Author Topic: Need help with spoket size  (Read 2490 times)

Ertech

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Need help with spoket size
« on: May 28, 2013, 03:49:55 PM »
Hi guys
I use my bike mostly in city . I have a problem , I like to ride in 3rd but when I am in 3 rd the revs are to low and when I bring the revs up my speed  is to fast.dont really care about high speeds.what good city gear sproket should I get
Thanks
« Last Edit: May 28, 2013, 04:40:42 PM by Ertech »

cloner

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Re: Need help with spoket size
« Reply #1 on: June 11, 2013, 05:31:49 PM »
OE sprockets are 15t at the transmission output and 38t at the rear wheel for a ratio of 2.53:1.  Primary drive ratio is 1.84:1 (between the crankshaft and the clutch hub).  Transmission ratios are 1st gear 2.47:1, 2nd gear 1.76:1, 3rd gear 1.35:1, 4th gear 1.09:1, 5th gear 0.96:1, 6th gear 0.86:1.

Final drive ratio with stock gearing in each of the gears should be:  1st gear 11.50, 2nd gear 8.19:1, 3rd gear 6.28:1, 4th gear 5.07:1, 5th gear 4.47:1, and 6th gear 4.00:1

I'm assuming you're using the OE 170/60-17 tire's theoretical circumference of 6.55' (nominal width*aspect ratio/25.4 to get inches of height of one cross section....multiply by two cross sections....then add the 17" wheel......then multiply by pi to get circumference and divide by 12 to get feet...we'll divide by 5280 feet per mile a bit later).

I like my bike to run around 3500 or 4000 rpm for a two valver....so let's look at ground speeds for 3500 rpm.  1st gear 304 wheel RPM or approximately 22.6 miles per hour.  2nd gear 427 wheel rpm or approximately 31.8 miles per hour.  3rd gear 557 wheel rpm or approximately 41.5 miles per hour.  4th gear 690 wheel rpm or approximately 51.4 miles per hour.  5th gear 793 wheel rpm or approximately 58.3 miles per hour.  6th gear 875 wheel rpm or approximately 65.1 miles per hour.

Saying "around town" is a bit vague.  What speed at what rpm are you looking for? 

I generally like to shorten gearing a bit on Ducati motorbikes, as they tend to gear them a bit tall to keep noise down.  From that standpoint, a 15t front sprocket and 41t rear sprocket would change the chain step to 2.73:1 and the final drive ratio in third gear to 6.78:1, yielding a change of speed in third gear at 3500 rpm from 41.5 mph to 38.4 mph. 

Does that help?
1967 Aermacchi/HD Sprint SS 250
2004 KTM 450 EXC
2012 Ducati 1199 Panigale ABS

Ertech

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Re: Need help with spoket size
« Reply #2 on: July 15, 2013, 05:41:08 PM »
Can I use a 14t front sprocket? Will this do the same?
What does the speed read from ? The 2 bolts holding it?

cloner

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Re: Need help with spoket size
« Reply #3 on: November 18, 2014, 03:53:32 PM »
I realize I'm quite late responding, but it is what it is.

I don't like 14t sprockets as they tend to let the chain rub on the swingarm sliders a bit hard.  My preference is to go larger at the rear wheel. 

As to what the speed sensor "looks" at, I've never cared enough to disassemble things to look.  The bolt heads would make sense, as they're a well defined element to sense.
1967 Aermacchi/HD Sprint SS 250
2004 KTM 450 EXC
2012 Ducati 1199 Panigale ABS

L4V

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Re: Need help with spoket size
« Reply #4 on: April 26, 2017, 08:42:10 AM »
I'm interested in installing a larger rear sprocket (+ 1T or +2T or +3T) and I cannot find what I'm looking for online.
Does the MH share a common rear sprocket with other Ducatis?...if so, which ones?
Or does anyone have a link where I may purchase a larger rear MH sprocket?
Thanks muchly.
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Don R.
A smooth sea never made a good sailor.

L4V

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Re: Need help with spoket size
« Reply #5 on: May 16, 2017, 07:59:26 PM »
I purchased and installed a Superlite Carrier with a 41T sprocket...also a new Regina Gold 520 chain that I've had in my stock for years.  It's a different bike now...easier to clutch off the line and suitable for my city and short local freeway runs.
At 4k rpm she's clocking 100 kph.
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www.sprocketcenter.com
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SLPCD1-KIT - $200.08 + Free Shipping (normally $214, found a discount code online).
Comes with a steel sprocket of your choice  (I chose the 41T to best match the drive sprocket)
~~~~~~~~
PS I have never dropped down a tooth in front on any bike I've owned which drive I've altered.
A smooth sea never made a good sailor.

cloner

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Re: Need help with spoket size
« Reply #6 on: August 10, 2017, 08:46:58 AM »
I'm interested in installing a larger rear sprocket (+ 1T or +2T or +3T) and I cannot find what I'm looking for online.
Does the MH share a common rear sprocket with other Ducatis?...if so, which ones?
Or does anyone have a link where I may purchase a larger rear MH sprocket?
Thanks muchly.
.
Don R.

Any Ducati with the smaller single sided swingarm system will use the same sprocket.  916 series bikes, various Monsters, 848, and others.
1967 Aermacchi/HD Sprint SS 250
2004 KTM 450 EXC
2012 Ducati 1199 Panigale ABS