Thankfully this allowed me to understand proper crank installation on my new build. I was starting to think I bought the wrong size spindle, in spite of "all the standards matching."
Thanks, this is my first time building a mtb bike, last bike I bought was the Gary fisher rig in 2011, Im not impressed with the MTB industry and the technical support is seriously lacking.
I found out that there are two variants of preload adjuster. Yours tighten if rotated clockwise. There is another variant which tightens if rotated counter-clockwise like on my 2015 Stumpjumper FSR Comp. Anyhow, just follow the direction of the + arrow and you are always good to go.
Yes, same goes for the Sram Red 22 bb30 cranksets. Thanks for pointing this out. I had it wrong the first time after watching this video since it still preloads bearings if turning toward bb shell, just incorrectly.
Yes!! There is very little information out there on the counter clockwise version. It is completely non intuitive. It works exactly opposite from the way shown in this video. In order to apply bearing tension you rotate the locking ring CC (outboard), as the plus sing indicator shows. When the ring hits the crank continued tightening moves the THREADS inboard, (The threads slide on the spindle). The threads hit the bearing cup and tension the system. Such a strange system, I don't think mine has ever been adjusted correctly till now.
Thanks for the video, I have 5mm of thread exposed I plan on using spacers when the stores open after the Xmas/ new year break. But in the meantime is it safe to ride with that much thread exposed?. Thank you.
Thats a lot of thread being exposed for this system. Are you able to turn it anymore or is it firm? At 5mm id guess there are some missing parts or the 54NM of torque was not reached. Check your torque as well as the correct layout for the bottom bracket of your bike.
Bearing preload is per design meant to push the bearing balls into the conical races for proper (smooth) operation of the bearing. Somehow the bike industry has hijacked the concept to simultaneously take up lateral play from poorly built parts (high manufacturing tolerances), so people generally follow the advice in this video to use the preload collar to adjust for only lateral play. This is probably ok for many cases, but as there doesn't seem a way to quantify preload force with these collars, I'm wondering how many times you're left with subpar performance due to insufficient or excessive preload
Generally I would agree that they should specify some amount of preload (very simple, something like "when you feel the adjuster make contact, add 1/8th of a turn"). However the bearings and races are the strongest parts in this assembly - preloading steel / ceramic bearings and races with parts that are aluminum / plastic would damage the other components before the bearings / races deform. In any case, I would also expect that the bearings used are also massively overbuilt for the low speeds and forces involved in pedaling a bike - I don't see a badly adjusted bearing being the limiting factor in lifespan of the drivetrain. Anyone have a bottom bracket bearing that failed (other than water ingress / lack of maintenance) and how many km's (or miles) did it last? I just put a SRAM Dub BB in 68mm BSA on a 20 year old frame to replace the 3x chainrings with modern 2x (and go from 3x8 to 2x11). The old bottom bracket was in perfect condition - albeit a quarter kilo heavier, all steel shell, with non-adjustable preload. The chainrings and carbon crank arms instead of aluminum saved another quarter kilo (going from Bontrager alloy and steel bits to SRAM Red aluminum and carbon).
@@justtheotherdave The thing that is odd to me about spindle crank sets is the fact that the action of tightening the drive side to its specified torque evidently does not preload the bearings. I was under the impression that it was the main function of the BB spacer(s) to ensure the spindle would sit without lateral play, inside of the BB.
I have an XTR crank that keeps tightening the preload against the bottom bracket resulting in increased drag in the drive train. Does anyone have a recommendation to stop this from happening?
Is this something that I NEED to do? I’m building my own bike. It’s a 2019 Alchemy Arktos with SRAM X01 cranks and DUB button bracket. Pls let me know. 🙏🏼
I never need to use the adjuster, is that normal? If I torque the cranks down, it's all super tight. I imagine it would spin more smoothly if the adjuster was not flush with the crankarm before installation, allowing for some fine-tuning? Thanks for a response :)
What model/brand of crank and bottom bracket is this? If you have this preload ring, it should be threaded against the crank, which is away from the bearing face.
