Gio X31 Rear Sprocket Replacement, suggestion??
 

I am looking for a 428 chain, 49 tooth sprocket, with enough material in the center to machine new holes, because the rear sprocket has bolt holes that are 68mm center to center, with a cut out of approx. 53mm.

Any ideas. I have access to some machines but I cannot machine a custom sprocket.

Answered own question, DS80 1982-2003.

Glad to hear you got it figured out :)

I don't think I understand. Is it that you're trying to fit a 49 tooth, but you couldn't find a direct fit?

I think he found a sprocket off a 82-03 DS80 that is a direct fit?

That's correct a 79-2003 ds80 sprocket is almost a direct fit, the center section needs approx. 2mm machined out. Lots of options, i think like 35-50 teeth.

Sorry, I'm still stuck on the machining point. Do you mean that you can't find an exact fit replacement sprocket for your Gio?

Ok, let me start from square one. The ratio for that stock gio 2007 x31 19/16 was 15 front, 48 rear. Or 3.2, for an mx bike the ratio should be between 3.5 to 5. So what I want is some tunability for my gearing.

I went to a 14 Front, and now I want a 49 tooth rear or even a 50 rear, that puts me at a 3.5 to 3.57 respectively. The stock rear available from gio is only 48 teeth.

Catch my drift. I am not racing anybody so I don't really care if I lose some top end, but it will make japanese riders wonder whats happening.

I get that you want to play with ratios; I've done plenty of that. I'm just surprised that you can't find a direct fit replacement sprocket that doesn't need modification.