digest number 1506

[Jsherlockholmz@aol.com]

In a message dated 6/23/01 7:11:13 PM Central Daylight Time, DSN_klr650@yahoogroups.com writes: >>

[RM]

On Sun, 24 Jun 2001 Jsherlockholmz@... wrote:

>and the hard carcass of the steel lines will increase brake performance. >Look at it this way. With the stock line, you have soft rubber, so some >of the energy that you created when you depressed the brake lever is >used up flexing and expanding the rubber lines. When you change to >Teflon/steel lines, that flex is reduced to an immeasurable amount. This >allows almost all the energy that you created when depressing the brake >lever to be spent on pressing the brake piston against the pads/disc >instead.

I'm not a fluid engineer, but my line of thinking is that "x" lever force will produce "y" line pressure which results in "z" braking force. The expansion of the OEM brake line will affect the *volume* of fluid used, but not the line pressure for a given lever force. The only way that a line could change the relationship is if you can squeeze hard enough to bottom the lever out against the grip. RM

[Barry Levine]

"X" lever force will produce "Y" line pressure which will produce "Z" braking force. Well, that would be true if the volume of fluid "in the line" did not increase. Look at it in this manner: Assume you had a child's balloon with two open ends. Connect one end to the master cylinder and the other end to the disc brake. Now squeeze the lever and watch the balloon expand. Do you really think the brakes are being applied with -any- measurable force at all? All the pressure on the lever is being used to expand the balloon with brake fluid. Why? Because the balloon is the part of the system with the least resistance to the pressure. Accordingly, substitute steel-braided lines that do not expand and all the pressure in the system goes to the caliper. *Presto* Hope this helps. Barry

--- In DSN_klr650@y..., RM wrote: > > On Sun, 24 Jun 2001 Jsherlockholmz@a... wrote: > > I'm not a fluid engineer, but my line of thinking is that "x" lever force > will produce "y" line pressure which results in "z" braking force. The > expansion of the OEM brake line will affect the *volume* of fluid used, > but not the line pressure for a given lever force. The only way that a > line could change the relationship is if you can squeeze hard enough to > bottom the lever out against the grip. > > RM

[Jim Jackson]

I'm not an engineer at all but it seems to me there is a 'feel' and time factor here as well. If you pull the lever in till you reach your desired braking force, the line will still be expanding and therefore decreasing the volume/pressure inside so that in order to keep the same braking force you must pull the lever in farther thus applying more pressure, expanding the line more and so forth in a decreasing curve. Does this make any sense? Jim Jackson II A13 "Gonzo" (still no takers?) Baltimore MD ----Original Message Follows---- From: RM CC: DSN_klr650@yahoogroups.com> Subject: Re: [DSN_klr650] Digest Number 1477 Date: Mon, 25 Jun 2001 12:15:02 -0500 (CDT) I'm not a fluid engineer, but my line of thinking is that "x" lever force will produce "y" line pressure which results in "z" braking force. The expansion of the OEM brake line will affect the *volume* of fluid used, but not the line pressure for a given lever force. The only way that a line could change the relationship is if you can squeeze hard enough to bottom the lever out against the grip. RM _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com

[Marc Illsley Clarke]

Well, I am an engineer with more than a little physics background, so I'll throw my 2 in. I agree with Krock's explanations 100%. Nonetheless, I measured that my KLR650 stopped in 25% less distance after I put SS brake lines on. I believe the fresh clean Bel-Ray brake fluid I put in when I changed the lines made a huge difference in how much pressure was transmitted to the brake's piston rather than being absorbed in moisture contaminated compressible old brake fluid. I believe that the SS brake lones greatly improve the feel of the brake lever so I can apply more braking force sooner. -- Marc, KLR650 A12, Loveland, Colorado, USA "Jim Jackson" wrote: __________

>I'm not an engineer at all but it seems to me there is a 'feel' and time >factor here as well. If you pull the lever in till you reach your desired >braking force, the line will still be expanding and therefore decreasing the >volume/pressure inside so that in order to keep the same braking force you >must pull the lever in farther thus applying more pressure, expanding the >line more and so forth in a decreasing curve. Does this make any sense? > >Jim Jackson II >A13 "Gonzo" (still no takers?) >Baltimore MD > > > >----Original Message Follows---- >From: RM >CC: DSN_klr650@yahoogroups.com> >Subject: Re: [DSN_klr650] Digest Number 1477 >Date: Mon, 25 Jun 2001 12:15:02 -0500 (CDT) > > >I'm not a fluid engineer, but my line of thinking is that "x" lever force >will produce "y" line pressure which results in "z" braking force. The >expansion of the OEM brake line will affect the *volume* of fluid used, >but not the line pressure for a given lever force. The only way that a >line could change the relationship is if you can squeeze hard enough to >bottom the lever out against the grip. > >RM > >

-- Marc Marc Illsley Clarke mailto:marcclarke@...

