Wilsons Sandbox

Posted: **Thu Aug 25, 2005 10:44 am**

I am grappling with just what sprung and unsprung weights are. What do the terms have to do with springs (sprungs?)? Do they have anything to do with center of gravity? I had a difficult time with high school physics, so if anyone can explain it in the most basic of layman's terms, I'll be quite thankful. John

Posted: **Thu Aug 25, 2005 10:53 am**

At 3:43 PM +0000 8/25/05, John Mellquist wrote:

>I am grappling with just what sprung and unsprung weights are. What >do the terms have to do with springs (sprungs?)? Do they have >anything to do with center of gravity? I had a difficult time with >high school physics, so if anyone can explain it in the most basic of >layman's terms, I'll be quite thankful.

Don't sweat it and don't waste your time thinking about it. The concept of unsprung weight is only an issue if you're a pro rider or if you plan on strapping a bowling ball to your fork sliders. Any discussion on the topic is just mental masturbation and windbaggery. Mark

Posted: **Thu Aug 25, 2005 10:58 am**

John, Imagine two weights sitting on a frictionless surface (a greased table) connected by a spring. If, when you compress the spring, you want one to move and the other not to move, you make the one you want to move as light as possible compared to the one you don't want to move. In the case of a motorcycle, when a bump compresses your suspension spring, the lighter you make the unsprung weight (wheels, tires, and everything that isn't supported by the suspension), the quicker the wheel will return to the pavement without substantially affecting the rest of the motorcycle. It essentially gives better suspension response. In the extreme opposite, if the wheels and tires were much heavier than the rest of the motorcycle, when a bump compresses the suspension spring and lifts the wheel off the ground, the sprung weight of the motorcycle (everything that is supported by the suspension, including the rider) will displace upward, instead of the wheel displacing back downward to the road. That would be very poor suspension response, as well as a very poor ride! In addition to suspension response, most of your unsprung weight is also spinning weight. Reducing your spinning weight greatly improves acceleration and deceleration, by reducing the moment of inertia of your wheel. Hope that helps... Brian Armstrong Greenwood Village, CO --

On Thu, 25 Aug 2005, John Mellquist wrote: > I am grappling with just what sprung and unsprung weights are. What > do the terms have to do with springs (sprungs?)? Do they have > anything to do with center of gravity? I had a difficult time with > high school physics, so if anyone can explain it in the most basic of > layman's terms, I'll be quite thankful. > > John > > > > > Archive Quicksearch at: http://www.angelfire.com/ut/moab/klr650_data_search.html > List sponsored by Dual Sport News at: www.dualsportnews.com > List FAQ courtesy of Chris Krok at: www.bigcee.com/klr650faq.html > > > Yahoo! Groups Links > > > > > > >

Posted: **Thu Aug 25, 2005 11:00 am**

John, "Sprung" is a form of the word "spring", ie. suspension. Unsprung weight includes the wheels, brakes, rear sprocket, etc. It's the stuff that roughly follows the ground when riding. It is good to reduce unsprung weight in order for the tires to remain in contact with the ground. Lower unsprung weight decreases inertia of the wheels and thus increases ground contact and therefore traction. Sprung weight; that is, suspended weight; includes the engine, frame, gas tank, rider, etc. Sprung weight doesn't follow the ground so precisely because of the suspension. hth -Greg Guithues.

On 8/25/05, John Mellquist wrote: > I am grappling with just what sprung and unsprung weights are. What > do the terms have to do with springs (sprungs?)? Do they have > anything to do with center of gravity? I had a difficult time with > high school physics, so if anyone can explain it in the most basic of > layman's terms, I'll be quite thankful. > > John > > >

Posted: **Thu Aug 25, 2005 11:12 am**

> I am grappling with just what sprung and unsprung weights are. What > do the terms have to do with springs (sprungs?)? Do they have > anything to do with center of gravity? I had a difficult time with > high school physics, so if anyone can explain it in the most basic of > layman's terms, I'll be quite thankful. > > John > >

Sprung weight is the weight of the parts of the bike supported by the suspension. Unsprung weight is weight of the parts of the bike not supported by the suspension. The effects of changing either will affect the center of gravity depending on their relationship thereto. Fuel is sprung weight. Due to the position of the fuel tank increasing fuel amount raises the center of gravity. The life expectancy of any engine is directly proportional to the amount of fuel burned within it's cylinders. The more fuel you burn the lower your center of gravity becomes unless you burn oil at such a rate that overcomes the fuel burn then your center of gravity will rise. This effect will reset itself when you refill the tank and top off the oil. Adding a fork brace increases unsprung weight and is the worst thing you can due to a KLR because Eldon Carl says so and only what works for him is right for you. Walt

