Tech Talks: Chain Line 101, Presented by Park Tool - Video

Feb 22, 2018
by Pinkbike Staff  
Tech Talks Presented by Park Tool


Tech Talks Presented by Park Tool is a monthly video series hosted by Park Tool's own wrench whisperer, Calvin Jones. The series covers the A to Zs of some of the most prevalent repair jobs, with the twentieth episode explaining the ins and outs of your bike's chain line.

Chain line isn't something that I'd call a must-know, but with Boost spacing and all sorts of stock and homebrew single chainring setups out there, knowing why chain line matters can save you a load of trouble. Not only that, a bike with a poor chain line will run rough, suffer from premature wear, and possibly give you all sorts of headaches when things get dirty. Calvin is here to explain how to figure it all out.


Chain Line 101

Views: 9,589    Faves: 20    Comments: 1



Need more Calvin in your life?

Episode #1 - Tubeless tire installation and conversion
Episode #2 - Saving that bent disc rotor
Episode #3 - Derailleur hanger alignment
Episode #4 - Shimano and Crankbrothers pedal service
Episode #5 - Trailside wheel repair
Episode #6 - Trailside chain repair
Episode #7 - Derailleur limits and cable tension
Episode #8 - Derailleur setup
Episode #9 - Fork wiper seal replacement
Episode #10 - Clipless pedal setup
Episode #11 - New cleat setup
Episode #12 - Top 5 next level shifting issues
Episode #13 - Fixing cassette play
Episode #14 - Gearing hacks
Episode #15 - Fixing sticky pistons
Episode #16 - Lubing fork seals
Episode #17 - A cleat's story
Episode #18 - Tricks of a mechanical mind
Episode #19 - Handlebar Trimming 101


Stay tuned for more mechanical how-to videos with Calvin returning on the last Thursday of every month to show you the easiest way to get the job done. Want to know more? Park Tool's how-to section has you and your bike covered.

www.parktool.com / @ParkToolCompany


55 Comments

  • 53 1
 How to stop chains dropping while backpedalling: don't backpedal. Well said Calvin.
  • 6 18
flag pinnityafairy (Feb 22, 2018 at 6:18) (Below Threshold)
 A poor-quality hub or freehub body will cause you to drop chains also. I cannot emphasize enough how important a quality friction-free rear hub is to keep a chain on a single ring setup without a guide.
  • 31 1
 @properp: please emphasize just enough...
  • 1 2
 @Obidog: please share your knowledge with us wise one. You can lead a horse to water but you can't make him drink. I can't emphasize this enough.
  • 1 1
 @properp: if I had knowledge of a 'friction-free' hub (or friction-free anything else for that matter) I wouldn't be sharing it here!
  • 1 0
 @Obidog: I9, Cris King. Now you do. Build bridges not barricades
  • 1 1
 @properp: Lets just revisit the key wording: 'friction-free', and again, 'friction-free'. Not sure you'll find that sort of performance promise on any product, be it from CK, I9, NASA or anyone else!
  • 40 3
 Someone needs to tell Calvin 28.99 isn't 29. Maybe put him in touch with a sram engineer
  • 18 3
 aaagh, and again as soon as pressed play: "15.1, lets go with 15" Does he not realise how much thought, time and marketing research went into deciding that 15.1mm was the way to go????
  • 11 1
 Calvin i love these videos

Can you please do one of how to fix a pool?

It needs to start with, 'i'm here to fix your pool'....
  • 10 0
 at 5:25 "there is no industry standard for this..." I can see some brainstorming in the bike industry now...
  • 7 0
 Damn, 6 millimeters is a whole gear change worth of difference. I like his total "eff-it" attitude, "if it ain't broke, don't fix it". That's what mountain biking is about, haha.
  • 5 0
 Is my chain on a line of any sort? Yes, cool keep riding. No, cool keep riding and figure it out later.
  • 10 2
 "75.8.....call it 76" Whaaaaaat??? Out of touch Calvin...! There's room for at least two whole new standards between 75.8mm and 76mm!
  • 9 4
 "a bike with a poor chain line will run rough, suffer from premature wear, and possibly give you all sorts of headaches when things get dirty"

