Sram Big Chain Ring Issue

Discuss light weight issues concerning road bikes & parts.
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Mr.Gib
Posts: 3552
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

I installed a new BB30 Sram Red crank. Immediately I noticed that sometimes it would fail to pick up the chain for an entire half rotation. Looked at it on the stand and discovered that two of those four little carbide steel protrusions absolutely will not pick up the chain. The chain just slips over them. I checked my other Red Cranks (7) and they are all fine except for one which also had two of those little protrusions that would not lift the chain. But they were not consecutive so it didn't seem to be much of an issue. On the new crank they are consecutive so you really notice it. Sram will replace the chainring no doubt.

I suspected chain wear but if that was the cause then why always missing on the same spots and never others. Also, I measured the chain and it is not elongated.

I was curious if this was a widespread issue - anyone else had this problem. Couldn't find mention on the net.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

dudemanppl
Posts: 914
Joined: Fri Feb 22, 2013 5:09 am

by dudemanppl

Prob FD setup issue then.

by Weenie


Mr.Gib
Posts: 3552
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

dudemanppl wrote:
Tue Feb 26, 2019 1:46 am
Prob FD setup issue then.
Good sir, you underestimate me. I naturally tried a spare used ring and indeed it shifts just fine.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

2lo8
Posts: 539
Joined: Thu Mar 31, 2016 10:32 am

by 2lo8

I don't have Red rings, but there was something similar for a 50t rival ring I had. I think there were 4 pick up pins in 2 pairs. The problem is the pins should be offset so if one pin in a pair gets an inner link, the other should get an outer link. Instead each pair was timed so both pins an a pair got either inners or outers and the pair on the other side got the opposite.
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wheelsONfire
Posts: 2750
Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

Do you use Etap?
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

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