Why Chain Length Matters & How To Get It Right | Maintenance Monday
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- เผยแพร่เมื่อ 8 ก.ค. 2024
- Getting your chain the right length can seem confusing, but it's important to get it right. The wrong length chain can lead to unwanted noise, poor performance and even damage in a worst-case-scenario! Luckily, Alex will walk you through two easy methods of getting your chain exactly right.
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When was the last time you changed your chain?
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When was the last time you changed your chain?
Last week, I converted a 1x crankset to a 3x, and had to install a longer chain
Unfortunately, this video wasn’t out yet, so it was trial and error :)
In June. Took me longer to locate the gloves and tools than to lengthen and change the chain…
Last week :)
Two weeks ago, I upgraded my Diamondback Podium (Campy Mirage 8-spd) and Trek 420 (Ultegra 9-spd) to larger cassettes, so I installed new chains. The Trek was easy, as there is actually a good range of chain lengths that will work with the new medium-cage derailleur; I left the chain full-length (116 links).
The Campy bike has a very critical requirement, due to its short-cage derailleur. I was very lucky that in the end, I was able to find a chain length that allows safe and smooth shifting to/from all 16 ring/cog combinations. Before I started, I didn't think I would be able to ride in the small-ring and small-cogs gears, but it still has chain tension there (although as the chain wears and elongates, that may not remain the case).
The second method becomes easy to understand if you know that the chain is 0.5inch pitch. Dividing the number of teeth by four is simply giving you the number of inches half way around the sprocket. So you are adding the top chain stay length, bottom chain stay length, and half the circumference of each sprocket.
I note that neither method takes into account the derailleur cage length. Does it not matter?
You didn't include a clip where there is a rapid whirring noise and all the chain ends up on the floor!
Thats in the next video!
Haha, you'd think after it happens 15 times we'd work out how to stop it ... Nope rope
When I replace a worn chain and don't mess with anything else, I just count pins (not links) on the old chain and use that number for cutting the new chain to the right size. It's a bit tedious, and it definitely pays to count twice, especially if you have toddlers running about, but it works perfectly every time.
Great tips, thanks !! Looks like the 1st method is much easier & straight forward.
Thank you for posting this video showing the correct methods!
I've encountered several videos recently, showing installation of chains that were actually cut too short.
I used to deliberately run a shorter chain to reduce slop, with the logic that I'd NEVER try to run big-big on my triple chainring setup. That worked until one long, tired, rainy climb up a moderate slope, in the middle of nowhere on a solo tour when I reached for the front shifter. Had to loosen the rear wheel to get out of that jam. Fortunately there was no permanent damage but I learned my lesson.
I am increasing my chain length now, on my ride I made a mistake and I just don't want to take the risk now.
Thank you so much. I'm happy that I got the same spot on my chain, by both methods (also confirmed with another pro video showing the same method); giving me confidence that the chain that was on the bike was 2 whole links too long. No wonder I could never get it all to operate smoothly. I'm so glad I took time for this, & didn't just assume I should make my chain the same as what was on there. It had seemed too long. I'm very happy to learn this. Blessings everyone. Peace. Love wins.
Thank you Alex, very straight forward and clear explanation.
Glad you have this Video up. I have a Raleigh Team Banana and upgraded to 10 speed from the 7 so I can't measure like I usually do with the old chain. This going to help a lot.
Very clear and useful description on how to size the length of a chain for road bikes🙌
My method is to use the same length as before.
Which works unless you have changed the size of your large chainring or sprocket.
FWIW, with my SRAM clutch derailleur I can switch between wheels with 11x42 and 11x36 or even 11x32 cassettes with a chain sized for 11x42 without any issues. The clutch takes up the slack, and shifting still works correctly, the chain doesn't sag or slap.
That's because your small sprocket stays the same which is where you have the most slack. The clutch isn't taking anything up it's just got the same amount of slack on the small end with both cassettes. The bigger gear on the cassettes will tighten the derailleur, eating up slack.
