Why high rpm on chainsaws during delimbing?

[Fordiesel69]

Take the husky 550XP or the infamous 562XP for example (there are many others) and they advertise it has "Rev Boost" which is extra rpms that occur during light loading, such as when you are delimbing a tree. I really gravitated towards the 5's in the husky lineup such 545, 555, etc as they lack rev boost and some argue they last longer.

My question is why do people need 12,000+ RPM to de limb a tree? I am not skilled in cutting and operation, I just cut and not think about stuff like this. I use a top handle T435 and I certainly do not need full throttle for most delimbing.

 

[mk378]

When the chain is moving slow it is more likely to snag making the saw jump and kick. A fast moving chain tends to just cut whatever it touches.

 

[jeepman3071]

My question is why do people need 12,000+ RPM to de limb a tree? I am not skilled in cutting and operation, I just cut and not think about stuff like this. I use a top handle T435 and I certainly do not need full throttle for most delimbing.

They don't. It's more of a need than a want. Right saw for the job in my mind, but I also own 4 saws. Time is money for professionals, so the faster you work the more efficient you can be, this is way different for Joe Homeowner. Many homeowners buy a professional big saw, then complain how heavy it is.

 

[Slick3914]

Engine has better cooling as well

 

[dnewton3]

They don't burn as clean at mid-throttle as they do at WOT. Those little 2str engines can only be "tuned" to be most efficient at one rpm. The greatest power is at/near WOT. That's where they operate best.

 

[MRC01]

Another factor is that power is torque * RPM. Rev boost sounds like a way to get more peak power, limited in time because the higher power level is not sustainable. It may be applicable to limbs that you can cut through quickly, within the limited time period that the saw can sustain the rev boost. But this implies it's not for light loading, but for brief periods of heavy load.

 

[Chris142]

When the chain is moving slow it is more likely to snag making the saw jump and kick. A fast moving chain tends to just cut whatever it touches.

Kinda like ripping a bandaid off or pulling it slowly.

 

[bullwinkle]

Seems like the lightweight pro models are set up for carrying up a tree & delimbing 30+ feet off the ground when tied on. The bigger ones run slower with more power, like my old Stihl 042 with it's 28 inch bar & double skip chain. You're not hauling that beast up a tree, that's the one that makes the trunk smaller! And disconnected from the stump!

 

[PontiacHO]

Snag and it’s too easy to bend a bar attempting to get it loose. I run mine WOT limbing a tree. Never cut limbs that are sprung by weight of another tree etc. without several relief cuts that takes the pressure off. That does take a slower speed. A sprung limb under pressure can do some serious damage when cut loose. A power company guy was cutting downed trees after a storm and cut a sprung limb that sprung back and caught him in the neck. That got him.

 

[spasm3]

Slow chain speed can grab and jerk the saw unexpectedly.

 

[SARG52]

Spoke with a "Treeman" when I hired him to remove a huge green ash. I asked why he had a truck full of only Husqvarna saws.
He advised that you want a fast cutting saw so the limbs drop straight down rather than "hinge" to the ground and he then said that he deems Husky as the best.

 

[Cujet]

I have a Husqvarna 346xp, with muffler mod. That thing is a 14,000 RPM ripper. I get it, the high RPM and Oregon full chisel chain go through smaller diameter wood like butter.