcycles geometry.



Obviously, we don’t want to be braking much when leaned over as the tires are asked to provide a higher percentage of their total available traction for the negotiation of the turn and there is less available traction for braking. At times, braking in a corner is unavoidable so I personally practice doing this “maneuver” under favorable conditions. If we apply the brake force smoothly and progressively, we can control what the bike is doing and have the chance to modulate the braking force in the case of traction loss. Try doing the exercise using the front and rear brake in tandem as I think the rear brake helps the bike stay more neutral under these difficult conditions. Also, as the forces build, you want to pick the bike up to get a more favorable contact patch on the tire. Doing this in a corner is not usually a problem, as the bike will want less lean angle in a turn as the speed scrubs off. If a rapid avoidance turn is required, we should stay off the brakes and turn the bike.



On the track we can use the front brake to help the bike “turn-in” and use “trailbraking” to set the tires contact patch, optimize the front trail and control the front spring as we transition to the apex of a turn.



All these riding techniques are fairly advanced and are best practiced in a careful way in a controlled environment.
 

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+1 to Butch and NCRick on this one. I agree with both. My ST2 doesn't show much tendancy to stand-up when braking in a curve, unless I start to hit it pretty hard......or, at least, I may be so used to it that I don't notice it until I brake a bit harder than I usually do. I've noticed that a bike with dual-disk has a tendancy to stand-up more than a single-disk. I'm sure a tire's profile can assist in this, too.

I mostly trail-brake, but will also use the front brake when needing to scrub off just a little more speed. On a ride in the mountains of NC with Butch, NCRick, Johnboy, and one or two others, Butch and Johnboy saw how often and how much I brake through a curve.....when riding two-up, also. It's just a practice I've been using for years and have never......never had a problem with it. I believe the main problem that people have with braking in a curve is that they do it before they know their bike's braking ability and the way it feels. I believe a lot of people don't truely know how to read what their brake system is telling them.
 
J

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Well, thanks for the input so far. I've been riding for 34 years, had the beemer for 27 of those years and am familiar with the concept of braking and how it feels. The rear brake on my Ducati makes my beemers rear drum look like a high performance work of art. I don't know where some of you ride but around here some of the roads are so curvy you are only upright for a second or so. Those are the kinds of roads I seek out. I don't know how I would avoid front brakes in curves unless I was going so slow I wouldn't need them, granted most speed should be scrubbed of earlier than the apex but the street isn't like the track, sometimes you see something that requires slowing down for.

Maybe I just need to experiment with ride height, the previous owner was quite a bit shorter than me.
 

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Chilehead
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I use the fact that the front brake will make the bike stand in a corner to quickly change directions in tight S-curves, of which there are many around here.

So to me, it's normal that it will do that. True for my ST2, SS and LeMans. The only bike I have that doesn't do that is my other LeMans (which has a sidecar).

Tom
 

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Hi Jim,

Please don’t take any of my input as being critical and I apologize if it was stating the obvious, I had no intention of talking down to your riding ability. I felt I may have a good perspective on your question as I have over 100K miles logged on the two BMW motorcycles I once owned. I transitioned to the Ducatis in 1999 any am working to that point with about 60k miles logged on those. We live and ride in the Appalachian mountains and ride twisty roads enough to understand where you are coming from with your (what I considered to be) very cool question. Having ridden street bikes extensively since the late 70s I know that I am still on a fairly steep learning curve and I certainly do not consider myself to be any kind of great rider. I do try to be a student of the game and really enjoy trying to become better at it as well as learning to better understand what happens when I ride. I started racing in the AHRMA BOTT ( battle of the twins) series on my 748 a few years ago (as a professional back-marker) just to get more track time so I can learn a little more.

I for one am always very interested to discuss any issues related to riding and chassis dynamics and look forward to learning from each opportunity. I am certainly no expert.

I suggest you check out the front and rear ride height and sag settings on your bike, it may well have been played with. If the previous owner flattentd the center of the tires, that too could be making the bike act strange.
 
J

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Discussion Starter #9
I read my original post and realize I didn't word it as well as I should have. Probably shouldn't be posting at 4am. What I meant is that the effect is much more noticable on the Ducati and I never felt the need to wrestle the beemer to hold the line, whereas the Duc takes noticably more effort.

