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Old 07-09-2014, 05:14 PM   #23866
scudrunner82
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Quote:
Originally Posted by Wreckchecker View Post
Back to motorcycle stuff. . .

That mark is the limit of traction (static coefficient of friction), where the overall contact patch of rubber is just barely on the edge of slipping but not quite yet there.
In other words the mark you show is why you do not need an off switch for the ABS, yours is giving you max possible braking.

A real skid which leaves a black tire mark is an expensive way to show that you reached the dynamic C of F, as one surface slides on another.
Along with loss of control, longer stopping distances, hitting things with more speed, a brown stain in your underwear, possible high side when the tires get out of line and you release the brake lever, etc.

I feel like I'm reading an accident report.
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Old 07-09-2014, 05:21 PM   #23867
BergDonk
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The CoF limit is actually the tensile strength of the rubber. On a textured surface, like nice hotmix, or rough concrete, there is a mechanical connection between the rubber and surface, like 2 gears meshing and friction as such is not the limiting factor. Different on smooth surfaces. When the rubber's strength is exceeded its torn off, leaving bits within the texture of the surface it was connected to for you to see. Some of the energy is released as sound, the squeal you hear as the rubber is torn off.

Without ABS you flat spot a tyre, with ABS, the rubber is torn off evenly around the circumference of the tyre.
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Old 07-09-2014, 05:40 PM   #23868
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And if you imagine a knobby on a softer surface, you get the reverse effect. The knobs engage the surface, creating a mechanical connection, leaving some sort of imprint behind. Under braking, or acceleration, when traction is exceeded, in this case, its the tensile strength of the dirt that is exceeded, and a skid mark results, but this time its the dirt that is weakest, so it gets spread about.
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Old 07-09-2014, 05:41 PM   #23869
William42
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Quote:
Originally Posted by scudrunner82 View Post
I feel like I'm reading an accident report.
Those come mostly from pluric as a result of his sand riding skills.

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Old 07-09-2014, 05:48 PM   #23870
twinrider
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Quote:
Originally Posted by Jim Rowley View Post
Some of us actually are French so maybe stick to S10 or ST or XT1200 or Super Ténéré topics? If you want to bash the French or BMWs, there's a forum for that.
Did I mention the French? I'm half French myself and wouldn't dream of slamming la patrie.



Quote:
Originally Posted by crazyjeeper View Post
how come I can do this:

K60s make wooden wheels seem grippy.
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Old 07-09-2014, 06:11 PM   #23871
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Quote:
Originally Posted by scudrunner82 View Post
I feel like I'm reading an accident report.
I think he just cured my insomnia!
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Old 07-09-2014, 07:28 PM   #23872
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Quote:
Originally Posted by twinrider View Post
Did I mention the French? I'm half French myself and wouldn't dream of slamming la patrie.





K60s make wooden wheels seem grippy.

Especially in the damp/wet. Hoooweeee! I'm not sure I'd like these things without traction control!
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Old 07-09-2014, 09:10 PM   #23873
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Quote:
Originally Posted by Old Blue View Post
Especially in the damp/wet. Hoooweeee! I'm not sure I'd like these things without traction control!
I switch the TC to off when I start the bike. Almost every ride I take hits dirt at some point, why wait?
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Old 07-09-2014, 10:44 PM   #23874
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Quote:
Originally Posted by crazyjeeper View Post
On that subject, if the Tenere needs an ABS off switch, how come I can do this:



Gee I know they are heavy but to crack concrete like that???.............Sheeeeeeesh
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Old 07-09-2014, 11:01 PM   #23875
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Quote:
Originally Posted by blax1 View Post
Gee I know they are heavy but to crack concrete like that???.............Sheeeeeeesh

First slags against Poles, the French, and BMW's...

Now somebody's taking "cheap shots" at the Super Tenere's weight and that poor, wimpy concrete...

What's next? Slagging Heidenau K60 tires?

Dallara



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Old 07-09-2014, 11:10 PM   #23876
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Quote:
Originally Posted by Starkmojo View Post
I switch the TC to off when I start the bike. Almost every ride I take hits dirt at some point, why wait?

What you said.
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Old 07-10-2014, 12:37 AM   #23877
twinrider
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Quote:
Originally Posted by Hack'dTiger View Post
What you said.
Me too. That's one more reason why I bagged on getting an Explorer. Have to scroll through about 4 menus to turn TC off. And repeat every time you start the bike.

The new Vstrom has the best setup, switchable on the fly.
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Old 07-10-2014, 01:50 AM   #23878
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Quote:
Originally Posted by William42 View Post
Those come mostly from pluric as a result of his sand riding skills.

But Pluric doesn't have any sand riding skills.......
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Old 07-10-2014, 02:13 AM   #23879
Starkmojo
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Quote:
Originally Posted by twinrider View Post
Me too. That's one more reason why I bagged on getting an Explorer. Have to scroll through about 4 menus to turn TC off. And repeat every time you start the bike.
That's a motorcyle designed by lawyers there
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Old 07-10-2014, 04:35 AM   #23880
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Quote:
Originally Posted by BergDonk View Post
FWIW you can also see the rubber streak is light and dark, ABS senses locking, releases, then the pressure reapplied.
Agree with everything you said but the part about the photo showing lock & release. The light & dark here is from the tire trying to follow the variations in the pavement.

Yamaha was (I think) first to the bike market with the new generation of antiskid systems which are entirely math model. No more sensing differential wheel speed for slippage and then release pressure. The new Bosch system used by the Euro bikes have adopted this. If you really want to get into it, somewhere on msgroup.org, Jim Davis wrote a big treatise about the math for motorcycle ABS.

The new ABS systems started in aviation and keep the tire right at the edge of adhesion and in the airlines, pilots of the new generation of jets are now essentially taught that as soon as the airplane is on the ground to basically stand on the pedals and let the airplane do the braking. You can still spot old system when looking at a runway and seeing dashed black lines for each main tire track like you mention.
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