12 Speed Chain & 11 Speed Drive Train - Less Noisy?

Discuss light weight issues concerning road bikes & parts.
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SgtRock
Posts: 41
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Just buuilt up a new ride which has a tight rear triangle (405mm) stays. Chain runs very quiet when in small chain ring in all rear gears but on the large chaingring (50t) it becomes increasingly noisy from 21 to 28t sprockets. Nothing terrible but I'm very noise sensitive and the rest of the bike is lovely and quiet. Checked that there is nothing rubbing on front mech etc. thats all good. The chainset is Sram Red with stock rings (which are new) and there are no spacers in the BB. The chain is fairly new and length is all correct.

So pretty much nothing else to look at. But I had a throught that with the introduction of 12 speed groupsets and their narrower chains would this give a move flexible chain that would run quieter on tighter chain angles? As I understand chain development, as the number of speed have gone up, the internal width has stayed the same, and by association so have sprocket and chainring widths but the outside diameter has narrowed i.e.the plates and pins are narrower. So a 11 speed chains runs ok on 10 speed rig. So that got me thinking would it be quieter?

Obviously not many 12 speed road chain choices out there at the moment other than Campg although I think KMC are just launching a 12 speed chain.

Any thoughts or experiences?

alcatraz
Posts: 2057
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Is the chain tension very low in small/small? If not you could use some less tension.

It's one of the reasons big/big gets noisy. That and the chain angles.

/a

by Weenie


SgtRock
Posts: 41
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Update on my chain noise issue.

No problem with B-screw position and chain tension. Tried switching out the SRAM Red chain for a Shimano Dura Ace chain, which is a tiny bit smoother, but the basic problem is still there. Since the noise is coming from the large chainring I check the chainset chainline. Sram lists Red Etap crank has having a 48mm chainline for the large ring. Shimano and Rotor have a 43.5mm chainline - so 4.5mm difference. Seems like a significant difference and could easily be the cause of the problem.

So anyone had a similar problem? I'm now thinking if I want things quieter I will have to fit a Rotor crank set. If I go with the 24mm axle option will have to change the non driveside bearing from 22 mm to 24mm.

Any experiences?

Hexsense
Posts: 807
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

wow that Sram chainline sound perfect for disc brake frame 135 or 142 rear spacing.
Did they know that the futire is disc brake a long time ago?

SgtRock
Posts: 41
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Maybe in error on chainline. Hadn't appreciated it is measured between chainrings. If SRAM quote 40mm inner and 48mm outer then 44mm is the chainline so not really any different from Shimano or Rotor. So no just got to learn to avoid the worst crossover. Certainly not been a problem on on other of my rides which all run SRAM. Chainstays are a bit longer which would help I guess.

SgtRock
Posts: 41
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Noise update.

After more digging around on the web it turns out chainline measurements are not necessarily straightforward to interpret. As I said the Sram chainset had an outer chainline of 48mm and an inner chainline of 40mm this makes a chainline of 44mm, measured halfway between the chainrings, which seems to be how most manufactures measure chainline. So Shimano and Rotor have a chainline of 43.5mm but I read somewhere that the inner chainring is at 41mm and the outer 46mm. 5mm difference which gets you to 43.5mm.

So when measureing at the centreline of the chainset there is only 0.5mm difference between the Sram chainset and a Rotor of Shimano chainset but at the outer position 2mm. So I decided to buy a Rotor 3D24 chainset. Changed out the non driveside bearing and installed the new unit and all is now quiet. So 2mm seems to make a big difference.

Happy boy now.

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wheelsONfire
Posts: 2750
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

Sram spec on chainline is 45mm
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

by Weenie


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