Shop Talk: What is Chainline, and How Do I Measure It?

[@truantray]

It is such a relief to see a guy on KZbin who knows his shit.

[@starshihtzupuppy3409]

There you go, back peddling "don't do it" says the living legend Calvin Jones. I actually watched this video twice and still loving it!

[@millipedic]

This is the clearest explanation of chainline that I have seen.

[@jsollien127]

Calvin is the undisputed master of bike repairs! I replaced an old BB and you can easily see (without measuring and math) that the chainline is off, even if only a few mm. Thanks Mr. Jones!

[@sKunKeNsTeiN]

Kudos for using the metric system

[@llamaoffspring]

I started a bike repair service less than a year ago and 80% of everything I know about fixing bikes I learned from Park Tool

[@michaelkirwan177]

You have greatly enhanced the image of bicycle mechanics everywhere and thank you for being such a straight talker that difficult seeming projects are less daunting. Due to your unflappable approach you instill confidence. Especially appreciated are the math derivatives and metric conversions when you put them in "plain speak" and expiates the 'goblin' factor. One for the Library Thank You Mike Kirwan - Kenmore, WA.

[@robertmcfadyen9156]

Calvin was honest about the advantages and disadvantages and was not afraid to admit to the limitations of the 1x 12 drive technology . Gearbox bicycle clutches will wear out and or need adjustment at times , also repair and replacement costs will be high .

[@Chrissotube]

Thank you for always being there for me Calvin Jones - whenever I'm working on a customer's bike and I'm hitting a wall I just think, "what would Calvin do?". I definitely read the BBB in your voice hahaha!

[@dennismicallef9350]

I love the solution to chain drops from back-pedalling. "Don't do that".

[@event4216]

Oh well. This has cured me instantly from considering 1x conversion. I don't want iphone in my drivetrain so no one can point out I'm pedaling wrong way.

[@randomusernumber1]

this is how things need to be , if doing something results in a problem then just dont doo that thing .Here is an example : a car crash leads to injury and or death , solution we have now is airbags , harnesses , sensors and all kinds of expencive , unreliable gimmiky complications , when in fact the only solution we need is just dont do that :) ( i am serious as a heart attack BTW )

[@kwoltersdorf]

@@randomusernumber1 Seriously, there is NO WAY you can not back pedal in certain situations.... It is DANGEROUS to not backpedal to having my comfort foot in the lead position when coming off a jump or making a step up. This is a DESIGN FLAW, not something you "shouldn't do".

[@trekkeruss]

@@kwoltersdorf Unfortunately, bicycle engineering is not as sophisticated as one might think. Also, we're essentially talking about a manufacturer...be it the component maker of the frame/bike builder...making their product compatible with every other other product made in the past, now, or in the future. That is impossible. So it is not necessarily a design flaw.

[@kelp0223]

usually, when i think something is simple, it turns out i'm just being simple minded.

[@letsgetscabs367]

Everytime - this dude brings the perfect delivery and information - thank you!

[@lekhapratap1652]

“If it ain’t broke don’t fix it.” Words to live by.

[@jxmtb]

Thank you so much for the video! The two issues you describe from 8:42 to 10:05 really helped me out. I just got a new Trek Slash bike with a 1x12 Shimano XT drive train. It's my first time with such a drive train (I had a 2x8 before). 1\ Indeed on the 3 largest cogs, I have some noise. (I tried various adjustments but was not able to get rid of this noise.) Now I know that there is little I can do about it :) I guess the only thing to be done is eventually replace the chain if it wears too fast. 2\ The chain also jumps down when I'm on the largest 1-2 cogs and try to pedal backwards. Now I know not to pedal backwards in those gears. Thanks again for the helpful video!

[@SignorLuigi]

This video deserves a "Super Nice!"

[@josereneducharme142]

And the winner of the Oscar for the most educating video of the year is... "Drum roll": Calvin!!! Standing ovation.

