Gear cable broke, can see individual threads
:notamused: welp. Definitely my fault. Didn't see the gears at night. Cross chained or whatever, had my right on 5 and left 1. Heard like the chain make this noise. I'm just disappointed.
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Also Chain is stuck between frame and the first gear. It's the 1-2-3 gear. Dumb gear cable ripped on me. It's Shimano. I know it'll unwind more and I have to replace it. :notamused:
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Crosds-chaining is not the issue likely .... sounds like bad derailleur adjustment. Your Low Stop screw should keep the chain from pitching off to the inside when the front cable breaks.
But, yeah. Replace the cable, adjust the derailleur properly, and after the cable stretches out in a few weeks, adjust it again, and you should be good for quite a while. |
Cables do not stretch.
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Originally Posted by cxwrench
(Post 22280173)
Cables do not stretch.
The rate of stretching changes over time. When a load is initially applied to a wire rope, the rope rapidly stretches as it adjusts to the operating conditions. After that initial phase, the stretching slows significantly and remains low for the majority of the rope’s lifespan. When the rope approaches the end of its service life, the rate of stretching increases due to wear and fatigue. |
Here we go again...no, they do not stretch on a bicycle. This has been discussed thousands of times. If you think they do, on a bicycle, prove it. And not w/ a chart. Physical proof.
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Originally Posted by DyingAndDying
(Post 22279892)
Also Chain is stuck between frame and the first gear. It's the 1-2-3 gear. Dumb gear cable ripped on me. It's Shimano. I know it'll unwind more and I have to replace it. :notamused:
I wouldn’t, however, say that a broken cable is due to cross chain shifting. That’s a problem for the chain, cogs, and chainrings but not for derailer cables. |
Originally Posted by cxwrench
(Post 22280184)
Here we go again...no, they do not stretch on a bicycle. This has been discussed thousands of times. If you think they do, on a bicycle, prove it. And not w/ a chart. Physical proof.
As for “physical proof”, I’ll refer you all the bikes that need cable adjustments after installation of a new cable. And, no, I’m not talking about cable housing. Put a new inner cable in old housing and the cable will need adjustment for cable stretch in relatively few miles and then won’t need it again. Almost like there’s an initial stretch followed by a long time of being stable. |
Originally Posted by cxwrench
(Post 22280184)
Here we go again...no, they do not stretch on a bicycle. This has been discussed thousands of times. If you think they do, on a bicycle, prove it. And not w/ a chart. Physical proof.
1. Replaced the rear shift cable on my 105-5700 Cannondale early last year. Perfectly adjusted when installed, two rides later was shifting off-center and had to re-adjust. Haven't touched it since. 2. Built a vintage Cramerotti late last year, with Campagnolo mech and Jagwire cables. Perfectly adjusted both front and rear shift cables. Had to adjust the rear one ride later, the front two rides later. No adjustments since (but to be fair I did hang it on the wall after riding it for a month or so). 3. Built a new carbon gravel bike this fall. Chinese frame with 105-7000 series groupo and again Jagwire cables (what can I say, Shimano only offers black...). Rear hasn't needed adjusting yet, front has been adjusted once and needs one more tweak. While these cables are mostly internal, I ran housings full length for better cable protection overall on gravel. I may accept that it's not the cable that's stretching, but there must be a mechanism that's letting the cable appear to slacken not long after it's installed. What do you say is that mechanism, if it isn't the cable stretching? |
Since you believe so much in the 'table', use it and figure out how much stretch happens. Don't forget to accurately measure how much force it takes to move a derailleur.
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Originally Posted by Snowflake6
(Post 22280226)
Well, if you'll take anecdotal evidence...
1. Replaced the rear shift cable on my 105-5700 Cannondale early last year. Perfectly adjusted when installed, two rides later was shifting off-center and had to re-adjust. Haven't touched it since. 2. Built a vintage Cramerotti late last year, with Campagnolo mech and Jagwire cables. Perfectly adjusted both front and rear shift cables. Had to adjust the rear one ride later, the front two rides later. No adjustments since (but to be fair I did hang it on the wall after riding it for a month or so). 3. Built a new carbon gravel bike this fall. Chinese frame with 105-7000 series groupo and again Jagwire cables (what can I say, Shimano only offers black...). Rear hasn't needed adjusting yet, front has been adjusted once and needs one more tweak. While these cables are mostly internal, I ran housings full length for better cable protection overall on gravel. I may accept that it's not the cable that's stretching, but there must be a mechanism that's letting the cable appear to slacken not long after it's installed. What do you say is that mechanism, if it isn't the cable stretching? But I have to admit that I don't see how a rather robust item like a chain can stretch. Again, maybe the bike is shrinking! |
:popcorn
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Originally Posted by kahn
(Post 22280300)
Actually, it is not cable stretch - the bike is shrinking! :lol:
But I have to admit that I don't see how a rather robust item like a chain can stretch. Again, maybe the bike is shrinking! |
Originally Posted by cxwrench
(Post 22280228)
Since you believe so much in the 'table', use it and figure out how much stretch happens. Don't forget to accurately measure how much force it takes to move a derailleur.