@@parktool PF92 DUB BB and Descendant cranks. I do indeed have it threaded against the crank, except I have never needed to adjust the preload ring. With 54Nm, the cranks are super tight and never have any play. They can barely spin one full circle when tightened. Not really noticeable when riding though...
Do you have the correct spacers snapped onto the outside of the bottom bracket? They have a few different options and the wrong one would cause this issue.
just head it recently serviced and now crank won't spin freely when I take the chain off. It makes maybe one full rotation when I spin it with decent force. Should it free spin just like wheel does or is some resistance ok?
The pre-load ring should be just contacting the bearing, and not be pushed into the bearing with force. You might try loosening it and try the adjustment yourself.
Hi, i have problem with my Shimano XTR M9100 crank, i am doing like you said, turning the preload ajustment until there is no movement, and testing crank and turning around with hand, it is smooth and secured, turning nicely. HOWEVER After a couple of km riding, getting harder to pedal and makes me tired fast, then i checked the crank arm with my hand. It's almost stuck, can't turn it smooth and freely with my hands, it requires a bit force to turn it with hand. The preload adjustment over tightened while i riding my bike. What is wrong with this ? i have changed my Bottom Bracket to see if BB is the problem, but it was same.... Installed my XT 8100 crank back, perfect and smooth turning, even after long rides....
What is the exact model number on the back of your 9100 crank? Also what is the exact model number off the back of the crank arms for your 8100? There are a few versions of each.
@@parktool Hi, it's one by XTR M9100 race crank 12 speed 10-51 system, 170 mm, same as XT one, m 8100 one by 12 speed 10-51 system. FC-M9100-1 1x12s w/o CR 52 MM says on the box.
Clavin, is there a way to replace this type of adjuster with spacers and wave washers? The preload on these never seams to get rid of all the play in my BB30. Also, why have an adjuster? My road bike has spacers and wave washers for the same type of BB... never had any issues with the road BB.
You could leave the adjuster loose and install a wave washer in the system to create the preload. It is not the manufacturers intention though so there may be issues that arise down the road. Typically the preload ring is more secure under load than a wave washer system.
Thanks for the video, Calvin. Having just installed my crankset onto my frame (pressfit 86.5), I also installed the recommended 3mm of spacers on the drive side crank. When adjusting the preload, I have about 3 full thread lines before the preload ring touched the non-drive side bearing. All feels good and there’s no play. However, I can’t help but feel like there’s a lot of thread showing between the preload ring and the non-drive side crank arm. Does this really matter? Should I perhaps add a spacer on the non-drive side?
@@Strop311964 thanks for the reply and question, Craig. I do have the shields installed, so we’re good there. I’ve put quite a lot of mileage on it this year and everything works great, no issues at all. 👍🏻
For a bottom bracket with angular contact bearings, it calls for 3-5 Nm of preload (Wheels MFG BB). Any tips on achieving this amount of preload using a threaded preload ring?
Could also get a small torque wrench (with needle and dial) with an Allen key to fit the non-drive-side crank. If you really wanted to go thru the trouble
Double check you are turning it the correct way. Remove the bolt entirely from the ring. Use a very light lubricant to wick into the threads. Start with your hand and turn the ring back and forth to free it. Avoid large pliers if you can, as it is easy to damage these rings. Good luck
If you remove your crankset you should have access to the preload adjusting ring. At that point you can clean it up, loosen the bolt and try to get it removed. Once removed you can grease it up and re install it. You should then have your pre load adjustment back.
Purchasing a replacement ring is the best option as the adjustment is very fine. Im sure you could do this with 29mm ID shims but that would be a hassle to have to remove and install a few times to get the adjustment right. "DUB preload adjuster kit" use that as a description to find a new ring.
Do you test the preload by moving crankset to different positions? I have seem that sometimes it feels ok but I rotate the crank and then there is one section where it has some play. Do I keep adjusting till no play at any position or it does not matter?
Could be a few things. Be sure that you have all spacers, seals and washers correctly situated based on the width of shell you have. If you have too many in the system it will cause quite a bit of resistance.