[@davidbee8178]

You're the best Calvin ! I met you YEARS ago as a student when you were teaching at the John Barnett Bicycle Institute . . . Cheers from Montreal ! :-)

[@seanporter113]

I love your videos. I trust your advice and work on my own bike. I sometimes will watch your videos over and over to be sure that I haven’t missed anything. Thanks for making them

[@megatfaizarif690]

I'm jut blown away by how well your tutorials come out. Another great video that I will be revisiting many times in the future. Thanks Calvin!

[@Jeff-bd4gg]

Best bike maintenance channel without a doubt. I learn so flipping much

[@Hipnosis65]

I just want to say how much I appreciate you guys.

[@mymorristribe]

This channel is like bike college! ...with science and everything. sweet!

[@gar2710]

I'm doing a budget conversion to 1x11, and this video is a lifesaver! Thank you!

[@dadstoygarage1878]

Nice! I came here wondering about chain ring spacing for the 1x9 conversion I did a while back, it makes more noise in the low range. But you explained it very well and not to worry about it. Makes sense why I get less mud in my derailleur than my friends bike etc.

[@tblakemusic]

I always learn something new from Park Tool. I didn't even know you could use the end of a caliper like that. Lol!

[@olegpetelevitch4443]

I got a 1 Lekkie 42 teeth on shimano 8 speed ! Does tops and a 1500 watt Bafang 52.7 volt battery dual suspension Dnm Usd size 6 hornettes forks 35 dh race and mid shock race Dnm rebound 2 air chambers ! both 120 travel does 68 and can go more ! I got programing cord and app for parameters of speed and to take cap off top speed in sport 75 clicks and you have ECO too and throtle and pedelec together meaning throtle over rides and helps together ! custom built love it ! 50 yurs old live on 30 degrees hills ! bad knees and hips ! sold car after DR said must exercise hip and knee ! Now their tops ride every were and love it !

[@mickchaganis6607]

Brilliant video, you are being realistic with 1 x expectations, just setting up my new Shimano XT 10 speed rear derailleur with extender to get 11/46 cassette and some of the issues I'm having are not issues. Still got one smaller cog that's slow to go down to, adjust that out and a bigger cog is slow to go up to.....ggrrrr

[@CyberdyneSystemsSkynet]

Came here for choosing a new BB spindle width for my fixed gear since I switched crankarms but this was actually super interesting with some things I've noticed with stuff on my rd and mtb after I upgraded to 11 and 12sp groupsets this past winter.

[@AleksiJoensuu]

Phew. Thanks for this

[@justinf1343]

Really helpful! I've never really considered it before, but thanks for the educational lesson on chain line.

[@guillaumecrance2213]

Thanks!

[@buggzo]

I like the way this guy teaches.

[@michaelvila3692]

Another great video Calvin. I just went from a Shimano 11 speed to a SRAM Eagle XX1 AXS group and I had an issue with the wrong crank for my Pivot Trail 429 SB+ BB. I had to move some spacers around on the crank spindle, off the manufacturer recommendations, or order another crank for $450. I did everything you described here including back pedaling, everything worked great. Thanks for the video my friend, I own a bunch of Park Tools because of your video's, it can be fun working on your bike, but not necessarily cheaper :-)

[@mucr7x]

This channel is like a TV show. Great !👌👌👌

[@josediaspinto7438]

ParkTool, what about the CLG-2 (chainline gauge tool)?

[@Mavczers]

Thanks for video. I have chain rubbing my smallest cogs on 10s cassette and I had no idea what to do. Now I know I have to add some spacers and it should be good.

[@matthiaspfeiffer7158]

What a great video. I have been pondering about these effects for too long. And here is the perfect explanation to all my questions.

[@wammo12345]

Best video I've watched in ages Calvin! Thank you!

[@eduardopiton7580]

Calvin Jones, I became a huje fan from you here in Brasil and Park Tool, and this video is very informative. So as I have a smal youtube chanel, I did a dubbing from part of this video, because a lot of my customers complains about "chain control issue"... at my bike sotore here in Brasil - Flash Bike... I will forward you the link as you can see your Brazilian voice, and I add some coments to make the video litle bit attractive for Brazilians.

