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Discussion Starter #1
I just put a 14 tooth front on my 95 900ss.. stock 37 tooth rear. I like the change, but now I have chain rubbing issues at the front of the swingarm. I have decided to go bigger in the rear and back to the 15 tooth front.

I made an excel spreadsheet to see the % increase in gear ratio so I could then calculate the RPM change based on the stock 15/37 combo at 4000 rpm

So based on the numbers.. i'm thinking about the 41 or 42 tooth rear. I rarely get the bike above 80 or 90 and see alot of stop and go in town.

Will my gears be too close?

FRONT....REAR.....RATIO....% INCREAS.....RPM CHANGE
15......37.........2.47.........0................4000
14.........37.........2.64.........7.14............4286
14.........39.........2.79.........12.93..........4517
15.........39.........2.60.........5.41............4216
15.........41.........2.73.........10.81..........4432
14.........41.........2.93.........18.73..........4749
15.........42.........2.80.........13.51..........4541
14.........42.........3.00.........21.62..........4865
15.........44.........2.93.........18.92..........4757
14.........44.........3.14.........27.41..........5097
15.........48.........3.20.........29.73..........5189
14.........48.........3.43.........39.00..........5560
 

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Old Wizard
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My recommendation is 15/40 which needs a longer 98-link chain. It's the equivalent of the 14/37 you've been running, but about another 50rpm at 75mph.
 

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Risk, the standard gearing upgrade (modification) on the pre-1999 Supersports is 15/39. That's what I have and it is plenty low enough. I'd suggest you don't go lower than 40. I plan to go back to 15/37 when I wear out my current sprockets and chain. I've found for track days, my SS (with Keihin 41 FCR carbs, HC Wiesco-FBF pistons, Marvic mag wheels and much weight removed) is geared a lot lower than it needs to be. I almost never use anything lower than 4th gear at Miller Motorsports Park, which is a pretty fast track. On the street 15/39 is good.
Joe
 

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Discussion Starter #4
15/39 as Joe-B said seems to be the concensus from what I've searched in the forums... I'm a heavy rider (240 lbs) and never really take the bike above 80mph...never do track days...etc.. wouldn't lower be better for me? like 15/41 or 15/42?

Additionally, and please excuse my ignorance here, I'm just wondering what application the 44-48 rear would be for? :confused: stunting maybe?.. and why would you want that low gearing? Wouldn't you be constantly running up and down thru the gears?
 

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sproket,chain

Sorry to change the topic slighty. I have a stock 15/37 right now. I'd like to try 15/39 but my wheel is one registration notch from full forward as it is. I'm guessing i will need a longer chain. Is anyone sure? While i'm at it, can links safely be added or do i need to buy a new chain. Thanks, George M.
 

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GM92SS:
I would suggest changing the chain when you change the sprockets. A lot of people recommended this to me when I was making the switch. I had stock 15/37 gearing and I went to a 15/39 and I like it a lot better. 4000RPM is right around 70MPH and it pulls away from a light a lot better. CA Cycleworks has 98 link DID Chains right now for $87. I went with good ole JT sprockets. I also got a T35 Chain breaker tool on eBay for like $40. Similar to the DID tool. Worked great!
 

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What Joe said; don't add links, buy a new chain, unless the chain and sprockets are brand new. Even then you'd have to buy 2 new rivet type master links (never use clip-type master links) and a chain breaker or pay someone else to do it.
Joe B
 

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I have 15/39 on mine and next time I am thinking of going to 15/40 or 41. For me, it's not some much about going fast but being able to go slow in 1st gear in traffic without having to use the clutch every couple of hundred yards that I would prefer.

Where I live, most of the local roads are 100 kph (62 mph) and my current gearing is just barely comfortable at the local speed limit. On the open highway it is marginally better at 110 (68 mph).

Generally a new chain in the box will be about 120 links and a few will need to be removed for the normal sprocket count combinations. I think I took about 6 links out of my new chain when I went with the 15/39 sprockets.
 

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chain

thanks for the thoughts. When shorteninga new chain will i need a breaker tool? What is the least expensive way to do this correctly? I know master links such as on my bicycles are not recommended.
 

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what would be people thoughts on a 14f 38r combo, okay or perhaps a bit to buzzy - tho here in west oz we have a state speed limit of 110 kph (68mph)
 

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I have just come across this and thought I'd put in my 2 cents worth.
I have a 95 600SS and have just recently changed my gearing from 15F 38R to 14F and 39R. Tops out at just over 180km indicated, but the power delivery is great!:D Makes it so much more rideable in town and more importantly in the twisties:yeah:
 

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any recommendations on where to purchase a new sprocket & chain?
 

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sprocket ratios

you didn't list the 15/40t combo, that's where I'm at and it's perfect for my riding style. spend most of my time between 60/80mph. ratio is 8% steeper than stock - perfect. 60mph is 3600rpm, 70mph is 4000rpm's.

to be further contrary, i did not have to add links. still have about 3/8inch travel left, but that's only gonna increase so no biggie. since the bike had only 4200miles on it when i bought it last april, did not buy a new chain. wait, there's even more! i opted for an aluminum Vortex sprocket. i spend way too much time on chain alignment and lube every other ride, so i think the Vortex will be ok.

some folks say going +2 on the rear is not quite enough, and that's what i found on my 02M750.

i think you'll be happy with a ratio change, but the choice of 39t or 40t (or higher) really depends on your riding intentions. good luck in your shopping, mods are great fun!
bobp
 

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combos

Chris Kelley @ California Cycleworks Inc. Best deal and great guy.

Fred
 

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Thank you guys for the feedback on these questions. I rescued a 94 900 ss/sp (#101) of 300? Thats the numbers we found so far, would like to know for certain. Anyways... This bike sat outdoors for 8 months in the elements, and here in Central Texas, thats not good. Now I need sprockets/chain. When I pulled up at Ducati San Antonio, I was immediately asked to sell it!! lol, What sprockets and chain? I will not be racing. Though I will take it to Ciruit of the America's in Austin for kicks every now and then. Primarily, It will be ridden around town, and some distances of approx. 80 miles one way, and back of course. So, 15/39, or 15/40? And what brand?
 

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Thank you guys for the feedback on these questions. I rescued a 94 900 ss/sp (#101) of 300? Thats the numbers we found so far, would like to know for certain. Anyways... This bike sat outdoors for 8 months in the elements, and here in Central Texas, thats not good. Now I need sprockets/chain. When I pulled up at Ducati San Antonio, I was immediately asked to sell it!! lol, What sprockets and chain? I will not be racing. Though I will take it to Ciruit of the America's in Austin for kicks every now and then. Primarily, It will be ridden around town, and some distances of approx. 80 miles one way, and back of course. So, 15/39, or 15/40? And what brand?
I run the 15/39 combo - but most of my riding is rural back roads, not towns. If I were doing LOTS of town riding - I'd probably go for the 15/40 combo, as first can be a little tall with the 15/39 and heavy traffic (you don't want to be slipping the clutch much or at all if possible - it kills the plates) at < 30kph (20mph).

Re brands - doesn't really matter - there's not much difference between them these days (well the major brands). I prefer the 'X' ring chains over 'O' ring, as there's less resistance from the X ring (the bike rolls easier) chain over the O ring. Steel sprocket (rear) for longevity. Anodised alloy rear sprocket for looks.
 

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I had issues with JT front sprockets where the little holes for the keeper bolts weren't properly threaded. Never had an issue with an AFAM front sprocket.
 

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I run 15/41 and find it almost perfect for mixed ridng, I have a 43 rear to try too and will chuck that on when I get the rebuild gong!!
 
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