#219 Chain, what is a good drive sprocket size?

[LI-ghtcycle]

Ok, I'm going to be re-gearing soon, and I want to make sure I optimize the gearing for both reduction of sound and chain life, so I am curious what a good standard or rule of thumb would be for the drive sprocket.

Since I am using 219 chain, it won't matter terribly how many teeth it has since I will be using a new set of sprockets, and even if I have a good amount of teeth on the driven sprocket on the NuVinci, it won't be a problem fitting.

I'm guessing something around 20T would be a good number? Currently I have a 9T and I know it will cause extra wear, and create more sound, so just looking for a good rule of thumb.

Thanks!

 

[LI-ghtcycle]

Oh, I forgot to mention, also, I have a 14mm bore, with a key. I'm not against having an adapter made for a more common bore like 3/4, but something that just bolts on would be great. :wink:

 

[liveforphysics]

After you go past #15t, chordal motion and its associated noise is roughly eliminated.

 

[LI-ghtcycle]

Kewl, thanks.

 

[LI-ghtcycle]

Ok, now my next question is where can I get an Extron motor sprocket? I have seen a couple places on kart sites with what looks like steel sprockets, but nothing in Extron or other composite.

Thanks!

 

[Thud]

http://www.excel-racing.com/product_p/compsprk1.htm
https://www.pegasusautoracing.com/productselection.asp?Product=9806
http://cometkartsales.com/store/sprocket/extron.htm
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p3984.m570.l1313&_nkw=extron+sprockets&_sacat=See-All-Categories

that should give you a few options.

 

[LI-ghtcycle]

http://www.excel-racing.com/product_p/compsprk1.htm
https://www.pegasusautoracing.com/productselection.asp?Product=9806
http://cometkartsales.com/store/sprocket/extron.htm
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p3984.m570.l1313&_nkw=extron+sprockets&_sacat=See-All-Categories

that should give you a few options.

Yep, those are all good sources for the driven sprockets, but I don't see anything especially in Extron for the motor shaft. :wink:

I do see something that meant for some kind of rotax engine, no idea what size shaft this is, or what kind of adapter I would need to allow for it to bolt-onto my 14mm keyed shaft.

http://cgi.ebay.com/ebaymotors/Rota...5991744?pt=Race_Car_Parts&hash=item27acfd1540

Or-

This one:

http://www.alliedmotorsports.us/id33.html

These are steel, maybe they don't make Extron on the motor sprocket side, looks like these are really reasonable, (cheap? hopefully not the bottom of the barrel ... case hardened steel sounds like it should be pretty good, but maybe aluminum is better since it generally deals with heat better?) looks like 3/4 inch shaft is the common size.

Or maybe I could adapt to this type:

http://www.out2win.com/catalog/sprkt_eng.html

Anyone know what size "Standard Yamaha Taper" is? I'd hate to modify the sprockets to fit my bore, rather have an adapter, or a bolt-on of course.

What kind of fastener is used for these tapered bores? I'm guessing along with the key there is some kind of cone shaped "mandril" or washer or what ever you'd call it that bolts into the shaft?