Bosch Chainring - How To Properly Change An Ebike Sprocket Bosch Gen 2 BDU250C / 255C Series

[@spessartknorz]

Just watched the video and for the first time I could actually follow instructions, you made it very clear, the best part was you were slow enough so we (read I) could also follow those instructions, well done you have me hooked.

[@SCOOTERETTI]

Thank you for the kind words and glad that the video was helpful.

[@wakeywarrior]

Worth pointing out the 3mm spacer is sometimes built into the chainring so if there is a 3mm ridge on the back of the chainring, and your new one doesn’t have that built in offset then you need a spacer. For example, the Sram Eagle versions come flat but with a spacer for boost in the bag.

[@Leviathandk]

where the hell do i get this spacer? It didnt come with the chainring. Im bosch affiliated but its nowhere to be found on their MBPS product pages... Hoping for a usable reply on a 2 year old comment

[@wakeywarrior]

@@Leviathandk not sure mine came with it with my Eagle. Does this help- could be bought from Bike 24 in Germany- SRAM Eagle X-SYNC 2 Direct Mount Chainring - for Bosch E-Bike Drivetrains - 16 Teeth

[@DGwhitehawk]

I had to change crankarms on my ebike and this video got me throught it with ease. Thank you so much for this awesome tutorial!

[@SCOOTERETTI]

Glad to hear the video was helpful. Appreciate your feedback!

[@alexsabolta]

Started out using this video to change my chainring on my 2019 trek dual sport +. Got caught out on the bni - gen 3 spindle. All sorted in the end.

[@genoafire1]

Great video thank you. Very professional and detailed. You could easily make a living teaching others on how to make an instructional video.

[@SCOOTERETTI]

Bob, Thanks for the kind words and appreciate the time you took to let me know. Glad it was useful for you. Ride safe. Will

[@infernokush4206]

Can we change the chainring to a bigger one or would I have to get a software upgrade

[@tc6912]

Ditto!

[@SCOOTERETTI]

You can typically change between 2-4 additional teeth (depending how many teeth your chainring is currently) without throwing an error code. Also make sure you have enough frame, motor cover, chainguard clearance when increasing the size. Note this won't change your top end speed but rather just adjust your cadence.

[@Cheradanine]

Great video, very informative. I played a drinking game and took a shot at every "go ahead". Was pissed before the video end....

[@SCOOTERETTI]

Sounds like a cheap date........ ;-)

[@HP-jd9mt]

A sprocket remover / chain whip is to be used in order to hold the sprocket in place while removing and fastening the lock ring. Also to be mentioned that most of the torque wrenches do not work anti-clockwise, regardless to the presence of the switch to rotate ratcheting direction.

[@madmoikmadmoik6290]

Great Video!!! Instantly subscribed.

[@SCOOTERETTI]

Glad to hear that the video helped you out! 👍

[@mike_oe]

1:30 thank you for pointing that out!!!

[@SoundsandSightsVideos]

Great video. For the Park Tool. Is it the CCP-22 or CCP-44 for Bosch Gen 4 Crank Removal tool, please?

[@QuadPawCreations]

Great video! I have a Trek Crossrip+ and need to change out the 20T chainring. I have a Park crank arm extractor tool but the crankset is hollow and there is nothing for the tool to push on. What does the tool you used push on? I need to purchase the 20T chainring and the locking tool. I don't see the links to purchase them from.

[@timburgess1528]

excellent video thanks!

[@SCOOTERETTI]

Awesome, glad the video was helpful. 👊

[@dbok6796]

What’s the name of the thing the chain ring slots onto and does anyone know if you can get replacements as mine has the threads torn up nearly flat from the past owner

[@riteandleft]

Truly excellent video and first class, unambiguous instructions. Thanks.

[@SCOOTERETTI]

Thank you for your kind comments and glad you enjoyed it!

[@normhapp8629]

I have a Fuji E Transverse One.3 with the Bosch motor in the sprocket. The Bike has 5600 miles. It is only used for road or a paved path. Yesterday the chain jumped the front sprocket and became very tightly wedged. I checked the chain wear with a Park CC-1 chain checker. The wear is in the blue (good) zone. Since there is no front derailleur, I am at a loss as to what would make it jump the front sprocket. The sprocket teeth do not appear to be worn. I plan to change the chain, but I am not sure that this it the cause of the problem. Any advice would be greatly appreciated. Norm

[@SCOOTERETTI]

Doing a quick search it appears the bike is not equipped with a derailleur clutch so this can happen on rougher terrain, bumps, curbs etc....... Depending on the condition and wear of your drivetrain components this can also be the source (chain wear or kink, work our chainring, cassette or a combination of these.