[debbie@carrabassett.net]

You all are forgetting something, the reason why braking is improved is because when I picked up the bike brand new I could squeeze the front brake all the way to the handlebar and wished it would go further. After putting a braided line on I could apply the brakes as hard as I wanted and would never go all the way to the bar. John

--- In DSN_klr650@y..., "Jim Jackson" wrote: > I'm not an engineer at all but it seems to me there is a 'feel' and time > factor here as well. If you pull the lever in till you reach your desired > braking force, the line will still be expanding and therefore decreasing the > volume/pressure inside so that in order to keep the same braking force you > must pull the lever in farther thus applying more pressure, expanding the > line more and so forth in a decreasing curve. Does this make any sense? > > Jim Jackson II > A13 "Gonzo" (still no takers?) > Baltimore MD > > > > ----Original Message Follows---- > From: RM > CC: > Subject: Re: [DSN_klr650] Digest Number 1477 > Date: Mon, 25 Jun 2001 12:15:02 -0500 (CDT) > > > I'm not a fluid engineer, but my line of thinking is that "x" lever force > will produce "y" line pressure which results in "z" braking force. The > expansion of the OEM brake line will affect the *volume* of fluid used, > but not the line pressure for a given lever force. The only way that a > line could change the relationship is if you can squeeze hard enough to > bottom the lever out against the grip. > > RM > > > _________________________________________________________________ > Get your FREE download of MSN Explorer at http://explorer.msn.com

[Riley Harlton]

RM wrote:

> On Sun, 24 Jun 2001 Jsherlockholmz@... wrote: > > >and the hard carcass of the steel lines will increase brake performance. > >Look at it this way. With the stock line, you have soft rubber, so some > >of the energy that you created when you depressed the brake lever is > >used up flexing and expanding the rubber lines. When you change to > >Teflon/steel lines, that flex is reduced to an immeasurable amount. This > >allows almost all the energy that you created when depressing the brake > >lever to be spent on pressing the brake piston against the pads/disc > >instead. > > I'm not a fluid engineer, but my line of thinking is that "x" lever force > will produce "y" line pressure which results in "z" braking force. The > expansion of the OEM brake line will affect the *volume* of fluid used, > but not the line pressure for a given lever force. The only way that a > line could change the relationship is if you can squeeze hard enough to > bottom the lever out against the grip. > > RM

I recently made the change or SS lines as well. It not sure what the physics behind it are, all I know is that no matter how hard I squeezed with the old rubber lines it never stopped like it does know. With old lines there was a lot less initial bite. The more you squeezed the old line the more it bulged. The more I squeeze now the more I stop. Riley A15

[Jim & Shannon Morehead]

Marc, Compressible liquids??? I can't think of any. Jim

----- Original Message ----- From: "Marc Illsley Clarke" To: "Jim Jackson" ; DSN_klr650@yahoogroups.com> Sent: Monday, June 25, 2001 9:12 PM Subject: Re: [DSN_klr650] Digest Number 1477 > Well, I am an engineer with more than a little physics background, so I'll throw my 2 in. I agree with Krock's explanations 100%. Nonetheless, I measured that my KLR650 stopped in 25% less distance after I put SS brake lines on. I believe the fresh clean Bel-Ray brake fluid I put in when I changed the lines made a huge difference in how much pressure was transmitted to the brake's piston rather than being absorbed in moisture contaminated compressible old brake fluid. I believe that the SS brake lones greatly improve the feel of the brake lever so I can apply more braking force sooner. > > -- Marc, KLR650 A12, Loveland, Colorado, USA > > "Jim Jackson" wrote: > __________ > >I'm not an engineer at all but it seems to me there is a 'feel' and time > >factor here as well. If you pull the lever in till you reach your desired > >braking force, the line will still be expanding and therefore decreasing the > >volume/pressure inside so that in order to keep the same braking force you > >must pull the lever in farther thus applying more pressure, expanding the > >line more and so forth in a decreasing curve. Does this make any sense? > > > >Jim Jackson II > >A13 "Gonzo" (still no takers?) > >Baltimore MD > > > > > > > >----Original Message Follows---- > >From: RM > >CC: DSN_klr650@yahoogroups.com> > >Subject: Re: [DSN_klr650] Digest Number 1477 > >Date: Mon, 25 Jun 2001 12:15:02 -0500 (CDT) > > > > > >I'm not a fluid engineer, but my line of thinking is that "x" lever force > >will produce "y" line pressure which results in "z" braking force. The > >expansion of the OEM brake line will affect the *volume* of fluid used, > >but not the line pressure for a given lever force. The only way that a > >line could change the relationship is if you can squeeze hard enough to > >bottom the lever out against the grip. > > > >RM > > > > > > -- Marc > > Marc Illsley Clarke > mailto:marcclarke@... > > Visit the KLR650 archives at > http://www.listquest.com/lq/search.html?ln=klr650 > > Post message: DSN_klr650@yahoogroups.com > Subscribe: DSN_klr650-subscribe@yahoogroups.com > Unsubscribe: DSN_klr650-unsubscribe@yahoogroups.com > List owner: DSN_klr650-owner@yahoogroups.com > > Support Dual Sport News by subscribing at: > http://www.dualsportnews.com > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > >

[Marc Illsley Clarke]

Make that "Krok's". Sorry, Chris. -- Marc, KLR650 A12, Loveland, Colorado, USA -- Marc Marc Illsley Clarke mailto:marcclarke@...

[Ted Palmer]

Jim Morehead wrote:

> Marc, > Compressible liquids??? I can't think of any.

Everything is compressible to some extent, more or less. IIRC, one of the concerns that racers had with the then-new silicone brake fluid was that it was _slightly_ more compressible than the polyglycol stuff. I notice that silicone fluid still hasn't taken over from polyglycol. Mister_T