Rotate/flip chainrings to spread wear?

ColinJ

Puzzle game developer
I have a triple chainset on my Basso. I have just stripped the transmission down to clean it and to replace the bottom bracket.

In doing so. I noticed that the middle and little rings are starting to show visual signs of wear. (The chain is not slipping so the wear is not yet too bad, but I don't want to wait that long before tackling the problem.)

The chain is ok (only about 1/32" wear over 12 pairs of links). I think there is scope for spreading the wear on the rings by turning the middle ring through (say) 2/5 of a revolution i.e. 2 fixing bolts worth. My thinking is that most of the drive from the ring comes through the downstroke of the pedal and the corresponding teeth on the ring.

The middle ring is a TA replacement for the original Campagnolo ring. It does not have any ramps or pins on it so it should not matter if I rotate it and reattach it. (I can't flip it because there are recessed holes for the mounting bolts on only one side of the ring.) If this trick works, I should be able to do it another few times to spread the wear out round the ring before it finally needs replacing.

The little ring is another non-Campag ring. That one does not have ramps or pins either so I can rotate it. I also have the option of flipping it because the two sides of the ring are identical. That would spread the wear out round the ring and also allow me to wear both edges of its teeth.

The big ring has a pin on it to stop a shipped chain getting trapped between the ring and the crank so that one's orientation is fixed. There is not much wear on the big ring anyway, so that doesn't bother me.

I will give this a go. I was just wondering if anybody else does this, and if so, what the results are? In theory, it ought to significantly extend the lifetime of the rings?
 

MisterStan

Label Required
I'm not convinced.
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
Check the offset of the teeth. Some rings are off set so the teeth may be further to one side of the ring. Down side is the bolts won't be recessed properly on the middle ring and may catch if on the granny ring.
 

Smurfy

Naturist Smurf
I rotated 1 bolt hole backwards last week. I think this is the best bet, as 72 degrees rotation is much closer to 90 degrees rotation than 144 degrees (2 holes) is, and anything close to 180 degrees rotation merely switches the load from one pedal to the other. Looking at the wear pattern also seems to suggest that 1 bolt hole backwards will load up previously unworn teeth from further forwards around the ring.
 
OP
ColinJ

ColinJ

Puzzle game developer
'Not worth it' = 'Money no problem'! If I had money to burn I wouldn't be asking ... :okay:

Chain rings wear very little ...
But they do wear out eventually ... I have worn chainrings badly in the past and noticed that the wear is not even round them. It seems daft to chuck away rings that could potentially be made to last quite a lot longer with a few minutes work.

As mentioned in the original post - the middle ring can't be flipped but can be rotated. The little ring can be flipped and/or rotated.

I rotated 1 bolt hole backwards last week. I think this is the best bet, as 72 degrees rotation is much closer to 90 degrees rotation than 144 degrees (2 holes) is, and anything close to 180 degrees rotation merely switches the load from one pedal to the other. Looking at the wear pattern also seems to suggest that 1 bolt hole backwards will load up previously unworn teeth from further forwards around the ring.
Ah - good point ... Rather stupidly, I forgot that the chainring is being maximally loaded twice per revolution not once - d'oh! :wacko:

... and Ribble sell stronglight rings cheaply.
Hmm, yes - those are pretty cheap! What are Dural and Zicral alloys like compared to the alloy used in Campag/Shimano/TA rings in terms of wear resistance?
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
Both are fine. I have used the cheaper Dural on my Ribble for years. The Zircal is a higher quality on a par with higher end Shimano and Campag. The finish is lovely and there are shift pins and ramps as well as laser etched. I have the Zircal on my Herety and I'd say as good if not better than the Dura Ace they replaced.
 
Location
Pontefract
Got to agree with @fossyant about the finish, @ColinJ you know spacycles, they have there own Zircal a £15 for the inner rings £20 for the outer both pinned and ramped. This is mine after 3,000 miles
_MG_4278.jpg
Bit mucky I know, this when new
_MG_2704.jpg
_MG_4380-2.jpg

Edit £15 for the middle rings, the inner are £10
 
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