[@steveproud2893]

Very help full and well presented👍👍

[@SCOOTERETTI]

Glad it was helpful!

[@nickp1420]

Brilliant, thank you!!

[@SCOOTERETTI]

Thanks for your feedback. Glad the video was helpful

[@grgmetube]

@scooteretti Is the Bosch lock ring tool you are selling, compatible with a locking nut of about 38mm outside diameter?

[@denesk2794]

Important warning: some torque wrenches only click clock-wise! Put your wrench into a MUCH LOWER torque setting and see if it clicks. Else you will need a long extender and reverse the torque action with an open wrench attachment.

[@chuckkoehler9526]

I want to install an 80T #40 1-inch bore size sprocket on my e-bike. It has a Prowheel 52T #40 sprocket on it right now. Are there any issues or concerns doing this? Can I just buy a type A sprocket with extra chain links or #40 chain. It would be nice to also have a sprocket guard also.

[@Renzsu]

I'm trying to find out what the offset is for these sprockets? Do you know the distance center of the BB to center of the sprocket? I've tried finding it in the Bosch manuals, but they're useless.

[@SCOOTERETTI]

The sprocket offset is determined my the bike manufacturer and not by Bosch. You will either need to measure the offset of your current sprocket or reach out to a shop that sells your brand of bike and ask them what that offset is. Bosch always recommends a flat chainring but some manufacturers have to use an offset due to the bike’s design.

[@Renzsu]

@@SCOOTERETTI Ahh that's interesting, so would the output axle then be custom for a bike manufacturer? Or just the sprocket? Thanks for replying so quickly, already very useful!

[@SCOOTERETTI]

Just the sprocket ⚙️

[@Renzsu]

@@SCOOTERETTI Thanks man, very helpful!!

[@VonPonzen]

Great video! Very detailed. Could you replace the sproket with a bigger one with more teeth?

[@SCOOTERETTI]

Thanks 🙏 for the feedback and glad it was helpful. Typically it’s recommended to stay at the same number of teeth that the OEM design the drivetrain with but we have not seen any issues with increasing them by 1 or 2 additional teeth. Just make sure you have enough clearance around the drive motor cover etc….

[@peterlord9199]

Great Video with just the right level of detail. However my Bike uses a spider with a larger chain ring can you please do a video for this setup.

[@SCOOTERETTI]

Great suggestion it's in the works. Thanks for your feedback!

[@pawelodz8050]

Hi, I need spacer from 7:40 What is typical size of this spacer? 2,5mm? 3mm?

[@wakeywarrior]

Paweł LODZ 3mm

[@ktm-bc1dw]

Excellent professional video. Helped me Thank you

[@SCOOTERETTI]

You are most welcome! Glad we could help.

[@SCOOTERETTI]

@Zaqqum Unfortunately not...... :-(

[@SCOOTERETTI]

@Zaqqum You cannot

[@SCOOTERETTI]

@Zaqqum anytime.

[@ebikeryorkshire6585]

Which way round do you install an FSA WA648 chain ribs on a gen2bosch active line motor which has a Miranda chain/ lock ring ?( the fsa chain ring has a inset on one side )

[@Mortimer50145]

I presume the chainring should be positioned on the splined shaft so the chain does not rub on the motor housing when the largest (innermost) cog on the cassette is selected and does not rub on the flange between chainring and crank when the smallest (outermost) cog is selected. Is the only adjustment the presence of the spacer ring? What if the chain still rubs on the motor housing?

[@SCOOTERETTI]

Hello, There should be no rubbing against the housing covers. If you are getting rubbing, you should ensure that the chainring has the same # of teeth as the OEM supplied the bike with. Also ensure that if a spacer came with the original chainring are being used as failure to use these (if originally equipped) will cause rubbing against the housing cover.

[@igetthepic]

If I have a 16T chainring, is it OK to go up to a 20T chainring to get a higher speed gear ratio?