[@ttmike42]

Manufacturers who are pushing the 1x drivetrains should review this video. Oh wait, they want to sell you more chains. Nevermind. They know what they're doing.

[@dougr550]

@thopkins22 the issue is specifically with 12 speed and that you have to run 52mm front chain line. 11 speed works better with a 49-50mm front chain line and has none of these problems. Unfortunately shimano has stopped producing 11 speed parts so it's just a matter of time until we run out, and many new bikes actually don't even have frame clearance to run 50mm chain line.

[@Shagolagal]

@@dougr550 That's not true at all. Shimano definitely still produces 11-speed parts. They even just released new 10, 11, and 12 speed Deore groupsets. Even if they did stop producing 11-speed, there are plenty of other brands to choose from.

[@bobbyhempel1513]

@@dougr550 you don't know what you are talking about.

[@DilbertMuc]

@@dougr550 Look at the brand new Shimano M5100 Stuff for 2021: 1x11, 2x11 with different cassettes and chainrings. Makes 1x12 almost obsolete due to better mud performance and using the old freewheel hub.

[@dougr550]

@@DilbertMuc I think you mean m5100? m6100 appears to be 12 speed. The Deore cassette doesn't come in 11-46 which is all I need, doesn't have hyperglide+, and is fairly heavy.

[@massimouguzzoni8631]

Many many thanks for your valuable advice. Best regards from Italy.

[@zoladkow]

Yeah, one more thing - about bikes with front derailleur. I think it's wise to try and match crank and derailleur chainline otherwise... 😁 Me i learned it the hard way - bought a Trek 520 and they fitted there a crank with 50mm declared chainline with a 45mm derailleur... imagine how fun it was changing to the biggest cog - not so much. there was simply not enough room to pull more line. What the retailer tried to do to fix this was adding BB spacers, nasty... that only alleviated the problem, but still on occasions I could not shift all the way up.... and my chainstay does not look great either 🤷‍♂ Why did Trek do it? Well, apparently at some point someone figured out it's neat to switch from 3x10 Deore and bar-end shifters to 3x9 mix of Alivio & Sora At least I learned my lesson...

[@williamstanke9210]

Mr. Jones, thank you for your excellent video. I am building up a Specialized Allez over the winter as a project. I’m using Campy nine-speed components and the old-style square-taper bottom bracket. I swapped out the Mirage BB for a Chorus BB to get a better chain line. It sounds now like I spent too much effort getting the front and rear chain lines as close as possible. It still seems to be that a bad chain line will burn excess watts and accelerate the wear on the chain’s side plates.

[@mushtikla1]

Awesome! I need to do the whole math but I'm thinking about switching from a 3x10 to a 1x11 so this will for sure help out! My cassette/chain will have to be replaced for next year anyway so I thought this would be a great upgrade, if I can make it work! I live in Serbia and bike shops here are very outdated and horrific when it comes to all this so I'm learning how to fix/maintain/upgrade my own bike! (Actually ordered your beginner/home mechanic tool box recently, should arrive soon! :)) (took "my bike shop" 13 days to instal new brakes so I just got fed up with them and decided to learn how to do everything by myself lol) Anyways, a couple of quick questions, if anyone can answer! :) What's kind of a "big NO" in the difference between front and back where it won't work properly, if there even is a ballpark number? My bike is from 2013 (BMC Team Elite 03) so I'm kind of worried that this won't actually work properly if I convert because 1x didn't exist back then lol. From my initial research, it looks like the current 3x has a 50 mm chainline (but will measure it to the middle cog) and I can only find a 52 mm 1x chainline crankset. Will these 2 mm more screw anything up considerably? I still need to figure out the math for the rear, but what would be "the number"/difference between back and fromnt, where things just won't work properly? In your example, it was 53 mm vs 47 mm and it works pretty good. So if mine turns out to be 52 vs 44, would that ruin things? it's not a very cheap upgrade considering I have to buy a new derailleur, cassette, chain and front crank... so I'm concerned with buying everything and it not working! And then have to buy a new cassette and chain anyway and deal with re-selling the new stuff... -.- I really don't want to do that lol So just trying to figure out the ballpark numbers before going for it so I can give up if the math doesn't work and just change the chain and cassette on my current setup and live with it. Sorry for the long message!

