Absolute Black chainring selection

one piece crank

Well-Known Member
I was looking at the Absolute Black web site to pick out an oval chainring for my 2019 Fatboy. AB states under their Oval Boost chainring, “On Fat Bikes using 26 or 28T chainrings, it is necessary to reverse the chainring dish. 26 and 28T chainring has a double-dimple mark on the front that you need to line up with the center of the crank arm to achieve proper position.” So, I’m confused.

I have the stock Raceface Aeffect/Ride crankset, and the stock 28T NW chainring is dished inward (toward the BB). Do I just measure my current chain-line (or chainring dish) and order 3mm or 6mm, whichever is closest???
 

serviceguy

Well-Known Member
Yes, what rear spacing and spindle length are being used? Race Face has a chart (actually a number of charts) that help to correctly size and install the chainring, same instructions apply to compatible rings from other brands.

I ended up with a 189mm spindle, boost chainring (not reversed) with a 197mm rear axle. Had I used a 169mm spindle I would have flipped the chainring.

Finally, I don’t thing the size of the chainring (number of teeth) has anything to do with this.

@jimvreeland may have a different take on it.
 

Dave Taylor

Rex kwan Do
I was looking at the Absolute Black web site to pick out an oval chainring for my 2019 Fatboy. AB states under their Oval Boost chainring, “On Fat Bikes using 26 or 28T chainrings, it is necessary to reverse the chainring dish. 26 and 28T chainring has a double-dimple mark on the front that you need to line up with the center of the crank arm to achieve proper position.” So, I’m confused.

I have the stock Raceface Aeffect/Ride crankset, and the stock 28T NW chainring is dished inward (toward the BB). Do I just measure my current chain-line (or chainring dish) and order 3mm or 6mm, whichever is closest???
#ovalded
 

Steve Vai

Endurance Guy: Tolerates most of us.
I was looking at the Absolute Black web site to pick out an oval chainring for my 2019 Fatboy. AB states under their Oval Boost chainring, “On Fat Bikes using 26 or 28T chainrings, it is necessary to reverse the chainring dish. 26 and 28T chainring has a double-dimple mark on the front that you need to line up with the center of the crank arm to achieve proper position.” So, I’m confused.

I have the stock Raceface Aeffect/Ride crankset, and the stock 28T NW chainring is dished inward (toward the BB). Do I just measure my current chain-line (or chainring dish) and order 3mm or 6mm, whichever is closest???

You can run it inwards on that bike. Do the 3mm.
 

T-Van

Member
Pretty sure AB site mentions 26 and 28 specifically because they have extra dots to line up with crank arm when flipped. You def dont want to get the timing off or youll end up with an old shimano biopace. lol
I never realize how much I like ovals until I ride with a round and I'm like wtf is wrong with this bike...
 

one piece crank

Well-Known Member
You can run it inwards on that bike. Do the 3mm.

Turns out 3mm is exactly the same as the stock NW ring. I finally installed the AB and took it for the maiden voyage - over a couple 100 yards last night I think I could feel it, but over 12 miles today it seemed like normal pedaling. I want to say tricky, loose climbing is better, but I also dropped two teeth so that adds to the contribution...
 
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