|
|
Thread Tools | Display Modes |
#71
|
|||
|
|||
Selecting An Appropriate Bolt
On Thursday, April 20, 2017 at 2:25:50 PM UTC-7, Doug Landau wrote:
This is false logic. There are at least 15 parts on your bike; by your policy we should expect catastrophic part failure once per year. Because weight is now being stressed over anything else we, unfortunately, can expect at least one catastrophic failures per year. Though I'm back to steel bikes I had a set of the top of the line Campy aluminum wheels. I did a local ride with a nice 12% climb and strong decent. That is a 40 mph drop. After I got back to town and was about a quarter mile from home a spoke broke on perfectly flat and what passes for smooth road around here. The rim distorted so much I had to carry the bike the remaining quarter mile. If this had happened on that decent... The wheel only had about 3-4,000 miles on it since new. |
Ads |
#72
|
|||
|
|||
Selecting An Appropriate Bolt
On Thursday, April 20, 2017 at 2:39:15 PM UTC-7, Doug Landau wrote:
That said, I still want a Habanero. You can get them in any grocery store around here. |
#73
|
|||
|
|||
Selecting An Appropriate Bolt
|
#74
|
|||
|
|||
Selecting An Appropriate Bolt
On Thursday, April 20, 2017 at 11:30:03 PM UTC-7, James wrote:
On 21/04/17 13:35, wrote: On Fri, 21 Apr 2017 10:21:56 +0700, John B Slocomb wrote: And it depends what you are threading the bolt into. Using fine threads in coarse grained cast iron is generally NOT a good idea. As far as the actual "thread area" there is very little difference. If you double the TPI the threads are only half as deep, but there are twice as many threads so the total load bearing area is not much different. Thread area isn't the issue that John brought up. That's what I was getting at with the discussion on course and fine threads.. If you use course threads the bolt is not as strong as a fine thread because the area of the metal inside of the threads is smaller. It used to be said that you could tighten fine threads to a higher torque because there was more "leverage" from the fine thread but that isn't the case at all. So if you are designing a bolt into an iron casting you use course threads but have to use one size larger than you would if it were a finer grain metal and a fine threaded bolt. Engineering isn't a case of choices as the Germans insist. Designing something to the lightest by making an design to the irreducible minimum while expecting the highest performance is simply asking for troubles. The English are another example. When I had a local mechanic troubleshoot my electrical system to find out why my battery was dying it turned out to be the battery had bitten the dust. It would only hold a charge for a couple of hours. While we were talking he pointed to a Jaguar coupe. That car had a four speed manual transmission that had failed. Anyone knows that manual transmissions do not fail. The replacement cost? $12,000 on a ten year old car. Jaguar would not stand behind their car. If some cheesy plastic part had failed that would be one thing - but manual transmissions DO NOT FAIL. Particularly when it's a little old lady that drives it like she's at Le Mans. She double shifts down better than I can. |
#76
|
|||
|
|||
Selecting An Appropriate Bolt
On Friday, April 21, 2017 at 7:05:54 AM UTC-7, AMuzi wrote:
On 4/21/2017 8:49 AM, wrote: On Thursday, April 20, 2017 at 2:25:50 PM UTC-7, Doug Landau wrote: This is false logic. There are at least 15 parts on your bike; by your policy we should expect catastrophic part failure once per year. Because weight is now being stressed over anything else we, unfortunately, can expect at least one catastrophic failures per year. Though I'm back to steel bikes I had a set of the top of the line Campy aluminum wheels. I did a local ride with a nice 12% climb and strong decent. That is a 40 mph drop. After I got back to town and was about a quarter mile from home a spoke broke on perfectly flat and what passes for smooth road around here. The rim distorted so much I had to carry the bike the remaining quarter mile. If this had happened on that decent... The wheel only had about 3-4,000 miles on it since new. We like Campagnolo wheels generally (within the set of 'modern boxed wheels' they are well above average) but consider for a moment that a wheel with 36 or 40 spokes may usually be ridden home with one out but a wheel with 21 spokes usually cannot. This doesn't make any product good or bad but it's a factor you might consider when choosing a wheel for a particular purpose (annual club TT vs 200mi ultra vs following Joerg up a goatpath, etc) I have decided that I will buy cyclocross wheels from now on. I can't tell any difference in the looks of the wheels so I suppose they only use larger diameter spokes. But that alone should increase the lifespan of an expensive wheel. |