So it loosened off I tightened it pretty good just using my hands it is still creaking did I mess up the bearings tightening it tight by hand looks like yall were pretty gently with it That would also explain why it's made of junk plastic for the adjuster that is if you are suppose to delicatly tighten it to the bearings I wish they had a way to put a torque spec on that plastic nut
You are looking to take out the play and put a small amount of pre load on the bearings. A gentle touch is all that is needed. no torque needed, just "Feel". Check that your pedals are tight as well as your thru axles.
This video is incorrect and will end up with most people having lateral movement in their cranks. You show the left crank arm being pushed all the way into the bottom bracket. If you really did that there would be no room to move the pretensioner and with the lock screw undone it will just slip on the thread if you try and use it to pull back a gap on the drive side (especially with Ceramicspeed bearings which grip the crankshaft rather tight). Somehow magically in the video you have a gap to unwind the pretensioner into with no explanation of how that gap got there. The correct technique is 1. Open the pretensioner to it's widest setting. 2. Install the non-drive side crank and shaft (with the pretensioner on). 3. Close the pretensioner to it's narrowest setting (this will leave a gap between pretensioner and *crank arm*). 4. Attach the drive side crank arm and torque to spec. This will push the small ring on the pretensioner to it's correct position. 5. Open the pretensioner until it is tight against the crank arm. 6. Lock with the locking screw.
I've tried to fix creaks of my bottom bracket for months and found out hand tightening the preload nut is not enough. What I've done to fix the creaks is to hand tight preload nut first and make sure it sit tight against the bearing. Then I torque the crank arm center bolt to specs. By doing this, the creaks are completely gone but I do know that I am actually using the cranks center bolt to push in on the bearings. I don't know if this is bad for the bearings or not, but at least the noise is gone
I suppose the argument is the threaded preload allows much finer adjustment than washers or spacers - you can just throw it away and use spacers if you really want to. Or buy a metal replacement. Muc-off make them for cheap enough 🤙
Finally a video that brings the mystery of preload to the RUclips community who actually explains how to do it in simple concise procedures
I always wondered what that ring on the side was for!
@@alainyong5737 brown-noserz
Park Tools: Best bike maintenance videos on RUclips. Quick, concise, educational and enjoyable!
Wow, thanks!
Thankfully this allowed me to understand proper crank installation on my new build. I was starting to think I bought the wrong size spindle, in spite of "all the standards matching."
Thank you! So many videos completely skip this part and I had no idea why I had play in my cranks!
yes I had aalso play..crazy to dont have this clear information
ME TOO FINALLY ITS SOLVED
Best bike maintenance channel on the internet
Thanks for the tip. It helped me a lot when installing a rotor crank. Greetings from Germany (Oldenburg)
That’s why I love Shimano XTR, so easy and fast to install and remove, a true racing product
Finally Finally, got chance to knew the actual function of that mystery ring on the left side...thanks
Great clear instructional video, respect. All the best Andy
Thanks for watching? Thanks for making this video!
Cheers Calvin helped me out enormously !
Thanks, this is my first time building a mtb bike, last bike I bought was the Gary fisher rig in 2011, Im not impressed with the MTB industry and the technical support is seriously lacking.
Great video guys. Well done with content that is relevant...🇿🇦
nice simple video easy to follow and a great help
I found out that there are two variants of preload adjuster. Yours tighten if rotated clockwise. There is another variant which tightens if rotated counter-clockwise like on my 2015 Stumpjumper FSR Comp. Anyhow, just follow the direction of the + arrow and you are always good to go.
Yes, same goes for the Sram Red 22 bb30 cranksets. Thanks for pointing this out. I had it wrong the first time after watching this video since it still preloads bearings if turning toward bb shell, just incorrectly.
Raceface I noticed is counter clockwise on my Next R carbon crank.