GCN out with the wisdom just one day before my new carbon bike build. Thank you guys!
Can't believe I've never heard of either method and I've built several bikes up from scratch. Definitely if the bike has a chain, that can be used but it's always been a mystery to me where to start on a new frame as I'm doing again today. Thanks!
I never assume the previous chain of any bike (except mine) is sized correctly. I almost always size new chains from scratch.
Got it, thanks!
I did both methods and came up with a two link discrepancy, I think that is because I have a triple chain ring in front. So with the measuring method when I go big chainring to big cog traveling more of a sideways distance ( more severe cross chain that I’d never do intentionally. ) so I’m going to go with the big to big method which is two links longer or 1 inch
Thank you,
Thanks Alex , very useful, I think I will use the second method
Since I normally don’t change my cassette or chainring size, I usually just take the old chain, and match up the new one to it. With a quick link, the new one needs to be slightly shorter with inner links on both ends.
I also change them quite early, at just above 0.5%. Chains are cheap - cassettes and chainrings are anything but…
In my last upgrade, I paid more for the (Shimano) chain, than the (SRAM) cassette.
Chains used to be cheap, now not so much at 40-60% of cost of cassettes.
I got a brand new Cannondale Topstone 105 SE 2 years ago and I didn’t realize for about 6-8 months that the chain was two links too long right from the manufacturer.
Biggie + big +2 links, that is all folks
Unless you run 1x lol
Thanks Alex...Peace
Method 1 works perfect for my sram Rival.
How to measure the chain length for the drivetrain with the oversized pulley?
When I’m at my parent’s house I’m using an old bike. I bet I need this info!
First method is easier and what I always use. Just pay attention when adding the extra links and breaking the chain, some how I managed to remove two links instead of adding two (when tired)
V2 to include long cages, oversized jockey wheels and changing cassettes (and the tension screw) please
I tried both methods and came out with exactly the same length of chain.
Oh man, fantastic video? Do you find that the two methods will generally make the same length chain? Which one is preferred? I think I like method 2 better. Seems more scientific. Thank you for the video!
The jockey wheel cage should point straight down in top gear(big chainring,smallest sprocket),so 90°.Its the method I've always used.Now I'm thinking it's not good enough!
Is there any extra steps needed if I am using OSPW or changing stock pulley wheels to some larger pulley wheels, e.g. using CeramicSpeed OSPW System or changing Shimano RD-R8000-GS stock pulley wheels to TRiPEAK 12-14 Tooth SHIMANO Compatible? If yes, how to determine the number of chain links needed to be added?
#AskGCNTech
I recall learning that chain length calculation from Dan. Thinking about that makes me feel old. Doesn't look like Dan's allowed on the Tech set nowadays.
Probably more like he doesn't have to do the tech show anymore.
Seems to me that as long as the rear derailleur isn't near the extremes of it travel, i.e. maintains chain tension on the small sprocket 1:11 & the derailleur isn't stretched horizontally 0:42 when on the largest sprocket then we are good to go!!
I have an 8 speed cassette 12-25T my chainring is 52/42/30 I wanted to put a new cassette on that's 11-28 and keep my current chainring. Can I do this? If so, would I need to change the size of the chain? Your vids are great!!
The problem with all those methods is that they do not take into consideration the length of the cage which is an important variable. Mathematically, it is much more accurate to use the following method. Sum up your largest and smallest sprockets and cogs in the front and in the back, for example for 11-32 and 50/34 that is 11+32+50+34=127. Divide this by 2 and you get 63.5. Now put the chain on front and back cogs so that the number is closest to 63.5, for example 50 up front and 13 or 14 in the back. Now pull the chain till the rear derailleur cage is making right angle with the floor. And that is your optimal chain length.
Followed the first method adding on 2 links. Also checked the length with the original chain. Works well. However, when in the largest front ring and largest rear cog, I notice that the upmost derailleur cog doesn't engage with the chain. All seems good otherwise. Does this matter? Thanks.
So if the rear derailer gear is hitting on the rear gears does that mean the chain is too long or could the derailers springs be worn?
