Crap service
- Thread starter Solecyclist
- Start date
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Ajax Bay
Guru
- Location
- East Devon
"The action of repeatedly shifting up and down, or braking and releasing, will tension and release these cables many times. This action is thought to cause the cables to “stretch” or in essence elongate."
BS. Elasticity. Young's Modulus. Hooke's Law.
And then some wriggling and defining one thing as another:
"“Cable stretch” is actually a broader term used to describe the action of the WHOLE cabling system settling into place. Your brake and shift cables pass through your brake and shift housing-the other key components in the WHOLE cabling system. When housing is cut and capped with ferules, it may not be fully seated into those ferrules, or fully seated into the frame stops, derailleur, brakes, shifters etc. As you shift and brake, a huge portion of the initial settling that occurs is actually the housing fully seating itself into place. Once settled, you can be left with a considerable amount of slack, causing the symptoms above."
All true except that the author is defining "cable stretch"as the "action of the WHOLE cabling system settling into place".
BS. Elasticity. Young's Modulus. Hooke's Law.
And then some wriggling and defining one thing as another:
"“Cable stretch” is actually a broader term used to describe the action of the WHOLE cabling system settling into place. Your brake and shift cables pass through your brake and shift housing-the other key components in the WHOLE cabling system. When housing is cut and capped with ferules, it may not be fully seated into those ferrules, or fully seated into the frame stops, derailleur, brakes, shifters etc. As you shift and brake, a huge portion of the initial settling that occurs is actually the housing fully seating itself into place. Once settled, you can be left with a considerable amount of slack, causing the symptoms above."
All true except that the author is defining "cable stretch"as the "action of the WHOLE cabling system settling into place".
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ozboz
Guru
- Location
- Richmond ,Surrey
ozboz
Guru
- Location
- Richmond ,Surrey
What Is Cable Stretch?
Two kinds of stretch occur in cable based on wire rope: constructional stretch and elastic stretch. This stretch is due to two different causes.
1. Constructional Stretch - When cable is made, the load at the closing head is light. Therefore, there are small clearances between the wires and strands, and between the strand and the core. The application of initial load causes wires and strands to seat properly and a slight overall elongation of the strand or cable accompanies this section. The amount of constructional stretch is not constant for all cables - it depends on such variables as type of construction, length of lay, and other factors, including the load applied.
2. Elastic Stretch - Elastic stretch is the actual elongation of the wires of a strand or a cable. This is caused by the application of a load up to the yield point of the metal. The stretch is approximately proportional to the load applied. When the load is released, cable subjected to elastic stretch returns to its approximate original length, providing the stretch has not reached the yield point of the metal.
When the elimination of as much stretch as possible is important, the cables or assemblies can be proof loaded to remove most of the constructional stretch. For assemblies, this process also verifies the holding power of the terminals. Proof loading is usually done by applying a 60% load to the cable or assemblies. This load is based on the minimum breaking strength of the cable or fittings, whichever is lower. Handling the cable as little as possible after prestretching helps eliminate putting constructional stretch back in.
Two kinds of stretch occur in cable based on wire rope: constructional stretch and elastic stretch. This stretch is due to two different causes.
1. Constructional Stretch - When cable is made, the load at the closing head is light. Therefore, there are small clearances between the wires and strands, and between the strand and the core. The application of initial load causes wires and strands to seat properly and a slight overall elongation of the strand or cable accompanies this section. The amount of constructional stretch is not constant for all cables - it depends on such variables as type of construction, length of lay, and other factors, including the load applied.
2. Elastic Stretch - Elastic stretch is the actual elongation of the wires of a strand or a cable. This is caused by the application of a load up to the yield point of the metal. The stretch is approximately proportional to the load applied. When the load is released, cable subjected to elastic stretch returns to its approximate original length, providing the stretch has not reached the yield point of the metal.
When the elimination of as much stretch as possible is important, the cables or assemblies can be proof loaded to remove most of the constructional stretch. For assemblies, this process also verifies the holding power of the terminals. Proof loading is usually done by applying a 60% load to the cable or assemblies. This load is based on the minimum breaking strength of the cable or fittings, whichever is lower. Handling the cable as little as possible after prestretching helps eliminate putting constructional stretch back in.