Yes!! There is very little information out there on the counter clockwise version. It is completely non intuitive. It works exactly opposite from the way shown in this video. In order to apply bearing tension you rotate the locking ring CC (outboard), as the plus sing indicator shows. When the ring hits the crank continued tightening moves the THREADS inboard, (The threads slide on the spindle). The threads hit the bearing cup and tension the system. Such a strange system, I don't think mine has ever been adjusted correctly till now.
Excellent sub 2 min video....thank you
Thanks, just in time for my new bike👍
Thanks for the video, I have 5mm of thread exposed I plan on using spacers when the stores open after the Xmas/ new year break. But in the meantime is it safe to ride with that much thread exposed?.
Thank you.
Thats a lot of thread being exposed for this system. Are you able to turn it anymore or is it firm? At 5mm id guess there are some missing parts or the 54NM of torque was not reached. Check your torque as well as the correct layout for the bottom bracket of your bike.
That was clearer than sram's version
Bearing preload is per design meant to push the bearing balls into the conical races for proper (smooth) operation of the bearing. Somehow the bike industry has hijacked the concept to simultaneously take up lateral play from poorly built parts (high manufacturing tolerances), so people generally follow the advice in this video to use the preload collar to adjust for only lateral play. This is probably ok for many cases, but as there doesn't seem a way to quantify preload force with these collars, I'm wondering how many times you're left with subpar performance due to insufficient or excessive preload
Generally I would agree that they should specify some amount of preload (very simple, something like "when you feel the adjuster make contact, add 1/8th of a turn"). However the bearings and races are the strongest parts in this assembly - preloading steel / ceramic bearings and races with parts that are aluminum / plastic would damage the other components before the bearings / races deform. In any case, I would also expect that the bearings used are also massively overbuilt for the low speeds and forces involved in pedaling a bike - I don't see a badly adjusted bearing being the limiting factor in lifespan of the drivetrain. Anyone have a bottom bracket bearing that failed (other than water ingress / lack of maintenance) and how many km's (or miles) did it last?
I just put a SRAM Dub BB in 68mm BSA on a 20 year old frame to replace the 3x chainrings with modern 2x (and go from 3x8 to 2x11). The old bottom bracket was in perfect condition - albeit a quarter kilo heavier, all steel shell, with non-adjustable preload. The chainrings and carbon crank arms instead of aluminum saved another quarter kilo (going from Bontrager alloy and steel bits to SRAM Red aluminum and carbon).
@@justtheotherdave The thing that is odd to me about spindle crank sets is the fact that the action of tightening the drive side to its specified torque evidently does not preload the bearings. I was under the impression that it was the main function of the BB spacer(s) to ensure the spindle would sit without lateral play, inside of the BB.
I have an XTR crank that keeps tightening the preload against the bottom bracket resulting in increased drag in the drive train. Does anyone have a recommendation to stop this from happening?
Is this something that I NEED to do? I’m building my own bike. It’s a 2019 Alchemy Arktos with SRAM X01 cranks and DUB button bracket. Pls let me know. 🙏🏼
It is a good idea to get the best bearing adjustment. The DUB® system uses the pre-load ring.
This helped thank you
Great videos
Do you have to buy this separately or does the nut come with the crankset or bottom bracket when purchased??
The preload adjuster typically comes with the crankset.
I never need to use the adjuster, is that normal? If I torque the cranks down, it's all super tight. I imagine it would spin more smoothly if the adjuster was not flush with the crankarm before installation, allowing for some fine-tuning? Thanks for a response :)
What model/brand of crank and bottom bracket is this? If you have this preload ring, it should be threaded against the crank, which is away from the bearing face.
@@parktool PF92 DUB BB and Descendant cranks. I do indeed have it threaded against the crank, except I have never needed to adjust the preload ring. With 54Nm, the cranks are super tight and never have any play. They can barely spin one full circle when tightened. Not really noticeable when riding though...
Do you have the correct spacers snapped onto the outside of the bottom bracket? They have a few different options and the wrong one would cause this issue.
@@parktool Just using the 4.5mm spacer which gives me a good chainline. Don't see how that could influence this...?