I would be curious if the two methods matched up to the same length in reality for you. Also, the third method I suppose would be to hand count the links in your old chain (assuming it was correct).
If you don't need to change your chain length, just lay the new chain stretched out on a table next to the old chain. That's easier and less error-prone than counting the links.
The two methods shown in the video are actually the same. They only differ in that the chain is the measuring device in the first method, while a measuring tape is used in the second method.
@@marianneoelund2940 Assuming you are changing a worn chain, you can’t just go by length side-by-side. The old one is “stretched”.
@@sunshinecycling
You just need to match the link plates side by side, starting from one end and shifting the new chain very slightly to keep the links aligned.
But hopefully the old chain is removed long before it stretches so much that it would cause a 2-link error!
@@sunshinecycling lol that would have to be a really , really badly stretched chain. Like the most stretched chain ever!
@@sunshinecycling i keep hearing this about comparing old chains due to "stretch". do people really think a chain stretches by more than a link? utter nonsense. additionally, it is my understanding the chain does not actually stretch, but the rollers wear, which gives the sense of an ill fitting chain.
Same method goes for oversized pulley like 12-19T?
How do you know how many links does the chain that you buy need to have?
I have a 3 speed bike. It slips badly, when I'm going up hill. Would taking a couple of chain links stop it or reduce it, as there is a fair amount of slack in the chain?
Maybe you should mention, that SRAM recommend to add 4 links to 1x systems.
Yeah that would have been good.
Yesterday I used the maths method to check the length of my chain. Shortened it by two links. Saw this comment, checked sram website. Tried to relengthen chain with quicklink, didn't run smoothly. Had to buy a new chain. £35 down the drain. Not cool gcn, not cool.
Why not use the smallest ring and sprocket and make the chain short enough for the derailleur to tension the chain?
I'm a qualified mechanic and this is how I've always sized a chain and never had issues
Yep, this. I fit about 300 chains a year using this.
If you use this method, the chain lengths of 11-28T and 11-34T cassette are the same. Assume the chainrings remains unchanged, will this cause any issues in either cassette?
@@matthewho1053 I would say one would need a pully cage and hanger for the combination of rings and cassette. Of course one could know not to use the extremes but I believe that would only be appropriate for those who would know what chain length to use.
Is 700c tire fits on 26 rim?
Sounds like a major hassle than it needs to be.
Just put the chain on the smallest cogs for front and back while routed through the rear mech; then just pull the chain ends closer together till there is no slack while also not dragging the chain against the jokey wheel closest to the cassette.
Then link up and your done, no faf no math ezpz.
What about 1x setups? Can they be measured the same way?
Put it on small/small, wrap the chain, and cut it so the rear derailleur is under a bit of tension. Done. Only an issue with di2, which doesn't allow small/small.
No, you're not done. You also need to make sure that you can shift onto, and off from, the largest cog while running on the big ring - without stressing the derailleur cage. You should also check shifting both directions between rings while the chain is running on the largest cog.
Jim, for most combinations your approach works fine. The issue comes when using a wide range cassette and a large 54-56 TT or oval chainring. If paired with a short or medium cage rear derailleur the chain won’t be long enough. (Granted most folks running a wide range cassette wouldn’t run a short cage rear derailleur.)
I usually just do biggie big, route the chain, then add the link.
I have an old Shimano ultegra derailleur when Its in small gears the chain rubs against itself at the rear derailleur. Why would the mech close so much that the chain rubs. The only way I can think to prevent this is to shorten the chain to pull the derailleur open more so it doesn't rub. This seems like a design flaw. On my 9100 Shimano mech this can't happen when the mech is fully closed the only thing that will happen is a floppy chain if it's to long.
Do both of these chain sizing methods apply to chain sizing for mountain bikes and road bikes?