[@whyshouldidothatnow]

I love this guy - thank you Luigi!

[@brentnearhood8874]

Calvin, What ever happened to just putting a straight edge in the middle of the cassette and seeing where it landed on the chainring?

[@billbrett365]

He's obviously never built a bike before. He doesn't know what he's doing.

[@jhobaugh45]

Favorite moment at 2:24 ... I wish I could edit out my mental math calculation times in real life!

[@playroomcreative]

Calvin is cool as heck!!

[@InCountry6970]

Calvin Jones, You-Da-Man !!

[@patrickstaudt2584]

7:23 you say that the crank can't move left and right. Isn't it possible to move the crank left/right with a bottom bracket spacer between the bearing cup and the BB shell. Sheldon Brown suggests this on his website; is that a technique that doesn't work on newer configurations?

[@Vilendank]

probably some spindles don't allow for it, I know i can get away with it on my raceface cinch, especially on my Fat bike, but it probably varies so much with brands (and might piss off vendors trying to sell their boost chainrings) that they probably thought it would just over-complicate the process of simply measuring chainlines

[@mjojrjr6231]

Well explained 👏, no issues at all. Just don't back pedal to avoid this chain dropping.

[@workhorsemtb7075]

To be honest I struggled to keep watching this video but I kept at it and saw the value by the end.

[@dennisduran8500]

I didn't do any measuring on my setup. I tried to get the front single chain ring lined up with the center cog on the rear cassette with spacers.

[@mrislam4546]

Thank you so much. What is the standard chainline measurements for triple ring in mtb bike??

[@dosetti]

Most difficult job building my own bike was to setup the chainline. Had to put spacer under the cassette stack.

[@ikariku]

Excellent video. Calvin shares some knowledge that all must we know!

[@hychua7545]

Very informative and insightful video. Thanks. What would the stacked width of the Shimano 12 speed cassette (trying to est the rear chainline)? Trying to decide whether to get a 52 or 55 chainline crankset..I am getting a boost full suspension frame…

[@MJCV75]

As always a great video, i'm learning a lot from you guys, I switched to a Deore 1 x 12 and after following your procedure I found out that I have a chainline of 52mm, and a 142mm O.L.D in the rear, I'm supossed to have a chainline between 46 to 49mm, is this correct? Can I fix the chainline with a 6mm offset chainring or should I just let it be? I'm riding a hardtail by the way.

[@ShooterMcNut]

Weird seeing a non QBP bike in the stand. But I was glad to see that Stache, I have one just like it, and was considering upgrading the drive train for a 10 speed to a 11 or 12. I'm also going to be upgrading the stock wheels to a set of I9's. Thoughts?

[@kelp0223]

Very helpful! Now i know what it means when my LBS says that and i don't have to just stand there pretending like i know wtf he's talking about

[@aajawo]

I have a 1.85mm spacer behind my 10 speed XT cassette on a 11-speed road hub. Should I add this to the width of the hub? So 37.5mm + 1.85mm = 39.4mm? This for a Soma Double Cross Disc frame with 135mm rear droupouts. With a 43.5 chain line up front, the silver pins on the large chainring of the 46/30t crankset were catching on the chain in small chain ring and three smallest cassette ring combinations. But, if the width of the rear hub spacer is added to the width of the cassette, then the rear chain line is 135mm/2 - (37.5mm + 1.85mm)/2 - 4mm = 43.8 mm. So my chain line at 43.5mm up front and 43.8mm in the rear should be near perfect! So why is my chain catching the pins on the large chainring?

[@NonLegitNation2]

I converted my bike to a 1x and I don't have problems with shifting, it shifts perfect (after watching your video on how to adjust the rear derailleur of course) but I'm still not comfortable with my chainline it's at a pretty sharp angle when I'm on the largest rear cog, my BB did come with spacers so I'm going to see if adding a spacer or 2 to the BB will solve my chainline issue.

