I've read a little about sprockets and gearing but am still in the dark about what is actually happening when you change the size of the sprockets (front and rear). If I add a 14t to the front to get top end speed what would have to be changed to the rear. And also would the chain be effected. What is the best way to understand the gear ratio set up.

 

You need to tell us what machine it is, so we can give you an idea whether your change is a good idea or not!

ATV gear ratio chart: http://pinnedoutracing.com/gearratiochart.aspx


Usually, if the changes are not great ones, you can find enough adjustment in your chain to take up the slack. It is also easy to take a link out if you need to go shorter (a link is quite a bit!), but if you need to go longer you will need a new chain.

Chains and sprockets are disposable items anyway, so it is often a good idea to just change out everything (both sprockets and the chain), and then chain length isn't an issue.

 

I ride an 03' warrior and thanks for the input

 

Yeah, for top end you can go bigger in front or smaller in the rear (or both if you want to get extreme).

One tooth in front = three teeth in back! So, if you want small changes, do the back, or if you want a larger change do the front.

The Warrior has descent low end grunt, so I think you could gear up a little without any severe consequences.....

 

That chart was useful but i still dont understand the numbers in the center. I see they're the remainder of rear divided by the front but what does that number mean?

I was thinking of going 14 and 37 for more top end speed. I already have smaller tires in the rear for a little more low end. I'm getting a new chain regaurdless but do you think i will need a bigger size?

 

The numbers in the table are gear ratios. The larger the number, the lower the gearing. The smaller the number, the higher the gearing.

If you go down any column, notice that as the rear sprocket gets bigger, the number gets bigger (lower gearing). If you go from right to left in any row, notice that the numbers get smaller (higher gearing).

For example, if your gearing is 13 front/28 rear, that means the front sprocket must turn 2.15 times to get the rear sprocket to turn once. If you changed to a 14/28, your gearing ratio would be raised to 2.00, and your front sprocket would only have to turn twice to turn the rear once.

So, you use the chart by taking the value for your present front and rear spockets, and compare the value you get from that to the sprocket sizes that you are thinking of changing to.

 

If everything else is equal, I will always choose the smallest front sprocket I can get away with. This reduces the effects of chain weight and chain friction.... and also the chain gets shorter this way (saving chain weight).

For instance, if I liked a 13/39 combo, I would try to find a 12/36 next time around (assuming the chain wouldn't hit the swingarm under power with the smaller sprockets)

The 3 tooth rule holds true for sprockets that are multiples of 3... Like 11/33, 12/36, 13/39, 14/42, etc all equal 1/3. For other combos it can be close, but doesn't always work.... 11/44, 12/47, 13/50, 14/53, etc are not all the same ratio (4, 3.92, 3.85, 3.79). 4 teeth works better in this case. 11/44, 12/48, 13/52, 14/56 are all 1/4.

 

thats very enlightening. This all makes a lot of sence now. But do you think i'll have a problem still with the chain size when i go to a 14 and 37 or 35??

 

Me??? A warrior??? According to the manual the stock gearing is 13/40.

The tranny is 2.685, 1.969, 1.505, 1.239, 1.066, and 0.947 with a primary reduction of 3.167.

The tranny on the atv I ride is 3.08, 2.14, 1.60, 1.23, and 1.00 with a primary ratio of 3.10. For my ride, I kinda like the 13/39 gearing with 20 inch tires.... which is close to the 13/40 you had stock. When I put on the 14/41, I hated it. 14 is too big in my opinion. It sucks up too much power.... Especially if you run an oring chain. I think the ideal ratio for me is 12/36 or 12/35.

But the Warrior has a lot of torque, so you might be able to get away with a taller gear, but 14/35 and 14/37 is pretty tall. You also have to check that the chain will clear the swingarm under power with the small rear sprockets.

Here's a speed chart for the warrior:



Let me know what changes you want to make to the chart.

 

I put 20" GNCC on the rears. I know that has given it more low end, so i figured by going in this direction with the sprockets i could level out a bit and mabey still gain a little speed. Thats the only change i have.