You've heard of Boost hub spacing, but what are Boost Cranks? Boost cranks, over locknut dimension O.L.D., chainline explained! Support the channel! www.thebikesauce.com/
This is one of the better explanations I have seen. I like the fact that you pointed out the chain suck issues when they are not lines up properly. My spectral does that and it's annoying.
The Shimano x100 cranks, are designed for boost. Which is why they are for 135/142/148 O.L.D and designed around chainline of 52mm. 51-53mm was apparently the best chainline for boost. With frame design changing and wider tyre clearance needed then the 55mm chainline has become a thing. x120 cranks. But the 6100/7100/8100 are still “Boost” Unless your frame is designed around a 55mm chainline you’re better off with the 52mm chainline cranks
...just to add that the FSA Modular (e.g., SL-K) crankset allows for nicely adjusting the chainline without changing Q factor by simply moving the spacer or installing a chainring with different offset (e.g., the Cannondale-compatible chainrings from Garbaruk with adjusted chainline dependent on tooth number). I converted my non-Boost MtB tandem from 3x10 to 1x12 and adjusted the chain line for the best shifting performance.
Great explanation I wish I found this video 2 months ago when I was to naive to swap cranks from 52mm to 55mm complete disaster, I can definitely confirm everything you said in this video 52mm chainline cranks are sweet spot. Cheers
Thank you, excellent guidance, all clarity, no ego and no b.s. It’s rare on youtube. I’ve subscribed. I have two questions related to SRAM Gravel cranks and chainlines which might be of interest to others: 1. SRAM mullet on gravel bike - why do bike makers spec ‘road’ cranks / 45mm chainline with a ‘mtb’ cassette? I’ve had to replace my Force 1x DUB ‘road’ cranks with DUB ‘wide’ cranks to acheive a 47.5mm chainline because the ‘road’ cranks chainring was only 1mm from the chain stay! 2. Where on earth is the definitive online up to date guide to ALL Cranks, bb's, chainlines, spacer, combinations? ...It’s like looking for a needle in a haystack. EG: unless you have a SRAM BB, the published SRAM BB spacer guidelines for both road and wide cranks is incorrect, because SRAM BB’s have spacers built in. The bike brands don't have a full guide online, even for the parts they use, and the bb manufacturers don't either.
This is the video that I’ve been needing! Thank you CZcams algorithm for serving it up and thank you for creating a great vid! I’m working on a brand bike build and figuring out the drivetrain has been a nightmare. My build is a 2022 V4 Santa Cruz Tallboy with Boost hub spacing. Santa Cruz doesn’t publish their chain line spec, but their support told me it’s 55mm for Shimano and 52mm for SRAM. Huh? I’m planning to run RaceFace Turbine cranks (1x 30T) with a Garbaruk 10-52 cassette (microspline) and Shimano XT chain & derailleur. I’m going to try a 52mm chain line using RF’s standard Shimano chainring. They also make a “wide” chain ring for Shimano. Hopefully it all works happily together! There’s a great article about the evolution (and controversy) around MTB chainlines on Radavist if you wanna deep dive into the hidden side of chain lines. Excellent read for bike nerds 🤓
Holy cow is this absolute best video on boost cranks. I could not find anything a month ago. It’s a way more simple concept that I thought. Thanks so much! Definitely a slept on topic by most.
Some bike manufacturers, like yeti tell you what their ideal chain line measurement for the specific bike model is. So when building a bike from the frame up see if you can find that measurement before buying the wrong crank set. When I was building my sb140 yeti recommended a 55mm chain line with a 148 boost spaced rear hub. So I referenced the crank set I wanted to use which was the race face era crankset and found it is offered in a 136mm spindle with a chain line of 52mm. So for my chainring I bought a 3mm offset wolf tooth chainring which enabled me to have that 55mm chain line. Had to add a couple 1mm spacers for the crank but it really was very straight forward getting the right chain line. Making sure you have the right spacers for your bikes bb spacing and the right spindle width is another thing that is easily messed up when building bikes from the frame up. Since shimano, raceface, and sram all have different width spindles for their cranks you need to take what bb you have into account before deciding what crankset to get. Or choose a crankset and then get a bb to accommodate it.
Thanks for the great clear explanation of what a boost crankset is, I've hesitated on upgrading my crankset on my Rift zone because I didn't want to make a wrong decision. Great job on the video!
Well put together video, thanks. I generally like to think I know a thing or two about bikes, but chainline is one of those things I take a guess at and just hope to be right.
Your explanation is well put together and easy to understand. Thanks for decoding the bike industry. I think one of my bikes has that problem- headed to measure my f.c.l. vs r.c.l. (Sweet! Now I have an excuse to upgrade cranks.)
Brilliant! I just so happen to now need to renew drivetrain components and a worn Truvativ powerspline bottom bracket and am taking the opportunity to switch to a Sram Dub bottom bracket, which of course means new cranks. When looking at this it became obvious there was going to be issues and care needed to be taken with spacing, chainline etc and it was looking confusing. Online retailers product descriptions are often too vague and inconsistent in that I found two versions of the same crank model, one actually stated the chain line measurement and the other simply said it was a boost fitting with no reference to chainline. This video explains the whole issue and now I know what to get. Thanks for the great video.