#77
|
|||
|
|||
Selecting An Appropriate Bolt
On 4/21/2017 9:08 AM, wrote:
On Thursday, April 20, 2017 at 11:30:03 PM UTC-7, James wrote: On 21/04/17 13:35, wrote: On Fri, 21 Apr 2017 10:21:56 +0700, John B Slocomb wrote: And it depends what you are threading the bolt into. Using fine threads in coarse grained cast iron is generally NOT a good idea. As far as the actual "thread area" there is very little difference. If you double the TPI the threads are only half as deep, but there are twice as many threads so the total load bearing area is not much different. Thread area isn't the issue that John brought up. That's what I was getting at with the discussion on course and fine threads. If you use course threads the bolt is not as strong as a fine thread because the area of the metal inside of the threads is smaller. It used to be said that you could tighten fine threads to a higher torque because there was more "leverage" from the fine thread but that isn't the case at all. So if you are designing a bolt into an iron casting you use course threads but have to use one size larger than you would if it were a finer grain metal and a fine threaded bolt. Engineering isn't a case of choices as the Germans insist. Designing something to the lightest by making an design to the irreducible minimum while expecting the highest performance is simply asking for troubles. The English are another example. When I had a local mechanic troubleshoot my electrical system to find out why my battery was dying it turned out to be the battery had bitten the dust. It would only hold a charge for a couple of hours. While we were talking he pointed to a Jaguar coupe. That car had a four speed manual transmission that had failed. Anyone knows that manual transmissions do not fail. The replacement cost? $12,000 on a ten year old car. Jaguar would not stand behind their car. If some cheesy plastic part had failed that would be one thing - but manual transmissions DO NOT FAIL. Particularly when it's a little old lady that drives it like she's at Le Mans. She double shifts down better than I can. Do not fail? Never say never. I split my MGB first/reverse gear in half racing my neighbor off a stoplight. British four manual gearboxes are quite simple devices and not challenging to rebuild. (or were anyway, don't know new ones) -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#78
|
|||
|
|||
Selecting An Appropriate Bolt
On Friday, April 21, 2017 at 7:35:55 AM UTC-7, AMuzi wrote:
On 4/21/2017 9:08 AM, wrote: On Thursday, April 20, 2017 at 11:30:03 PM UTC-7, James wrote: On 21/04/17 13:35, wrote: On Fri, 21 Apr 2017 10:21:56 +0700, John B Slocomb wrote: And it depends what you are threading the bolt into. Using fine threads in coarse grained cast iron is generally NOT a good idea. As far as the actual "thread area" there is very little difference. If you double the TPI the threads are only half as deep, but there are twice as many threads so the total load bearing area is not much different. Thread area isn't the issue that John brought up. That's what I was getting at with the discussion on course and fine threads. If you use course threads the bolt is not as strong as a fine thread because the area of the metal inside of the threads is smaller. It used to be said that you could tighten fine threads to a higher torque because there was more "leverage" from the fine thread but that isn't the case at all. So if you are designing a bolt into an iron casting you use course threads but have to use one size larger than you would if it were a finer grain metal and a fine threaded bolt. Engineering isn't a case of choices as the Germans insist. Designing something to the lightest by making an design to the irreducible minimum