WARNING! To Bosch powered ebike owners (pre 2020)

[Daev]

Just check our Facebook page and scroll down to the Trek post. Not sure if the cover we speak about is fitted to your model but if it's you may want to read this post or you will be changing bearings every week!

Oh dear - thanks for that. Unfortunately I don't do social media anymore. Started with them from day 1 way back when but gave it all up a couple of years ago. Never got into Twitter or Instagram

 

[Daev]

Oh dear - thanks for that. Unfortunately I don't do social media anymore. Started with them from day 1 way back when but gave it all up a couple of years ago. Never got into Twitter or Instagram

I'll use my wife's to check it out - cheers

 

[RsGaz]

Hi @Bearing Man, just wondering if you are aware of any issues with the gen 4 cx motor, or if there’s anything you recommend to increase its longevity.

 

[Bearing Man]

Yes, remove, clean and re-grease the bearing covers every two to three months. At the same time, remove the chain from the front chainring and rotate the pedals backwards and forwards, the motor should feel free and sound quiet. Any noise, play or resistance should be looked into as soon as possible. Catching a motor problem early is the difference between replacing one bearing or one motor. BOSCH GEN 4 SEAL KIT

 

[Daev]

Just check our Facebook page and scroll down to the Trek post. Not sure if the cover we speak about is fitted to your model but if it's you may want to read this post or you will be changing bearings every week!

Yeah, got one of them - what's the solution d'y reckon ? Bigger sprocket ? Any idea where I can get one from and is it just a case of swap it for the original and all should be good or do I then have to leave the chain guide off as well ? Any idea what effect the larger sprocket would have on the gearing / strain on the motor ? Cheers ( sorry for queries but genuinely ignorant )

 

[Bearing Man]

Yeah, got one of them - what's the solution d'y reckon ? Bigger sprocket ? Any idea where I can get one from and is it just a case of swap it for the original and all should be good or do I then have to leave the chain guide off as well ? Any idea what effect the larger sprocket would have on the gearing / strain on the motor ? Cheers ( sorry for queries but genuinely ignorant )

Remove the cover and put it in the draw. Trust me, it doesn't look bad. The cover also stops you fitting a larger sprocket too! Fit a 17 tooth sprocket if you are using an 11-42 rear cassette or a 17 or 18 tooth if you have an 11-46 cassette.
The larger sprocket will help any mud that builds up to break away before coming too compacted.
It will also encourage you to use a wider range of gears because you will not be spinning out on the lower cogs all the time, this in turn will make your rear cassette last longer!
Do all that and fit a MudStop and seal and you should extend your motors life exponentially for about £45.00

 

[Daev]

Remove the cover and put it in the draw. Trust me, it doesn't look bad. The cover also stops you fitting a larger sprocket too! Fit a 17 tooth sprocket if you are using an 11-42 rear cassette or a 17 or 18 tooth if you have an 11-46 cassette.
The larger sprocket will help any mud that builds up to break away before coming too compacted.
It will also encourage you to use a wider range of gears because you will not be spinning out on the lower cogs all the time, this in turn will make your rear cassette last longer!
Do all that and fit a MudStop and seal and you should extend your motors life exponentially for about £45.00

Cheers - so very much appreciated

 

[Daev]

@Bearing Man - looks like I've got one of these cassettes, so guessing 18 tooth should be ok ?
SRAM XG-1230 Eagle, 11-50, 12-speed

The crank is one of these - Race Aeffect, 15T w/chain guard

I'm assuming this 18t should do the trick -

Sram EX1 eBike X-SYNC Bosch Sprocket – e-bikeshop.co.uk

The new Sram EX1 X-SYNC Bosch Sprocket for the complete EX1 eBike specific group set, designed to meet the demands of electric mountain biking.

www.e-bikeshop.co.uk

 

[Zimmerframe]

Yes, remove, clean and re-grease the bearing covers every two to three months. At the same time, remove the chain from the front chainring and rotate the pedals backwards and forwards, the motor should feel free and sound quiet. Any noise, play or resistance should be looked into as soon as possible. Catching a motor problem early is the difference between replacing one bearing or one motor. BOSCH GEN 4 SEAL KIT

I didn't know you did a gen4 kit. You need to do a post !!!

I take it it's really heavy if it comes with a lifting tool ?

 

[IndigoUnicorn]

How can I determine the year of my Bosch motor?

 

[Phil3]

Yes, remove, clean and re-grease the bearing covers every two to three months. At the same time, remove the chain from the front chainring and rotate the pedals backwards and forwards, the motor should feel free and sound quiet. Any noise, play or resistance should be looked into as soon as possible. Catching a motor problem early is the difference between replacing one bearing or one motor. BOSCH GEN 4 SEAL KIT

Great bit of advise
I’m all new to eMTB’s and have just got a Focus Thron² 6.9 last week with the Gen4 motor… what you’ve described above, is this fairly straight forward to do? or do you have a quick link to any video’s/instructions? cheers

 

[Bearing Man]

@Bearing Man - looks like I've got one of these cassettes, so guessing 18 tooth should be ok ?
SRAM XG-1230 Eagle, 11-50, 12-speed

The crank is one of these - Race Aeffect, 15T w/chain guard

I'm assuming this 18t should do the trick -

Sram EX1 eBike X-SYNC Bosch Sprocket – e-bikeshop.co.uk

The new Sram EX1 X-SYNC Bosch Sprocket for the complete EX1 eBike specific group set, designed to meet the demands of electric mountain biking.

www.e-bikeshop.co.uk

Yes, 18 tooth will be good with an 11-50 cassette. Not familiar with "Race Aeffect, 15T w/chain guard" so can't comment on this.

