Chain ring Line??

[Husky430]

Looking to overhaul my drive line on my now 2 year old Sam 6.9.
Got nearly all the components except the chain ring, looking at buying a Race Face one from Fox Australia as only one I can find but there is a section for chain line in mm's, one is 52mm and the other is 55mm's.
Anyone know what they are measuring or which is the correct one for my bike? Can't really see what a BIG difference 3mm will make but it must be for some reason.
Thanks in advance, cheers Steve

 

[irie]

I may be completely wrong and stand to be corrected, but I think that 52mm is Boost whereas 55mm is Super Boost ...

 

[steve_sordy]

See Husky430's post on "chain ring line". If you have a 12-speed it will, be a 52mm chainline.

 

[irie]

See Husky430's post on "chain ring line". If you have a 12-speed it will, be a 52mm chainline.

I was replying to the first post in this thread, made by Husky430.

 

[Husky430]

Thanks fellas, have been looking for one in oz online but can only seem to see a 36 tooth version, all the 34 s seem to be sold out, there are some alloy ones but are 3 times the money of a steel one so need to keep looking or ask where I bought the bike for a genuine Focus one. Have any of you tried a 36 over a 34, guessing there won’t be a huge difference, I’m thinking this way as a last resort.

 

[irie]

Thanks fellas, have been looking for one in oz online but can only seem to see a 36 tooth version, all the 34 s seem to be sold out, there are some alloy ones but are 3 times the money of a steel one so need to keep looking or ask where I bought the bike for a genuine Focus one. Have any of you tried a 36 over a 34, guessing there won’t be a huge difference, I’m thinking this way as a last resort.

Am in the UK. Looked for 34T steel Bosch E*Spec DM Chainring (CR4USA-100), seems to be out of stock everywhere. As you say, the alloy version is available but 3 times the price.

 

[steve_sordy]

I was replying to the first post in this thread, made by Husky430.

My apologies, I was replying to @RustyMTB in his Focus Jam2 chainring thread, I was swapping back and forth between the two and got it wrong!

 

[Alfmeister]

I have a 2024 Orbea Wild, and was looking at changing my chain ring, but also baffled by which version I need, 52mm or 55mm?

 

[Mikerb]

I have a 2024 Orbea Wild, and was looking at changing my chain ring, but also baffled by which version I need, 52mm or 55mm?

my understanding has always been as was stated further up the thread............most 1x12 systems are 52mm chainring= boost.

I think 55 is however now recommended for SRAM T Type 1x12 transmission? Maybe someone else can confirm that...or not.

 

[Amber Valley Guy]

Not sure on your specific bike frame so take this with "possible" but might not be a problem. A larger chainring with, even only two extra teeth, will have a larger diameter which can cause clearance problems with the kink in the chain stay.

 

[Alfmeister]

I’ve just removed the chain ring (after ordering and receiving the correct castle nut tool), and my espec erhirteen sprocket is a 53mm chain lin, but on the rear it has the following text “spacer on this side: 55mm chain line”, and there is a 2mm spacer, giving my Orbea Wild Bosch gen 4, a 55mm chain line.

Need to get a new O ring, as Orbea had mashed it up at factory installation!

 

[irie]

When I changed the chain ring, as recommended by Bosch, I used a new nut but didn't bother with the O-ring because it was bound to be squashed and/or ripped when the nut goes on. Used a bit of blue Loctite. And IIRC the new nut had 35Nm marked on it instead of the 25-30Nm marked on the old nut.

Bosch Gen 4 Chainring Nut printed Torque of 25 to 30 NM is likely wrong

Okay so Europe and US Bosch disagree. Indeed. Or verbal statements differ from written statements as the latter could engage responsibility in case a strong torque would create damages. you could try to get a written statement of the US support, as I managed to get in EU ;)

www.emtbforums.com

Then marked tell-tales on the cranks so can see if it they've moved.

 

[Stihldog]

I’ve recently installed a partially refurbished Bosch gen4 motor. The original castle had come loose (after multiple R&R’s) on the original motor.

I suspect that the fine-threads , on the aluminum castle nut, have become stretched or worn. Blue loc-tight would no longer keep the nut in position or the correct torque.

For a few dollars I installed a new castle nut and keep another as a spare.


I also ordered the rubber O ring but I never used it. I used the thin plastic O ring along with gobs of grease. The chain alignment of the e-thirteen wouldn’t allow for the brass O ring. But it still works

 

[Mister cube]

I’ve recently installed a partially refurbished Bosch gen4 motor. The original castle had come loose (after multiple R&R’s) on the original motor.

I suspect that the fine-threads , on the aluminum castle nut, have become stretched or worn. Blue loc-tight would no longer keep the nut in position or the correct torque.

For a few dollars I installed a new castle nut and keep another as a spare.

View attachment 152728
I also ordered the rubber O ring but I never used it. I used the thin plastic O ring along with gobs of grease. The chain alignment of the e-thirteen wouldn’t allow for the brass O ring. But it still works

Castle nuts are single use only,as you correctly assumed they are stretch threads,i do same as you,put a new one on,and get a spare.

 

[Mister cube]

I’ve just removed the chain ring (after ordering and receiving the correct castle nut tool), and my espec erhirteen sprocket is a 53mm chain lin, but on the rear it has the following text “spacer on this side: 55mm chain line”, and there is a 2mm spacer, giving my Orbea Wild Bosch gen 4, a 55mm chain line.

Need to get a new O ring, as Orbea had mashed it up at factory installation!

View attachment 152717 View attachment 152718 View attachment 152719

Get a new castle nut as they are a stretch threads and single use only,and get a spare,30 nm is the torque for it

 

[irie]

Get a new castle nut as they are a stretch threads and single use only,and get a spare,30 nm is the torque for it

The torque for the new castle nuts is engraved on them, it is 35Nm.

Bosch Gen 4 Chainring Nut printed Torque of 25 to 30 NM is likely wrong

Okay so Europe and US Bosch disagree. Indeed. Or verbal statements differ from written statements as the latter could engage responsibility in case a strong torque would create damages. you could try to get a written statement of the US support, as I managed to get in EU ;)

www.emtbforums.com

"Guess what the new Bosch lockring that I just bought and installed says on it? 35 nm

Lockrings dated 11-2018 said 25-30nm

This lockring dated 10-2023 says 35nm"

 

[Mikerb]

Torque for any nut is determined by the manufacturer so a new supplier using a higher grade ally is probably the reason for change in torque for later castle nuts.
I agree that the nut is single use simply because it is ally with very threads being such a thin nut.