[@joemccabe3029]

What happened? Will adding bb spacers not increase the angle between front crank cog and small (easiest) gears an make it worse?

[@NonLegitNation2]

@@joemccabe3029 yeah you're 100% correct. I ended up not adding the spacers.

[@manrod4871]

In an 3 × 8 transmition: Whith wich sproket should the midle plate should align? Mine seems to align between 5th and 6th.

[@themeatpopsicle]

I've bookmarked this video to show to my customers who complain they can't spin their cranks backwards as fast as they can and not have their chain go haywire

[@that70sschwinn]

Nice demonstration Calvin...🔧🚲 your back-pedaling solution reminds me of what the doctor told his patient when he complained about his shoulder hurting when doing Pete Townsend windmills 🙋‍♀️😲 Don't do that🙄

[@jonathanzappala]

I love my trek stache. A great example for this video.

[@PanchoShelby]

I bought the new KCNC 9-52 cassette from R2 Bike and the chain falls in the last 3 big cogs when doing backpedal. I put on a new chain and he keeps doing it. Crank at the front is a 32t boost 3mm offset. My bike is a Specialized Epic Expert 2018 1x12 full Eagle XX1 and had no issues with the Eagle 10-50. It seems as the chain looks crossed. Somebody told me to use a 6mm offset chainring other told me to use a 28t instead of a 32t. Also I don't know why the last 3 cogs skipped the chain on torque when the chain is new

[@londontrialscat]

I run 9 speed and X2 on front, when I'm running the inner gear on the front the 3 higher gears at the back (7,8,9) randomly skip (jumps) almost feeling like the cogs are worn...but they aren't. This isn't a problem once I put it on the large outer gear on the front. I've checked for a bent rear mech hanger and it's all straight, so am I guessing that I might need a small spacer on my BB on the drive side? I've ridden with the large cog on the front and lowest gear on the back and they don't skip.

[@parktool]

Sometimes it appears the rear is skipping but the chain is actually catching on the shift pins of the crank. Look down from above or up from below while pedaling and you may see the pins catch the chain as they pass by. Spacing this out will help but is sometimes unavoidable for certain setups.

[@lawrencelibby3607]

It's a different deal when you drop the chain off the front and there's no derailleur there to shift it back on. It's good to get it right.

[@Pens4Life85]

If you're building a Frameset from scratch (386EVO BB, 12x142 rear), how to calculate the optimal chainline in 1x?

[@axisludi]

Calvin, could you make a video to explain the difference between MTB vs road chainline setups and issues? It would be super useful and instructive.

[@96mcorsa]

How is that 141 measurement calculated? Is it found in the frame specs?

[@robertfranks4209]

I watch this video along with a video from October 27th 2017 what I would like to know where did you get the 16 gear tooth I have an XR Pro mongoose it's an 8-speed I I'm changing the front sprocket trust single all over 32 tooth and I'm changing the back sprocket from a 32x11 to a 34x11. Now i seen the chart you had , so what problems will that cause. Should I go a 10x1 and where did you come up with the 16 tooth cog? And should I set it up like you did in the video. Thanks from franks

[@cedriceveleigh]

Great video! Would a boost chainline 1x crank (for example, 52mm chainline at the front) with a super boost rear hub make sense, given that it would make the chainring more centered on the cassette?

[@danielbull6709]

Interesting video about the chainline. It appears the bias in offset between the rear cassette and front chainring is to give you a straighter chainline on the higher gears. I wonder if in future someone could invent a 1x chainring that can move in and out on the crankset to maintain a straighter chainline across the rangr of gears.

[@christianpeters6579]

A pivoting chainring with a rubber bushing perhaps.

[@vampetaradu]

This video makes me keep my 2x11 even more. My logic is telling me that 2x11 has a better chain line, less friction and no problems while back pedaling. 😉

[@truantray]

Who back pedals. Pointless activity.

[@peterlang5047]

okleydokley I backpedal when I’m going backwards

[@th_js]

@@peterlang5047 But are you in the largest cog?