Thank you!
just head it recently serviced and now crank won't spin freely when I take the chain off. It makes maybe one full rotation when I spin it with decent force. Should it free spin just like wheel does or is some resistance ok?
The pre-load ring should be just contacting the bearing, and not be pushed into the bearing with force. You might try loosening it and try the adjustment yourself.
Nice.. very helpful.. many thanks..
Can i ask why my bottom bracket looseing? Thank you!
Nice vid
Best to bin the plastic Sram preload ring and go with the Cane Creek aluminium version for durability
16,000mi on the plastic one and no signs of failure here.
Hi, i have problem with my Shimano XTR M9100 crank, i am doing like you said, turning the preload ajustment until there is no movement, and testing crank and turning around with hand, it is smooth and secured, turning nicely.
HOWEVER
After a couple of km riding, getting harder to pedal and makes me tired fast, then i checked the crank arm with my hand. It's almost stuck, can't turn it smooth and freely with my hands, it requires a bit force to turn it with hand. The preload adjustment over tightened while i riding my bike.
What is wrong with this ? i have changed my Bottom Bracket to see if BB is the problem, but it was same....
Installed my XT 8100 crank back, perfect and smooth turning, even after long rides....
What is the exact model number on the back of your 9100 crank? Also what is the exact model number off the back of the crank arms for your 8100? There are a few versions of each.
@@parktool Hi, it's one by XTR M9100 race crank 12 speed 10-51 system, 170 mm, same as XT one, m 8100 one by 12 speed 10-51 system. FC-M9100-1 1x12s w/o CR 52 MM says on the box.
What is the FC-8100- number on the backs of your XT cranks?
Can I use the Sram dub system without boost? Or do I need the sram dub boost crank and rear? Hearing lots of conflicting stories with vendors, thanks
You can.
I'm using DUB on my non boost Marin Bobcat Trail 3 (2020) (upgraded from 2x8 to the 1x12 SRAM Eagle NX) so yep, definitely can!
This come with new cranks or BB?
The preload ring is always on the crankset.
@@yonglingng5640 thanks😁
Clavin, is there a way to replace this type of adjuster with spacers and wave washers? The preload on these never seams to get rid of all the play in my BB30. Also, why have an adjuster? My road bike has spacers and wave washers for the same type of BB... never had any issues with the road BB.
You could leave the adjuster loose and install a wave washer in the system to create the preload. It is not the manufacturers intention though so there may be issues that arise down the road. Typically the preload ring is more secure under load than a wave washer system.
Thanks for the video, Calvin. Having just installed my crankset onto my frame (pressfit 86.5), I also installed the recommended 3mm of spacers on the drive side crank. When adjusting the preload, I have about 3 full thread lines before the preload ring touched the non-drive side bearing. All feels good and there’s no play. However, I can’t help but feel like there’s a lot of thread showing between the preload ring and the non-drive side crank arm.
Does this really matter? Should I perhaps add a spacer on the non-drive side?
@@llanfair Did you install the bearing shields? The preload should never be touching the bearing directly.
@@Strop311964 thanks for the reply and question, Craig. I do have the shields installed, so we’re good there. I’ve put quite a lot of mileage on it this year and everything works great, no issues at all. 👍🏻
For a bottom bracket with angular contact bearings, it calls for 3-5 Nm of preload (Wheels MFG BB). Any tips on achieving this amount of preload using a threaded preload ring?
Thats a tough one to measure. Perceived effort is about the only way. it should feel "snug".
@@parktool thanks for the reply and confirming what I suspected, much appreciated!
Could also get a small torque wrench (with needle and dial) with an Allen key to fit the non-drive-side crank. If you really wanted to go thru the trouble
He is like Dumbledore of the bike world. The all-knowing wizard.
My preload adjusted seems to be seized and harden as it doesn't rotate when I loosen the bolt and turn it. What should I do?