It isn't unpredicable or unmanageable by any stretch, and I imagine it would be second nature after awhile. I've got 200,000 miles on bikes but the last 170,000 has been on the airhead. The duc lets me go in corners much hotter and the brakes working much better so maybe it's as simple as that. But I know the rear height is adjustable and that might exaggerate it too. Or would that only effect how quickly it falls into the curves?
 

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Chilehead
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Perhaps it's simply having a lighter bike.

My LeMans did it more after going to magnesium wheels and better brakes, and my Ducatis seem to do it more with the lighter wheels as well. As I said, I use the characteristic to my advantage, hitting the front brake in the middle of a fast S-curve to get a faster transition.

Tom
 

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I hope my comments in that thread on standing-up were not taken wrong, also. I, like you, brake in curves all the time and don't have an issue with it. I mentioned about single vs dual disks up front. Did your BMWs have single or dual? My Harley (single disk) shows no signs of wanting to stand up in a curve. This may also be a characteristic of the difference in weight/less rake/center of gravity/braking efficiency. I don't know anything about your BMWs, but the Ducati may just be a lighter bike and have better brakes, which makes the tendancy to stand-up more noticeable. You may also be hitting the brakes harder than you did with the BMWs, as you state you ride the Ducati hotter into the curves. Tire profiles may influence this, too. I would venture there are a lot of variables as to when it would be more noticeable.
 

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Chilehead
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I will often trail-brake with the front brake in down-hill situations (usually not necessary uphill), and as long as it's light braking, there is no such effect. But it is there if I hit the brakes harder, and as I mentioned, I use that to my advantage for quick direction changes.

I have three different bikes, and they all will do this under the right conditions. I'm sure that my 170kg SS does it easier than my 195 kg LeMans (both of which have EBC HH pads), and my 200kg ST2 the least (which has 911CP* pads). Weights are wet/no fuel. All have CF or magnesium wheels.

Tom
 

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mals900ss said:
Ummm... I'm not sure how to suggest this...

The ST4 behaves like a bike should.. If you apply the brakes mid corner 99% of bikes will stand up... they just DO.. If you really HAVE to brake IN a corner.. you can apply a little rear.. it won't stand up but you run the risk of high siding..

Please tell me WHY you are braking IN the corner..

Also please read and re-read Keith Code's Twist of the wrist.. then Twist of the wrist II.. then read them both again.


Mal
The above is right on, especially Code's book.

Even thinking about braking in a corner gives me cold sweats at night. I mean it, when I have had bike nightmares, some have included braking in a turn.

I can't count on one-half of one hand the number of times I had to. Once it was to avoid going straight off a cliff [went too fast into the turn:eek: ]. But generally, I don't like and avoid braking in a turn.

And speaking about braking, how many of you use mostly the front brake? I do. Besides, my rear brakes cause me nothing but trouble. I find I am a better rider by pretending there is no rear brake causing me to use the engine and front brake more than both front and rear brakes, albeit I have practiced downshifting, and max front and rear brakes to see how quickly I can stop without losing control or to see how steep a hill I can stop on, here in San Francisco.
 

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NCRick said:
Hi Jim,

Please don’t take any of my input as being critical and I apologize if it was stating the obvious, I had no intention of talking down to your riding ability. I felt I may have a good perspective on your question as I have over 100K miles logged on the two BMW motorcycles I once owned. I transitioned to the Ducatis in 1999 any am working to that point with about 60k miles logged on those. We live and ride in the Appalachian mountains and ride twisty roads enough to understand where you are coming from with your (what I considered to be) very cool question. Having ridden street bikes extensively since the late 70s I know that I am still on a fairly steep learning curve and I certainly do not consider myself to be any kind of great rider. I do try to be a student of the game and really enjoy trying to become better at it as well as learning to better understand what happens when I ride. I started racing in the AHRMA BOTT ( battle of the twins) series on my 748 a few years ago (as a professional back-marker) just to get more track time so I can learn a little more.

I for one am always very interested to discuss any issues related to riding and chassis dynamics and look forward to learning from each opportunity. I am certainly no expert.

I suggest you check out the front and rear ride height and sag settings on your bike, it may well have been played with. If the previous owner flattentd the center of the tires, that too could be making the bike act strange.
You posts are most informative and helpful. Thanks for taking the time to publish the information. Hopefully, some of the lesser-informed members will take the time to learn from your experience and knowledge.
 
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