8tooth VS 7tooth rim

[oldsaw-addict]

I am thinking about upgrading the rim size on my jonsered from a 7 tooth to an 8 tooth rim sprocket. Would a 670 with a 66.8cc engine and some engine modifications have the power to run an 8 tooth sprocket on it? Or am I missing something or other here about such configurations?

[qatanlison]

Technically speaking, you'll gain 14% in chain-speed and thus loose this in power as well...

Ola

[Rocky_J]

For $3 (assuming you use a rim sprocket), just try it. To rephrase what Q said, you will be using the same amount of power to spin the chain 14% faster.

[Kevin]

You also increase the chance to throw a chain because there's less contact on the bar near the mount.
I wouldn't say it's a huge problem but it happens.

[oldsaw-addict]

Yes I am using a rim and drum setup on my saw, Thanks for helping me out.

[Oregon_Rob]

I run a 8 tooth on my Jred 801 and it works great. The top end is something like 8k RPM's, so the extra 14% really helps and the saw has plenty of torque to run the 8.

Also,
This was my first saw and for the years before this and other forums, i didn't know much about chains or saws, i would take it in and have the shop put a chain on it. Well they would take a look at the chain which was already there and replace it with the same type. It was a semi-chisel, with full safety links...

I recently bought a full chisel, Stihl RS chain. WOW, what a difference!

[SasquatchMan]

Rob, there's a bit of difference in cutting speed with that Stihl RS as compared to a safety chain, eh?  I was blown away too.

[Oregon_Rob]

Yep, it must be like having your saw power ported, only quieter, oh and a whole lot less expensive!

[qatanlison]

...and then try square filing it...and the revelation is complete...

Q

[oldsaw-addict]

...and then try square filing it...and the revelation is complete...

Q

Yeah, I just dont have the time to square file my chains, I prefer the round filing method, they still cut MUCH faster than semi chisel chain but tend to get dull faster in sandy conditions. I used to use only semi chisel chains on my saws, then I stepped up to the big leagues and I'll NEVER go back to those semi chisels in clean wood again.Theres a purpose for every type of chain, but I prefer the full chisel over the rest. Its been decided now I'm going with the 8 tooth rim for my 670, Thanks for your advice guys I appreciate it a lot.

[tony_marks]

  id have to agree,although i do like my square filed chain [done br eric  ecopsey and one by john lambert.
 art matin had a post on another forum about how the best modification on a saw,, is to get the cuttin end o the saw rite.

[Mark M]

I replaced the bar and chain on my Jonesred 630 not long ago and they recommended an 8 tooth sprocket. I had a heck or a hard time getting the chain on and once I did I've thrown it 2 or 3 times. As soon as I get the chance I'm going to get a 7 tooth to replace it. I never thrown a chain on that saw and I've over 100 cords of firewood with it.

Mark

PS - it did cut nice though

[Kevin]

Mark;
You might be able to get another bar of a different manufacture that is a little larger at the mount end of the bar.

[oldsaw-addict]

I should look into that bar issue to PREVENT the saw from throwing my chains first. I dont want to throw any of my chains with a larger sprocket so I will look into some different brands of bar for my saw. Funny I never really thought about it until someone else mentioned it.