Hey, man, first timer here. Your illustrations are awesome, so as your content. I did not even know there were boost cranksets to be honest, now I know! As feedback, your quality is impeccable, you clearly know what you're saying and make it easy to follow throughout the whole video. Just got subbed to learn more! Greetings from Brazil!
i'm getting your vids recommended more and more and they just happen to be talking about something very relevant that I'm dealing with lol. As i mentioned in your vid yesterday/day before yesterday I bought that Norton frame which has boost spacing. I currently have a SRAM GX crankset with the 6mm offset chainring since my current bike isn't boost. I ended up buying the 3mm boost chain ring to prepare for this boost frame, lol. I guess I might not need it now, but we'll see. Monday can't get here fast enough.
This was really helpful, thanks for putting it out there. I enjoy learning about the science of bike mechanics but don't have much of an engineers brain so the visual/diagrams really helped.
Very well explained, thanks. Incidentally my Canyon Spectral has always had that annoying "chain shift when back pedalling in the big sprockets" issue, even from the factory.
I'm new to mtb and currently building my own dream bike. With this video, it's clear that I have to settle for a non-boost crankset for my boost frame with a shimano slx boost hub rear. Thank you so much for this great explanation!
Greta video on the subject of chain line. I discovered that best chain line for me, was closet to the frame. I have a sram rear set up with a Garburuk 6mm offset and standard easton crankset. I spend all of my time in the lower gears, it works out great for me.
This was such an excellent overview! I have been looking at crank options on my flat-bar gravel bike which is a 135 OLD frame, so it looks like SRAM cranks will be my best option since Shimano's non-boost cranks seem to have excessively wide FCL for my application. I'm looking at running something like a 38T Wolftooth ring on a SRAM DUB crank which seems like that will work A-OK with my narrower RCL hub...I think.
Awesome video man! Very well explained. I run a boost spindle with my Sram crank arms, for the extra stability. This is on my Enduro bike (148mm rear spacing) 👍🏼
I love the one by system, except for the extreme chain lines. In my writing I am more in my lower gears than high gears and would think a tighter chain line upfront would be better. Although I am running 26 x 2.8 on rabbit hole rims which gives a super wide profile and in first gear I had times would have chain rubbing on my tire. Rather than going super boost chain line up front I dished the tire a little to the left and now I have just enough clearance. Although in muddy conditions I have a muddy chain. I am now a new subscriber and look forward to your next video thanks for the content!
This is a great overview of an otherwise confusing topic. I had a non-boost Shimano 8100 crankset, and based on this video, I tried that on my boost mountain bike (Canyon Spectral CF8) to straighten out the chain line (getting a rough sound in the lowest gear on the front chain ring). However, it was too narrow and made contact with the frame - so I went back to the 8120 boost crankset. However, with the right bike, this could work to straighten out the chain line. I will have to live with rumble on the front chain ring (yes, I already tried adjusting the b-tension screw).
Thanks for the video. I just recently went from 2x11 to 1X10 so I could have used this video then. What's more in was on a Cannondale Scalpel-Si which happens to be Ai (not artificial intelligence). Luckily I was able to find an Ai offset set of cranks (although) they were expensive. I found out the hard way that Cannondale's proprietary approach makes it difficult (and expensive) to change what comes stock. At any rate, I have really been enjoying the microshift 10 speed while dropping one of the chainrings. I have lost some gears but not many (and not the ones I need for climbing). At any rate, at the outset a lot of this seems somewhat complex, but once you understand the lingo, it's really not so bad. I called numerous vendors trying to get answers (including cannondale). In the end, I just had to try a few different things until I found the solution.
Thanks for a great video. Simpler and easier than the one from Park Tool in my opinion. I use 6 mm offset chainring (SRAM GX drivetrain) on my FS bike with boost due to a former wheelset. As I more often use the bigger cogs when I ride, this actually seems like a better chainline ("eye-wise"). I'm building a wheelset for my HT (Shimano drivetrain) with non-boost hubs and have a crankset with 55 mm FCL. Been looking for a Shimano compatible chainring, but the ones I've found are as expensive as a new 52 mm FLC crank...
Thank you so much for doing this video. It really cleared up a lot of confusion for me. Regarding boost there is not much choice if I wanted, or more like needed short crank arms (less than 165mm best 155mm for me) Dont know if thats a potential video subject in the future, nevertheless I have to give up on boost simple because of this reason alone. Which is a huge disappointment. Keep rocking on!
Great explanation with better drawings to help us understand science behind it. If for MTB is a mess for Gravel is even worse. I think. For example the Lauf Seigla has a BSA 73 bottom bracket where you can installa a wide Sram XPLR but also play with MTB cranckset with the right length if you wanna try any other MTB brand instead, which is my preference to have choices instead being trapped with Sram/Lauf setup
Good video, listen to it while walking my dog this morning. I run a non-boost Loc you factor XTR 780 something crankset on my Santa Cruz chameleon 2022. Haven’t had problems with shifting or backpedaling even while using the inner ring spacing, I think it’s not necessary like you said unless you’re running super boost
Really good video. This mess is the exact reason (well 1 of 2 reasons) I decided to just switch to using a WolfTooth CAMO system. Just need to change 1 modular part rather than messing with owning multiple cranks.