while expecting the highest performance is simply asking for troubles. The English are another example. When I had a local mechanic troubleshoot my electrical system to find out why my battery was dying it turned out to be the battery had bitten the dust. It would only hold a charge for a couple of hours. While we were talking he pointed to a Jaguar coupe. That car had a four speed manual transmission that had failed. Anyone knows that manual transmissions do not fail. The replacement cost? $12,000 on a ten year old car. Jaguar would not stand behind their car. If some cheesy plastic part had failed that would be one thing - but manual transmissions DO NOT FAIL. Particularly when it's a little old lady that drives it like she's at Le Mans. She double shifts down better than I can. Do not fail? Never say never. I split my MGB first/reverse gear in half racing my neighbor off a stoplight. British four manual gearboxes are quite simple devices and not challenging to rebuild. (or were anyway, don't know new ones) Uhh, they've made a few improvements in steel since the days of the MGB. And my mechanic is the best guy around and if that transmission was rebuildable it would have been rebuilt. You can't rebuild it if it has a split casing or a broken bearing mount. I don't know what the problem was but if Tom couldn't rebuild it it couldn't be rebuilt. He accepts nothing but the best work and the best components. |
#79
|
|||
|
|||
Selecting An Appropriate Bolt
|
#80
|
|||
|
|||
Selecting An Appropriate Bolt
On Friday, April 21, 2017 at 7:15:05 AM UTC-7, wrote:
On Friday, April 21, 2017 at 7:05:54 AM UTC-7, AMuzi wrote: On 4/21/2017 8:49 AM, wrote: On Thursday, April 20, 2017 at 2:25:50 PM UTC-7, Doug Landau wrote: This is false logic. There are at least 15 parts on your bike; by your policy we should expect catastrophic part failure once per year. Because weight is now being stressed over anything else we, unfortunately, can expect at least one catastrophic failures per year. Though I'm back to steel bikes I had a set of the top of the line Campy aluminum wheels. I did a local ride with a nice 12% climb and strong decent. That is a 40 mph drop. After I got back to town and was about a quarter mile from home a spoke broke on perfectly flat and what passes for smooth road around here. The rim distorted so much I had to carry the bike the remaining quarter mile. If this had happened on that decent... The wheel only had about 3-4,000 miles on it since new. We like Campagnolo wheels generally (within the set of 'modern boxed wheels' they are well above average) but consider for a moment that a wheel with 36 or 40 spokes may usually be ridden home with one out but a wheel with 21 spokes usually cannot. This doesn't make any product good or bad but it's a factor you might consider when choosing a wheel for a particular purpose (annual club TT vs 200mi ultra vs following Joerg up a goatpath, etc) I have decided that I will buy cyclocross wheels from now on. I can't tell any difference in the looks of the wheels so I suppose they only use larger diameter spokes. But that alone should increase the lifespan of an expensive wheel. True CX wheels will use a wider rim, which may or may not be to your taste or tire profile. For your retro bike, just build a set of 32 spoke wheels on ordinary hubs. Use a mid-weight rim like a DT450 (also cheap) or maybe something more aero. 14/15 spokes with brass nipples. My fancy wheels are Dura Ace C35s which have been bomb-proof. Everything else is conventional 32 spoke wheels. I'd go 36 or 40 if I were building a touring wheel. Any high spoke count wheel with conventional spokes can tolerate a broken spoke. I have a spoke wrench on my key chain. If I break a spoke on my commuter, I just adjust the tension, ride home and throw in a new spoke. -- Jay Beattie. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Converting Brake mounting bolt to recessed bolt? | Sir Ridesalot | Techniques | 18 | August 23rd 09 12:49 PM |
Selecting a Bike | Katuzo | General | 46 | July 26th 08 03:11 PM |
selecting a BB | [email protected] | Techniques | 5 | September 12th 07 03:10 AM |
Selecting the right chain | heedcase | Techniques | 10 | August 28th 04 02:32 AM |
Selecting a new saddle | Nick Kew | UK | 18 | December 25th 03 10:47 PM |