[@SCOOTERETTI]

Typically we do not recommend going more than 2 teeth higher as this can trigger an error code as the original programming in the firmware will see a cadence vs speed differential. Also depending on which bike you have, you need to ensure there is enough clearance to accommodate a larger chainring. Our recommendation is to stay with the same tooth spec that the originally put on the bike from the factory to avoid any issues.

[@leo76dragon22]

Do u recommend blue locktite on the lockring? Or just grease? My 4th ride on my trek rail had a very loose chain ring...

[@SCOOTERETTI]

Always use grease never locktite and torque to the correct spec and you’re good to go

[@mikekearsley2407]

Great video, Thanks!!!!! I have a Tern Vectron with the Bosch Active line mid-drive motor. How many miles do you think I will get on the original Bosch front chainring? I have had the Tern Vectron for 5 months / 1,300 miles. I changed the chain at 1,200 miles.

[@SCOOTERETTI]

Thanks Mike. There are several factors that will determine changeout frequency like chain quality, chain wear etc... On average I would say 2000-3000 miles would be a good figure to use. If using high end chains like our Connex ones your service intervals will be longer vs say using a more standard chain. As the chains wear they cause the teeth on the rings to wear quicker. So a good thing to initially is to keep an eye on the tooth shape and when you see them change swap out the ring as it’s cheaper to do that than wear your chain and cassette out prematurely. Hope this helps. Will

[@beachmotorsport]

I need a crank bolt (Left) for a 2017 felt bike with bosch perf ..has a lasco eb06 crankset. do you sell or can you offer a link to this hardware?

[@genniz]

150$ shipping for 5 bosch orings to Norway thats insane! btw great video! :)

[@SCOOTERETTI]

Hello Eid, Our online shop can sometimes act up with the weights. If you send our admin's an email asking for a custom shipping rate they can get something to you at a lower price for sure. You can email them at [e-mail]. regards, Will

[@kvmods]

Hey, is this a gen 3 performance line CX ? are it the same chainrings of a gen 2 and 3?

[@SCOOTERETTI]

The motor shown in the video was a Gen 2 Bosch Performance CX motor and the chainrings will be different.

[@kvmods]

@@SCOOTERETTI Strange, i orderd now a new chainring and it whas for a gen 2 and i have a gen 3 performance line cx and the ring fits like a glove.

[@andymoffat8393]

Hi I see this video is based on the Bosch system. Can you do a video of how to do this on the Yamaha pw-se model ?

[@MrPinnokio]

does anyone know how many NM the hex screw needs on a bosch gen 4 fsa crankstel ? thank's

[@SCOOTERETTI]

45-55Nm is a good number to use and is what Bosch recommends typically. *Note that the manufacturer may have a different spec but these would be generally safe torque settings to use when these are not available from the manufacturer.

[@tom8181]

How do we troubleshoot it to be replaced

[@SCOOTERETTI]

You need to look at the teeth for wear. If not sure if worn replace every 3500km’s or 2200 miles to be sure.

[@kristiantomelthy6902]

Very informative! Do you know the torque for the drive unit bolts?

[@SCOOTERETTI]

This depends on which drive motor you are referring to as well as which generation as there is a difference. We suggest reaching out to the shop the bike was purchased from to get the specs on your bike to get the correct torque specifications. It's super important to get these correct.

[@NomadFM]

Why front chainring so small?

[@markotrieste]

Thank you very much for the explanation. Did all as you said, it was a piece of cake. I am still wondering however (hint for a new video ;-) ) if there is a cheap way to replace the Haibike proprietary chainrings with 5 mm offset with something non-OEM. Had to shell out 100€ for that ring...

[@SCOOTERETTI]

Indeed the Haibike chainrings are quite expensive. A colleague tried to come up with one for his Fatsix and unfortunately, it did not work out and went back to getting the original part. Not sure if anyone has had any good success using a non-Haibike offset chainring. Miranda may have something but I have personally not tried it yet. - Will

[@virkelie2]

Is that a standard seat-post or a dropper post by which you're holding the bike in the stand? Is it okay to hold an ebike by its dropper post?

[@SCOOTERETTI]

In the video, we are holding by the dropper. Ideally, you don't want to support it there. This dropper was one that was not in great shape and was being replaced anyways. Good eye!