Good video. I recently built a Chromag Rootdown and had to install a 8120 crank as the spindle on the 8110 (which I had from a previous build) was about 5mm too short and I couldn’t get enough bite on spindle with the none-drive side crank arm. After installing the 8120, the chain line was a mess and I then installed a chainring with a 3 mm offset, which seemed to correct the chain line. I will have to compare the rear and front chain line measurements to see how they compare to you suggested distances.
I purchased the FC-M7000 11 speed crankset from eBay. It was advertised as Boost, but it did not have an extended spindle like the one you show. It has a 3 mm offset which is matched to the 148 mm wide Boost rear hub. I needed Boost due to the tire size I want to run, and the desire to have a 2x setup. I looked for 10 speed, because I like the chain line on my 2x-10 speed 2013 Fargo. No luck, and even the 11 speed is going away for the SLX.
Excellent video. For reference M7100-1 has 52mm chainline and compatible for both boost (148mm) and non-boost (142/135) OLD although I would argue that 52mm is too much for non-boost and should be closer to 49mm which is what SRAM uses with its 6mm offset chainrings. M7120-1 has 55mm chainline for boost and M7130-1 has 56.5mm chainline for super boost (157 OLD). These chainlines are the same for M91XX/81XX/61XX series
Practically speaking whatever it is FCL you always consider frame BB shell width. You may encounter problems with long crank spindle if your BB FRAME SHELL is around 83mm only.
Great presentation. I love contemt like this. 😁 For those of us who like to build our own bikes (or restomod. with frames from the 90s), we run into a lot of challenges. Bottom bracket, cranksets and crankbearings are to me the elements thas easyes to get wrong. The threads are usually the same (BSA 1.37), so you can then easily use modern Shimano Hollow teck crank/ crenkbearing on a vintage 90/ 00s MTB. So my crankrelated question is: Can one install a BB30 crank on a 68mm BSA1.37 bottom bracket??
I shimano chainring I purchased was -3 offset. I had to do extensive searching to verify but it was also confirmed after measuring. I have the same SLX cranks.
Great explanation! Yours is the Best explanation of the boost crank I've found. The illustrations are great. I tried to setup a Shimano Boost crank 2x12 yesterday that came with 2 spacers but the safety plate doesn't click in if I use both. It's strange. This is fc-m8120-b2. If I use one spacer it clicks right in. Not sure how that works as I need to bridge 6mm of Q-factor compared to the non boost version but only use 1x 3mm spacer. Not much info on these 2x12 crank sets either.
One thing to note is that 135 and 142 are actually the same hub, thus the same chain line. The OLD is technically different, but that's just because 142 was made for thru-axles. The 142 dropout has a shoulder/inset for locating the hub to ease thru-axle installation, so the "locknut"/endcap is just a little longer as opposed to actually changing the chain line and/or hub flange width.
Brilliant video. I changed my son's mtb from 2 by to 1 by using a 'cheap' sensah mtb group set and have since had issues with dropping the chain when back pedaling. This content is the 1st I've found (on the internet) that may explain why. I'll now go and measure the front and rear chain lines. Any other suggestions as to why there could be an issue? I was thinking the lack of clutch in the sensah derailer might be the problem.
I've recently bought a Canyon Stoic. I ditched the stock Sram SX set to a Shimano. I've choosen the 7100 crankset for the narrower Q fucktor and the chain line. And here comes the fun part. I had access to a 6100 Deore crankset with the stock 32t chainring and a 8120 XT with 30t. I've ordered 7100 crank and a SLX 32t chainring. Installing the SLX components reveald a clearance issue. Due to the innen bolts of the SLX chainring (32t) got interfered with the frame. I've tried with the similiarly constructed 30t XT which showed no promblem because the bolt heads have room at a lower radius. If I want to use a 32t chainring I need to install the Deore, bc it has no innen bolt heads, it's a much flatter design. So clearance is an issue nowadays. It's really helpful if you have access to other components to try on, especially when you kinda know what you want.
I'm 6'3" with a relatively wide stance, so i got myself an Shimano superboost crank for my singlespeed because of the higher q-factor. Combined it with the stein 104bcd to Directmount adapter (aliexpress) to move the chainline in again by 3mm, with a my 6hole cog in a cog carrier on the most outer position of the freehub of an 135mm hub i was able to make it work.
Nice content, I always try to keep my chain straight with my 3x9 speed setup for the best efficiency..but it feels like I only have 3 good gears per chainring. So I basically just use 4-7 on the middle chainring for 80% of the time..really thinking of going 1x but 2x is probably the sweet spot for efficiency
Oke q and A question: Do you think choosing a bike with the wallet/eye is a good idea? Explaining from my side: I think it’s the only possible way. There is soo soo many brands, with soo many different bikes, builds, setups, geometry, price point, looks, etc etc. I think with the market this saturated and most of us not the possibility to test 5/10 bikes all we can do is: Find what category bike. enduro/single track etc.. Find brands you like the looks of. Find best deal. Buy, accept it, imagine its the perfect bike for you and get used to it and schred
Thanks ! You're putting word on a problem i have with my SLX boost groupset. On the 51 tooth, the chain is "crossed", and i can't pedal backward. I am going to switch to a non boost crankset. And yes, Sram got it right, it is easier to switch chainrings with differents offset than the entire cranks.
