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Discussion Starter · #1 ·
ok I have been riding for years and I always hear people say that they go down in the front usually by one tooth which equated to going up three in the back. I have a problem with this as Mechanical Theory says that if you have a larger front sprocket you will achieve more rear wheel horsepower. I understand that going down in the front provides more leverage that is not my argument but what if you went up a tooth in the front and went up six in the back. would have the same feel as going down one in the front or just three up in the back. My point is this, think of it like a steering wheel in a car, now imagine there was no wheel and just the steering shaft coming out of the column, try to grap that ****er and turn it with your hands or better yet try to stop it from turning when you hit a bump driving down the road, yeah its gonna be a bitch to turn, not put that big mack truck steering wheel on it, see my point. while you may not notice the power difference mechanical theory says the larger you in the front the less power you will lose to the rear wheel. I think the average power loss to rear wheel is approximately 15% so if you can find ways to change that percentage you will achieve more power at the rear wheel ie; actually use the potential of the motor. go with a larger sprocket, lighter chain and rear sprocket, lighter wheels, tires and brake rotor, good wheel bearings are a huge contrabution to this. I have found that stock wheel bearings are shite, a decent set of aftermarket wheel bearings can net an additional 3 horsepower at the wheel.

now changing to a slightly different topic, smaller front sprocket, think about the size of the sprocket, now think about the path that sprocket takes ie; the actual turning or diameter. now go look at your chain and the links, changing to a smaller sprocket is hell on your chain. I work with a guy who happens to be one of my best friends, he rides a CBR600RR and has this set up, 1 down in the front stock in the back, nice aftermarket AFAM set with a nice 525 DID VMX Ring chain. I installed it for him, his chain is newer than mine as are the sprockets, was looking at his chain the other day and it is a all stretched out, kinked up and ready for replacement. I am using the same set except mine is 530 and mine is two seasons old, I raced with mine and I am on a heavier bike and pulling about 30 more horse power than he is. I have stock size up front and four up in the back, my chain does not stretch and my chain is not kinked, when I dyno my bike I always hear people say, "wow thats really good for a TLR" again lighter race tires, wave rotors, race wheel bearings and good chain and sprocket not to mention good clean working brakes that dont drag. most TLRs I have seen pull in the range of 115 and I am at 130.

point of all this rambling on is, use a larger front sprocket and suck it up, buy a longer chain and rear sprocket, I usually replace my drive line every year, I never suggest replacing just a sprocket as all these parts wear together, if you put a new sprocket in with an old chain it will wear twice as fast.

someone please prove me wrong, I may very well be and all of this rambling is just coincidence.

;D
 

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Going up 1 in the front and up 3 in the back cancel each other out. It is the ratio of the 2 that determine the final drive. You could add a bunch of sprockets in between and it wouldn't matter. All you care about is how many turns of the counter shaft equal one turn of the wheel. As for the steering wheel analogy; The engine is not turning the outside of the sprocket. It is turning the shaft. Now try turning the shaft on the steering column with your hand while someone else holds the outside of the steering wheel and you will see what happens when you put a larger front sprocket on.
 

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silentbob said:
Going up 1 in the front and up 3 in the back cancel each other out. It is the ratio of the 2 that determine the final drive. You could add a bunch of sprockets in between and it wouldn't matter. All you care about is how many turns of the counter shaft equal one turn of the wheel. As for the steering wheel analogy; The engine is not turning the outside of the sprocket. It is turning the shaft. Now try turning the shaft on the steering column with your hand while someone else holds the outside of the steering wheel and you will see what happens when you put a larger front sprocket on.
If anything, gint up 1 in the front and 3 in the back you'll get LESS HP to the ground due to increasing rotating mass. The potential big problem with decreasing the front sprocket is that the chain has a much smaller circumferance to make it's change in direction, which could lead to premature wear of the chain and sprocket.
 

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Well, while I don't agree with your theory, I don't think you can go up in the front on most Monsters anyway. Even if you could get a 16 tooth for the front (don't think anyone makes it), it and the chain together wouldn't clear the engine cases...
 