BalkanExpress
Guru
- Location
- Brussels
Please remember that some of us have almost no mechanical ability. Today I had a bit of time alone so did some “fettling”
An hour to index the daughter’s 8 speed. This does not include time spent warching the bloke with the ‘ tâche on the Park tools video while wondering “why does the rear mech not move when I turn either of the high low screws “
About the same time trying to get my single pivot brakes to centre after braking and releasing the brake.
Then finally, I Stuffied up taping the bars..again.. no, I have no idea where that daffing gap came from.
And you don’t want to know what happened when I tried to fit a bottom bracket
So, please show some understanding as to why some of us entrust our bikes to “ professionals “ and why we then get doubly frustrated if they end up doing no better a job than we could.
An hour to index the daughter’s 8 speed. This does not include time spent warching the bloke with the ‘ tâche on the Park tools video while wondering “why does the rear mech not move when I turn either of the high low screws “
About the same time trying to get my single pivot brakes to centre after braking and releasing the brake.
Then finally, I Stuffied up taping the bars..again.. no, I have no idea where that daffing gap came from.
And you don’t want to know what happened when I tried to fit a bottom bracket
So, please show some understanding as to why some of us entrust our bikes to “ professionals “ and why we then get doubly frustrated if they end up doing no better a job than we could.
- Location
- London
Ajax Bay
Guru
- Location
- East Devon
All good no doubt, but not relevant to cycle cables, which are not "based on wire rope" and have no "core".
A cycle inner cable is composed of strands of wire braided and/or twisted together.
https://www.cyclist.co.uk/tutorials/1246/the-importance-of-cables-and-how-to-fit-them
"One myth to dispel is that cables stretch over time. Some may do a tiny amount, but really any changes in performance are down to all of the components of the system individually ‘settling in’."
When an additional (tensile) force is applied to a cable it will stretch, elastically, and when that force is removed the cable will return to its original length (in accordance with Hooke's Law). And do so for the life of the cable. In the case of gear cables, this will not affect indexing accuracy.
ozboz
Guru
- Location
- Richmond ,Surrey
https://www.outsideonline.com/1916521/how-fix-skipping-bike-chain
I’d say this person has a good handle on this
I’d say this person has a good handle on this
Ajax Bay
Guru
- Location
- East Devon
Which he has gripped firmly with a well-used right hand.
ozboz
Guru
- Location
- Richmond ,Surrey
Whatever
I've experienced several cases of bad bike shop service recently, but the less said the better...!
When 'Cyctech certificate trained' youngsters do not even know basic technical knowledge, like how to correctly fit a Hollowtech BB, or tighten a cassette fully, or what a chain that is too long looks like, it makes me wonder what we pay our money for?! (Thankfully, I can now do these things myself!)
Of course, I should point out (to stop any generalising or catastrophising) that of course, there are still some good shops around with old fashioned knowhow and sense
When 'Cyctech certificate trained' youngsters do not even know basic technical knowledge, like how to correctly fit a Hollowtech BB, or tighten a cassette fully, or what a chain that is too long looks like, it makes me wonder what we pay our money for?! (Thankfully, I can now do these things myself!)
Of course, I should point out (to stop any generalising or catastrophising) that of course, there are still some good shops around with old fashioned knowhow and sense
Crankarm
Guru
- Location
- Nr Cambridge
On the occasions in the distant past I had dealings with LBS grease monkeys I wouldn't let them be in charge of a knife and fork let alone a spanner and some one's bike or mine! The only person worth going to in a bike shop is a guy who can properly build wheels. Once you have found this guy stick to him like you would a good dentist. The rest of them are no better than surly teenagers who'd rather be on their playstations than working in a bike shop. My experience of working with these types in retail albeit a slightly different sector was pretty soul destroying and demoralising. Most have pretty low standards and couldn't give a monkeys about providing good customer service and getting things right for customers. But then you can't blame them as business owners pay peanuts which only attracts young monkeys with little commitment to such a dead end job. The lesson to learn here is do you own bike servicing. It's not particularly hard. There are now lots of tutorials and 'how tos' on YT covering most bike servicing topics.
You cannot blame the bosses alone for low pay, blame the customers who want cheap prices as well, not many bike shops making a fortune nowadays.
Crankarm
Guru
- Location
- Nr Cambridge
And bosses and owners of businesses trousering huge amounts of cash compared to their low paid young staff on national minimum wage?
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