 

[Sander23]

Yes, 18 tooth will be good with an 11-50 cassette. Not familiar with "Race Aeffect, 15T w/chain guard" so can't comment on this.

Does it matter having the chainguard of miranda?
Is it necessary?
In difference with mud build up?

 

[Bearing Man]

I didn't know you did a gen4 kit. You need to do a post !!!

You just did it

 

[Bearing Man]

How can I determine the year of my Bosch motor?

Only by plugging into diagnostics.

 

[Bearing Man]

Great bit of advise
I’m all new to eMTB’s and have just got a Focus Thron² 6.9 last week with the Gen4 motor… what you’ve described above, is this fairly straight forward to do? or do you have a quick link to any video’s/instructions? cheers

Good instructions in the pack but you do need a C-clip tool which many do not posses. I will scan and add instructions soon.

 

[Daev]

Yes, 18 tooth will be good with an 11-50 cassette. Not familiar with "Race Aeffect, 15T w/chain guard" so can't comment on this.

Cheers, another cup of coffee on the way - thanks for all your help

 

[Bearing Man]

Does it matter having the chainguard of miranda?
Is it necessary?
In difference with mud build up?

Stops you ripping your trousers on the sprocket No, it makes no difference to your motor if mud packs down the front of the sprocket because it can't get into your motor from there.

 

[RustyMTB]

Wait! What, Pete? I can do a bearing clean & re-grease with just circlip pliers? This is music to my ears!

 

[RustyMojo]

it would be really helpful if there was a home ‘regular service’ guide for the Bosch 4 series motor? Or have I missed something. @Bearing Man thanks for the above. I can see me ordering the seal service kit from you regularly. But a guide would be helpful so I know what I’m letting myself in for.

In terms of annual servicing of the Bosch Gen4, what’s normally required and cost? I think I’m going to drop my motor each year to send to you.

 

[Bearing Man]

Wait! What, Pete? I can do a bearing clean & re-grease with just circlip pliers? This is music to my ears!

No, you can do a seal clean and re-grease

 

[Bearing Man]

it would be really helpful if there was a home ‘regular service’ guide for the Bosch 4 series motor? Or have I missed something. @Bearing Man thanks for the above. I can see me ordering the seal service kit from you regularly. But a guide would be helpful so I know what I’m letting myself in for.

In terms of annual servicing of the Bosch Gen4, what’s normally required and cost? I think I’m going to drop my motor each year to send to you.

No annual servicing is required. Just the seals from time to time. These motors are not really something you want to keep taking apart and putting back together again. They are the epitome of "if it aint broke don't fix it". But if anything starts to go wrong, feel wrong, sound wrong, STOP! Get it looked at because every pedal turn will cost you more money.

 

[RustyMTB]

No, you can do a seal clean and re-grease

I should choose my words more carefully Either way, I'm putting on my ordering pants.

 

[RustyMojo]

No annual servicing is required. Just the seals from time to time. These motors are not really something you want to keep taking apart and putting back together again. They are the epitome of "if it aint broke don't fix it". But if anything starts to go wrong, feel wrong, sound wrong, STOP! Get it looked at because every pedal turn will cost you more money.

That’s great thanks… is there a how to guide on the seal change so I can look at what’s involved?

FWIW you have my business moving forward, just on the amount of time you guys invest helping folks on here! Thank you!

 

[RustyMTB]

That’s great thanks… is there a how to guide on the seal change so I can look at what’s involved?

FWIW you have my business moving forward, just on the amount of time you guys invest helping folks on here! Thank you!

There's a PDF link to the process in Pete's reply to me above.

 

[RustyMojo]

There's a PDF link to the process in Pete's reply to me above.

Thanks for pointing to that, I missed it completely!

 

[Gyre]

Yes, remove, clean and re-grease the bearing covers every two to three months. At the same time, remove the chain from the front chainring and rotate the pedals backwards and forwards, the motor should feel free and sound quiet. Any noise, play or resistance should be looked into as soon as possible. Catching a motor problem early is the difference between replacing one bearing or one motor. BOSCH GEN 4 SEAL KIT

Hi Bearing Man. Thanks for your input. Do you have a video or written guide on how to do this? I skimmed through the Bosch videos you have but it didn't seem like any of them were applicable.

 

[RustyMTB]

Embarrassing but - fell at the first hurdle. Crank bolt, 8 mm allen, is locked solid. I know it should turn anti-clockwise and I'm guessing twatting it with a big 'ommer is not a good idea.
Any useful suggestions in how to get it done would be very gratefully received

Crank bolts are normally right hand thread on the drive side & left hand on the non drive side to prevent precession. You are turning the right way on the right crank, right?

 

[Daev]

Crank bolts are normally right hand thread on the drive side & left hand on the non drive side to prevent precession. You are turning the right way on the right crank, right?

yeah, sorry Rusty - just deleted the post as I sorted it - all it required was a bit of creative leverage with a breaker bar and using a mallet to prevent the crank spinning - worked a treat - onwards and upwards ..... Thanks again.

 

[Daev]

@Bearing Man - well, false starts and hiccups aside, definitely think this needs doing - many thanks. I'm now about to put an Sram 18t sprocket on. However, the 15t seems to have a 3mm offset for some reason whereas the 18t doesn't. Also, if I ditch the cover, how do I secure the sprocket in place ?. I need to clean it all up properly and observe. It's dark here now and can barely see what I'm doing.
The 15t sprocket has no label on it so can't i.d. what to look for.

Check this muck out! - 350 miles, eh?