[@peterlang5047]

Tomi Saaranen I was in the second to largest cog on a 7 speed cassette, and the middle chainring. Switching to 1x7 and making a chain guide from a pvc pipe fixed my problems.

[@lowelllomberio]

Front and rear chain line means the upper and lower chain line right? Coz in was wondering if it normal for my bike to have the lower chain line closer to the rear wheel by about 5 mm than the upper line while on the biggest cogs

[@Temporalplace]

So for offroad bike front chainline needs to be about 6mm bigger or whats the point ? Im now choosig crankset for my gravel bike and im not sure what chainline on front i should have (since i switched cassette too), bigger than rear chainline ?

[@DK-wr9nd]

11 speed 1x had no issue at all with back pedaling. 12 speed 1x drivetrain drops chain like crazy.

[@maxisaez20]

I would like to hear about beltline, math are pretty the same but I know this system has more restrictions...for example using IGH is quite a headache

[@maurolocatelli5836]

Any video on compatibilties betwin derailleurs and crankset and BB?

[@mindlesspear8840]

i just recently replaced the wheel on my bike that i ride to school and this might be the exact reason why i can't put power down in 6th 7th or 8th, i've checked my hanger and its straight, the chain is relatively new and so is the cassette

[@jogasingh1516]

What to do in a triangle set up of three sprocket gears drive by a chain.where two gears r properly connected and the driven gear is only connected to few teeth.will the driven sprocket tranmit completed power or will there be lose in efficiency?

[@2old4u]

Excellent explanation. Great info.

[@jen3800]

Hello, Mr. Jones. Excellent video, as always. I have a question; I am running 10 speed on my road bike. if I buy 11 speed wheels ( in case of future upgrades ) and add a spacer, then a 10 speed cassette, is there a performance issue between this and an actual 10 speed rear wheel? Thank you in advance for any advice! Jim

[@contentity]

Not Jim but the answer is: Most likely no as long as the rear derailleur is properly adjust especially regarding the limit screws.

[@jamesgoc-ong5549]

I have problem with the shifting..11speed cogs 11-50T to 36T chainring,im using shimabo 11speed shimano cues and 11speed shimano cues shifter

[@Shtmmng]

Good day sir.i would like to ask planning to buy gxp crankset.about the offset.1mm,3mm,6mm offset are available.planning to upgrage to 1x10 speed.what offset thats best to my gears?

[@sicksmiffshady]

I might be missing something, but how do I determine what chainline I need in front for a new crankset?

[@parktool]

The Crankset should list a chainline on its spec sheet.

[@jopal]

When im on my biggest cog i do notice the chain is significantly off. It doesn’t make that low rubble sounds from the front chainring... from what I picked up from tbis video. That low rubble sound is fine? It will just wear out my chain a little faster? Cheers for the guidance!

[@TeacherNickoy]

Thank you for the explanation. I have a question, does a chainring be limited by your derailuer? example i have a stock 9 speed rd with 11-36T cassette. And i like to chain my crankset to 1x and make it a 38T chainring, and i will be replacing the chain, because it will be way too short. Will this be possible? Thanks for the answer.

[@parktool]

Yes that will be possible. If there are multiple chainrings in the front you can run into issues with what is called capacity. But with a 1x you are good to go. If your derailleur does not have a clutch you may need to use a chain keeer to retain the chain on the ring even with a wide narrow ring.

[@TeacherNickoy]

@@parktool thank you so much. I have trouble planning on how to make my ride more faster, because i have a 36/26 chainring with my bike, and my buddies has 44/32/22, i am using high rpm just to keep up with them on flat roads, and i maxed out my gears. So planning to move up to 38 with 1x since i am not using my 26t often, maybe i could keep it if there is a very long steep climb, i could manually transfer it there just for emergencies, or upgrade my drivetrain to 12 speed with 10-51T, could it be possible to match 38T with a 10-51 cassette? So i could climb anywhere, at the same time i can run like a standard cassette with 42t?

[@DilbertMuc]

@@TeacherNickoy You can use any front chainring with a 1x system. The rear derailleur adjusts the difference between the rear cogs regardless of the front ring. But you need to change the chain for the right length if you change to 38 tooth.

