Chain wheels and mechs compatibility.

[Andy in Germany]

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

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

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

 

[Cycleops]

If you're keeping the existing BB spindle all you need to do is just move the mech.

 

[Deleted member 1258]

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

View attachment 675566

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

View attachment 675567

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

Is it the same BCD?

 

[Cycleops]

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

 

[Ian H]

Assuming the mech will slide down that far, you should be fine.

 

[Andy in Germany]

Is it the same BCD?

Sorry; I'm a relative beginner especially in chainwheels/front mechs and besides, my understanding of specific words depends on which language I happen to learn about a particular component. What's a BCD?

 

[Deleted member 1258]

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.

 

[Andy in Germany]

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.

I think I understood that. I'll take a picture tomorrow to check.

 

[Deleted member 1258]

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

Sorry. I read it as just the chainring.

 

[Jameshow]

I doubt you can swap the chainrings as the original chainset dosent have bolts unless they are concealed. I'm thinking it's a welded steel cheap jobbie.

 

[Ajax Bay]

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.

 

[Deleted member 1258]

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.

 

[Ajax Bay]

The post can be read either way.

'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.

 

[Deleted member 1258]

'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.

 

[Andy in Germany]

The post can be read either way.

Good point; poor communication from me there. Ironically I'm translating into English from German.