I recently changed from x2 9 speed to X1 12 speed. I kept the same Sora crank but installed a wolf tooth chain ring. It was really difficult to shift into the big cog it just wouldn’t stay. Not being able to adjust the front chain line I had to look to the rear axle. Moving the spacers to shorten the drive side axle to bring the cassette closer towards the frame and re-centering the wheel will hopefully help. Bike is at the LBS as they have more skill than I.
Mtn bikers Sunday school session before “dirt church” lol. My only geared MTn bike is a 1x11 with a non-boost RF SixC crank, WT oval non-boost ring and my rear OLD is 142 that uses my retro non-boost Hadley hubs. I honestly never saw a need to get Boost 148 hubs or wheel sets since the hub body width and respective flange width is not really any wider and doesn’t creat a less dished wheel. Of course this limits my frame choices but I’m only riding hardtail’s and SS MTB’s so I don’t really need to worry. When I decide to get a new full squishy I’ll worry about which boost to choose then.
How to make bikes fat like cows. Makes me appreciate my 125mm QR rear axle and LOW Q FACTOR 113mm bottom bracket so much! And GREAT cornering clearance. Be jealous! Most will never experience it today.
Good explanation. I had a lot of confusion with this stuff when trying to upgrade drivetrains on my non boost bikes and identifying problems with grinding sounds in the biggest cog (worn out narrow wide chainring was to blame). I read some good explanations on wolftooth and/or one up components websites. Anyways, what’s the best option for replacing an old mtb suspension fork with a straight steerer? All the decent modern forks have tapered steerers.
THANK YOU for making this video. Wish I had seen it yesterday before spending 4 hours reading about this crap. Why does cranksets have to be this complicated (!)
Very clear and concise, thanks. I am building an "adventure touring" bike from the frame up. I am going to use a 2X (24-34) in this build and I want it to accept 2.6" wide 29" tires. The chain stays are flared for a plus size tire, they are totally tubular, no solid piece on the drive side like the Honzo. I am thinking boost crank and hubs would be wise. Do you agree?
On my Geometron G1 I run a non boost chainring to get good chain line. If I run a boost chainring it shifts slightly worse, but chain scratches the cassette also randomly derails if backpedalling, so if I rode something bumpy and then back pedal I might derail. I only test the boost 3mm offset one ride. As my bike can us both I will keep using 6mm offset non boost. I have direct mount Raceface crank, bike is Geometron G1, it has the clearnace for regular chainring, but some bikes don't.
When you do your Ritchey Outback build could you talk about your assessment of its frame geometry, what sort of riding you intend to do on it and how that effects the choice of components, wheels, tyres etc. With my RO build I want to select what suits the bike rather then throwing my favourite components on it.
6:20 Interesting, I have a new Marin that does this! 148mm rear hub paired with FSA Gradient "boost spacing" crankset. I'd have thought from factory they'd have paired up the FCL and RCL adequately!
5:05 you can shift gears fine, but the chain will clip the next cog. Put pressure on the rear wheel while pedaling backwards, WATCH the chain on the cassette. If its clipping another cog try a boost spaced chainring
This is one of the better explanations I have seen. I like the fact that you pointed out the chain suck issues when they are not lines up properly. My spectral does that and it's annoying.
Your illustrations are always so amazing and really help to make your points even more clear. Keep up the great work!
Thx!
@@TheBikeSauce you must be an engineer
🤘
Good 👍 👍 👍
Bike standards just get more and more insane.
Good 👍 👍
"standards" seems like too strong of a word.
More and more profitable
Insanely confusing
No standars😂
THANK YOU! it's so frustrating that more people haven't spread the word about how limited boost crank applications actually are in reality
Was about to get a boost crankset because my hardtail has a boost rear hub. Turns out non boost is the way to go. Thank you for the explanation man!
The Shimano x100 cranks, are designed for boost. Which is why they are for 135/142/148 O.L.D and designed around chainline of 52mm. 51-53mm was apparently the best chainline for boost.
With frame design changing and wider tyre clearance needed then the 55mm chainline has become a thing. x120 cranks.
But the 6100/7100/8100 are still “Boost”
Unless your frame is designed around a 55mm chainline you’re better off with the 52mm chainline cranks
Good 👍 👍 👍
...just to add that the FSA Modular (e.g., SL-K) crankset allows for nicely adjusting the chainline without changing Q factor by simply moving the spacer or installing a chainring with different offset (e.g., the Cannondale-compatible chainrings from Garbaruk with adjusted chainline dependent on tooth number). I converted my non-Boost MtB tandem from 3x10 to 1x12 and adjusted the chain line for the best shifting performance.
Great explanation, I’m 15years out of riding and just starting to wrap my head around all this….
Clear concise info, great work.
Great explanation I wish I found this video 2 months ago when I was to naive to swap cranks from 52mm to 55mm complete disaster, I can definitely confirm everything you said in this video 52mm chainline cranks are sweet spot. Cheers
Thank you, excellent guidance, all clarity, no ego and no b.s. It’s rare on youtube. I’ve subscribed.
