Ducati Scrambler Forum banner

Front & Rear Sprocket Options?

59K views 87 replies 25 participants last post by  franky 
#1 ·
After riding my Icon for a couple of weeks I've decided the stock gearing is too short for my purposes. I'm willing to trade acceleration for lower engine rpms/road speed, and hopefully pick up the fuel economy. In AZ riding distances can be large and fuel tank range tends to be somewhat of a priority (at least for me ;) Sometimes an extra 10 or 15 miles can make all the difference!

Based on Gearing Commander calculations I'm looking to use a 16T front sprocket and 44T rear sprocket. I've trolled various forums and learned that the rear sprocket from an 899 Panigale should work on the Scrambler - I'd like to confirm this with anyone in the know here. I haven't learned which front sprocket from another Ducati model will work on the Scrambler, so I'd appreciate any input on that.

BTW, I've noticed that the gearing information in our owner's manual seems to be a copy/paste from the Monster 796, including the front/rear sprocket sizes of 15T/39T which don't match the 15T/44T provided with the Scrambler.

Thanks!
 
#3 ·
I appreciate the information on the rear sprocket, thanks :) Pardon my mistype on which rear sprocket is provided on the Scrambler, as it's the 44T rear sprocket that I want to eventually use, not the stock 46T.

Do you have any idea which other Ducati model uses the same style front sprocket? I'd like to swap both sprockets out simultaneously as I'm comfortable that gearing will work for me. I'm a fairly light weight rider and would rather have tall overall gearing. Downshifting for more 'ooomph' works well enough for me ;)

I'm also hoping that using a taller sprocket up front and a shorter in the rear will let me avoid having to change chain length. From what I see on Gearing Commander this might be possible.
 
#5 ·
'Wait, you guys are going TALLER???'

Exactly! The 796 Monster from which our bike is derived has much taller gearing. From what I see on 'Gearing Commander' the Scrambler is setup for brisk acceleration in every gear, not top speed and economy. The Scrambler's calculated top speed at redline in 6th is about 116 mph. A 75 HP bike can usually do 130 mph or more (depending on aerodynamics), so the gearing is pretty 'short'. For the type of rider the Scrambler is targeted for this is fine. Most won't care about fuel economy/engine life/top speed and want maximum 'fun' (acceleration) with a twist of the throttle ;) I have different needs and am willing to trade some of the 'fun' in top gear for a more relaxed engine and a little better fuel economy. Besides, I have no problem with using the time honored method to improve acceleration on a bike that revs freely - drop a gear!

I looked at the front sprocket and it had some numeric markings (see photo). I reasoned they might be the last few digits of a full part number, so I cross referenced complete part numbers from some other Ducati bikes. I believe our front sprocket is the same as what's used on the Ducati Monster 696, which is p/n 449.1.052.1A. There's a couple of possible sources to get a 16T version of this sprocket, so I'll be chasing those soon. I also don't know if there's room for a slightly larger sprocket - I may have to just risk the purchase and try it out ;)
 

Attachments

#8 ·
Interested parties are watching :nerd:. (A prev owner of a M796)

I've only have about 600 miles at this point and prob will not change any gearing until at least 5,000. I'll see who breaks in first.

Not really worried about mpg. Gas is nothing compared to the farkles and riding gear. Plus, stopping every 100 to 120 miles is a good excuse to stretch anyways.

Of course, I'm in New England not AZ. I used to wonder why the M796 had a 6th gear, now I want a 7th.

I do keep playing with the Gearing Commander website thinking about a compromise though - a little lower rpms on the slab would be nice.Thinking that if I do a change, it will just be the rear sprocket, 44.
 
#9 ·
I used to live and ride back East (about 38 years ago) and it's sure different
here in AZ ;) I like high fuel economy but it's really about range. Gas stations can be sparse out here in some areas... When I meet my friends on the edge of Phoenix metro I'm almost 40 miles into my tank, and we haven't gone anywhere yet!

I've decided to start with a 16T front sprocket and just ordered this:
SUPERLITE (#52604R) 520 Pitch Chromoly-Steel Front Sprocket - DUCATI - 696 Monster 2008-2014 - Ducati - STREET Products

Hopefully my assessment is correct and it will fit properly and have enough clearance ;)

While it won't be dramatic the change should be noticeable. I'll post the Gearing Commander comparison when I get a chance.
 
#10 · (Edited)
I've attached images of the Gearing Commander comparison charts showing speed in gears for a stock 15T front sprocket, 16T front sprocket, and a 16T front/44T rear sprocket.
 

Attachments

#14 ·
I feel that could have slightly higher gearing and just change more to keep on song
But thought standard had 39t on rear so changing to 44 would lower gearing if correct
Bigger on front is higher gearing and smaller on rear equals higher gearing
Think 1 tooth on front increase is equivalent to approx 3 tooth decrease on back
 
#17 ·
The Scrambler standard rear is 46T ,so the gearing is much shorter than the 796 Monster which is at 39T. From what I understand the 796M is a little fussy at lower speeds in town, so many riders shorten the gearing to help that out. With a 15T/46T stock combination the gearing on the Scrambler is too much in the other direction for me. The Scrambler engine is tuned for more mid-range torque and doesn't need to spin so much to make useful power for my purposes. And like you said, just shift gears to keep the engine in the sweet spot if needed ;)
 
#16 ·
I was surprised to see my rear sprocket stamped Sunstar instead of Ducati even though Sunstar is an OEM manufacturer for several companies. Since the engine is a detuned Monster, is it a bad idea to try to push 39 teeth in the rear? Any thoughts on not mixing even and even sprocket teeth?
 
