I have oval chainrings on all my bikes as I just like them.
I started commuting on an ebike with round chainring and it's a really weird transition between bikes.
It's got square taper 130bcd 5 bolt cranks. It also need to be narrow wide because I keep dropping the chain even with a clutch mech. So it basically meant new crank time.
The bottom bracket has all sorts of sensors in it so I am stuck with square taper. I also like the 42T ratio so my only choice is a Middleburn with a 110bcd 5 bolt spider paired with a Absoluteblack chainring.
The instruction from Absoluteblack is to mount it in the outer chainring position. Unfortunately, the chain line isn't ideal, so I flipped the chainring and mounted it in the middle ring position which gave a really good chain line. I also rotated it to match the clock.
Correct:
Planned:
I can't see anything wrong but asked Absolutblack if it is OK to mount it like that anyway. They just reply saying it will cause "full drive train failure" I asked them to explain, also sent them the photo above in case I didn't explain it very well first time round.
No reply yet but I am going to ride it into work like that tomorrow, am I going to cause "full drive train failure" or am I going to be fine?
The owner of absoluteblack is a bellend and compulsive liar, not sure if that's the problem here though.
I think you'll end up with excessive wear on the chain which will also impact all of the other parts....
By flipping the ring , you've also flipped the orientation of the teeth which are profiled so that they don't wear the chain. The chamfer on each tooth is greater on one side?
But I could be wrong.
Also the orientation of the ring is incorrect in that bottom photo....
I'd use it in the middle ring, in the correct rotation and orientation, but with longer bolts...
The problem is the thread is in the chainring:
That's why I couldn't just use a longer bolt. I am thinking the chain is symmetrical so must the profile of the ring, but I could be wrong there.
They just reply saying it will cause “full drive train failure”
I wonder if that reply came with a heavy dose of sarcasm from someone who couldn’t be bothered?
I also rotated it to match the clock.
So long as the built in standoff is between the ring and the spider I suspect it will be fine or, if you haven’t got the clock right, it will feel a bit weird at worst
That potential teeth profile chamfer difference worried me as it makes sense, so I have flipped the chainring back to the correct orientation.
Let's see if I get another reply from them. If I don't hear anything by middle of next week, I am going to do some measurement on the tooth profile before trying it again. I am so boring...
I tried riding with the bad chainline and it was absolutely horrible. The chain was super noisy and it change gear when I am back pedaling, so I have to do something about it.
I looked at the tooth profile and it's definitely not symmetrical so mounting it in reverse is not an option:
So did a bit of thinking and decided to lock a single ring chain ring nut onto a stack bolt. I have ordered some proper chain ring washers but the brake caliper banjo crush washers I have in my toolbox are the right size so I have used them for now:
Perfect chainline now with one washer each side and I am finally happy, just wished I thought of that first:
