sprocket sizeing

[2006TRX400EX]

i have a 06 trx 400ex and i want to get some more speed out of my quad with sprockets, What sizes would be best?

I do alot of crosscountry and road racing


i have on it
-Amr hot ignition stage 2
-Amr cdi stage 2
-Hmf Ballance exaust (full system)
-DynoJet stage 2
-K&N Filter with prefilter & open airbox
-

[ohsobad_chevy]

What is your current gearing? I would just go up one tooth on the front sprocket for more top end.

[2006TRX400EX]

My gearing right now is stock 14Front and 39Rear

[86 Quad R]

with the mods that you currently have and if its dialed in right you should be able to pull a 15/39 easily. :cool:

[ohsobad_chevy]

Yup, put a 15 front on and you will get more top end.

[400cc]

what about a 16/36?

[chipworkz]

You can either go UP in the front or DOWN in the rear for more top end speed. I would prefer to go down in the rear since this can give you more ground clearance and you don't have to worry about clearances around your front sprocket. Most of the time when you make the front sprocket bigger you will need to grind or file you chain guide to allow for the larger sprocket. I did this and a lot of people do but the rear is easier.

A general rule is 1 tooth larger in the front is about 3 teeth smaller in the back.

Right now you have a 2.79 ratio.
Going up 1 tooth in the front will give you a 2.60
Going down 3 teeth in the rear will give you a 2.57.
The smaller the number the more top speed.

Going to a 16/36 would put you at a 2.40 which might be a little much and loose to much on the bottom end.

[John451]

Originally posted by chipworkz
You can either go UP in the front or DOWN in the rear for more top end speed. I would prefer to go down in the rear since this can give you more ground clearance and you don't have to worry about clearances around your front sprocket. Most of the time when you make the front sprocket bigger you will need to grind or file you chain guide to allow for the larger sprocket. I did this and a lot of people do but the rear is easier.

A general rule is 1 tooth larger in the front is about 3 teeth smaller in the back.

Right now you have a 2.79 ratio.
Going up 1 tooth in the front will give you a 2.60
Going down 3 teeth in the rear will give you a 2.57.
The smaller the number the more top speed.

Going to a 16/36 would put you at a 2.40 which might be a little much and loose to much on the bottom end.

Hey, do you think you could give me the formula for the sprocket ratio? I knew it before and i said " oh i dont need to write that down... i'll remember it" well of corse i didnt. lol.

[chipworkz]

The formula is easy, it is just the REAR divided by the FRONT. 39 / 14 = 2.785 rounded to 2.79.

If you don't want to do the math just look at this chart provided by Renthal.
Ratio Chart (http://www.renthal.com/File/gearing_ratios.asp)

[John451]

Originally posted by chipworkz
The formula is easy, it is just the REAR divided by the FRONT. 39 / 14 = 2.785 rounded to 2.79.

If you don't want to do the math just look at this chart provided by Renthal.
Ratio Chart (http://www.renthal.com/File/gearing_ratios.asp)

woww... someone told me this rediculously long formula for it that took like 10 mins to do lol.. thanks!

[chipworkz]

Maybe they were getting really technical and including the transmission final ratio and rear tire circumference.:D

[John451]

Ohh, yea i think it was the tire size that was in it too.