#18 ·
Mine is also stamped Sunstar. I've read that they're a decent manufacturer of sprockets so no worries there. I haven't considered using a 39T rear sprocket. Possibly it's too tall for my purposes although you might get even better highway fuel economy. It would likely slow the bike down noticeably in top gear, although you could drop a gear to make that up. But you also might need to slip the clutch a little more in first to get launched - it's all a trade off ;) With gearing you usually set it up for your end goal - acceleration, top speed, fuel economy etc. I've attached a Gearing Commander chart for the speed in gear with a 39T rear sprocket. Without aerodynamic changes it would likely never reach the predicted the speed of 137.2 mph. The Scrambler has about 10 less HP than the 796 Monster which from my reading might be able to reach that speed.

Mixing even/odd teeth count between front and rear sprockets is OK, so long as sprockets are matched in width and pitch to the chain. The stock Scrambler has a 15T/46T combination. Any changes to that ratio are compensated for by adjusting chain length via the adjusters or adding/removing links if needed.
 

Attachments

#22 ·
Warranty coverage with user modifications is a gray area that's been widely discussed/debated. In the US the Magnuson-Moss Warranty Act protects the consumer to the extent that a dealer/manufacturer has to prove the modification specifically lead to a failure that is being covered. Details in a manufacturers warranty statement could make certain situations less clear. The discussion could 'hi-jack' this thread and might be best handled elsewhere in the forum.

That said I'm not worried about this particular modification. Experience tells me that if it's properly done the chances of causing damage to the Scrambler are very small, unless you modify the ratios extremely. I'm going to adjust the ratios within limits Ducati itself has used on similar models and I feel comfortable with that :)
 
#27 ·
I didn't count either so haven't confirmed, but the manual states 104 links. I'm hoping to get my gearing changes done without changing the number of links.

My new 16T sprocket shipped today in the early morning hours and is estimated to arrive next Monday. Due to other commitments I won't be able to mount it until late next week or the following weekend. I'll keep everyone posted... :)
 
#31 ·
This is good information - seems like you managed to do the swap to a smaller 14T sprocket with reasonable effort :)

I have a bit more challenge since I'm switching to a larger 16T sprocket. The diameter will grow by roughly 6.7% and I have concerns whether it will fit. On one side the sprocket will be closer to the swing arm. On the other side the chain will be closer to the engine casting. I measured and there's room to spare near the swing arm. It will however be pretty close to the engine casting, but it should just fit... I'll know when I have the new sprocket.

I'll have the same challenge of getting it past the foot peg bracket and hope I can ease it by like you did :)
 
#33 ·
Gearing change

I think you went the wrong way - just my $.02 - I am going to fit a 16 tooth countershaft as soon as I can get one. I don't like spinning it close to 6000rpm to go 80 mph. one tooth up will slow rpm approx 6% at any given speed. A small but noticeable change. I took my countershaft cover off and measured clearance yesterday - I think a 16 will fit but will have only about .020 clearance (.5mm) so it will be very close.
 
#35 ·
I think you went the wrong way - just my $.02 - I am going to fit a 16 tooth countershaft as soon as I can get one. I don't like spinning it close to 6000rpm to go 80 mph. one tooth up will slow rpm approx 6% at any given speed. A small but noticeable change. I took my countershaft cover off and measured clearance yesterday - I think a 16 will fit but will have only about .020 clearance (.5mm) so it will be very close.

I also measured clearance today and came to the same conclusion. As I mentioned in my other post, the engine casting area that comes close seems to be a 'blank' with a plastic cover. After looking at the Ducati Monster I reasoned that it's used for a hydraulic clutch setup which the Scrambler doesn't have. If there is an interference I might file down the area slightly knowing that it won't affect anything or be a safety issue.
 
#41 ·
Thanks for the info. I may follow your lead on this. Although I do mostly city driving around town in lower Michigan, when I do get on the expressway I fell like I need one more gear. 70 MPH is at about 5000 RPM.
I just returned from an out of town trip and my 16T sprocket was among my delivery items :) Today I focused on doing the majority of the first service, but I hope to try the sprocket installation within the next day or so. I'll update once I attempt the install...
 
#42 ·
Close fitting sprockets on other bikes I changed gearing on would sometimes get the sprocket pretty close to the engine cases. The chain has a tendency to lift off the sprocket on the bottom side at higher speeds. In one case it slightly grooved the alloy case from the link plates. No harm done, just two slight grooves. That might occur with the 16T. I'd install the 16T when I get my bike just to lower the RPMs at speed (75 here in KS). No canyons or forest service roads here. And I'm not taking this bike on our off road racing tracks. Going over the handlebars and letting the bike bounce off terra firma is not a good idea. I leave that for my KTM 300 XC.