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Discussion Starter · #5 ·
silentbob said:
Going up 1 in the front and up 3 in the back cancel each other out.
I understand that these two cancel each other out, what i am saying is that i think if you did that and dynoed compared to dynoing with stock setup you will achieve more of your potential hp at the wheel
 

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All scientific/engineering theory aside, I like the way my bike rides with the 14T front sprocket waaaay better than stock. ;D
 

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The problem with your theory is that you are thinking of this in terms of leverage. The is not about leverage but about gear ratios. The smaller front sprocket turns the back wheel at a slower rate than the larger front sprocket. This causes the bike to move less sistance at the same rpm. This lowers the gear ratio and allows you to get to a "usable" rpm much more quickly. 3000 rpm is cool, but 5-6000 is where the power is at.
 

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Discussion Starter · #8 ·
ok I think there was too much of my rambling going on earlier, I will break this down easy.

down one in the front equals up three in the rear correct? yes

I am saying stay with the stock gearing up front and just go up three in the rear

When I see people go down in the front the only thing I can think of is that the person doesnt want to spend the money to do it the right way and just get an entirely new chain and sprocket set but would instead rather save money, go down in front, cause long term damage to the chain & sprockets.
 

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YES 1 in front = 3 in the rear. but keep in mind that an even # of teath will cause the chain to eat the sprocket faster then on odd one will. I think ::)
 

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sconly said:
When I see people go down in the front the only thing I can think of is that the person doesnt want to spend the money to do it the right way and just get an entirely new chain and sprocket set but would instead rather save money, go down in front, cause long term damage to the chain & sprockets.
What exactly is long term damage if you replacing your drive line every year? I say no factor.
 

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sconly said:
ok I think there was too much of my rambling going on earlier, I will break this down easy.

down one in the front equals up three in the rear correct? yes

I am saying stay with the stock gearing up front and just go up three in the rear

When I see people go down in the front the only thing I can think of is that the person doesnt want to spend the money to do it the right way and just get an entirely new chain and sprocket set but would instead rather save money, go down in front, cause long term damage to the chain & sprockets.


Down 1 UP 3, Whatever it takes!!
 

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I've had to do some looking to find bigger than a 44 tooth rear sprocket. I like right around 3.07/1 ratio. That takes a 14/43 (3.07/1) or a 15/46 (3.06/1).

FWIW, I've put 13,000 mi. on a 520 Drive set using a 14 tooth front and didn't have any problems.

LA
 

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Going lower in the front will reduce the effective HP output at the rear wheel, but it will increase the torque that the motor can apply, The 14 tooth mod is done to make the Monster less choppy at lower RPM. You could just as easily achieve the same result by keeping the stock sprocket and going up 3 teeth in the rear. This is what I did.

However moving to a 15 tooth front, and therefor stepping up 6 teeth in the rear to achieve the same result is not only ridiculous, but would have the chain rubbing the cases if not at all times at least when the rear suspension was compressed.

Justin
 

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Some arithmetic (39/15 is stock on my M1000S):

39/15
2.60000000000000000000
39/14
2.78571428571428571428
40/15
2.66666666666666666666
41/15
2.73333333333333333333
42/15
2.80000000000000000000
43/15
2.86666666666666666666

-1 front (39/14) != +3 rear (42/15), although that is the closest match.

-1 front is a VERY simple and inexpensive change, doesn't require a new chain, when adjusted, lengthens the swingarm, and reduces the rotating mass (inertia). very well MAY cause some extra wear on 525 and 530 chains, but fun-for-the-BUC (Basic Unit of Currency) is high.

+1, 2, 3, 4, ... rear either requires a new chain or shortens the swingarm, increases the rotating mass (unless you replace steel with Al or Ti), generally costs quite a bit more, but doesn't seem to be causing any additional wear and allows more incremental adjustment to suit specific combinations of bike, rider, and style.

there are some accompanying differences in mechanical advantage (ratio of the radii of the front and rear sprockets), too, but those are directly proportional to the changes in diameter due to tooth count, so smaller front OR larger rear sprockets have the same effect.

as already pointed out, the real reason for the change is to be higher RPM (hence, more power) at the same road speed. even if I could get the bike to the power peak in 6th (yeah, right), I don't need 150 MPH on the freeway, but I can definitely use just "a bit more" power on the streets and freeways I use for commuting and in the back roads and tracks for fun.
 

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I only went down to a 14T in front since it was $30 bucks. Compare that to the $200+ I'd have to spend to get a new chain and rear sprocket... When my chain wears however, I'll go back to the 15 and go up 3 in the rear. I just have to be a little cost concious, cause this bike is bleeding my bank account dry! ;D
 
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