@gcntech
Oh wow, this might actually solve my issue of not being able to shift onto the largest ring on the cassette without the chain immediately jumping back to the next smaller one!!! I bought my bike via friends of friends and my bike repair guy hasn’t been able to figure out why it kept doing that although he did suspect it might be the chain. Since it seemed to be almost new still, I decided to just leave it until I need a new one and then see if whoever installed this one picked a wrong type. But now I’m going to take it off and check the length!!
I'm sure your bike guy has checked the cable tension in the rear derailleur, but that could also be it.
@@klarkolofsson yeah, he has checked that repeatedly, thanks! I actually quickly popped over after watching the vid to have him check the chain length. 😂 Unfortunately it wasn’t that but worth a shot. When he’s less busy during winter he’ll have another go at it as he’s quite annoyed himself that he cannot find out why the chain outright refuses to stay on the big sprocket.
I imagine your guy has checked these, but my first instincts would be:
1 - limit screw on the rear derailleur
2 - a bent derailleur hangar
@@lgsweeting Thank you! Yes, he actually showed me when he was checking the limit screws trying to fix that. I don’t think he would have missed a bent hanger, but then again he’s been swamped with work like all bike shops and still squeezes me in and even teaches me while he does, so it’s not impossible. I’m going to check if I can detect any bendiness myself later, thanks so much! 🙂
@@kitkat5153 No problem. A bent hangar isn't something I've been able to spot by eye, the issue that's always occurred for me is finding it impossible to get the gears indexed over the whole cassette. If I set up one end of the range perfectly, it would always be out of alignment at the other end of the range.
Buying a derailleur hangar alignment tool about a year ago was a game changer.
I'm sure your guy knows exactly what he's looking for, so unlikely to have missed it. Good luck with getting it sorted
Does the second (2nd) method's calculated length, in the case of presenter Alex, 52.5 inches, include the length of the quick link? @gcntech
I like your method of calculation but the plus one inch doesn't necessarily account for different lengths in pulley cages or oversized pulley wheels. On my vintage Campy Record derailleur the distance between the center of the pulleys is about 1 3/4 of inch and, on my vintage Suntour XT and Shimano Deore XT derailleurs the distance between the pulleys is 3 1/2 inches. The plus one inch might work well for one chain length setup but not necessarily for the other. So would you add 2 inches for a longer pulley cage? How much would you add for a oversized idle pulley?
I was wondering the same thing about oversized jockey wheels...
Recently I went from a 11T+11T cage (Shimano 105) to a 13T+16T cage, but I didn't adjust the chain length. Despite the extra tension, it works fine for me. But when I will replace my chain then I would like to compensate for the jockey wheel differences. I came up with a rule of thumb and I wonder what you think of it. I think it works reasonalby well cause jockey wheel teeth directly translate to chain links.
From 11T+11T to 13T+16T is a total difference of 7 teeth. The chain roughly runs over half the jockey wheels, so for the same cage angle (i.e. tension) the chain needs to cover like 3.5 more teeth. To adjust for that, I would add 4 links, 2 inner links and 2 outer links, compared to my current chain.
Rule of thumb here is: Use either method from the video and compensate for half the extra teeth compared to an 11T-11T setup.
PS: In my case, the jockey wheel axel distance didn't change, so I didn't have to compensate for that.
@@HoudiniNL You can use the following method that takes into account the length of the cage. Sum up your largest and smallest sprockets and cogs in the front and in the back, for example for 11-32 and 50/34 that is 11+32+50+34=127. Divide this by 2 and you get 63.5. Now put the chain on front and back cogs so that the number is closest to 63.5, for example 50 up front and 13 or 14 in the back. Now pull the chain till the rear derailleur cage is making right angle with the floor. And that is your optimal chain length.
Why measure with the big chainring and big sprocket when it's recommended not to use that combination (unless when using 1x)? Wouldn't you save a little weight if you measure on 2nd or 3rd biggest sprocket?
If your chain was shorter, the chain would not be able to fit onto the biggest gears. The right chain length allows you to shift into every gear combination.