I have two questions related to SRAM Gravel cranks and chainlines which might be of interest to others:
1. SRAM mullet on gravel bike - why do bike makers spec ‘road’ cranks / 45mm chainline with a ‘mtb’ cassette? I’ve had to replace my Force 1x DUB ‘road’ cranks with DUB ‘wide’ cranks to acheive a 47.5mm chainline because the ‘road’ cranks chainring was only 1mm from the chain stay!
2. Where on earth is the definitive online up to date guide to ALL Cranks, bb's, chainlines, spacer, combinations? ...It’s like looking for a needle in a haystack. EG: unless you have a SRAM BB, the published SRAM BB spacer guidelines for both road and wide cranks is incorrect, because SRAM BB’s have spacers built in. The bike brands don't have a full guide online, even for the parts they use, and the bb manufacturers don't either.
Love the production and efficient delivery of valuable information! Staying for more!
Good video. Cleared up a couple of things I had questions about. Thanks.
This is the video that I’ve been needing! Thank you CZcams algorithm for serving it up and thank you for creating a great vid! I’m working on a brand bike build and figuring out the drivetrain has been a nightmare. My build is a 2022 V4 Santa Cruz Tallboy with Boost hub spacing. Santa Cruz doesn’t publish their chain line spec, but their support told me it’s 55mm for Shimano and 52mm for SRAM. Huh? I’m planning to run RaceFace Turbine cranks (1x 30T) with a Garbaruk 10-52 cassette (microspline) and Shimano XT chain & derailleur. I’m going to try a 52mm chain line using RF’s standard Shimano chainring. They also make a “wide” chain ring for Shimano. Hopefully it all works happily together! There’s a great article about the evolution (and controversy) around MTB chainlines on Radavist if you wanna deep dive into the hidden side of chain lines. Excellent read for bike nerds 🤓
Holy cow is this absolute best video on boost cranks. I could not find anything a month ago. It’s a way more simple concept that I thought. Thanks so much! Definitely a slept on topic by most.
Learned a ton in this video. Thank you for making this video very informative and easy to understand.
Some bike manufacturers, like yeti tell you what their ideal chain line measurement for the specific bike model is. So when building a bike from the frame up see if you can find that measurement before buying the wrong crank set. When I was building my sb140 yeti recommended a 55mm chain line with a 148 boost spaced rear hub. So I referenced the crank set I wanted to use which was the race face era crankset and found it is offered in a 136mm spindle with a chain line of 52mm. So for my chainring I bought a 3mm offset wolf tooth chainring which enabled me to have that 55mm chain line. Had to add a couple 1mm spacers for the crank but it really was very straight forward getting the right chain line. Making sure you have the right spacers for your bikes bb spacing and the right spindle width is another thing that is easily messed up when building bikes from the frame up. Since shimano, raceface, and sram all have different width spindles for their cranks you need to take what bb you have into account before deciding what crankset to get. Or choose a crankset and then get a bb to accommodate it.
Thanks for the great clear explanation of what a boost crankset is, I've hesitated on upgrading my crankset on my Rift zone because I didn't want to make a wrong decision. Great job on the video!
Thank you so much for discussing this subject and explaining, I'm building a bike and now i understand what cranks to buy
No question for me - just wanted to thank you for the clear explanations and schematics - I appreciate your efforts!
Thx for the explanation. Simple and to the point. Being new to MTB, trying all the new terminology. This helped 👍
Well put together video, thanks. I generally like to think I know a thing or two about bikes, but chainline is one of those things I take a guess at and just hope to be right.
No questions here, sorry. I love these nerdy videos and how you keep the outtakes in. I learn some, laugh some each time. Keep it up!
Glad to see the illustrations showing up again. I love this format where you geek out on one thing. It reminds me of the one you did on brake temp.
I think the viewers enjoy the format - will probably do more soon.
Great presentation, nice and clear. Definitely helps make an upcoming crank and chanline decision with a new frame easier. Thanks
Your explanation is well put together and easy to understand. Thanks for decoding the bike industry.
I think one of my bikes has that problem- headed to measure my f.c.l. vs r.c.l.
(Sweet! Now I have an excuse to upgrade cranks.)
Brilliant! I just so happen to now need to renew drivetrain components and a worn Truvativ powerspline bottom bracket and am taking the opportunity to switch to a Sram Dub bottom bracket, which of course means new cranks. When looking at this it became obvious there was going to be issues and care needed to be taken with spacing, chainline etc and it was looking confusing. Online retailers product descriptions are often too vague and inconsistent in that I found two versions of the same crank model, one actually stated the chain line measurement and the other simply said it was a boost fitting with no reference to chainline. This video explains the whole issue and now I know what to get. Thanks for the great video.
Hey, man, first timer here. Your illustrations are awesome, so as your content. I did not even know there were boost cranksets to be honest, now I know! As feedback, your quality is impeccable, you clearly know what you're saying and make it easy to follow throughout the whole video. Just got subbed to learn more! Greetings from Brazil!
