help picking a sproket

[Eiler2641]

ok so what is the differance between an 8 tooth and 7 tooth sprocket. Also is there any advantage to using 3/8 vs 375. I am trying to pick the right one to put on a stihl 360pro that I want to run a 20in b&c. Thanks for any advice

 

[Sagetown]

The 3/8 and .375 are the same size chain. Someone else will have to explain the sprocket.

 

[cpr]

Unless your saw is ported, forget the 8. You're driving chain with a taller gear by going to an 8 and that takes power. The smallest saw I have with an 8 is 88cc. FWIW.

 

[oscar4883]

Generally speaking an 8 tooth sprocket will give you more chain speed at the expense of some torque. A 7 tooth sprocket is what would be considered "standard" so to speak for a stock saw running 3/8ths chain. An exception may be running a bar much shorter than normal, I.E. a 20 on a 660, or something similliar. Depending on your wood, bar to cc ratio, and also how heavy handed you are, will all be deciding factors on whether an 8 tooth will work well for you. IMO a 7 tooth is a good choice for the set-up you describe. More forgiving than an 8. Sprockets are cheap so try both and see what is best for you.

 

[cutforfun]

i would go with the 7 tooth, it will give you more torque with less speed, a 8 tooth will have more chain speed with less torque. think of it like a 21 speed bike, smaller the front sprocket the easier it is to peddle but as you go up in sprocket size it gets harder to peddle but you can peddle at the same speed but you go faster.

long story short a stihl 036 does not have the power to turn a 8 tooth in 20 in wood. imho

 

[Sagetown]

I knew it had something to do with rpm and torque. So the 7 tooth sprocket has more torque, where the 8 tooth gives more rpm, but needs more horses to pull the load, right?

 

[cpr]

I knew it had something to do with rpm and torque. So the 7 tooth sprocket has more torque, where the 8 tooth gives more rpm, but needs more horses to pull the load, right?

Correct. I tried both on my MMed 372. With the 8 in 20" wood it was at 8600 rpms and I had to be gentle. With the 7, I lost chain speed, but gained it back by cutting at 98-9900 rpm and I could still dog in.

 

[Sagetown]

Correct. I tried both on my MMed 372. With the 8 in 20" wood it was at 8600 rpms and I had to be gentle. With the 7, I lost chain speed, but gained it back by cutting at 98-9900 rpm and I could still dog in.

ALRIGHT !P

 

[Eiler2641]

I meant to write 3/8 vs 325. I was told by some guys that the 325 should only be used on smaller saws and that the 3/8 chain should be used with saws that have more power. I do not know the reason why though.

 

[Brian VT]

I knew it had something to do with rpm and torque. So the 7 tooth sprocket has more torque, where the 8 tooth gives more rpm, but needs more horses to pull the load, right?

You've ridden a bicycle with selectable gears, right ? If you put the chain on a larger front sprocket you get more RPMs at the rear wheel per turn of the crank, but it's harder to pedal.

 

[Sagetown]

Generally speaking an 8 tooth sprocket will give you more chain speed at the expense of some torque. A 7 tooth sprocket is what would be considered "standard" so to speak for a stock saw running 3/8ths chain. An exception may be running a bar much shorter than normal, I.E. a 20 on a 660, or something similliar. Depending on your wood, bar to cc ratio, and also how heavy handed you are, will all be deciding factors on whether an 8 tooth will work well for you. IMO a 7 tooth is a good choice for the set-up you describe. More forgiving than an 8. Sprockets are cheap so try both and see what is best for you.

Repped

 

[Brushwacker]

My first choice would be 3/8 chain, 7 tooth. If you go with .325, use 8 tooth.
If you were to go with 7 tooth .325 , fuel consumption would increase enough to me it is an inconvenience, and it slows progress. Just takes longer to get a load of wood. Thats my experience with multiple Stihls 50 to 60+ cc.
3/8 chain, I find easier to maintain. .325 8 tooth is very slightly taller for gearing but, doesn't feel much different for cutting speed.

 

[Sagetown]

My first choice would be 3/8 chain, 7 tooth. If you go with .325, use 8 tooth.
If you were to go with 7 tooth .325 , fuel consumption would increase enough to me it is an inconvenience, and it slows progress. Just takes longer to get a load of wood. Thats my experience with multiple Stihls 50 to 60+ cc.
3/8 chain, I find easier to maintain. .325 8 tooth is very slightly taller for gearing but, doesn't feel much different for cutting speed.

Interesting. I would like to go the 3/8 chain route with my ms270, but my .325 chain is going to have to do for now.

 

[galde]

Whenever possible go with the rim rather than spur sprocket. Rims are cheap and easier to change pitch and/or pin count. Rims are also easier on chains, since the chain rides on the tie straps on a rim but only on the spur teetn with the spur srrocket. Once the spur wears just a little it starts "eating" the chain, and an eaten chain will eat the bar.

 

[SteveH]

My 036 Pro is used for firewood cutting. I've had it 12 yr. or more and the best combo for me is 3/8 and a 7-tooth rim sprocket. Only bar I use on it is a 20". I've tried other combinations, this is best. As someone said, though, the rims are cheap and you can fool around with various combo's and see what you like best for your sawing purposes.

 

[Sagetown]

Whenever possible go with the rim rather than spur sprocket. Rims are cheap and easier to change pitch and/or pin count. Rims are also easier on chains, since the chain rides on the tie straps on a rim but only on the spur teetn with the spur srrocket. Once the spur wears just a little it starts "eating" the chain, and an eaten chain will eat the bar.

Rim Sprockets were the 1st thing I converted to with my latest saws.

 

[Brushwacker]

Interesting. I would like to go the 3/8 chain route with my ms270, but my .325 chain is going to have to do for now.

20" bar 7 3/8 might accelerate a little sluggish in comparison with .325 7 with a 270, but it should pull good in average hardwood up to 12 to 14". You would notice more power with the .325 7 in the larger diameter cuts and if you were cutting much large rounds with that saw and a 20 " the .325 7 would make more sense. I really like a 16" 3/8 7 on an 026 and very often carry it used primarily for cutting off small stumps and brush close to the ground where I drive, mow etc.. Its easy to hand sharpen, more fuel efficient and usually see's some limbing and I cut some of the smaller firewood up with it especially when getting close to fatigued using the bigger chainsaws. At 1 time I carried another good running 026 with a 20" bar and was happy with its performance but seldom used it when the wood got bigger then 14" as I most often have multiple size saws with me. 034's-36's are perfectly fit for 20" 3/8's IMO from my experience.
I would suggest for some people, carry in your vehicle a different bar chain-combo and with the inboard clutch, carry an extra sprocket and clip to change combinations when conditions change.
Works great on big, long jobs.

 

[Sagetown]

I was all set to make the change, when I pulled down my old Pioneer with a 3/8" chain, and noticed my .325"x .63 gauge chain was heavier, and the teeth were larger, so dropped the idea.
I use a 20" bar with the .325", and it does pretty good in large oaks, postoak, redoak, and whiteoak. Granted it won't cut as fast as my sons' 70cc saw.

 

[blsnelling]

No reason to read past the first post. Don't even consider an 8-pin on a stock or MMd 360.

 

[Eiler2641]

My 036 Pro is used for firewood cutting. I've had it 12 yr. or more and the best combo for me is 3/8 and a 7-tooth rim sprocket. Only bar I use on it is a 20". I've tried other combinations, this is best. As someone said, though, the rims are cheap and you can fool around with various combo's and see what you like best for your sawing purposes.

Thanks that is probably what I will go with on my 360pro. Do you run all stihl chain on it or have you tried anything else.