Stu
 
#43 ·
That's a very good point regarding the 'chain lift' at speed. Even if I don't have to file material away for a good 'static' fit, I'll be inspecting after some hard riding to check on that issue. And as the chain wears and stretches/loosens up the clearance from the case might tighten even further. I like that the sprocket cover is easy to remove for inspection purposes :)
 
#44 ·
I finally managed to get the 16T sprocket installed today. I installed the sprocket without breaking the chain, but I feel the job would have been much easier by breaking the chain or removing the passenger left foot peg support. I didn't have what I needed for the other approaches and I wanted the bike up for a ride tomorrow. The sprocket barely fit - I'll provide pictures and more details later.

I took it for a short shakedown run and I'm very happy with the results so far. I've noticed no difference in acceleration but the engine is more relaxed at highway speeds. I'll be doing an extended run tomorrow morning and will report my findings ;)
 
#51 ·
You're welcome Sarah. I've had further thoughts about this mod ahead of my ride this morning, and it might be a case of 'Don't do this at home'. From my perspective this is NOT a 'plug & play'. I'm recommending that owners DON'T perform the swap unless you're comfortable with removing a SMALL amount of material at the locations that are close to the sprocket/chain as indicated in the photos. There may be enough variation in engine castings and/or aftermarket sprocket diameters to cause an interference fit on other Scramblers, either immediately or down the road. I'll get experienced opinions this morning with my ride group, and report back here after I do a post ride inspection.
 
#53 ·
I had a great ride and a good test of the 16T sprocket :) Summarizing:
1. The engine feels less hurried at freeway speeds but the bike is just as 'frisky' - no apparent change in acceleration. In the lower gears the change is imperceptible to me. Some numbers as indicated on the speedometer:
4000 RPM - 15T sprocket~56 mph; 16T sprocket~60 mph
5000 RPM - 15T sprocket~70 mph; 16T sprocket~75 mph
2. No change in speedometer/odometer error. Speedo is still ~5% optimistic and Odo is still ~0.8% optimistic. This suggests that the sensor is either at the front or rear wheel, not at the transmission.
3. Fuel economy for the run was 54 mpg - no dramatic change from what the past couple of tanks have netted. Each outing has different wind & speed conditions and this run was only 85 miles, making it tough to be accurate.
4. My friends and I inspected the Scrambler sprocket area at the meetup point - no indication of the chain/sprocket contacting the engine. We all agreed that anyone doing the install 'from scratch' would be wise to remove some material from the engine casting at the closest point I've shown in photos - the capped unused 'slave cylinder' area at 10 o'clock. We also agreed that 'watchful waiting' for my particular installation was OK to catch changes as the chain wears. It's easy to remove the cover and inspect from time to time.

Other notes:
1. After installing the 16T sprocket the chain adjustment required one notch of movement to place the rear axle closer to the engine. This arguably now gives more adjustment range for chain stretch. But if I now remove a tooth or two at the rear it will compensate in the other direction and I'll likely be able to still use the stock chain length.
2. I'm happy with the result if for no other reason than reducing engine wear and tear and having the bike feel less frantic at highway speeds. I may leave it this way for now and consider a rear sprocket change when it's time to replace the rear tire.

I'll post more info as I learn more, but so far so good...:)
 
#55 ·
I'm only at 663 miles so far but I believe/hope the fuel mileage will improve as the engine continues to break-in.

I didn't buy the Scrambler for high speed capabilities - it's the light weight and agility that has me hooked. But I'm curious about the effect on top speed with the new sprocket. Currently the rev limiter should kick in around 116 mph, and with 16T that should bump up to around 124 mph. Perhaps in a couple of weeks I'll have a chance to check that for a few seconds on a safe section of road after my friend's ZX1400 starts sucking me into his aerodynamic wake while he squeezes the throttle ;)
 
#59 ·
Got my 16 tooth today from Dennis Kirk - tomorrow I will attempt the installation. I have a dremel tool at the ready should I need it.
Good luck with the install! Hopefully if you choose to you'll be able to mount it as I did without breaking the chain or removing the passenger peg support. It was fussy enough that I'd probably do one of the latter if starting from new. About the time I had given up I somehow got it on the shaft with the chain on the sprocket. I managed to gently tap it the rest of the way using the plastic handle of a screwdriver, but it was tough going.

I'll be taking my second excursion with the 16T sprocket installed tomorrow morning so I'll get more of a feel for how it's working :)
 
#61 ·
Is it not more easy And less dangerous to change the rear sprocket by a 44 tooth.????
If I could buy a lightweight steel rear 42 or 43 tooth sprocket I would probably do that. I want the full 6 or 8 % reduction in engine rpm. Don't particularly want to break the chain and deal with a master link. The thing I am most concerned with is removing the 16 tooth counter to go back to stock if I should want to. The Scrambler just feels like it's revving its guts out at 80 mph - even though I doubt it's hurting anything.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top