Bosch sprocket/lockring upgrade

[batmick1]

New Haibike owner here. Despite being a longtime bike mechanic I ran into the mid-drive Bosch trap and neglected to change my chain early. I got a total of 2500 miles out of the drivetrain before noises and loose feel had me swap the chain and, sure enough, it was too late and the sprocket and smaller cogs on the cassette started slipping. D'OH!!!
My bike (2016 XDuro Trekking RX) came with an 18 tooth drive sprocket, which was a tad too small for my taste and made me spin out on a long downhill and a flat section of my commute. I ordered a 20 tooth from Connex, which also was significantly cheaper and easier to obtain than a Haibike sprocket. I like the built in chainguard of the Haibike and found a decent replacement in the form of a Miranda lockring/chain guard combo. It even comes in many different colors so I picked a red one and I think it makes for a nice eye catcher now. To round out the money saving I ordered a VAR lockring tool, which runs about half of the OEM Bosch tool, even when shipped from Spain.
See the pictures below for documentation.

Oh, and I managed to restore the 11-42 Deore XT cassette too. Only the first two cogs (11 and 13t) were worn to the point of slipping with a new chain. Turns out you can order those two cogs separately for about a quarter of the cost of a new cassette. I am using a brand new cassette now but am keeping the old one with the two new cogs as backup and should be able to milk another 1-2k miles out of it, I think.

Hope this helps some of you fellow Bosch riders out there save some money too!

 

[rich c]

I keep my chain a lot cleaner than you do, but will stop by the shop to have them check stretch. I have a little over 2,100 miles on two XDURO Haibikes. What happened to that sprocket nut in img 5089, it looks pretty beat up?

 

[batmick1]

I keep my chain a lot cleaner than you do, but will stop by the shop to have them check stretch. I have a little over 2,100 miles on two XDURO Haibikes. What happened to that sprocket nut in img 5089, it looks pretty beat up?

That chain is almost new. Has two days of commuting on it, maybe 75 miles. I have a stretch tool but didn't care to check it as early as I should have. From my regular bikes I am used to 2k+ miles and my previous commuter had a Gates belt drive where I didn't have to deal with the whole lube and stretch issue at all.

I chewed up the lockring because I was impatient and tried with a spanner tool that wasn't made for the Bosch ring. Another reason I wanted to replace it. The Miranda works great for that.

 

[rich c]

That chain is almost new. Has two days of commuting on it, maybe 75 miles. I have a stretch tool but didn't care to check it as early as I should have. From my regular bikes I am used to 2k+ miles and my previous commuter had a Gates belt drive where I didn't have to deal with the whole lube and stretch issue at all.

I chewed up the lockring because I was impatient and tried with a spanner tool that wasn't made for the Bosch ring. Another reason I wanted to replace it. The Miranda works great for that.

What lube do you use? Surprised that it looks like that in 75 miles.

 

[batmick1]

What lube do you use? Surprised that it looks like that in 75 miles.

I swear by the stuff below. Chain-L No.5.

Very sticky so it a little harder to apply but once it is inside all the rollers it lasts a long time. Because it is so sticky it tends to attract more dirt on the outside but I don't mind. It keeps it running smooth and quiet for much longer than anything else I tried.

 

[rich c]

You don't think it attracts dirt on the inside too? I don't find it a big deal to clean and lube. I use Boesheild T9. I'll let you know what the gage says when they test it for stretch. I never have a slip on a gear, I'll be surprised if they are worn out.

 

[Johnny]

Although my sprocket and Cassette (except the second cog) works fine I am planning to change the cassette and the sprocket after the third chain.

I am planning to go for Connex 20T as you did, I was wondering if chain guard is necessary? I could only find Miranda on EU stores and if it is ok to run bosch motors without a chain guard I will just install the sprocket.

Another question is that can Connex sprockets be flipped and used on both sides (they look symmetric)?

I couldn't find individual cogs (I need the second smallest cog) for sram pg 1030 (or 1020 I don't know which one I have) so next time I will also go for Shimano XT cassette where individual cogs are also available. How is the durability of XT cassette?

