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So with 15/35 I need 108 links? I can't use stock 106 links right...?
My bike's setup with a Bazzaz, MNNTHBX intake, DCR cam, Yosh exhaust and Kitaco clutch cover. The 35 tooth rear sprocket and a new DID chain from MNNTHBX were the last bit of polish for the drive train, perfect! I tried a 14 tooth Sunstar, as pointed out earlier it just revs out too fast. With the 15/35 the bike pulls hard in the hills and still gives you decent cruising speed on the flats.
 

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This is definite? Cause I got people saying both 106 is fine and....nooo you need 108 cause you went up a tooth.
i said you can shove axle all the way up with 106...
Don't waste your time going any direction in single tooth on the rear.. you'll notice no gain at all.

1 tooth on the front is equivalent to roughly 3 teeth on the rear which translates to about 2.3mph @ 9200rpm
1 tooth on the rear is equivalent to 1/3rd a single tooth in front which translates to about .7mph @ 9200rpm

Considering you'll never be cruising at 9200rpm the difference at 6000rpm is even more negligible.
 

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So, thinking about changing gearing to give me a lower cruising RPM.

Ive seen 74 mph with my current setup. It had more, but I was so close to the rev limiter, I backed off.

I'd love to be able to cruise at 70, and not be looking at my tach above redline.

not sure if I should go up a tooth in the front, or down two or three teeth in the rear. Is there a benefit to one over the other? They should theoretically yield roughly the same results, but my gut is telling me it's still easier to turn a 15 tooth sprocket up front with a smaller rear, than it is to turn a 16 tooth up from with a stock rear.
 

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There's really no benefit going one or the other aside from cost. Rear sprockets are more expensive and larger, sometimes requiring a longer chain.
 

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FrontRearRatioTorqueSpeed
14T32T2.29+0.8% -0.8%
14T33T2.36+3.8% -3.8%
14T34T2.43+6.7% -6.7%
14T35T2.50+9.3% -9.3%
14T36T2.57+11.9% -11.9%
15T32T2.13 -6.3%+6.3%
15T33T2.20 -3.0%+3.0%
15T34T2.27
15T35T2.33+2.9% -2.9%
15T36T2.40+5.6% -5.6%

https://sprocketcalculator.com/
 

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Tire size is a factor also : example

Rear tires >
130/70-12 vs 140/70-12

Tire Diameter - inches (mm) :

130/70-12 19.17 in (486.8 mm)

140/70-12 19.72 in (500.8 mm)

Difference
0.55 in (14mm) 2.9%

So, a 140/70-12 rear would correct the actual MPH discrepancy with several setups, see post above.
 

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BBK kit such as Koso 170-4v Finbro 183-2v Takegawa 181-4v or any other bigger cc engine, 16/32 with rear tire will make you life better in the fast lane topping out about 85mph if all your mapping A/F and hardware are in sync, if you want to go faster change the rear sprocket to 34T.

Light to Light or 1/8m or 1/4m 16/32 sprocket is fine.

If you want to do wheelies all day long than you have to change either your front or rear sprocket by trial and error or search on this website for people who have done the sprocket change setup for wheelies, just make sure you have the oil pump mod to suck the oil to your engine while your front is in the air

If you want correct speedo reading and you own a smart phone, download the GPS app to your phone and you should be able to read your correct mph. If you don't have a smart phone get a garmin or some stand alone portable GPS device.
 

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I'm considering 17/32 so I can cruise at 75mph around 7500 rpm, giving me the option to use the interstate for a few miles if needed. 17/34 still wheelies well in 1st, I believe 17/32 won't be too bad.
Hi, noob here, yours is the first post I've seen about a 17/34 combo. My wife has a MSX here in Thailand, she's petite and the bike fits her well. Its quite buzzy at 95 KPH/7000 RPM (pretty much top end) and I'm thinking the 17 tooth front would work well for her. Can you tell me what RPM you're turning at 60 MPH? Also what length chain?
TIA, looked for answers via search but haven't found yet
 

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Hi, noob here, yours is the first post I've seen about a 17/34 combo. My wife has a MSX here in Thailand, she's petite and the bike fits her well. Its quite buzzy at 95 KPH/7000 RPM (pretty much top end) and I'm thinking the 17 tooth front would work well for her. Can you tell me what RPM you're turning at 60 MPH? Also what length chain?
TIA, looked for answers via search but haven't found yet
Put the 17/34 combo on, wife is very happy with lower RPM at cruising speed. Took her for lunch on it two-up and while noticeably slower off the line it didn't bog down, think this is a fine combo!
 

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I have a stock bore, with cam, and an exhaust and decided to stick with the stock gearing. I have a 14t, 15t and a 16t front sprocket (since they were only 5 bucks each) and tested them all with a stock rear sprocket and a 30t rear sprocket. I tested them after the mods.
With stock rear sprocket;
The usual; smaller sprocket more torque, less top end, bigger sprocket less torque, more top end. But honestly the difference in speed was only +-2 mph from stock.
With 30t rear sprocket;
Ideal for big bores or serous power because 4th gear is total granny gear. I could get up to 55 in 3rd (with a 15t front sprocket) but when I would shift into 4th my bike didnt have the power to maintain or even pull away from 55 so i would end up slowing down to about 45. I did try the 14t front with the 30t rear but results were the same. I was able to draft behind some cars and keep it at 70 with the 14/30 ratio but no drafting = slowing back down.

I went back to the stock sprockets because even a 5 mph head wind will keep me at 55 even with my mods and since i live in a rural area the stock gearing is good for me. One nice days she will run at 65. But by all means get some gears and get the set up that works for you. This is just my expieriance with my bike and the gears I have.
 
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