Author Topic: 7 tooth vs. 8 tooth ?  (Read 1192 times)

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Offline alsled

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7 tooth vs. 8 tooth ?
« on: November 05, 2013, 07:07:10 pm »
So whats every ones input on this?   Thinking of putting a 8 tooth sprocket on a 390xp with a 20'' bar. Good, bad Idea?

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Offline mdavlee .

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Re: 7 tooth vs. 8 tooth ?
« Reply #1 on: November 05, 2013, 07:33:07 pm »
It should be fine.

Offline HolmenTree

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Re: 7 tooth vs. 8 tooth ?
« Reply #2 on: November 05, 2013, 07:41:59 pm »
So whats every ones input on this?   Thinking of putting a 8 tooth sprocket on a 390xp with a 20'' bar. Good, bad Idea?
Limbing and topping with falling included go for it. If round filed and heavy bucking go with the 7 tooth.
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Offline jockeydeuce

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Re: 7 tooth vs. 8 tooth ?
« Reply #3 on: November 05, 2013, 08:11:57 pm »
A 390 with a 20" bar, I wouldn't consider anything but an 8 pin!

Offline HolmenTree

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Re: 7 tooth vs. 8 tooth ?
« Reply #4 on: November 06, 2013, 09:20:26 am »
A 390 with a 20" bar, I wouldn't consider anything but an 8 pin!
Yes the almighty short 20" bar will make any big cube saw cut like a banshee ha ha.
Time both 7T and 8T with a round filed chain on your 390XP in a log and see which one cuts faster. The only gain you may see with your stock 390 with the 8T is when your running square ground chain.
BTW when I bought my 395XP brand new it came from the factory with a 7T 3/8
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Offline 660magnum

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Re: 7 tooth vs. 8 tooth ?
« Reply #5 on: November 06, 2013, 09:25:45 am »
I use 8T rims with 3/8 X .050" X 60DL (reworked)square chain on my 372 & 066 cookie cutter saws.
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Offline SawTroll

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Re: 7 tooth vs. 8 tooth ?
« Reply #6 on: November 06, 2013, 11:02:35 am »
It is easy and cheap to swap back and forth anyway, but 8-pin sounds like the obvious choise for a 20" on a 390xp.... ;D

Offline HolmenTree

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Re: 7 tooth vs. 8 tooth ?
« Reply #7 on: November 06, 2013, 11:19:41 am »
It is easy and cheap to swap back and forth anyway, but 8-pin sounds like the obvious choise for a 20" on a 390xp.... ;D
So whats every ones input on this?   Thinking of putting a 8 tooth sprocket on a 390xp with a 20'' bar. Good, bad Idea?
Limbing and topping with falling included go for it. If round filed and heavy bucking go with the 7 tooth.
As I said earlier run the 8T, I found even with the higher chain speed the larger diameter sprocket is easier on bars and the chain's chassis . 8T great for limbing and general tree work.
But for cookie cutting at a GTG or chainsaw contest using a 7T rim on a fast cutting round filed chain can beat a average square filed chain with an 8.
It takes a lower gear to pull an aggressive angle round filed chain well.
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Offline mdavlee .

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Re: 7 tooth vs. 8 tooth ?
« Reply #8 on: November 06, 2013, 05:42:45 pm »
It is all what your preference is on torque available and how you sharpen chain and how hard you push on a saw.

Offline 660magnum

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Re: 7 tooth vs. 8 tooth ?
« Reply #9 on: November 06, 2013, 07:42:53 pm »
But for cookie cutting at a GTG or chainsaw contest using a 7T rim on a fast cutting round filed chain can beat a average square filed chain with an 8.
It takes a lower gear to pull an aggressive angle round filed chain well.

I takes a lot of power to pull an aggressive square ground chain too. I use a lot of cubes on a short bar for cookies.
We should share what we know... someone may learn...
That knowledge can live after us... and that "Pays It Forward".
Be all that you can be . . .

 

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