 

[Alaskan]

I get around 2500 to 3000 miles on an XT cassette and around 1,200 miles on a chain. I replace the chain at .5% stretch. I went from 15 to 18 tooth chain ring on my Riese & Muller Delight in order to get a taller top end speed. However that lost some low end hill climbing ability. I went from a 11-42 tooth cassette to and 11-46 cassette which recovered some some low end climbing. I wish the Delight had the same belt drive as my Homage...not chain cleaning, no oil or mess, just keep on riding...I really hate chains. Where did you buy the 11 and 13 tooth replacement cogs for the cassette?

 

[batmick1]

I also get around 1200 miles per chain, on average. Like Alaskan, I replace the chain when I hit 0.5% stretch according to my Park tool. When sticking to this regimen I get about 5k miles per cassette or more. I'm approaching 10k miles on my bike and am on the third cassette.
I got those cogs from WorldwideCyclery.com but have seen them elsewhere too. But they are only available for Shimano, as far as I know.
You can ride the Connex sprocket without a guard but two problems arise: 1) you are directly exposed to grease and grime on that side so you need to make sure pants, socks etc. stay away from it. 2) depending on the chainline on your bike, the chain has a tendency to jump off the small sprocket and with a chain guard this usually has no consequence but without it will fall off. There are washers to place under the sprocket to correct chainline issues. The original Haibike sprocket with the integrated guard sits 1-2 mm further out than the Connex.

 

[Alaskan]

Sram makes a really nice Bosch compatible chain ring with a variety of teeth numbers. In order to take full advantage of the Bikespeed RS delimiter I installed on my Riese & Muller Delight Mountain I bought a 18 tooth chain ring made by Sram for $15.99 shipping included on ebay. It is way better made than the stamp cut ring made by Connex. It is cast and has more substantial teeth and comes with a 2mm spacer ring to use or not in aligning the chain ring. My bike came with the Miranda lock ring/chain guard combo which is now just large enough. It would not really be functional with more teeth than 18.

Now I am spinning at 90 rpm going 33mph in top gear (11 tooth). In order to regain lost climbing power I swapped out the 11 speed Diore XT8000 11-42 cassette for an 11-26 tooth one.

 

[batmick1]

Sram makes a really nice Bosch compatible chain ring with a variety of teeth numbers. In order to take full advantage of the Bikespeed RS delimiter I installed on my Riese & Muller Delight Mountain I bought a 18 tooth chain ring made by Sram for $15.99 shipping included on ebay. It is way better made than the stamp cut ring made by Connex. It is cast and has more substantial teeth and comes with a 2mm spacer ring to use or not in aligning the chain ring. Now I am spinning at 90 rmp and going 33mph in top gear. My bike came with the Miranda lock ring/chain guard combo which is now just large enough. It would not really be functional with more teeth than 18.

In order to regain lost climbing power I swapped out the 11 speed Diore XT8000 11-42 cassette for an 11-26 tooth one.

View attachment 38329

Yes, those SRAM sprockets are much better quality. I have an 18t one as well but could not find any bigger ones. But this came with a washer that I am using under the Connex 20t now. I am keeping the SRAM as backup.

 

[Alaskan]

Yes, those SRAM sprockets are much better quality. I have an 18t one as well but could not find any bigger ones. But this came with a washer that I am using under the Connex 20t now. I am keeping the SRAM as backup.

Isn't the 20 tooth chain ring sitting a bit proud over the circumference of the Miranda chain guard? or were you able to find a larger diameter chain guard?

 

[batmick1]

Isn't the 20 tooth chain ring sitting a bit proud over the circumference of the Miranda chain guard? or were you able to find a larger diameter chain guard?

Check the picture from earlier up. The 20t has the edge of the chain flush with the Miranda guard. Good enough for me.

I did make a modification, though, because I had the occasional chain drop and it got stuck between the sprocket and the Miranda guard. I cut a thin plastic disk to fill the gap and filed it so any dropped chain is slid right back onto the teeth of the sprocket.