[@virkelie2]

@@SCOOTERETTI Hey, thanks for your quick answer!

[@BlacqueJacqueShellacque_]

Chain whip works too if you've already taken the chain off.

[@OnzeManInKazakhstan]

Isn’t the chainring asymetric? As it has a front and a back?

[@joruna1]

Hi my bike motor bosch. sprocket for motor bosch xx1 eagle? Then which sprocket should I take for needles? stood x01 11 speeds, put 12 and at 3 speeds from the bottom, the top breaks the chain. from the front sprocket. on the rest is normal. Sprocket 25t. what to do?

[@daliborjani25]

Hi, what is it for bike holder with lift you are using?

[@SCOOTERETTI]

Hello, this is one of a few Park Tool PRS-33 electric lifts that we use.

[@BrianCarr]

brilliant tutorial 👍

[@SCOOTERETTI]

Thank you! Cheers!

[@yooyaa1279]

i cant unscrew the bolt, actually i can lose it but than it stops and i feel like im tightening it opposite direction

[@SCOOTERETTI]

You may have a self-extracting crank bolt. May want to check with your dealer as to whether you have a standard or self-extracting one. You want to avoid causing any damage to it.

[@yooyaa1279]

@@SCOOTERETTI hm its bosch performance line cx motor, so if its self extracting than how to remove it?

[@yooyaa1279]

@@SCOOTERETTI yes i see now, i have to use 2 allen key to take off the crank, thanks

[@gerdbartel5012]

very well done, thanks

[@SCOOTERETTI]

Much appreciated Gerd!

[@michielnoback4359]

Op 11:40 zit z'n broek vol! Linksom klikt z'n momentsleuteltje niet 🤨 Voor de rest van de video: TOP💪

[@reidwelch8419]

Subscribed! Belled! Waiting for a ring. (yep: a new fan)

[@SCOOTERETTI]

Awesome!

[@reidwelch8419]

I knew of you from the EBR forum but never till today had seen your video work. Really inspiring. Nice guys like you are the best of the best. Don't blush for being praised, for being told the truth.

[@SCOOTERETTI]

Really appreciate the kind words! Made my day

[@triv7252]

Hi Scooteretti - I want to increase the gearing (for higher top speed) on my Bosch CX, if I add a 20 tooth chain ring in place of the 17 tooth that's fitted, will it affect the electronics at all?

[@SCOOTERETTI]

I would recommend going with a 19T as 20T may trigger an error code. Make sure you have enough clearance around the plastic cover around the drive unit so that the chainring/chain doesn't rub. Some covers don't allow for much space to increase the chainring diameter. Keep in mind that you may need a longer chain as well as you may be a little short. Hope this helps, Will

[@triv7252]

SCOOTERETTI thanks Will, very helpful

[@SCOOTERETTI]

My pleasure, if you ever need anything let us know or check out our website at shop.scooteretti.com all the best!

[@JasperJanssen]

That chain looks on the long side, the derailer is very far back. Although I’d have to see the large cog to know for sure.

[@keithslater340]

Nice tool racking system. What is it?

[@SCOOTERETTI]

Hello Keith, it's simply a wood slat board system that we ended painting.

[@keithslater340]

@@SCOOTERETTI Thanks. What do you use for the tool hooks?

[@SCOOTERETTI]

@@keithslater340 I believe they are just called slat board hooks. There's a ton of different options available online. They should be pretty easy to find.

[@keithslater340]

@@SCOOTERETTI Thanks. Great videos!

[@SCOOTERETTI]

Thanks for the feedback, much appreciated!

[@Flyer2303]

Oh. Warning. Should you not remove the battery before working on the motor?

[@WeeSmokey]

That's my buddy's new bike 😂

[@AlexNijv]

Should you Grease the Sprockets inside the motor unit?

[@SCOOTERETTI]

The motors are completely sealed so there is nothing to grease internally within the drive unit. If the drive unit is exposed to excessive dirt/water there is a plastic dust cover that can be removed/replaced on the ISIS drive through. We suggest removing the cover and applying the Bosch grease in this area then replace the dust cover.

[@mrswinkyuk]

That's a lot of stress on the seat post / frame tube at that point.

[@lynnettekelley7430]

For safety sake you should have people remove the bikes battery first.

[@crozwayne]

these german built bikes are shit