|
|
Thread Tools | Display Modes |
Ads |
#22
|
|||
|
|||
Maintenance Manuals
Peter Cole wrote:
wrote: On Sat, 29 Sep 2007 16:38:15 -0400, Peter Cole wrote: Frank Drackman wrote: "jim beam" wrote in message t... Ryan Cousineau wrote: In article .com, BigJulie wrote: sutherland's http://www.amazon.com/Sutherlands-Ha...herland/dp/091 4578065/ref=pd_bbs_2/102-4791940-4852967?ie=UTF8&s=books&qid=1191039436&sr=8-2 On Sep 29, 12:05 am, Mark wrote: Well as I am increasingly intrigued by the mechanics of bikes. There is a lot I just have never taken apart, put back together, and frankly don't fully understand how things work. I wondered if there is a book that is accepted as "the book to have on bike maintenance" that shows pictures and step by step instructions much the way the Chiltons book does for auto repair. I'd also be interested in books on bike design. Now I would like to keep the theory to a practical level. No I have no idea to turn this into an engineering project. I am already married to an engineer and the last thing one needs is two engineers in the same house. lol At a much lower price, Zinn and the Art of Mountain Bike Maintenance (and the similar Road Bike Maintenance) are good Chilton-level books. I'd just get the one for your primary kind of ride, as much of the material overlaps, and the differences aren't liable to catch you out unless you're a roadie and you decide to start doing your own fork maintenance on your MTB. Sheldonbrown.com seems like it has directions on virtually every mechanical repair known to cycling, so it's almost as good as having your own bike manual. I make no submission on most bike design books, but regular contributor here Jobst Brandt literally wrote the book /a/ book. on bicycle wheels, called "The Bicycle Wheel," and it covers both the theory of wheels and the proper procedure for wheelbuilding. procedure, yes. theory? some of it is badly awry. spoke tension "as high as the rim can bear" for example is based on a fundamental misunderstanding by the author and that is of the most practical [and costly] consequence to the novice builder - excess tension can cause a higher propensity for rim buckling and directly cause rim cracking. the book should should be amended to specify spoke tension "as determined by the rim manufacturer". I guess that we all saw that coming...sad And completely wrong, it's not what the book says at all. Dear Peter, Here's what the 3rd edition says: FINDING THE RIGHT TENSION The following method works well in determining proper spoke tension for conventional road rims of up to 43 0 grams with 36 spokes. Tighten all the spokes a quarter turn at a time, starting at the valve stem hole. Once a distinct tone can be made by plucking, and spokes are not easily squeezed together by grasping them in pairs, it is time to check tension. After each round of tightening, test the tension by stress relieving. If the wheel becomes untrue in two large waves during stress relieving, the maximum, safe tension has been exceeded. Approach this tension carefully to avoid major rim distortions. When the wheel loses alignment from stress relieving, loosen all spokes a half turn before retruing the wheel Cheers, Carl Fogel Yes, I know, I have that edition. It also describes, in a previous section "Final Tensioning", use of a tensiometer (with drawing), and comparison by tone to a known good wheel as methods of achieving proper tension. In the context, the method described above is given as an alternative with the stated qualifications (430g, 36 spokes), presumably for those without tensiometers. He goes on to say that for heavy rims or road rims with less than 32 spokes that tensioning is usually at the limit when nipples can no longer be easily turned. The overall impression I get is that Jobst is trying to give people a feel for how tight spokes should be. It seems obvious that, for rims where the manufacturer has specified a maximum spoke tension, those limits should be observed, and a tensiometer is required to do that. From its online manual, Mavic indicates that conventional 3 cross wheels should have tensions in the 70-90kg range. They also set weight limits on their road wheels (2008) for 100kg, bike rider & gear. Both seem low. Perhaps wheel builders using Mavic product should read the fine print carefully and never build without a tensiometer. It would be interesting to know what the actual tension would be if the quoted procedure was followed for the kind of rim described. As far as I know, no one has reported that. to avoid pretzel? what's the point? longevity depends on avoiding rim cracking and fatigue, and the manufacturer has reported that already. increasing tension doesn't increase strength so there's no point seeking more of it. |
#23
|
|||
|
|||
Maintenance Manuals
In article . com,
"Qui si parla Campagnolo-www.vecchios.com" wrote: On Sep 29, 10:44 pm, Ryan Cousineau wrote: In article , "Frank Drackman" wrote: I guess that we all saw that coming...sad Actually, thanks to killfiles, I didn't see it at all. -- Ryan Cousineau / "I don't want kids who are thinking about going into mathematics to think that they have to take drugs to succeed." -Paul Erdos Which killfile do you use And is it applicable to Google groups? Been here before...some authors beg for killfile. My primary newsreader is the venerable MT-Newswatcher on the Mac. It has an integrated killfile system which allows me to kill articles by subject, author, with or without a time limit, and in a single group, across all groups, or in just one branch of a hierarchy (eg I could kill an author, but only in rec.bicycles.* groups, so I could still read their sci.astronomy posts). It surely has more power than even that, but I have not yet needed it. -- Ryan Cousineau http://www.wiredcola.com/ "I don't want kids who are thinking about going into mathematics to think that they have to take drugs to succeed." -Paul Erdos |
#24
|
|||
|
|||
Maintenance Manuals
jim beam wrote:
Peter Cole wrote: It would be interesting to know what the actual tension would be if the quoted procedure was followed for the kind of rim described. As far as I know, no one has reported that. to avoid pretzel? what's the point? I'm not sure what you're trying to say. Jobst infers that following his alternate procedure will result in a spoke tension of around 100kg. longevity depends on avoiding rim cracking and fatigue, and the manufacturer has reported that already. increasing tension doesn't increase strength so there's no point seeking more of it. Mavic (and most others I presume) spec a min and max. I haven't seen anyone (including Jobst) recommending using more than the max spec. So what's the problem? You seem to be sure that Jobst's alternate method will produce higher than max spec spoke tensions. How do you know that? I've used lots of wheels, Mavic & others, the only cracking I ever got was with Mavic Reflex rims (2). I don't know what tension they were built to, I don't think it was very high, they had to be Locktited. All of my other rims just wore out on the brake track. |
#25
|
|||
|
|||
Maintenance Manuals
"jim beam" aka evan williams wrote:
Ryan Cousineau wrote: ... I make no submission on most bike design books, but regular contributor here Jobst Brandt literally wrote the book /a/ book. on bicycle wheels, called "The Bicycle Wheel," and it covers both the theory of wheels and the proper procedure for wheelbuilding. procedure, yes. theory? some of it is badly awry. spoke tension "as high as the rim can bear" for example is based on a fundamental misunderstanding by the author and that is of the most practical [and costly] consequence to the novice builder - excess tension can cause a higher propensity for rim buckling and directly cause rim cracking. the book should should be amended to specify spoke tension "as determined by the rim manufacturer". I wonder if "jim" has a macro for anti-Jobst replies? -- Tom Sherman - Holstein-Friesland Bovinia A Real Cyclist [TM] keeps at least one bicycle in the bedroom. -- Posted via a free Usenet account from http://www.teranews.com |
#26
|
|||
|
|||
Maintenance Manuals
Tom "Johnny Sunset" Sherman wrote:
"jim beam" aka evan williams wrote: Ryan Cousineau wrote: ... I make no submission on most bike design books, but regular contributor here Jobst Brandt literally wrote the book /a/ book. on bicycle wheels, called "The Bicycle Wheel," and it covers both the theory of wheels and the proper procedure for wheelbuilding. procedure, yes. theory? some of it is badly awry. spoke tension "as high as the rim can bear" for example is based on a fundamental misunderstanding by the author and that is of the most practical [and costly] consequence to the novice builder - excess tension can cause a higher propensity for rim buckling and directly cause rim cracking. the book should should be amended to specify spoke tension "as determined by the rim manufacturer". I wonder if "jim" has a macro for anti-Jobst replies? that's "corrective", not "anti-jobst". |
#27
|
|||
|
|||
Maintenance Manuals
Peter Cole wrote:
jim beam wrote: Peter Cole wrote: It would be interesting to know what the actual tension would be if the quoted procedure was followed for the kind of rim described. As far as I know, no one has reported that. to avoid pretzel? what's the point? I'm not sure what you're trying to say. Jobst infers that following his alternate procedure will result in a spoke tension of around 100kg. "infers"??? how can you infer a number??? oh, wait, it's /convenient/ to state it after the fact! my mistake. longevity depends on avoiding rim cracking and fatigue, and the manufacturer has reported that already. increasing tension doesn't increase strength so there's no point seeking more of it. Mavic (and most others I presume) spec a min and max. I haven't seen anyone (including Jobst) recommending using more than the max spec. So what's the problem? what is numerical about "as high as the rim can bear"??? modern deep profile rims can take much more stress before they buckle, but the alloy from which they are made is just as anisotropic and very similar in yield. a rim stiff enough to take double spoke tension [as determined by the jobstian method] before buckling isn't going to make rims last very long when it comes to cracking. use of a tensiometer is therefore essential. You seem to be sure that Jobst's alternate method will produce higher than max spec spoke tensions. How do you know that? because i've tried it! I've used lots of wheels, Mavic & others, the only cracking I ever got was with Mavic Reflex rims (2). I don't know what tension they were built to, er,... I don't think it was very high, that's a cop-out - for someone purporting to be an engineer, it's also remarkably incurious. they had to be Locktited. eh? aren't you one of those that condemns loctite? All of my other rims just wore out on the brake track. as will happen to all rims if accident or excess spoke tension doesn't kill them first. |
#28
|
|||
|
|||
Maintenance Manuals
On Sep 30, 11:23 pm, jim beam wrote:
Peter Cole wrote: snip You seem to be sure that Jobst's alternate method will produce higher than max spec spoke tensions. How do you know that? because i've tried it! Specifically, which 36 hole, conventional cross-section rim of 430 or less grams did you try this on and what is your source for the manufacturer's recommended spoke tension range? I'm asking because I've learned from previous threads to not believe anything you say. The exclamation point you put after your statement doesn't lift it above the normal credibility level of zero. modern deep profile rims can take much more stress before they buckle.... a rim stiff enough to take double spoke tension [as determined by the jobstian method] before buckling isn't going to make rims last very long when it comes to cracking. use of a tensiometer is therefore essential. Everyone would be aware of this either from their own knowledge, experience and common sense or from having read Jobst's book. Nothing like stating the obvious as if it's an original and profound revelation from the sage of RBT, jim - never in doubt, often in error - beam. -- Spike |
#29
|
|||
|
|||
Maintenance Manuals
|
#30
|
|||
|
|||
Maintenance Manuals
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Anyone have the old Marzocchi manuals? | Slack | Mountain Biking | 3 | April 4th 05 04:09 PM |
FA - Just found Campagnolo Tech manuals | Remove No Spam to Reply | Marketplace | 0 | March 4th 05 05:06 AM |
Time ATAC Alium manuals | Bajji | Techniques | 0 | August 6th 04 06:31 PM |
Manuals | Katanga-Man | UK | 1 | July 15th 04 05:20 PM |
Bike manuals | One Step Beyond | UK | 6 | October 22nd 03 08:28 AM |