Posted: **Thu Aug 25, 2005 11:36 am**

Walt: I don't post a lot, but I love to gleen from the list any information that can be useful to me in maintaining my bikes. Many times, it is difficult to determine when somebody is being humorous, sarcastic, telling an inside joke, etc. What was your meaning in referencing Eldon Carl in the below statement? Thanks, Lloyd Rauschkolb Gulfport, Mississippi --- a14@... wrote:

> > I am grappling with just what sprung and unsprung > weights are. > > Adding a fork brace increases unsprung weight and is > the worst thing you can due to a KLR because Eldon > Carl says so and only what works for him is right > for you. > > Walt > > > > > > > > > Archive Quicksearch at: >

http://www.angelfire.com/ut/moab/klr650_data_search.html

> List sponsored by Dual Sport News at: > www.dualsportnews.com > List FAQ courtesy of Chris Krok at: > www.bigcee.com/klr650faq.html > > > Yahoo! Groups Links > > > DSN_KLR650-unsubscribe@yahoogroups.com > > > > >

____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs

Posted: **Thu Aug 25, 2005 1:14 pm**

Lloyd, I'm sorry that I confused you by melding my serious answers with my strange sense of humor. The way you snipped out the rest of my post by only including the first part of the question with the last part of my answer makes it look like I was making some kind of a personal attack towards Eldon. That was not my intention. If you go back and read the replies in the order they were posted you will see my post was after the one by Mark which hit the nail on the head on how discussions about unsprung weight progress. They usually end with references to Eldon's opinion about fork braces which gets elevated to gospel status. I simply began my post by answering his question seriously and then progressed, as Mark puts it, to mental masturbation and windbaggery. I thought that at some point it would become obvious that I was now joking and it would be upon the reader to decide where this point began. I guess I should have added NKLR to the subject but figured the KLR reference would exclude its need. And yes, I am guilty of confusing you by slipping in my opinion of Eldon's opinion on the subject of fork braces in the end, however, that is where discussions on this topic arrive toward the end so that is why I included it there.. My choice of words was not the best but if you want to know the meaning of what I really was thinking when I wrote that it is that I disagree with his opinion on the subject of unsprung weight and fork braces and anyone who uses one also disagrees or they wouldn't be using one. For the record I do respect and also agree with most of Eldon's opinions but not that one. I've been here since 1999 so certain subjects have been experienced over and over by me on this list and it gets tiring so therefore the sarcasm follows. I know you have been here at least a few years so you should have a sense of what I mean. Of course this isn't quite fair to the newbees but when I was a newbee the veterans of the list kept my entertained in the same fashion. Walt P.S. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy. All work and no ply makes Jack a dull boy.

> Walt: I don't post a lot, but I love to gleen from > the list any information that can be useful to me in > maintaining my bikes. > > Many times, it is difficult to determine when somebody > is being humorous, sarcastic, telling an inside joke, > etc. > > What was your meaning in referencing Eldon Carl in the > below statement? > > Thanks, > Lloyd Rauschkolb > Gulfport, Mississippi > > --- a14@... wrote: > > > > I am grappling with just what sprung and unsprung > > weights are. > > > > Adding a fork brace increases unsprung weight and is > > the worst thing you can due to a KLR because Eldon > > Carl says so and only what works for him is right > > for you. > > > > Walt > > > >

Posted: **Thu Aug 25, 2005 1:52 pm**

Walt: Thanks for clarifying. Because I live in Mississippi, and most list members seem to live out west where there are great KLR riding areas, I have had no physical contact with list members other that Fred. Therefore I don't really know who knows who personally, and who is kidding unless you use those (What do you call them? Emoticons?) I call them Email Dohickeys

BTW, next year my son is moving to Salt Lake City for his last two years of college. You might remember he was nearly killed while riding his KLR in 2001. He still rides a KLR daily to school and work. Perhaps I can then get out and meet some of the list members after I get him settled in. I'm retired, have plenty of free time, and will be paying for my son's housing, so I intend to squat at his place when I get the urge and get in some of that great riding you guys are always getting and take for granted. Lloyd --- a14@... wrote:

