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Discussion Starter #1
Does anyone know the tranny differences in these two bikes. I suspect the S4 has a close ratio and the S4R does not. What are the final drive differences? My S4R seems to be geared way tall for top gear highway cruisin at 65mph. Any thoughs from those who have owned both or who know the difference.

Thanks
 

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Ducati.com has all the info you want. The Monters in general are geared pretty tall.
 

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Finnster: You are absolutely correct. The S4 has a close ratio box, while the S4R does not. It is one of the reasons I wanted the S4 when I investigated my options to buy a new one of either this past January.

Here are the ratios:

S4:
1 2.47
2 1.76
3 1.40
4 1.18
5 1.04
6 0.96

plus final rastio of 37/15 = 2.47

S4R:
1 2.47
2 1.76
3 1.35
4 1.09
5 0.96
6 0.86

plus final ratio of 42/15 = 2.80

Because the FINAL ratios are so different, both bikes are close in RPM in top gear at 60mph:
S4 is 3500 rpm at 60
S4R is closer to 3600 rpm at 60

Both are ridiculously overgeared at 60mph.

I have changed my S4 final gearing to 42/14, giving me about 4300 rpm at 60 in top. It MOVES when I hit the gas to pass.

Still in break-in, so no idea of how badly it will wheelie in 1st under power.

Jim G
 

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Discussion Starter #4
Finnster: You are absolutely correct. The S4 has a close ratio box, while the S4R does not. It is one of the reasons I wanted the S4 when I investigated my options to buy a new one of either this past January.

Here are the ratios:

S4:
1
 
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I have changed my S4 final gearing to 42/14, giving me about 4300 rpm at 60 in top. It MOVES when I hit the gas to pass.
careful jim... i'm running a 14/39 and it's "easy-on-the-throttle" in the lower gears. now that i've shed so much weight off the bike, i'll be going back to 15/39 to help prolong chainlife and keep the behavior more "civil".
 
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Great info guy's, but a I was looking for something a little more straightforward to answer a similar question of how best to address the way to tall gearing on my S4.
Should I simply start out going from 15 to 14 on the front or change the rear at the same time, if so to what...?
 

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Selkie69,
Probably best to try a 14 tooth front to begin with, and see how you like it. It's economical and easy.

As a counterpoint to you 'low-gear' guys, here in SoCal, when traffic is light on the freeways, 60 mph in the slow lane gets big semis filling your mirrors. I've got the stock 15/37, and regularly cruise the fast lane at 85 mph, which is about 5000 rpm. If I had the 14/42, I'd be spinning about 6100...

You'll definitely get more miles out of your front tire tho... ;D
 

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Gearing options on the S4R are limited. 42T is the largest available rear sprocket (and comes as standard) for the S4R and 14T is the smallest front (15T standard).

My approach is to gear to a top speed, and in the case of the S4R that would be 140mph, even at that speed, it is difficult to hang on to as the slipstream tries to peel you off the bike.

A nice tool to see the effects of gearing can be found here.
http://faq.f650.com/FAQs/gearing_v12.xls
 

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SpeedDog830: What's wrong with 6100 rpm at 85 mph? My engine doesn't seem to vibrate at higher cruising revs, and the rpm is not an issue as the S4 is a 10,000 rpm engine (10,700 is actually the limiter cutoff if you fit the Corsa kit that includes the Corsa cams - mine has ony the pipes / airbox / injection kit whose limiter is factory set at about 10,000).

6100 rpm gives me about 73 hp on tap at 85 mph in top gear, versus the 57 hp I'd have available with stock gearing.

And at 3500 rpm at 60mph with the stock gearing, I'd have only 36 hp versus the 47 I have with my 14/42 gearing, plus if the guy in front of me slows down, I'd need to downshift because an S4 is pretty unhappy below 4000 rpm.

I try to avoid using my bike in heavy traffic because of the obvious high potential for injury in a collision with ANY 4 wheeled vehicle, but if I have to be there, I want the bike to respond RIGHT NOW without downshifting when I see a need to move away from where I am.

By the way, this gearing does not reduce my top speed at all over stock, because the stock gearing is too numerically low to meet noise and emissions requirements.

Oh, and by the way, the gearing chnage described above, from 15/37 to 14/42, is enough to lower the quarter mile time by a full half second, because the stock gearing is WAY out of line for 1/4 mile use.

Jim G
 

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Has anyone with an S4R gone to a 14T front ?? If so, can you comment on the results ?
 

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Discussion Starter #11
Gearing options on the S4R are limited. 42T is the largest available rear sprocket (and comes as standard) for the S4R and 14T is the smallest front (15T standard).

My approach is to gear to a top speed, and in the case of the S4R that would be 140mph, even at that speed, it is difficult to hang on to as the slipstream tries to peel you off the bike.