You need to be able to safely engage large ring and large sprocket simultaneously, to avoid damage to your derailleur and other components. It's just too easy to accidentally go into that combination when riding, and a broken derailleur hanger can ruin your whole day:
th-cam.com/video/qPLasomhTCw/w-d-xo.html
In terms of chain direction, on Shimano chains some links have the writing facing direction of the chain and some are upsidedown... How do you know which direction is correct. Specifically for Shimano 11spd chains would be great to know as well
The arrow should point in the direction of the chain's travel.
I just changed my chain 2 days ago as I had 3 broken links. 8000km out of my old Dura-Ace one
Sounds like it was definitely time for a new chain!
@@gcntech how many miles should a chain roughly last?
@@lennymccartney1 Around 12-1300 miles. Get a chain checker tool, cheap and professional ones are available. Or ask your local bike shop if possible.
@@lennymccartney1
There is a huge range, depending on riding conditions, maintenance, and the amount of stress meted out by the rider. On my old Trek 420 road bike, I ran the same drive train components for more than 25,000 miles and the chain still measured within the wear limit. But that bike is only used in dry weather, and I always kept it lubed (and women usually aren't as hard on chains). Also, it's 9-speed, and 8-spd/9-spd chains may last longer than the 10/11/12-spd chains.
Does the length of the derailleur cage make a difference? Long cage vs short cage?
No, but if you have a long cage you could add an extra 2 links so there's some room for re-connecting the chain if it ever breaks.
I used the first method after I got it wrong by following my own “logic”, which was old chain length plus the number of teeth added to the biggest rear sprocket plus or minus the change made to the big chainring. Didn’t work. The chain was too long.
Yes, the adjustment that's needed is only *half* of the difference in tooth counts, because the chain only wraps half-way around the rings and cogs.
@gcntech but with a 52.5" chain (which is what you need) you add the master link and its 53". So actually, don't you need the whole chain (with master link included) to measure 52.5"? because a 53 is too long now.
I was wondering if I remove a chain from my bike to give it a deep clean, can I use the same joining pin for that chain to put it back on or do I then need to switch to a quick link? Thanks
No you can't reuse a pin, you either need a new pin or use a quick link. You're not supposed to reuse quick links but people do, I buy the sort labelled as reusable quick links. The best are connex links, they're expensive but last years. I remove my chain every 1-2 weeks to rewax.
@@dh7314 great thank you
for the first method, why couldn't you run it through the RD and just see where it all matches up?
#AskGCNTech - I recently had the misfortune to suffer 2 flat tires on a single ride. (the second one was likely due to my poorly patched extra tube). It got me wondering: i run 30 mm tires: if I have to use a tube that isn’t sized properly for my tire, would I be better off using an inner tube that is too small (sized for 23-25mm tires) or one that is too large (say a 35-43)?
Too large can make installing tube in some tire/rim combos really difficult, but in any case more difficult than using an undersized tube. Main problem with undersized is any tiny defect in the tube will be preferentially thinned out more in inflation increasing the risk of failure. Too small generally better than too large IMO.
I'm looking at changing the front sprocket on my bike from a 30 tooth to 34 will I need a longer chain or should it be okay?
You'll need a longer chain.
What about the calculation using metric ?!? Thanks!
I just take the old chain put it next to the new one and chop it to right length. Keep in mind it'll work if it's the same chain model- brand as the previous one 🤷🏻♂️🤷🏻♂️🤷🏻♂️🤷🏻♂️🤷🏻♂️🤷🏻♂️
Sadly I followed the second method and it made the chain too short, so had to re-add links and have probably compromised longevity
Kinda feel like this should be called "how to determine the proper chain length."
would the first method work on a mountain bike thats 12 speed
Yes, but if it's a soft tail, you need to fully compress the suspension to make sure you are measuring with the maximum chain-stay length.
For MTB, I would suggest you to check out Park Tool’s video. This videos only shows methods which work on bikes without suspension.
Alex, your valve is not aligned with the tire logo ! Bodge !
Dont use any of those. I just make sure the rear derailleur arm is under tension in small/small, and the chain dont rub.
couldnt you just count the number of links on the old chain and use the same number of links on the new chain.