I've been watching a couple of your videos. Very good stuff
Just discovered your channel. Great explanation of this issue. Subscribed.
i'm getting your vids recommended more and more and they just happen to be talking about something very relevant that I'm dealing with lol. As i mentioned in your vid yesterday/day before yesterday I bought that Norton frame which has boost spacing. I currently have a SRAM GX crankset with the 6mm offset chainring since my current bike isn't boost. I ended up buying the 3mm boost chain ring to prepare for this boost frame, lol. I guess I might not need it now, but we'll see. Monday can't get here fast enough.
This was really helpful, thanks for putting it out there. I enjoy learning about the science of bike mechanics but don't have much of an engineers brain so the visual/diagrams really helped.
Very well explained, thanks. Incidentally my Canyon Spectral has always had that annoying "chain shift when back pedalling in the big sprockets" issue, even from the factory.
My Honzo frame is in the mail, so this was really helpful. Thanks!
I'm new to mtb and currently building my own dream bike. With this video, it's clear that I have to settle for a non-boost crankset for my boost frame with a shimano slx boost hub rear. Thank you so much for this great explanation!
That was excellent! It helped me to pull it all together in my mind. Great job!
Greta video on the subject of chain line.
I discovered that best chain line for me, was closet to the frame. I have a sram rear set up with a Garburuk 6mm offset and standard easton crankset. I spend all of my time in the lower gears, it works out great for me.
EXCELLENT presentation, and it all makes sense now! Thanks!
So well and concisely explained! thank you!
This was such an excellent overview! I have been looking at crank options on my flat-bar gravel bike which is a 135 OLD frame, so it looks like SRAM cranks will be my best option since Shimano's non-boost cranks seem to have excessively wide FCL for my application. I'm looking at running something like a 38T Wolftooth ring on a SRAM DUB crank which seems like that will work A-OK with my narrower RCL hub...I think.
Excellent vid! Thanks for sharing!
Brilliant! Not enough people talking about this topic; thanks🤙🏻
Awesome video man! Very well explained. I run a boost spindle with my Sram crank arms, for the extra stability. This is on my Enduro bike (148mm rear spacing) 👍🏼
I love the one by system, except for the extreme chain lines. In my writing I am more in my lower gears than high gears and would think a tighter chain line upfront would be better. Although I am running 26 x 2.8 on rabbit hole rims which gives a super wide profile and in first gear I had times would have chain rubbing on my tire. Rather than going super boost chain line up front I dished the tire a little to the left and now I have just enough clearance. Although in muddy conditions I have a muddy chain. I am now a new subscriber and look forward to your next video thanks for the content!
This is a great overview of an otherwise confusing topic. I had a non-boost Shimano 8100 crankset, and based on this video, I tried that on my boost mountain bike (Canyon Spectral CF8) to straighten out the chain line (getting a rough sound in the lowest gear on the front chain ring). However, it was too narrow and made contact with the frame - so I went back to the 8120 boost crankset. However, with the right bike, this could work to straighten out the chain line. I will have to live with rumble on the front chain ring (yes, I already tried adjusting the b-tension screw).
Thanks for the video. I just recently went from 2x11 to 1X10 so I could have used this video then. What's more in was on a Cannondale Scalpel-Si which happens to be Ai (not artificial intelligence). Luckily I was able to find an Ai offset set of cranks (although) they were expensive. I found out the hard way that Cannondale's proprietary approach makes it difficult (and expensive) to change what comes stock. At any rate, I have really been enjoying the microshift 10 speed while dropping one of the chainrings. I have lost some gears but not many (and not the ones I need for climbing). At any rate, at the outset a lot of this seems somewhat complex, but once you understand the lingo, it's really not so bad. I called numerous vendors trying to get answers (including cannondale). In the end, I just had to try a few different things until I found the solution.
Thanks for a great video. Simpler and easier than the one from Park Tool in my opinion. I use 6 mm offset chainring (SRAM GX drivetrain) on my FS bike with boost due to a former wheelset. As I more often use the bigger cogs when I ride, this actually seems like a better chainline ("eye-wise"). I'm building a wheelset for my HT (Shimano drivetrain) with non-boost hubs and have a crankset with 55 mm FCL. Been looking for a Shimano compatible chainring, but the ones I've found are as expensive as a new 52 mm FLC crank...
Wow..great explanation and well edited video.
This video is excellent 👌 Building a custom bike at the moment and been scratching my head over cranks😂
Thank you so much for doing this video. It really cleared up a lot of confusion for me. Regarding boost there is not much choice if I wanted, or more like needed short crank arms (less than 165mm best 155mm for me) Dont know if thats a potential video subject in the future, nevertheless I have to give up on boost simple because of this reason alone. Which is a huge disappointment. Keep rocking on!
Great explanation with better drawings to help us understand science behind it. If for MTB is a mess for Gravel is even worse. I think.
For example the Lauf Seigla has a BSA 73 bottom bracket where you can installa a wide Sram XPLR but also play with MTB cranckset with the right length if you wanna try any other MTB brand instead, which is my preference to have choices instead being trapped with Sram/Lauf setup
On point brother! Very detailed explanation! Thanks 🎉
🙏🙏
Excellent job, Sauce!
