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Just bought new middle chainring for my worn truvativ noir chainset (plus chain and cassette)
The big ring states 104bcd so I've bought a 104 PCD SHIMANO xt ring and it doesn't fit. Are they different standards?
Do I have to buy a truvativ ring?
In what way does it not fit?
The flat edge of the ring inside the bolt holes that locates against the crank spider are way off
Shimano like making their parts incompatible with other brands. You can remove some material to make it fit.
BCD - Bolt Circle Diameter (Bike specific)
PCD - Pitch Circle Diameter (Universal standard)
What he said, just file the chainring down till it fits
Shimano like making their parts incompatible with other brands
Campagnolo cunningly put one hole on a slightly different BCD to the others too 👿
Ok will do thanks
Had to take a surprising amount of material off but did it evenly on all 4 and all fits nicely now. Thanks
What he said, just file the chainring down till it fits
This.
Campagnolo cunningly put one hole on a slightly different BCD to the others too
As do Shimano on their newest groupsets, but on the road that does mean you can run compact or standard rings without having flexy rings or needing to change spider.
I've just had same problem with truvativ chain set. Bought FSA chainrings and had to file the middle one. Also noticed on the truvativ rings the bolt holes wer recessed a bit but not on the FSA ones making the bolts not gripping as much on the threads. Longer bolts would cure this. I wish I'd bought truvativ rings!