Funnily enough, they don't put that in all the BS persuading everyone that 1x is the future.
  • 5 1
 Haha, it was the future 5 years ago. Most bikes come 1 by and it's not a problem.
  • 1 0
 @longlongpelaman: It's not a problem now as we are expected(or told) to change our chain at least once a year. More money for them.
  • 8 0
 If it ain't broke don't fix it. If it ain't broke don't make a new standard.
  • 4 0
 Just don't back pedal too much... Explain that to a customer! I had a guy who wanted to return a bike because it would derail on the cassette when he back pedaled a bunch... I tried to explain effective back pedaling is a nonessential function. Dude just didn't get it. It didn't help the sales manager convinced the customer we didn't build the bike correctly. I was shocked that pedaling backwards was so important to this customer!
  • 4 0
 A mechanic friend once shared a story with me that was similar about frame flex. A Jackass... I mean customer was mashing on the pedal from one side of the bike and complaining that the frame was broken because it flexed to much. My friend looked at him and said well I've never seen anyone ride a bike like that so you have nothing to worry about.
  • 5 0
 Maybe he likes to do long fakies in the skatepark
  • 3 0
 Raceface suggests the following for the chainline:
142mm hub 48-50mm chainline
148mm boost hub 51-53mm chainline

The bike on the video fits these guidelines. I guess as long as you don't have weird dropouts or try to mix parts that are not designed to be mixed together you are good with those numbers.
  • 7 0
 At least he didn't pour any beer out this time... #neverforget
  • 4 1
 Ditch the calipers and calculations and get a chain line measuring tool. If you do lots of climbing and not alot of flatland riding it makes sense to move your chainring just inside the center of the cassette.
  • 3 1
 Its easy enough to just eyeball it no need to measure anything, depending on your crank type a few washers to bring the chainring in a mm or 2 will extend the life of your drivetrain if you spend a lot of time climbing.
  • 3 0
 I'm an idiot..I thought that hole under the bottom bracket was designed for those people who let their bikes under the rain...drainage engineering ;D
  • 3 0
 Hahaha me tooo!!!
  • 1 0
 I though it is for some production needs, hanging in drying room or something
  • 2 0
 It is for drainage.
  • 2 1
 Calvin I love your videos but one comment - at 4:30 in you describe a technique to zero out the rivets on the back of the cassette. You could simplify your life and just measure the cassette with the smaller sprockets face down rather than the way you do it in the video. Just avoid the rivets when using your depth gauge. Keep up the good work!
  • 1 0
 Another tip - carbon down-tubes are often not centered (or symmetrical) to the BB, so measuring the DT and halving it doesn't give you the center of the BB. I measure at the the BB, extend a line on the DT and measure the chainline from the ring.
  • 3 0
 Acktually, the big cog is dished so he would need a straight edge across it if he did that.
  • 2 0
 The b-limit on that Shimano derailleur was like a mile away, that's gonna cause a lot more shifting issues than your chainline haha
  • 1 0
 I just realized Calvin is left handed. I now have to rewatch all of his videos and figure out the mirror procedure. Also, he almost slipped the bike swap right by me. Calvin is a shifty dude who needs to eat a burger or 5.
  • 3 0
 It not more easier check if the chainring is in line with the 5th sprocket (10 speed) or the 6th (on 11 speeds)???
  • 5 1
 I love my Pinion!
  • 2 0
 Neat video by Calvin Here is an article by wolftooth components regarding boost chainlines that some may find interesting.
  • 4 2
 ``75, 8 it is called 76...`` I don`t think that sram would like it...
  • 2 0
 40.99 cassette width? I'm buying.
  • 1 0
 Is that a pedal susbtitute for fixing the bike? Holy molly
  • 3 2
 Brought to you by Park Tool. Wouldn't want those hands to get mashed up on a real pedal. It can be yours for 4 easy payments of $49.99!
  • 3 0
 Yes, they make some sense for shops building up new bikes that don't come with pedals. The tool is only around $10 for a version without threads that just sticks in the crank. There's also one with a couple threads to keep in place if you're going back and forth on other adjustments. Then install the pedals near the end of the build, or never because the customer has their own pedals to install at home
  • 2 0
 Absolutly enjoy this !
  • 1 0
 didn't know park made a pedal...i'm kidding.
  • 2 0
 quick maths...
  • 1 0
 Great cuvée comments that is
  • 1 0
 Come on Pinion, hurry up and perfect that thing......
  • 1 0
 This guy drunk? Stoned? Or drunk AND stoned?
  • 2 1
 nice job
  • 1 0
 Bent axle at 9:02?
  • 1 3
 video doesn't work....(((((
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