Ah! Now I know why I had to spec an offset chainring. Thanks for explaining.
Good video, listen to it while walking my dog this morning. I run a non-boost Loc you factor XTR 780 something crankset on my Santa Cruz chameleon 2022. Haven’t had problems with shifting or backpedaling even while using the inner ring spacing, I think it’s not necessary like you said unless you’re running super boost
I think I'll just stay with what my bike came with..Mahalo for explaining that though it went right over my head. Aloha.🤙
Great video, you always have so much helpful information. What is your day job?
Really good video. This mess is the exact reason (well 1 of 2 reasons) I decided to just switch to using a WolfTooth CAMO system. Just need to change 1 modular part rather than messing with owning multiple cranks.
Good video. I recently built a Chromag Rootdown and had to install a 8120 crank as the spindle on the 8110 (which I had from a previous build) was about 5mm too short and I couldn’t get enough bite on spindle with the none-drive side crank arm. After installing the 8120, the chain line was a mess and I then installed a chainring with a 3 mm offset, which seemed to correct the chain line. I will have to compare the rear and front chain line measurements to see how they compare to you suggested distances.
It's got way too complicated but your vid did go in some way to explain it all, thanks
I purchased the FC-M7000 11 speed crankset from eBay. It was advertised as Boost, but it did not have an extended spindle like the one you show. It has a 3 mm offset which is matched to the 148 mm wide Boost rear hub. I needed Boost due to the tire size I want to run, and the desire to have a 2x setup. I looked for 10 speed, because I like the chain line on my 2x-10 speed 2013 Fargo. No luck, and even the 11 speed is going away for the SLX.
Super helpful, thank you!
Best breakdown of all!
🙏🙏🙏
Nice job as usual! Your breakdowns are great...how about a rim/spoke length/hub flange measurement video?
I like it. That’s a bigger project. I may do an asymmetric rim explainer first
Excellent video. For reference M7100-1 has 52mm chainline and compatible for both boost (148mm) and non-boost (142/135) OLD although I would argue that 52mm is too much for non-boost and should be closer to 49mm which is what SRAM uses with its 6mm offset chainrings. M7120-1 has 55mm chainline for boost and M7130-1 has 56.5mm chainline for super boost (157 OLD). These chainlines are the same for M91XX/81XX/61XX series
Thank you for a clear, concise explanation of chainlines. Suddenly makes more sense. And what IS your day job :-)
Great vid. thanks. all explained😊
Thanks for the information.
Practically speaking whatever it is FCL you always consider frame BB shell width. You may encounter problems with long crank spindle if your BB FRAME SHELL is around 83mm only.
Great presentation. I love contemt like this. 😁
For those of us who like to build our own bikes (or restomod. with frames from the 90s), we run into a lot of challenges.
Bottom bracket, cranksets and crankbearings are to me the elements thas easyes to get wrong.
The threads are usually the same (BSA 1.37), so you can then easily use modern Shimano Hollow teck crank/ crenkbearing on a vintage 90/ 00s MTB.
So my crankrelated question is:
Can one install a BB30 crank on a 68mm BSA1.37 bottom bracket??
I shimano chainring I purchased was -3 offset. I had to do extensive searching to verify but it was also confirmed after measuring. I have the same SLX cranks.
Great explanation! Yours is the Best explanation of the boost crank I've found. The illustrations are great.
I tried to setup a Shimano Boost crank 2x12 yesterday that came with 2 spacers but the safety plate doesn't click in if I use both. It's strange. This is fc-m8120-b2. If I use one spacer it clicks right in. Not sure how that works as I need to bridge 6mm of Q-factor compared to the non boost version but only use 1x 3mm spacer. Not much info on these 2x12 crank sets either.
Comprehensive. Thanks champ!
One thing to note is that 135 and 142 are actually the same hub, thus the same chain line. The OLD is technically different, but that's just because 142 was made for thru-axles. The 142 dropout has a shoulder/inset for locating the hub to ease thru-axle installation, so the "locknut"/endcap is just a little longer as opposed to actually changing the chain line and/or hub flange width.
Right on! Thx for the contribution
Brilliant video. I changed my son's mtb from 2 by to 1 by using a 'cheap' sensah mtb group set and have since had issues with dropping the chain when back pedaling. This content is the 1st I've found (on the internet) that may explain why. I'll now go and measure the front and rear chain lines. Any other suggestions as to why there could be an issue? I was thinking the lack of clutch in the sensah derailer might be the problem.
I've recently bought a Canyon Stoic. I ditched the stock Sram SX set to a Shimano. I've choosen the 7100 crankset for the narrower Q fucktor and the chain line. And here comes the fun part. I had access to a 6100 Deore crankset with the stock 32t chainring and a 8120 XT with 30t. I've ordered 7100 crank and a SLX 32t chainring. Installing the SLX components reveald a clearance issue. Due to the innen bolts of the SLX chainring (32t) got interfered with the frame. I've tried with the similiarly constructed 30t XT which showed no promblem because the bolt heads have room at a lower radius. If I want to use a 32t chainring I need to install the Deore, bc it has no innen bolt heads, it's a much flatter design.
So clearance is an issue nowadays. It's really helpful if you have access to other components to try on, especially when you kinda know what you want.