> Lloyd, I'm sorry that I confused you by melding my > serious answers with my strange sense of humor. The > way you snipped out the rest of my post by only > including the first part of the question with the > last part of my answer makes it look like I was > making some kind of a personal attack towards Eldon. > That was not my intention. If you go back and read > the replies in the order they were posted you will > see my post was after the one by Mark which hit the > nail on the head on how discussions about unsprung > weight progress. They usually end with references > to Eldon's opinion about fork braces which gets > elevated to gospel status. I simply began my post by > answering his question seriously and then > progressed, as Mark puts it, to mental masturbation > and windbaggery. I thought that at some point it > would become obvious that I was now joking and it > would be upon the reader to decide where this point > began. I guess I should have added NKLR to the > subject but figured the KLR reference would exclude > its need. And yes, I am guilty of confusing you by > slipping in my opinion of Eldon's opinion on the > subject of fork braces in the end, however, that is > where discussions on this topic arrive toward the > end so that is why I included it there.. My choice > of words was not the best but if you want to know > the meaning of what I really was thinking when I > wrote that it is that I disagree with his opinion on > the subject of unsprung weight and fork braces and > anyone who uses one also disagrees or they wouldn't > be using one. For the record I do respect and also > agree with most of Eldon's opinions but not that > one. I've been here since 1999 so certain subjects > have been experienced over and over by me on this > list and it gets tiring so therefore the sarcasm > follows. I know you have been here at least a few > years so you should have a sense of what I mean. Of > course this isn't quite fair to the newbees but when > I was a newbee the veterans of the list kept my > entertained in the same fashion. > > Walt > > > P.S. All work and no ply makes Jack a dull boy. > All work and no ply makes Jack a dull boy. > All work and no ply makes Jack a dull boy. All work > and no ply makes Jack a dull boy. All work and no > ply makes Jack a dull boy. All work and no ply > makes Jack a dull boy. All work and no ply makes > Jack a dull boy. All work and no ply makes Jack a > dull boy. All work and no ply makes Jack a dull > boy. All work and no ply makes Jack a dull boy. > All work and no ply makes Jack a dull boy. All work > and no ply makes Jack a dull boy. All work and no > ply makes Jack a dull boy. All work and no ply > makes Jack a dull boy. > > > > Walt: I don't post a lot, but I love to gleen > from > > the list any information that can be useful to me > in > > maintaining my bikes. > > > > Many times, it is difficult to determine when > somebody > > is being humorous, sarcastic, telling an inside > joke, > > etc. > > > > What was your meaning in referencing Eldon Carl in > the > > below statement? > > > > Thanks, > > Lloyd Rauschkolb > > Gulfport, Mississippi > > > > --- a14@... wrote: > > > > > > I am grappling with just what sprung and > unsprung > > > weights are. > > > > > > Adding a fork brace increases unsprung weight > and is > > > the worst thing you can due to a KLR because > Eldon > > > Carl says so and only what works for him is > right > > > for you. > > > > > > Walt > > > > > > >

____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs

Posted: **Thu Aug 25, 2005 4:12 pm**

Wow! What a resource this list is. My thanks to all who responded to my questions. I think I get it now, but what happens if I turn the bike upside down (just kidding)?

--- In DSN_KLR650@yahoogroups.com, a14@a... wrote: > > I am grappling with just what sprung and unsprung weights are. What > > do the terms have to do with springs (sprungs?)? Do they have > > anything to do with center of gravity? I had a difficult time with > > high school physics, so if anyone can explain it in the most basic of > > layman's terms, I'll be quite thankful. > > > > John > > > > > > Sprung weight is the weight of the parts of the bike supported by the suspension. > > Unsprung weight is weight of the parts of the bike not supported by the suspension. > > The effects of changing either will affect the center of gravity depending on their relationship thereto. > > Fuel is sprung weight. Due to the position of the fuel tank increasing fuel amount raises the center of gravity. > > The life expectancy of any engine is directly proportional to the amount of fuel burned within it's cylinders. > > The more fuel you burn the lower your center of gravity becomes unless you burn oil at such a rate that overcomes the fuel burn then your center of gravity will rise. This effect will reset itself when you refill the tank and top off the oil. > > Adding a fork brace increases unsprung weight and is the worst thing you can due to a KLR because Eldon Carl says so and only what works for him is right for you. > > Walt

Posted: **Thu Aug 25, 2005 5:08 pm**

One little addition to this, Too much unsprung weight is a bad thing because it reduces your vehicles suspension's ability to keep the tire in contact with the road/ground. If you were riding along with a very heavy wheel and hit a bump, the wheel would be forced up with more momentum/energy than if you hit the same bump at the same speed with a lighter wheel. The additional energy makes it harder for the suspension to control the upward thrust and get the wheel back down quickly. Hence, obviously you have to have some (brakes, hub, tire, etc.), but other things equal, less unsprung weight is better than more unsprung weight, because your suspension will work better. Jett, A15/GL1800a, AZ --- In DSN_KLR650@yahoogroups.com, "John Mellquist" wrote:

> Wow! What a resource this list is. My thanks to all who responded > to my questions. I think I get it now, but what happens if I turn > the bike upside down (just kidding)? > > --- In DSN_KLR650@yahoogroups.com, a14@a... wrote: > > > I am grappling with just what sprung and unsprung weights are. > What > > > do the terms have to do with springs (sprungs?)? Do they have > > > anything to do with center of gravity? I had a difficult time > with > > > high school physics, so if anyone can explain it in the most > basic of > > > layman's terms, I'll be quite thankful. > > > > > > John > > > > > > > > > > Sprung weight is the weight of the parts of the bike supported by > the suspension.

...

Wilsons Sandbox

nklr 650 phillips-drive screw head tear-out prevention

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight

sprung vs unsprung weight