Chain wheels and mechs compatibility.

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I'm working on a bike for Middle Son, which is set up for a large chainwheel as seen below:

20230124_155648.jpg


I'd like to swap it for this one, because it's better quality:

20230124_155719.jpg


Is this a matter of moving the existing mech, or do I need to use a different mech to throw the chain further?
 

Cycleops

Legendary Member
Location
Accra, Ghana
If you're keeping the existing BB spindle all you need to do is just move the mech.
 
D

Deleted member 1258

Guest
Sorry; my understanding depends on which language I happen to learn about a particular component. What's a BCD?

Bolt Circle Diameter, the diameter of the circle formed by the bolts holding the chain rings together, if thats the same for both sets of chainrings it should fit.
 
D

Deleted member 1258

Guest
He's swapping the entire unit as I understand it @dave r

Sorry. I read it as just the chainring.
 

Ajax Bay

Guru
Location
East Devon
I think I understood that. I'll take a picture tomorrow to check.
No need. You are replacing the complete chainset. (Stick, wrong, end of, Dave)
The one you are putting on [edit: maybe] looks like a biopace (ovalised rings) so take care to set the FD cage at the correct height for the large diameter.
Also you don't know if the BB spindle length needed by the new chainset is the same as for the current one, so your chainline may not be quite the same. It's possible the FD will not 'reach', but I'd fit it and see (unscrew limit screws) manipulating by hand. Also check how close the (new) inner ring is to the chainstay.
 
Last edited:
D

Deleted member 1258

Guest
No need. You are replacing the complete chainset. (Stick, wrong, end of, Dave)
The one you are putting on looks like a biopace (ovalised rings) so take care to set the FD cage at the correct height for the large diameter.
Also you don't know if the BB spindle length needed by the new chainset is the same as for the current one, so your chainline may not be quite the same. It's possible the FD will not 'reach', but I'd fit it and see (unscrew limit screws) manipulating by hand. Also check how close the (new) inner ring is to the chainstay.

The post can be read either way.
 
D

Deleted member 1258

Guest
'Splain me how you think the OP can swap the rings (see images in OP: no "reading" required") I can see why you were confused, though.

Now I'm on the desktop rather than the tablet I can see better that the top one is either a welded one, a riveted one or one that bolts from the back so no it ain't going to work. :blush::sad:
 
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