Im not sure of the reasoning lately to get the sprockets as small as possible. Sure it helps weight a small amount but it really wears on the parts faster. either one should be fine but i went with the 16t front sprocket. i left the back alone for now since the front one is really all thats needed to cure the lurching.
I believe the real wear problems come into play when you step down to the 14t front sprockets. Chains have a had time making that tight of a bend to an wear out much faster.

 

...but i went with the 16t front sprocket. i left the back alone for now since the front one is really all thats needed to cure the lurching...

Does this really help get rid of that frustrating lurching? I've been wondering about how to get rid of this...

 

I use 15/43 at the advice of burn-z on here. It does what you want and not so aggressive to loft the front wheel at every opportunity.

 

15/43 without a tranny gearing change seems like it would lose massive top end. That's down 2 down 4

 

But that equates to about +2 on the rear. Going down on both cancels out. So you just need a shorter chain, probably 116-118 links instead of 120, but the overall gearing is similar to less than -1 front. Probably wears the chain/sprockets ever so slightly faster, but it's not too bad.

I did the in between, I did 16/45 which is essentially stock gearing but with less teeth on both. I could've done a 118 link chain, but i have 120 just because i didn't want to cut it.

 

Some decent lit:

http://www.motorcycleanchor.com/motorcycle/how_to/mc_sprocketmath.html

 

Ok, so I'm still not getting this right I guess...

Because if you go down in sprocket sizes you lose top end. I know everyone hates the gearing calculator, but it says a 10mph top end drop doing down 2 down 4 :dunno

 

Stock is 17/47=2.764

Graves is 15/43=2.866

so you are actually going with slightly lower (Higher number) gearing thus loosing a little top speed but gaining slightly in acceleration. It's just kind of a tradeoff. If you do the -1/+2:16/49=3.0625 you know how quickly it will accelerate and/or wheelie but loose a significant amount of top speed. EDR says if they go to a very fast track they will even go 15/41 which will give you a final drive of 2.733 which will actually yield a higher top speed than oem gearing. There are many combinations you can use to achieve the same gear ratio. Just look at a chart and you can see.


Explanation on gearing: http://www.r1-forum.com/forums/showpost.php?p=4444379&postcount=119

Here was Eric's build thread: http://www.r1-forum.com/forums/showthread.php?t=281492&highlight=

He's an incredible tuner: http://www.r1-forum.com/forums/showthread.php?t=281492&highlight=

 

Correct, since -1 front is approx +3 rear (not exactly), then -2 -4 is approx 0 +2 rear, which is still transferring some to the low end, it's just not as drastic as it sounds because the -4 in the rear is offsetting -1.3 in the front. You are still going down .7 though.

 

Right, so the only way to raise top end is raise teeth. What's bugging me is the final drive for down 2 down 4 is higher than stock, but lower top end. Do the drive ratios only affect rpm? Meaning higher ratio puts you at higher rpm at a certain speed.

 

Meaning higher ratio puts you at higher rpm at a certain speed.

Higher ratio means lower number. A lower gear ratio is a higher number...which means more acceleration.

Think of a car with 4.11 gears vs one with 3.73 gearing. The 4.11 will be quicker off the line but the 3.73 will go faster at any given rpm.

Another way to think of it is for every rotation of the driveshaft the wheel will turn x number of rotations. Which would accelerate quicker 4.11 rotations or 3.73 rotations?

 

How on earth can 15/41 get higher top speed than stock ?? I don't understand that

 

15/41 is a 2.733 ratio and 17/47 is 2.764 which is a lower gear ratio (higher number). At max speed rpm's will be lower with 15/41. I think you are confusing a higher number to mean a higher gearing. It's actually the opposite. A lower number is a higher ratio and a higher number is a lower gear ratio.

Look at the chart below. As the ratio goes lower (higher number) across to the right the corresponding speed at any given rpm goes down.

 

I can't wrap my head around it right now :lol

 

Let me take a stab at it...

Ok, lets throw out all internal engine gearing, and assume that Every turn of the engine turns the front sprocket once.

If we use an evenly dividing final drive ratio like 15/45, then it will be 3.000. Meaning for every 1 turn of the engine(front sprocket), the rear wheel turns three times (rear sprocket). You get this because 45 divided by 15 = 3.

Therefore, if your rear wheel circumference is 1 foot (for fun), every engine turn moves you 3 feet across the ground.

If you go to 15/43 (43 divided by 15 = 2.866), then that one engine turn only turns the rear wheel 2.866 times, or with that same 1' wheel, only moves you 2.866 feet. So you need more engine revolution to move the rear wheel the same distance. This is easier on the engine, but you run out of rpm faster.

 

I was thinking about doing a gear change as well. Would be going from 16/47. I'm curious about the 15/43 ratio so I might try that out.

My question is this: Do I need to get my FlashTune re-done to compensate for the gearing change? Or do I leave it alone? I would be doing the gearing change at the same time I'm planning on doing the Graves clutch kit.

 

I know the gearing will not affect your tune at all per the conversation i had with my guy today.

 

Think about it in terms of a bicycle's gears. Assuming the front cog stays the same when you shift through the rear gears, by going with the largest rear sprocket you will be able to accelerate quickly or use the same amount of energy or workload to go up a steep hill spinning the pedals at a constant rate. Switching to the smallest gear pedaling get more difficult but you will go faster with the same number of revolutions on the crank. The rear wheel will make more revolutions with the chain moving at the same speed.

