Ok. I'm out of my element. Going riding [?] On Fri, Feb 20, 2015 at 4:52 PM, ted <ted.ke...@comcast.net> wrote:
> Mark, > > From the BQ writeup you cite > > The angle of the straddle cable also af- fects the mechanical advantage. A > low straddle cable means that the pads travel less for a given brake lever > pull. Less travel means more power. > and > > Unless the straddle cable is at a right angle to the brake arm, the > effective length of the brake arm is shortened, which in turn reduces the > braking power. > > The first is pretty straight forward, but the second overlooks the fact > that, for a given brake, the tension in the cable changes when you change > the angle. As you raise the angle towards 90 you reduce the tension which > counteracts the increase in "effective length". > I think its much simpler to work out if you decompose the cable tension > into vertical and horizontal components and stay away from notions like > "effective length". > > On Friday, February 20, 2015 at 2:25:28 PM UTC-8, Mark Reimer wrote: >> >> Deacon, >> >> I agree with you on this. Getting the straddle as close to 90 degrees has >> always been the position which yielded the greatest stopping power for me. >> With my neo-retro's (Aka the 'weaker' of the paul canti's) I have the cable >> long and up high, and I have enough power to lift up the back wheel if I >> really wanted. >> >> Lower straddle usually results in less power, and obviously less mud >> clearance as well. >> >> As I understand it, the idea is to get the cable as close to 90 degrees >> as you can WHEN the brakes are in contact with the rim. >> >> To read a much more exhaustive explanation than I'm willing to >> regurgitate, take a look at BQ's great write-up on setting up canti's. >> >> In the end, I'm sure we can all agree that Paul canti's are awesome. >> >> On Fri, Feb 20, 2015 at 4:18 PM, ted <ted....@comcast.net> wrote: >> >>> Deacon, >>> >>> I am glad that you were able get your brakes to work the way you want. I >>> suspect you were told the opposite of what I am telling you, and that you >>> understood what they were saying. Sadly they told you wrong. But happily >>> they still steered you to something that worked for you. >>> >>> The phrase "slushy brakes" suggests to me low effort producing large >>> brake lever travel with little braking effect. If that's what you had it >>> was likely due to elasticity in the brake system, which is a separate thing >>> from leverage. If you experience that sort of thing, look for what moves >>> when you squeeze the lever hard after the pads hit the rim. For example, I >>> found the steel front cable hangers flex a lot. Replacing mine with the >>> aluminum ones improved the feel of my brakes significantly. Cables that >>> change shape as the brakes are applied can be another source of excess >>> travel. >>> >>> >>> On Friday, February 20, 2015 at 4:21:44 AM UTC-8, Deacon Patrick wrote: >>>> >>>> Ted, et al engineer types: I happily bow to your knowledge on the >>>> angles and leverage, though I was told the opposite (as I understood it) >>>> before I made the change. Interestingly, either way, the experience went >>>> from slushy brakes (short saddle cable, < 90˚ intersection with the brake >>>> arm) and salmon pads, to passable strength except in single track steep >>>> descents (long saddle cable, close to 90˚ intersection with the brake arm). >>>> But that point is mute now, as the Paul's are wonderful! I look forward to >>>> snow-free trails so I can try them out! >>>> >>>> With abandon, >>>> Patrick >>>> >>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "RBW Owners Bunch" group. >>> To unsubscribe from this topic, visit https://groups.google.com/d/ >>> topic/rbw-owners-bunch/5HXsqAEXrWM/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> rbw-owners-bun...@googlegroups.com. >>> To post to this group, send email to rbw-owne...@googlegroups.com. >>> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- > You received this message because you are subscribed to a topic in the > Google Groups "RBW Owners Bunch" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/rbw-owners-bunch/5HXsqAEXrWM/unsubscribe > . > To unsubscribe from this group and all its topics, send an email to > rbw-owners-bunch+unsubscr...@googlegroups.com. > To post to this group, send email to rbw-owners-bunch@googlegroups.com. > Visit this group at http://groups.google.com/group/rbw-owners-bunch. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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