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Where to get bosch cx chainring ?

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Hey guys and girls, im new to the site and have a similar problem as i purchased a KMC super narrow 20 tooth chainring for bosch performance line cx gen 2, it fits snug in the splines but can slide laterally as the lock ring does not press against it. I will send a few photos, any advice would be much appreciated
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was the sprocket you took off of set? ie spaced out from the motor so there was a gap?

Thanks for you're quick reply, Yes it was a 16 tooth offset as the wheels are boost, i was thinking i might grind the original cog down and use it as a spacer.

Also is there any app for this website or a way to get notifications when receiving a reply?

Go to the top of this thread and click the 'Watch' button and then you'll have a choice as to whether to receive notification by email.

 

1644228316663.thumb.png.4d2964e5af21f17a086911054bd18b9e.png

Go to the top of this thread and click the 'Watch' button and then you'll have a choice as to whether to receive notification by email.

 

[ATTACH type=full" alt="45634]45634[/ATTACH]

i didn't see that before, much appreciated bikes4two

https://www.ebay.co.uk/itm/124728654778?hash=item1d0a683bba:g:OA4AAOSwpHpbKRAb

 

this has a 2.5mm off set so if you can find a 20t one you can run a normal 18t behind it and then the lock ring you have will work.

 

you could also grind of the thread of one lock ring and the use that as a spacer with another lock ring.

 

the sprocket is off set for a reason so using one with no off set could wear the cassette down faster as the chain line wont be right.

 

https://www.ebay.co.uk/itm/124728654778?hash=item1d0a683bba:g:OA4AAOSwpHpbKRAb

 

this has a 2.5mm off set so if you can find a 20t one you can run a normal 18t behind it and then the lock ring you have will work.

 

you could also grind of the thread of one lock ring and the use that as a spacer with another lock ring.

 

the sprocket is off set for a reason so using one with no off set could wear the cassette down faster as the chain line wont be right.

 

https://www.ebay.co.uk/itm/124728654778?hash=item1d0a683bba:g:OA4AAOSwpHpbKRAb

 

this has a 2.5mm off set so if you can find a 20t one you can run a normal 18t behind it and then the lock ring you have will work.

 

you could also grind of the thread of one lock ring and the use that as a spacer with another lock ring.

 

the sprocket is off set for a reason so using one with no off set could wear the cassette down faster as the chain line wont be right.

 

i dont have a spare lockring as the bike came with a miranda chainguard nut and the 20t i bought had no lockring with it, not that i expected one as it was just under 13 pounds.

 

I will try grinding the original cog first, if it does not work for whatever reason i will defo look at buying another cog from the site you mentioned above, thank you so much for taking the time to help me out, also is that your bike in video?

yes it is my bike but when i had it from new it had a haibike sprocket fitted so the lock ring is 2 times the thickness of a normal one and i cant find one for sale anywhere atm.

 

 

 

might be a long shot but try peter and see if he has one or can get hold of one as fixes alot of bosch motors.

 

https://www.ebikemotorcentre.com/

 

DSC_0160_02.thumb.JPG.570bf935da7592e021d18b67896b4078.JPG

 

as you can see if i used that blue lock ring it is to short but will work with 2 sprockets on the front like in the vid above.

Edited by soundwave

https://www.ebay.co.uk/itm/294605966688?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D236786%26meid%3D87c9f3c7846e4a4992d86f916d6cd978%26pid%3D101195%26rk%3D1%26rkt%3D12%26sd%3D275087120140%26itm%3D294605966688%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv9PairwiseWebMskuAspectsV202110NoVariantSeed%26brand%3DBosch&_trksid=p2047675.c101195.m1851&amdata=cksum%3A29460596668887c9f3c7846e4a4992d86f916d6cd978%7Cenc%3AAQAGAAACEEz4ynONEHbFb2Jj2rUwHbK4ZiFKD6EakGPWjuBMt7socmo3fcX%252F2Xqp50DnCtkB8hCHGN%252BEzR8i8HRvhpZhlbZP57TA8pUtWdNPZAuBorI0xZFtmV0tHi5Qg%252FRKe6u5tg8XgQDfM5oXyRovwQ826Vdh26UvHgh5C%252BTQ5Ww0JCBuxOlwbyORJbIUYw0ud6SR3YnDRvOWxipKdEA448zjsOgDSK%252F%252FnaZkeXlexd%252FES3lTV7NsuKsmZ9NL%252FcdWsW8jdeM%252BMBuyW8vr%252FZn9TAvRZEDo286akgrXUm%252FYral13e%252FUdNOnPIjRYhhgG7bDy0rmmZqHy%252B1irkQCjfzw6kaMSTwiy9Va6n%252FCGSywJ5%252F0Xw0kV%252BaLKhDhrncXgxfJyrSjt9wqFXDZUsyz03sZ276rGG%252BiNyqyeeDg8DB51N4DKNGjIbd97FcFiDzwmiYA0wX760qmuUGIvapCl2mUVe6%252FEBOx2BASDvil9LcE2ceEm8Iy%252F7oELPKZcypW3%252F4BiaFuN1EdZKaT5i3ZVp5TfwiJhNE3ZARhGETpNFdIW%252Fph4ZaCHWK5i2dTI28mZf3%252Bx26eHMD0rnajXm12Z5d4XRya9MZA7qdTSWNapWCbH3moBd%252FPqo9EkKO%252F8NoUzi1w4vM%252F%252FEpHwzhSEkjPV9WEjWLDc6D6%252FAtB%252Fs3F0aRoXI6DT5wnzsMVtbNaIPhqUGu53fXPlA%253D%253D%7Campid%3APL_CLK%7Cclp%3A2047675

 

it still does not look as thick as the one i have tho.

so many options to choose from and thanks for the photos they really help, i may invest in a decent digital caliper so when i grind the original sprocket i can make both exactly the same thickness as the original. i will also send a few photos soon so you can have a gander, also i think you have the same sprocket as me

i have 3 options for front sprockets.

 

1 20t

dual 20t and 18t with the blue lock ring

18t xsync as use 12spd eagle

 

DSC_0110_02.thumb.JPG.b14f6d62d3741756470c43e7c0bac4ce.JPG

 

you can not pull that chain off as locked on to it but only go up to 18t, haibike make a 20t one with xsync and its £100, and that one cost 20 quid :rolleyes:

 

20t is about as far as you can go any more and it out gears the motor with 25t it is pretty much useless even on the flat.

DSC_0673_01_01.thumb.JPG.73e9ca8356b84fd875eea8cb9a28f5d4.JPG

  • 2 weeks later...
hope everyone is well, been very busy lately but the modifications to the cog are finally underway. annoyingly though i have strange wear marks on every other tooth of the new sprocket i think thats why im feeling a buzzing in the frame (it is not audible only felt)

20220217_140813.thumb.jpg.8010851018b55b5dfaca59079f8c1d62.jpg

Edited by Chris vicious

here is the cog with custom spacer on the shaft, still needs about 1mm shaved of but my main objective is keeping it level both sides

20220217_140916.thumb.jpg.21ebbd5431735c5f1ba6452742876c03.jpg

that spacer is way to thick as the sprocket is pushed to far out.

indeed, im grinding it down by hand as we speak, it takes longer but i dont want it to thin as i want to make sure the lockring will compress againgst the sprocket

any ideas about the wear marks in first pic? it must be from the inner links but it never happened on the original cog, chain is kmc e11 so it should fit fine, maybe it is wearing in but still srange

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