I'm 6'3" with a relatively wide stance, so i got myself an Shimano superboost crank for my singlespeed because of the higher q-factor.
Combined it with the stein 104bcd to Directmount adapter (aliexpress) to move the chainline in again by 3mm, with a my 6hole cog in a cog carrier on the most outer position of the freehub of an 135mm hub i was able to make it work.
Nice content, I always try to keep my chain straight with my 3x9 speed setup for the best efficiency..but it feels like I only have 3 good gears per chainring. So I basically just use 4-7 on the middle chainring for 80% of the time..really thinking of going 1x but 2x is probably the sweet spot for efficiency
Very informative. Thanks
According to Shimano the M7100 and M7120 are both for boost. I ride the M8100 on a boost rear XC bike and it works great.
Oke q and A question:
Do you think choosing a bike
with the wallet/eye is a good idea?
Explaining from my side:
I think it’s the only possible way.
There is soo soo many brands, with soo many different bikes, builds, setups, geometry, price point, looks, etc etc.
I think with the market this saturated and most of us not the possibility to test 5/10 bikes all we can do is:
Find what category bike.
enduro/single track etc..
Find brands you like the looks of.
Find best deal.
Buy, accept it, imagine its the perfect bike for you and get used to it and schred
Thanks ! You're putting word on a problem i have with my SLX boost groupset. On the 51 tooth, the chain is "crossed", and i can't pedal backward. I am going to switch to a non boost crankset.
And yes, Sram got it right, it is easier to switch chainrings with differents offset than the entire cranks.
Cool! Just want to make sure you’ve got space for a non boost crankset in the bb area
I recently changed from x2 9 speed to X1 12 speed. I kept the same Sora crank but installed a wolf tooth chain ring. It was really difficult to shift into the big cog it just wouldn’t stay. Not being able to adjust the front chain line I had to look to the rear axle. Moving the spacers to shorten the drive side axle to bring the cassette closer towards the frame and re-centering the wheel will hopefully help. Bike is at the LBS as they have more skill than I.
Mtn bikers Sunday school session before “dirt church” lol. My only geared MTn bike is a 1x11 with a non-boost RF SixC crank, WT oval non-boost ring and my rear OLD is 142 that uses my retro non-boost Hadley hubs. I honestly never saw a need to get Boost 148 hubs or wheel sets since the hub body width and respective flange width is not really any wider and doesn’t creat a less dished wheel. Of course this limits my frame choices but I’m only riding hardtail’s and SS MTB’s so I don’t really need to worry. When I decide to get a new full squishy I’ll worry about which boost to choose then.
How to make bikes fat like cows. Makes me appreciate my 125mm QR rear axle and LOW Q FACTOR 113mm bottom bracket so much! And GREAT cornering clearance. Be jealous! Most will never experience it today.
Good explanation. I had a lot of confusion with this stuff when trying to upgrade drivetrains on my non boost bikes and identifying problems with grinding sounds in the biggest cog (worn out narrow wide chainring was to blame). I read some good explanations on wolftooth and/or one up components websites. Anyways, what’s the best option for replacing an old mtb suspension fork with a straight steerer? All the decent modern forks have tapered steerers.
THANK YOU for making this video. Wish I had seen it yesterday before spending 4 hours reading about this crap. Why does cranksets have to be this complicated (!)
😆
Thanks dude, have a good one
Likewise!
Very clear and concise, thanks. I am building an "adventure touring" bike from the frame up. I am going to use a 2X (24-34) in this build and I want it to accept 2.6" wide 29" tires. The chain stays are flared for a plus size tire, they are totally tubular, no solid piece on the drive side like the Honzo. I am thinking boost crank and hubs would be wise. Do you agree?
Thanks for this.
Who's your barber? You always have a fresh fade
😄🙏 local barber’s home studio in Anaheim
Yes a real technical breakdown
On my Geometron G1 I run a non boost chainring to get good chain line. If I run a boost chainring it shifts slightly worse, but chain scratches the cassette also randomly derails if backpedalling, so if I rode something bumpy and then back pedal I might derail. I only test the boost 3mm offset one ride. As my bike can us both I will keep using 6mm offset non boost. I have direct mount Raceface crank, bike is Geometron G1, it has the clearnace for regular chainring, but some bikes don't.
Harbor Freight sells a lazer skil saw guide . Magnetic base very adjustable , and cheap
When you do your Ritchey Outback build could you talk about your assessment of its frame geometry, what sort of riding you intend to do on it and how that effects the choice of components, wheels, tyres etc. With my RO build I want to select what suits the bike rather then throwing my favourite components on it.
100%!
This guy is the GOAT
This is like khan academy, but with bikes. Wild. Good stuff
ha, nice.
6:20 Interesting, I have a new Marin that does this! 148mm rear hub paired with FSA Gradient "boost spacing" crankset. I'd have thought from factory they'd have paired up the FCL and RCL adequately!
Well said young man,👍
‘Young man’ I’ll take it!
Great video
5:05 you can shift gears fine, but the chain will clip the next cog. Put pressure on the rear wheel while pedaling backwards, WATCH the chain on the cassette. If its clipping another cog try a boost spaced chainring