 

[Johnny]

Some very good info thank you Alaskan and Batmick1.

I wanted to go Sram but the largest I found was 18T, I really want a 20T since I don't want to use 11T cog in the cassette that much.

Also it would be great to have a chain guard like this https://www.electriccyclery.com/sho.../bosch-parts-motor-electric-bike/chain-guard/ . Do I still have to use miranda guard with a guard like this?

 

[Alaskan]

Some very good info thank you Alaskan and Batmick1.

I wanted to go Sram but the largest I found was 18T, I really want a 20T since I don't want to use 11T cog in the cassette that much.

Also it would be great to have a chain guard like this https://www.electriccyclery.com/sho.../bosch-parts-motor-electric-bike/chain-guard/ . Do I still have to use miranda guard with a guard like this?

The Miranda would not be needed for that one but you need to make sure it will work with your particular motor cover. I had the exact same one on my Cube Touring Hybrid 500EXC It requires you to remove the right crank and chain ring and take off the motor cover, install the mounting plates with the tab extending through 2 slots in the motor cover, reinstalling the chain ring and the cover then mounting the chain guard and finally the crank. Make sure your motor cover has the slots in the correct location for the mounting tabs to poke through,

Another one that I like and have on my wife's homage is made by Hebie and available HERE The chain guard extension is a bit longer on this one than the one you showed and also needs a different 3 slot pattern in the motor cover than the one you showed which has two slots.

 

[batmick1]

Some very good info thank you Alaskan and Batmick1.

I wanted to go Sram but the largest I found was 18T, I really want a 20T since I don't want to use 11T cog in the cassette that much.

Also it would be great to have a chain guard like this https://www.electriccyclery.com/sho.../bosch-parts-motor-electric-bike/chain-guard/ . Do I still have to use miranda guard with a guard like this?

I don't think you do. I have only seen pictures of this guard, never seen one in person. I'm curious as to how it is attached.

 

[MarkF]

I have a FSA 38 tooth chain ring on my Raleigh retroglide ebike with active line plus motor. I'm spinning like a hamster close to 20 mph. It has a 12-32 8 Speed cassette. I know I can add an 11-34 but wonder if I can get a 40 or 42 for the front. Any ideas? Iv'e tried searching but not sure what I'm looking at is the right one that will fit.

 

[Quito]

Sram makes a really nice Bosch compatible chain ring with a variety of teeth numbers. In order to take full advantage of the Bikespeed RS delimiter I installed on my Riese & Muller Delight Mountain I bought a 18 tooth chain ring made by Sram for $15.99 shipping included on ebay. It is way better made than the stamp cut ring made by Connex. It is cast and has more substantial teeth and comes with a 2mm spacer ring to use or not in aligning the chain ring. My bike came with the Miranda lock ring/chain guard combo which is now just large enough. It would not really be functional with more teeth than 18.

Now I am spinning at 90 rpm going 33mph in top gear (11 tooth). In order to regain lost climbing power I swapped out the 11 speed Diore XT8000 11-42 cassette for an 11-26 tooth one.

View attachment 38329

@Alaskan - thanks for posting this chainring info. Do anyone know if this will also work on my wife's 2018 Bulls SixFifty E2 Street, that uses the Bosch Performance Line Speed motor? Her bike currently has a 15T chainring, and we want to swap it out with an 18T. Thanks in advance!

 

[Johnny]

@batmick1 I am reviving this thread since I will be changing the chainring (plus cassette) on my CX. I will also be installing Connex 20t, current one is 18T like yours, I was thinking maybe I should cut the new chain a full link longer. Did you change the size of the chain or is it the same length as before ?

 

[batmick1]

@batmick1 I am reviving this thread since I will be changing the chainring (plus cassette) on my CX. I will also be installing Connex 20t, current one is 18T like yours, I was thinking maybe I should cut the new chain a full link longer. Did you change the size of the chain or is it the same length as before ?

Honestly, I do not remember. But I would just give it a shot and see if you have too much slack for your derailleur spring or not. Then shorten if needed.