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Discussion Starter · #1 ·
I don't understand the subtleties of motorcycle traction well. For example, people hang off to "get more traction." But I'm not convinced hanging off gives you more traction--more space between the road and the bottom of the bike, yes, but more traction? I'm not so sure.

If I ride around a 40 foot circle at a 30 miles per hour, I don't think the tire knows if I'm hanging off or not. I'm going 30 around a 40 foot circle no matter what. If I lean out and push the bike under, the pegs will be closer to the ground, and if I lean in, the inside peg will lift up and be further off the ground, but the tire is round, it adjusts automatically. I'm still going around a 40 foot circle at 30 mph. The tire is still subjected to the EXACT SAME G-FORCES either way.

People say, "The bike is more upright, so you have a wider part of the tire on the road, so you have more traction." But I know that tire width is irrelevant to tire friction. It literally is not part of the equation. Yes, hanging off (or leaning your upper body IN) gives you more ground clearance before touching hard parts, but more traction? I don't think so.

What do you think? Anyone have the equations to prove me wrong, or explain why I'm right. (I don't, that's why I'm asking.)
 

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It is my "Limited" understanding that leaning on a motorcycle doesn't per se give you more traction. Leaning on a motorcycle changes the center of gravity of the unit, bike + rider, and therefore reduces the amount of lean angle required of the bike to complete a particular radius of a turn. By reducing the lean angle you also reduce the amount of centrifugal force, side force, being exerted on the tire at the road surface. The reduction of side force is where your better traction comes into play.

Quick Google search provided with site with plenty of math.
http://www.stevemunden.com/leanangle.html

As I said at the top, this is my "Limited" understanding on the subject.
 

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.....People say, "The bike is more upright, so you have a wider part of the tire on the road, so you have more traction." But I know that tire width is irrelevant to tire friction. It literally is not part of the equation........
Tire "patch" ( the part that touches the pavement) has to be relevant.....if it were not dragsters would be able to use skinny tires....If tire width contributes to more rubber on the pavement then there has to be more friction/traction.....assuming dry conditions of course.

Granted, a true round tire configuration would not change the patch no matter what the lean angle, but saying that "tire width is irrelevant" has to be a misstatement.

The other part of all this, which I am ignoring, is directional forces acting on that patch....a vertical tire, under power, exerts force in only two directions against the patch, gravitational and rotational.....lean the bike and you now have three directional force vectors to account for......and that makes my head hurt so I'm going to stop right here!
 

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Tire "patch" ( the part that touches the pavement) has to be relevant.....if it were not dragsters would be able to use skinny tires....If tire width contributes to more rubber on the pavement then there has to be more friction/traction.....assuming dry conditions of course.

Granted, a true round tire configuration would not change the patch no matter what the lean angle, but saying that "tire width is irrelevant" has to be a misstatement.
As I see it, you have to increase the weight (pressure) to get more friction regardless of patch size. Tire composition also plays a big part. :shrug:
 

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As I see it, you have to increase the weight (pressure) to get more friction regardless of patch size. Tire composition also plays a big part. :shrug:
I would agree but the composition of the tire will not change between the time he leaves the garage and the time he gets back no matter how much he leans so I think we can take that off the table. And I agree that weight plays a part.....but only vertical weight helps.....you increase the "weight" of the bike on the tire by centrifical force in a corner....i.e. faster and tighter equals more force/weight on the patch and you know from personal experience that "weight" in that form and direction will reduce the co-effiecient of friction to zip darn quick!
 

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Coincidently i just got through reading my NOV Cycle World, and a young man ,Marc Marquez, is pictured on pg 28, Unbelievable the guy is the wildest racer I have ever seen. I have watched almost all of his races this year and he does not know how to lose. The photos defy anything your logic is trying to explain in the above posts. Nothing applies to this guy!!! photo # 11, look where the bottom of his front wheel is compared to his body!! http://www.cycleworld.com/2014/09/1...marquez-motogo-practice-session-save-at-brno/
 

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Discussion Starter · #7 ·
... Granted, a true round tire configuration would not change the patch no matter what the lean angle, but saying that "tire width is irrelevant" has to be a misstatement.

The other part of all this, which I am ignoring, is directional forces acting on that patch ... a vertical tire, under power, exerts force in only two directions against the patch, gravitational and rotational ...
Yes, a dragster will use big fat tires, but experts assure me that this is NOT because they get more traction out of the larger contact patch. The extra width spreads the forces out, makes the tires heat up more slowly, last longer, stay in one piece and such. So, within reason, trying to stay more upright can't be about keeping more tire on the road. Although, WEIGHT is a big factor, and Wings have plenty of that to give us more grip.

