Ducati Monster Forum

Moto Board => Accessories & Mods => Topic started by: davehong on November 23, 2010, 10:21:47 AM



Title: new sprokets on a 03 M620?
Post by: davehong on November 23, 2010, 10:21:47 AM
So....i've planning on having my bike lowered soon, since it's the winter, and im not riding it as much.

I figured while the bike is in the shop, I should get other stuff done too...so I was looking at get the front and back sprokets replaced. Pros/cons? Brands?

I typically do more city riding and the occassional 2-3 ride...but thats it.


Title: Re: new sprokets on a 03 M620?
Post by: Slide Panda on November 23, 2010, 10:48:18 AM
I'd start looking here:
http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html (http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html)
- Besides having a good selection, and the stock sprocket configs and popular alternatives, they are a sponsor.

Pros? Cons? Of getting your worn stuff replaced... um it's all pro. So I'm not sure of your question.

Occasional 2-3 ride? whats' that mean?


Title: Re: new sprokets on a 03 M620?
Post by: atomic410 on November 23, 2010, 11:14:51 AM
vortex sprockets.  well made color options and any size.  plus they put alot into the sport. [bacon]


Title: Re: new sprokets on a 03 M620?
Post by: davehong on November 23, 2010, 12:11:06 PM
I'd start looking here:
http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html (http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html)
- Besides having a good selection, and the stock sprocket configs and popular alternatives, they are a sponsor.

Pros? Cons? Of getting your worn stuff replaced... um it's all pro. So I'm not sure of your question.

Occasional 2-3 ride? whats' that mean?

sorry i mean 2-3 hr ride.

and the sprokets arent worn yet by any means...but ive read that most people swap toa 14T front and i THINK...39T back?


Title: Re: new sprokets on a 03 M620?
Post by: Slide Panda on November 23, 2010, 12:23:57 PM
Well, the number of hours really doesn't matter.

15/46 is the stock gearing for a 620. Going to a 14/39 roughly equates to a 15/42, which is not going to be  good idea. The bike will be terrible to ride at low RPMs especially around a city. A common swap is 14/46 where you just replace the front sprocket. Having done that swap on a 620, it makes a big difference, especially for the cost at around $30.

Alternately you can leave the front sprocket as is and get a larger rear - it's about 3 to 1 from back to front, so you'd be looking at a 49 rear. The catch there is you *will* need a bigger chain if you go down that road. But if you're lowing the bike, it's possible you'll need a slightly longer chain due to the change in the geometry.



Title: Re: new sprokets on a 03 M620?
Post by: atomic410 on November 23, 2010, 01:07:50 PM
i have a pretty new red 48 vortex i'd sell [bacon]


Title: Re: new sprokets on a 03 M620?
Post by: davehong on November 23, 2010, 01:23:33 PM
Well, the number of hours really doesn't matter.

15/46 is the stock gearing for a 620. Going to a 14/39 roughly equates to a 15/42, which is not going to be  good idea. The bike will be terrible to ride at low RPMs especially around a city. A common swap is 14/46 where you just replace the front sprocket. Having done that swap on a 620, it makes a big difference, especially for the cost at around $30.

Alternately you can leave the front sprocket as is and get a larger rear - it's about 3 to 1 from back to front, so you'd be looking at a 49 rear. The catch there is you *will* need a bigger chain if you go down that road. But if you're lowing the bike, it's possible you'll need a slightly longer chain due to the change in the geometry.



oh, cool, thanks for the heads up. just the front sproket it is! ($30 bucks, im sold. - plus, while my guy's working on the bike, might as well right?)

What kind of a difference will i be noticing with the 14T swap?


Title: Re: new sprokets on a 03 M620?
Post by: davehong on November 23, 2010, 01:23:53 PM
i have a pretty new red 48 vortex i'd sell [bacon]

ill pass, but thanks!


Title: Re: new sprokets on a 03 M620?
Post by: Slide Panda on November 23, 2010, 04:19:33 PM
What kind of a difference will i be noticing with the 14T swap?

You'll notice the bike picks up more quickly and you'll be able to use a greater portion of the low end of your engines RPMs. In the grand scheme you'll loose a little bit off the tip-top speed... but that's  [leo] speeds. So for day to day you'll never know. For long highway cruise, you will be a little higher in the RMPs


Title: Re: new sprokets on a 03 M620?
Post by: seevtsaab on November 27, 2010, 05:13:18 AM
I notice with the 14T the RPM's .vs MPH matched such that it's easier to cipher what gear I'm in, the few times I loose track.


Title: Re: new sprokets on a 03 M620?
Post by: rideserotta on November 27, 2010, 08:55:47 PM
Well, the number of hours really doesn't matter.

15/46 is the stock gearing for a 620. Going to a 14/39 roughly equates to a 15/42, which is not going to be  good idea. The bike will be terrible to ride at low RPMs especially around a city. A common swap is 14/46 where you just replace the front sprocket. Having done that swap on a 620, it makes a big difference, especially for the cost at around $30.

Alternately you can leave the front sprocket as is and get a larger rear - it's about 3 to 1 from back to front, so you'd be looking at a 49 rear. The catch there is you *will* need a bigger chain if you go down that road. But if you're lowing the bike, it's possible you'll need a slightly longer chain due to the change in the geometry.



If you go to a 14 from a 15 do you need to shorten the chain or will it be fine as is? Also, that won't make any difference in the indicated speed? Where does the speedo measure speed?


Title: Re: new sprokets on a 03 M620?
Post by: Slide Panda on November 28, 2010, 05:51:08 AM
If you go to a 14 from a 15 do you need to shorten the chain or will it be fine as is? Also, that won't make any difference in the indicated speed? Where does the speedo measure speed?
Unless your chain is extra long for some odd reason - no. You will need to take up the slack you just introduced, but the adjusters have plenty of range to soak of the difference from a 15 to 14. To do the swap you'll have to introduce as much slack as possible to the chain to slip the 15t off, so after the swap you'll just be adjusting the chain as normal.

It will make not difference at the speedo. Vehicles that use engine RPM and gear to derive the speed is a silly system IMO. Especially on bikes where it's common to change the final drive ratios. On a duc, the speed is picked up from the wheel speed. Older bikes is a mechanical drive on the front wheel. Bikes after 2002 (ish) it's an electronic pick at the back wheel.

If you've got a 620 like the original poster, just look at the caliper mount, and you'll see a thick black wire running from it along the swing arm into the frame. That's a magnetic pick up that's tracking the nuts on the rear rotor. The computer knows that every 6 signals equals one wheel revolution and does the math from there.


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