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Originally Posted by Maelochs
(Post 22280092)
Crosds-chaining is not the issue likely .... sounds like bad derailleur adjustment. Your Low Stop screw should keep the chain from pitching off to the inside when the front cable breaks.
But, yeah. Replace the cable, adjust the derailleur properly, and after the cable stretches out in a few weeks, adjust it again, and you should be good for quite a while. |
Originally Posted by Snowflake6
(Post 22280315)
Since you believe so strongly that it's not the cables stretching, what is the mechanism by which new cables need to be adjusted not long after they are installed, and then usually don't need adjusting again?
It is similar with a guitar string and tuning machines / bridge assembly. I will always 'stretch' the strings manually to help with tuning stability on a new set of strings, but am well aware that the strings are not actually getting longer, only settling into position as more tension is applied than what is typical during playing, thus expediting the settling process, and increasing tuning stability. |
Unless you simply hate picking up a tool or two and doing your own maintenance there are few excuses for doing it wrong these days with all of the YouTube videos out there, Look for the one that matches the type of shifters on your bike, example: Gripshift gear cable replacement (the most difficult one to replace)
The two websites that are most often cited for elementary maintenance are the Park Tool site already mentioned by Maelochs and the Sheldon Brown website https://www.sheldonbrown.com/ Both will teach you how to adjust the limit screws on derailleurs so the chain doesn't get wedged between the frame and the wheel or go off the chainrings (your "1,2,3 gears"). Buy a cable and fix it yourself as that will a lot less expensive and will get it fixed right away versus taking the bike to a shop, leaving it for a time, and returning to pick it up. You can buy expensive cables but in my experience the standard stainless steel gear cables are just fine since I usually get around 3K miles between replacements. If you intend to ride a lot and replace cables over the years it pays to buy them in lots of 10 for under $10 with free shipping on eBay https://www.ebay.com/itm/402262687206 versus buying just one for $6. No bike shop can match the online prices. |
Originally Posted by Snowflake6
(Post 22280312)
LOL!
Read the discussion again... not CHAIN, but CABLE. Cables can, and do, stretch. Chains do as well, but by so small an amount i'd be surprised if you could measure it... And you'd never notice it when riding because the derailleur would take up the slack anyway. |
Originally Posted by kahn
(Post 22280528)
. But chains are linked together pieces of metal. And, I understand, chains to stretch since they sell gauges to measure them before they damage the cassette.
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This is probably a more realistic cable stretch calculator for bicycles than the link.
https://www.spaceagecontrol.com/calc...bmit=Calculate |
Maybe no one else has ever had their cables seem to stretch. And i don't care what vocabulary people choose to describe it.
Whenever someone says, "Trust me, not your lying eyes" I know either the speech or the speaker is a joke. |
Next you’ll tell me guitar strings don’t stretch either.
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Originally Posted by cxwrench
(Post 22280228)
Since you believe so much in the 'table', use it and figure out how much stretch happens. Don't forget to accurately measure how much force it takes to move a derailleur.
Loos & Co also says in that link Structural Stretch is the lengthening of the lay in the construction of cable and wire rope as the individual wires adjust under load. Structural Stretch in Loos & Co., Inc. products is less than 1% of the total cable length. This form of stretch can be completely removed by applying a cable or wire rope prestretching operation prior to shipment. Applying that to a meter of 1.2mm derailer cable give 2.5mm for a prestretched cable and 5mm for unstretched cable. Taking up 2 to 2.5 mm of slack out of a new cable isn’t out of the ordinary. The TL;DR is that both elastic and construction stretch are well known, well documented, and, in the case of elastic stretch, easily calculated. |
Originally Posted by DyingAndDying
(Post 22280326)
Thought I just had to remove the crank or whatever to access the chain to place it back on the gear. and put the chain back in the gear. I have to adjust this limiter screw or whatever I don't even know where that is at. I heard about the limiter not letting the chain fall off in between the frame.
If it is the latter, it is likely that you suffered “chain suck” which is when a burr on the smallest chain ring doesn’t allow the chain to release smoothly on the bottom of the gear and “sucks” the chain upward where it jams between the crank and the chainstay. In both of these scenarios, you can’t stop pedaling fast enough to prevent the chain from jamming. It has nothing to do with the cable nor does it have anything to do with the limit screws. Often you can get the chain unstuck by pulling on it but sometimes it can get jammed enough that crank removal is required. Pulling the crank isn’t the hardest job to do but it does require some tools. If you have the tools and you’ve pulled a crank before (or seen it done on video or in person) and you can’t get the chain out any other way, pull the crank. Alternatively (and perhaps easier) see if you can loosen a chainring bolt or two which will loosen the grip the gear has on the chain. Can I tape up the strands that loose it's at the end of the Shimano cable Pictures would help. |
Like most quality cables 300 series SS, pre stretched.
1.2mm dia/33 length/5# pull Elastic stretch - 0.23mm, 0.027% https://www.spaceagecontrol.com/calc...bmit=Calculate |
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