On the other hand, I believe you are right about side forces. Weight pushes down. Good. The engine adds forward motion/rotation and that uses some grip. Fine. And we have some traction left over. Adding a sideways force uses up some of that left-over traction. So, we still have the same amount of grip available from the tire, but some is bring spent turning the corner and some on maintaining forward momentum. This leaves less in reserve.

This makes me wonder if being gentle on the gas and brakes while leaned over is more important than manipulating 5-degrees of lean angle by hanging off.

On the other hand, if you are scraping your pegs, and about to scrape something that doesn't fold up, it might be nice to have that 5-degrees of lean angle back. :lol:
 

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Here's a nice example of leaning off with the bike more upright as a result. ;)



The physics is explained quite clearly and simply... here: :thumbup:



I don't remember do so well in physics... ;)
 

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I would suggest you talk to a motorcycle "expert" such as a moto GP driver and ask him why his lean angle helps; why he trail brakes into corners; why tire composition is critical in regards to track surface, condition, wet or dry.

So far you have argued with every answer given so I'm not sure what you're really trying to accomplish with this post.
 

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So far you have argued with every answer given so I'm not sure what you're really trying to accomplish with this post.
The OP posed his argument and is defending it in discussion...nothing wrong with that...he just wants to be convinced with facts.

Most threads like this are less about fact and more about pooling ignorance.....Over the years I have contributed significantly to that pool.

Carry on gentlemen!
 

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Discussion Starter · #11 ·
So far you have argued with every answer given so I'm not sure what you're really trying to accomplish with this post.
Argued with every answer? No. I really liked those pictures. :lol:
 

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here ya go

wanna hang off? just do it


don't want to hang off? don't do it

next subject?
 

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YW, now don't go and make sense on this forum, this ain't the place for that.:lol:
 

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Simple question and a very complicated answer or answers. Friction, contact patch, composition of the tires you are running, surface condition and type of road, tire pressure-lower pressure wider contact patch-lower pressure less load and the hotter the tire runs, warm day-hot soft tires, cold day-cold hard tires, Suspension, speed, braking-lighter back tire and more downward pressure on front tire, acceleration-lighter front tire more downward pressure on rear tire, lean angle. NO simple answer and far to many variables.

If you want a couple of good reads, Total Control by Lee Parks. He spends a lot of time on this subject and technique.
Proficient Motorcycling by David Hough (2 book series) 1 st was great, the second felt like a repeat reworded but still a good read.
 

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I would suggest you talk to a motorcycle "expert" such as a moto GP driver and ask him why his lean angle helps; why he trail brakes into corners; why tire composition is critical in regards to track surface, condition, wet or dry.
If you talked to a Moto GP rider as an "expert" on the physics of lean angles, trail braking and tire composition about all he would say is "It makes my lap times faster. That's all I know or care about."
 

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Coincidently i just got through reading my NOV Cycle World, and a young man ,Marc Marquez, is pictured on pg 28, Unbelievable the guy is the wildest racer I have ever seen.
By a factor of like, 10 million.....Amazing talent. Saw the same pics and was POSITIVE it wasn't going to end well. He rides like he is from a different planet....Seriously.

Traction..who needs stinking traction! I think he willed the bike upright with his mind ;-)
 

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Wow, ridden 250k on 1800s in the last 10 years and I have never heard anyone say or post that you get more traction by leaning off.. Not saying it ain't true, just never heard that.

in my experience, leaning off just gives a Wing more lean angle before dragging the parts that don't give .......such as the front crash bars. :shock:
 

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In the OP's example about a constant speed in a given circle the amount of traction will be static. But when leaning off, the rider is able to proceed at a higher rate of speed; which in the turn results in a higher gravity force. The higher G force is additional weight upon the contact patch an thus MORE TRACTION. But that is not part of the original supposition.

Trailsman's statement is about what really matters, not jacking-up the bike on hard parts and losing traction.

prs
 

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I disagree that hanging of gives you more traction. what hanging of does is allow you to make a turn without having to lean the bike as much as you would by not hanging off. when approaching maximum lean angle in order to make a sharper turn you need to hang off to the inside of the turn. it does two things, it allows the bike to stay more upright as to not drag hard parts and lowers your combined enter of gravity.

that's my $.02

John
 

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I disagree that hanging of gives you more traction. what hanging of does is allow you to make a turn without having to lean the bike as much as you would by not hanging off. when approaching maximum lean angle in order to make a sharper turn you need to hang off to the inside of the turn. it does two things, it allows the bike to stay more upright as to not drag hard parts and lowers your combined enter of gravity.

that's my $.02

John

Let's not forget it also makes you look really 'cool'. Although maybe not so much hanging off a fat girl....;)
 
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