[@juanpabloppl]

Hello, I tell you that I have changed the transmission of my Trek marlin 5 (3x7 speed) to 1x12 sram eagle sx, the well calibrated gears worked well but when it is on the largest crown and I pedal backwards it jumps and reaches the lower crowns, what could it be due to? I have seen the chain line and it is the same as other bikes, is it because the axis of the marlin 5 is 135 mm? Maybe I should change the bottom bracket that is a traditional threaded cartridge to a dub? I hope comments, thank you.

[@parktool]

With a 1x12 or even a 1x11 this will happen. It is simply due to the angle the chain is leaving the cassette. pedaling forwards teh derailleur is keeping the chain inline for the real but when pedaling backwards the chain is being fed onto the cassette in a way that it wants to go to smaller cogs. The simple answer to preventing this is "don' do that". Changing chainline can improve it but it will happen on a properly setup system.

[@johnnyboy1586]

My old mtb is 2x7 no problems back peddling

[@maupa64]

Perfecta explicación. Gracias

[@robert8077]

What about single speed jump bikes? Please can u do one chain line would be helpful

[@cheungarrie123]

For anyone who lives in a mostly flat area and uses the bike for commute, 1x system prevails. Yes, there are slight rubs on larger sprockets and, yes the chain does wear out a little sooner. So what? Try it, be amazed, go back home confused - why would I ever want more than one chainring?

[@QuietMikeW]

I put a new freewheel on my bike, same 1st gear as before, but now when i roll the bike backwards, or turn the pedals backwards, the chain is knocked off and falls into 2nd gear, and then jams if you continue to turn backwards, just like you showed, but i does it even when turning very slowly and in like half a turn. the last freewheel that was on didn't do this and it had the same first gear, --can i put some kind of spacer behind the freewheel to move it outward or something?

[@vulnerablerummy]

got the same issue with 9 speed sunshine road cassette, previous shimano hg just doing fine but i want tighter teeth so i try another cassette

[@clint2627]

So you said chainline will be off on mtb. What should it be? How do I know if I need spacers?

[@wileyc175]

I can live with the noise but i wore out my chain within 3 months...... i had upgraded my screw spro ket from 6 to 7 speed. And also used a 2 or 3 mm longer bottom bracket... is it really the chainline thats vausing premature chain extension???? Plz help me out

[@parktool]

That seems like excessive wear no matter the chainline. Unless you put on a ton of miles.

[@wileyc175]

@@parktool nope, it could not have been more than 600 or so kms cos it was winter. I really hope that i got a knock_off shimano chain and there is no other problem..thnx for the reply though

[@Piplodocus]

So I just had the not-quite-so-cunning plan of changing my 1x Shimano GRX 11-42t cassette to a SRAM XD freehub and SRAM 10-42t, giving me a slightly wider gear range as I heard they were compatible and I can't get a 10t on the shimano freehub. The SRAM cassette on it's new freehub is further out though (seems to have increased its rear chainline offset) so I've had to adjust the indexing outwards on the derailleur. Seems a bit noiser on the highest gears though and the switching isn't quite a good. Fail. So does this mean I need to change my front chainring now (to be basically flat, not slightly inwards offset) and it'll keep the same original large difference in chainline offset and work perfectly? Or am I disappearing down an expensive rabbit hole that'll never really work with any available parts, and should give this all up as a bad job and go back to 11-42t? Anyone tried this or know any shimano vs SRAM offset numbers I should be aiming or could be using without me trying to work out how much I think it's shifted? Anyone else tried this and got is working/failed miserably?

[@justjordan8018]

So you telling me we got the 1x12 but if I actually use that last Big 3, I get crackling, it feels really wrong and it literally is destroying my drive train ... what an improvement i made to my bike... At least it's easier to pedal with a 32 chainring upfront.

[@likejustchiII]

So, how boned am I going with the SLX 7130 on a 12x148 frame?

[@jasonwu9287]

2:28 😂 love the edit!