A nice tool to see the effects of gearing can be found here.
http://faq.f650.com/FAQs/gearing_v12.xls
Actually the Ducati Performance Cat. shows a 43T and a 44T option for the S4R. Maybe 1 up on the rear would help. The problem with the S4R is that it has the same lower ratios as a S4 but is much taller in top gear. In order to make it cruise at a nice RPM you will have to regear it to be a handful in the lower gears. It wheelies in second with just rolling on the throttle now and I am 215lbs!

Jeff
 

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A change of only 1 tooth on the rear is only 1/42 = 2.5%, which you won't really feel at all.

A change of 1 tooth on the front is 1/15 = almost 7%, which you WILL feel.

To make a menaingful change of at least 6%, you need to add 3 or more teeth to the rear, whcih means 45 tooth sprocket, BUT (1) as stated above, you probably will not find one of that size for the S4R, and (2) you would need a new longer chain to accomodate it if you don't reduce the size of the front sprocket at the same time.

That's why most people reduce the front to 14 first, and then see how much more they want.

I knew what I wanted based on a computer simulation I wrote myself. I want to try the 42/14 combination more thoroughly after my break-in is complete (only 650 miles on my brand new 2002 S4). If I don't have problems in the lower gears, I'd like to go further, as 1st gear is STILL good to about 55 mph with 42/14, and 4300 rpm at 60mph is still nothing in terms of revs. In fact, with 14/42, 80 mph is only 5700 rpm, 7500 rpm in top gets you to 105 mph, and 10,000 gets you to 140 mph (and yes, an S4's power will pull that speed).

Jim G
 

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Quote[Gearing options on the S4R are limited. 42T is the largest available rear sprocket (and comes as standard) for the S4R and 14T is the smallest front (15T standard).]

I`ve just ordered a 44 tooth rear from the DP catalogue
 

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Yes, 44 tooth is available. Be careful in looking at the Ducati catalog section on sprockets though. Nearby, there is a selection that shows MORE sizes available, up to 47 teeth I think, that will fit the S4R, BUT require a change in chain pitch from 525 to 520.

I'm guessing that the extended size range available in the 520 pitch was originally made for the 620ie - that's why the different chain pitch.

Jim G
 

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I have the DP catalog open right now, and I see on page 43 only a 42T for the S4R part # 96842503B.
Did I miss something?
 

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Jim, the DP catalog I have is entitled Monster S4/S4R, the publication is 96731303B. Apart from the aforementioned page number and part reference, I can also find rear sprockets on page 73 (Wheel section) however these are for the S4 not the S4R.

Now I am confused :eek:
 

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Chupa: Yes, you did miss something.

You are in the wrong catalog.

Try the CURRENT MONSTER ACCESSORY catalog, page 79, where it lists, for the MS4, rear sprockets in ALLOY, for 525 pitch chain, in sizes from 35 teeth to 43 teeth.

Directly below that, they show, for MS4, in 520 pitch ONLY, rear sprockets from 34 teeth to 47 teeth. This would obviosuly require a matching 520 pitch front sprocket and 520 pitch chain.

Jim G
 

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Oops, one more set of choices for the MS4 on the same page of the catalog:

On left side of the page, alloy sprockets in 40 to 44 teeth, in 525 pitch.

Our cup runneth over . . .

Jim G
 

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Chupa: Oops again, being in such a hurry, I misread "MS4" for "S4R".

The LAST choices I showed above on page 79 are the ONLY valid ones for the S4R with its single sided swingarm:
40 teeth to 44 teeth

Coupled with the 14 tooth versus 15 on the front, you could get as high as a 12% increase in gearing overall, giving a maximum of 4000 rpm at 60 mph.

Anything beyond that would require having a reasonably suitable rear sprocket specially machined to fit the S4R rear wheel assembly.

As you can see from all the other choices I listed above, the choices are much broader for the S4. That, coupled with the close ratio gearbox on the S4, gives it a very substantial advantage in gearing choices, and also the theoretically superior setup for pure 1/4 mile acceleration (if you can figure out how to position yourself to keep the bike from wheeling more than the ideal inch or two).

The mechanic who set up my S4 with my specified 14/42 referred to it as "an animal" after his test drive, and I accidentally wheelied 3 times driving it home from the dealership.

Jim G
 

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Thanks for the info Jim. Is the catalog you refer to available on line?

I find my new S4R overgeared as delivered and want to raise the ratio (in numerical terms), until your info, it seemed there was only one option the 14T. I checked out Renthal, Afam etc who produce a single sided carrier but again it seemed 42T was the max.

Not sure about using the 520, it does have desirable weight savings but for sure will require more frequent replacement of sprockets & chain.

One again Jim thanks for your help.
 
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