That's dirty. And assumes it was correct last time :)
I thought you guys used the metric system over there.
bicycle chains have a 1/2 inch pitch (one pair of links = one inch). So it's much easier to work in inches than in cm in this case.
Why can't you just take the old chain off, lay old and new side by side and match the length?
Am I over simplifying it?
Yes...... I replaced a 32t chain ring on my new XL "Argon 29er" hardtail, with a "Tongsheng TSDZ2", which has a 42t chain ring, to convert the 29er mtb into a "go anywhere" E bike, so comparing chain lengths was not an option open to me.
The "Argon 29er" has a Shimano Deore 1 by 10 set up, with an 11 - 42 freewheel cassette with a long cage derailleur.
Further to this, being a newby, I had a look at several clips on how to size a chain, and really liked what I saw on "#GCN Tech" where the tech showed the "traditional" and newer "maths" derived sizing methods.
This enabled me to try both methods, to hopefully find both answers in agreement. Rear axle to crank spindle is 18".
This did indeed occur and both indicated that a 116 link chain was what was required.
However after purchasing a 116 link KMC X10, I found the chain was in a straight line thru the derailleur going on to the 42t granny gear, with a tendency to drop back into next gear when selecting the granny gear. The chain is too tight.
I was wondering if both methods resulted, in my case, an incorrect result, due to no account being taken of the long cage derailleur? In hindsight I think chain should have had 119 links.
"Need to measure in inches"... naah what was the alternative?
Measure in cm, then divide by 2.54.
@@marianneoelund2940 or just measure in cm and then add 2.54cm at the end, rather than 1 inch.
@@Aerialdan1
Hello, Dan!
Yes, seems I completely overlooked converting back to cm at the end. And it can be simplified a bit, as well. So to be complete, where Lcs is the measured chain stay length in cm, Tring is the teeth on the big chain ring, Tcog is the teeth on the large cog, and Lchain is the result in cm:
Lchain = 2*Lcs + 2.54*[1 + Tring/4 + Tcog/4]
Example -
Lcs = 41cm
Tring = 53
Tcog = 38
Lchain = 2*41 + 2.54*[1 + 53/4 + 38/4]
= 142.3cm, which is a 112-link chain.
I prefer Sheldon Brown's method.
What???
Why is GCN remaking Jon's videos.
How is possible that Method 2 is working if you use...short cage, long cage or OSPW?!?! If it doesn't count lenght/dimension of the cage is not possible that chain lenght calculated will fit same bike but with different cage. If should be work method 2 as it shown, it means that if I upgrade from a short cage to a Ceramicspeed OSPW I can reuse same chain, but is not correct. As cages are different, I should increase lenght of the chain. With the math calculation shown is not considered the cage lenght and is not possible that is working
not gonna lie I'm very mad you are remaking every Jon's how to.
can you not just measure the old chain? 🤷♂
Do a video about riding a mountain bike on road instead of off road
I could make one. There is a rider who usually joins the group rides I'm on, who always uses his mountain bike. It might slow him down a bit, but he's such a strong rider that no one notices.
Alex where is the gold chain?
Well... no fist bump!
C'mon, use metric instead ... you're a UK channel.
Chains are made in inch measurement pitch lengths
@@AnvilAirsoftTV so is it in fact difficult to calculate in metric system?
@@alexgraves6842
No, just measure in cm and then divide by 2.54. Of course, once you've done that, you're still working with inches.
You're using a chain already the correct length to show how to get the chain the correct length? 🤣
If you are using quick links, thus need to have to an inner plate at each end of the chain without the quick link after cutting the chain, but at your exact calculated length in method #2, you do not arrive at chain length that ends in an outer plate and inner plate, do you need add on extra length to the chain, namely, an extra link, to arrive at desired goal of an inner plate at each end of the chain without the quick link after cutting the chain?
@gcntech
Is 700c tire fits on 26 rim?
Do these two methods apply to chain sizing for both mountain bikes and road bikes? @gcntech