Double check you are turning it the correct way. Remove the bolt entirely from the ring. Use a very light lubricant to wick into the threads. Start with your hand and turn the ring back and forth to free it. Avoid large pliers if you can, as it is easy to damage these rings. Good luck
If you remove your crankset you should have access to the preload adjusting ring. At that point you can clean it up, loosen the bolt and try to get it removed. Once removed you can grease it up and re install it. You should then have your pre load adjustment back.
any alternative if the preload is broken? i accidentally tighten it and the plastic part where the screw broke
Purchasing a replacement ring is the best option as the adjustment is very fine. Im sure you could do this with 29mm ID shims but that would be a hassle to have to remove and install a few times to get the adjustment right. "DUB preload adjuster kit" use that as a description to find a new ring.
✌️Calvin for president ✌️
Do you test the preload by moving crankset to different positions? I have seem that sometimes it feels ok but I rotate the crank and then there is one section where it has some play. Do I keep adjusting till no play at any position or it does not matter?
Yes, rotate to several positions. Eliminate play if seen anywhere.
@@parktool thank you so much 😊
Do all cranks have a preload adjuster?
No, not all cranks have this.
the bottom bracket nx eagle measurement is standard?
The newer NX DUB spindle is consistent. Bottom bracket shells will vary though.
@@parktool thanks bro. 👌👍👍👍👍👍👍👍
What do I do if the preload spacer snapped?
The best thing to do in that case is to replace the pre load spacer. They are fairly cost effective.
My cranks not spinning 😁.
What am I doing wrong?
Could be a few things. Be sure that you have all spacers, seals and washers correctly situated based on the width of shell you have. If you have too many in the system it will cause quite a bit of resistance.
So it loosened off I tightened it pretty good just using my hands it is still creaking did I mess up the bearings tightening it tight by hand looks like yall were pretty gently with it
That would also explain why it's made of junk plastic for the adjuster that is if you are suppose to delicatly tighten it to the bearings
I wish they had a way to put a torque spec on that plastic nut
You are looking to take out the play and put a small amount of pre load on the bearings. A gentle touch is all that is needed. no torque needed, just "Feel". Check that your pedals are tight as well as your thru axles.
Cane Creek Ewings?
Those would fall into this category as well.
There are two options to the Ewings preloader ring, 30mm and 28.99 what one do I need for my Sram GX crankset? Thanks!
This video is incorrect and will end up with most people having lateral movement in their cranks. You show the left crank arm being pushed all the way into the bottom bracket. If you really did that there would be no room to move the pretensioner and with the lock screw undone it will just slip on the thread if you try and use it to pull back a gap on the drive side (especially with Ceramicspeed bearings which grip the crankshaft rather tight). Somehow magically in the video you have a gap to unwind the pretensioner into with no explanation of how that gap got there. The correct technique is
1. Open the pretensioner to it's widest setting.
2. Install the non-drive side crank and shaft (with the pretensioner on).
3. Close the pretensioner to it's narrowest setting (this will leave a gap between pretensioner and *crank arm*).
4. Attach the drive side crank arm and torque to spec. This will push the small ring on the pretensioner to it's correct position.
5. Open the pretensioner until it is tight against the crank arm.
6. Lock with the locking screw.
mmm your both right just applied differently
I've tried to fix creaks of my bottom bracket for months and found out hand tightening the preload nut is not enough.
What I've done to fix the creaks is to hand tight preload nut first and make sure it sit tight against the bearing. Then I torque the crank arm center bolt to specs.
By doing this, the creaks are completely gone but I do know that I am actually using the cranks center bolt to push in on the bearings. I don't know if this is bad for the bearings or not, but at least the noise is gone
@@BranXonX lol i feel bro, bikes man! The endless nightmare itll never be right
Why don’t they just use washers? I feel the plastic preload on the sram cheapens the experience.
I suppose the argument is the threaded preload allows much finer adjustment than washers or spacers - you can just throw it away and use spacers if you really want to.
Or buy a metal replacement. Muc-off make them for cheap enough 🤙
Am I the only one who over tightened mine and broke the little plastic thing?
Probably lol
✔️🫡🚴🏼🚴🏼🚴🏼
thanks, thats really useful