 

I understand what you guys are saying as in to the ratios, I get it.

So using this math, why wouldn't a 13F/30R be better? It's a closer ratio :dunno

 

It would have a higher top speed but now both sprockets are getting so small it would be impractical. Where have you seen a 13 tooth front sprocket for sale? Here is a gear chart and you can see that you can arrive at the same ratio with multiple combinations.

 

15/30 would be too small of a chain. I don't think it would clear the swingarm. Even if it did, while theoretically you would have a really high top speed, it would take forever to get to that speed.

 

 

Ok so let me ask this. How much top end would I lose running a 15/43, and how much top end would I gain using a 15/41.

And finally, how much acceleration would I lose switching to a 15/41?

 

How are you supposed to measure acceleration?

Using the Gearing Commander http://www.gearingcommander.com/ and plugging the numbers in based off a stock bike running to 13k rpm you will be able to hit 183.9 mph. With 15/43 gearing you will be at 177.4 mph at 13k rpm. With 15/41 gearing your top speed will now be at 186 mph at 13k rpm. These are all hypothetical conditions as drag, tire diameter, etc and many other variables come in to play but you should be able to get an idea of speed with different gearing. Let's plug in -1/+2 to see the difference. At 16/49 you will drop to 166 at 13k rpm. As you can see that's a change of 20 mph so you need to figure what will work best for you.

 

I think gearing all depends on the situation, some gear ratios work on the street some work on the track.

 

Can we get back on topic?

 

I didn't read every page of the thread but were all the calculations using the same size tire

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Yes

 

Wow, this turned in to quite the thread !!! LOL :sing:

Burn-Z,
You did a hell of a job explaining everything too bro !!

I'm glad I understand all the ratios and how the different gearing works. I'm just not good at explaining any of it haha

SO it looks like I will be going with the 15/44 gearing

 

I'm going to chime in here because I think I get what Gear is saying...

I have an FZ6. The standard gearing is 16/46. I want to drop a tooth from the front to improve acceleration at the expense of some top speed.

15/46 gives me a ratio of 3.06

I can also get 3.07 by installing a 17/52 set of sprockets. Hypothetically of course, I wouldn't do that because it would cost me $250 instead of $25.

Using Chris's gearing calculator site, I can see that at 6000rpm in 5th gear, I am doing 100kph with either set up.

Am I not achieving the same effect of increased acceleration and reduced top speed, by either of these combinations?

 

Thanks Ben

I never claimed to know everything about motorcycles, but I do know loads more about cars :fact

 

:corn



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gearheaded: You want to run the smallest gearing normally to get the ratio you want. Too often people put too much emphasis on the ratio and have no clue what it means or more importantly what it does. We get people all the time asking for x tooth counts because of the "ratio" but then we tell them "well, you're going to lose about 25mph off your top speed and they drop their jaw "that would suck". Just think about it was does more so then the final ratio. down in the front or up in the rear will yield more acceleration at a loss of top speed.

Now, if you go with smaller sprockets you'll drop weight and can achieve the same thing.
However, you can't go too small in the front or the chain will have to turn in too tight of a radious and you'll destroy the chain. A 14T is the smallest you can go in the front before destroying the chain with a 13T, however most, and I, would agree that you should avoid a 14T as it's borderline. In the rear you need the sprocket tall enough to clear the swingarm. Yes, this will lower the weight of the sprockets, but in all reality unless you're racing it won't make a damn bit of difference. You're talking about saving like 1-2 ounces of weight. It's one of those things I wouldn't over think. If the sprocket you need isn't in stock somewhere you can change the gearing so you can get your bike back on the road fast by say going down 3 in the rear and also one in the front and the gearing will be nearly the same thing. If you're racing as a pro then sure, most go with the smallest sprockets to accomplish what they want, but it's nothing you'll notice by any means.

Just think of how you use your bike and what means the most to you before you pick a gearing as that will determine what gearing you should get. As for trying to get the smallest sprockets you can...you can do that, but it's nothing critical by any means. You'll shed a little weight, but it's even more funny to see someone do that then pick a front sprocket without lightening holes drilled into it. They went with smaller sprockets, but in the end have a heavier set up due to the fact that AFAM doesn't drill all their front sprockets, and Driven or Vortex do. Etc. The brand matters just as much as the size of the sprockets when you're talking about a tiny few ounces.

 

Thanks Corey, I was understanding the end goal of going with smaller sprockets, just wanted some clarity. :bow

I never plan on going that low in teeth, that was just a hypothetical. I should have emphasized.

 

OK...well unless I'm mistaken...that's what our poor mate gearheaded has been saying all along! :hammer:

 

:blush

 

However a rear sprocket is larger and has more leverage on the rotation then a smaller front sprocket so if you really dig into the physics of it things start to change. Wouldn't the rear sprocket play a larger roll as it gets to be a larger sprocket? Kind of like brake rotors do

Just to really blow your mind gearheaded No gearing chart makes up for this does it?

 

I try not to use gearing charts just because they aren't real world applicable. When I use a gearing calculator I feel like I should be confessing my sins at church that weekend