More information on high torque trimmer heads

cold-beer

LawnSite Senior Member
So I made a thread several months ago on high torque gearing on string trimmers.
Recently, I picked up a Shindaiwa T302 trimmer and now have a 21cc, 25cc, and 30cc Shindaiwa/Echo trimmer or power-head (split shaft) for apples to apples comparisons. For these comparisons I used .095, .105, and .130 trimmer line with (17" swath) and without (22" swath) the guard using both a standard gearing (1.62 to 1) and high torque gearing (2 to 1) head. The information below is of my opinion from using all of these combinations on extremely thick waist high field grass in western Oregon.

-M235 21 cc split shaft trimmer (same motor as Echo SMR 225) Rated at 1.03 HP
The high torque gearing outperformed the standard gearing with all line sizes with and without the guard. I honestly don't understand why all trimmers in this power range are not geared 2 to 1. There really is no comparison. The little motor simply performs better with the high torque gear head. It even winds out better with no resistance when not even cutting in every string size with and without the guard????

-Conclusion: All trimmers in this power range should utilize high torque gearing IMO.


-Shindaiwa M262 25cc split shaft trimmer (Same motor as Echo SMR 2620) Rated at 1.35 HP.
The high torque gearing outperformed the standard gearing with all line sizes without the guard; however, when utilizing the guard (17" Echo trimmer attachment with guard), the standard gearing outperformed the high torque gearing with .095 line, and performed equal to the high torque gearing with 105 when utilizing a guard with a 17" swath.

-Conclusion: If you run a trimmer with a guard on, the standard gearing works better until you step up to .130 line. This is with an Echo trimmer attachment, which uses a 17" swath. Shindaiwa uses a 20" swath and results would most likely favor the high torque in all scenarios wit the larger swath IMO

Shindaiwa T302 solid shaft Trimmer (Same motor as Echo SMR 3020) Rated at 1.8 HP
The high torque gearing only outperformed the standard gearing when using .130 line without the guard. Performance was similar with .105 line when using and not using the guard between both gearing ratios (a wash). I again used an echo 17" guard for consistency and not the 20" guard that came with the unit.

-Conclusion: The high torque gearing performs well when there's a lack of power, but when power is there to actually get you the RPM's you need, The high torque is only needed when swinging big line without a guard


What performed the best of every combination? The T302 using .095 line with a guard and the standard gearing cut the cleanest on the thick field grass. If I wanted to clear a bank of said grass, that would be my choice; however, the high torque does well when the power isn't there or when using big line for stuff like small shrubs or berry bushes.
 
Last edited:
OP
cold-beer

cold-beer

LawnSite Senior Member
Good comparison. Which trimmer is your favorite after using them all when looking at power to weight ratio and high torque vs standard heads?

Shindaiwa T302 with .105 line and no guard using the high torque gearing.

There's only about a pound of difference in all of them, so I'll take the extra power of the 30cc motor, and I like running a mile of string when doing gullys, so I take the high torque.

I don't ever run guards and prefer the .105 line over the .095 because it lasts much longer when edging with a trimmer like I do.
 

Jashley73

LawnSite Member
Location
Louisville, KY
This is a pretty hot topic of interest for me at the moment.

I'm torn on investing in a Stihl-Kombi setup with a big powerhead for heavy duty stuff, or go with a cordless/battery setup for the light-duty weekly work. The real answer is "BOTH," but the immediate question is, which one first...?

I really want a trimmer with more torque for taking the guard off and letting out 20"+ of line for the bigger area trimming. My older Stihl FS80 is a great gas trimmer for daily stuff, but it does not have the torque for letting our more string than the guard allows.

I've often wondered how some of the small diameter (.080"?) "silent-twist" stuff would perform in lower-torque trimmers, without the guard.
 
OP
cold-beer

cold-beer

LawnSite Senior Member
This is a pretty hot topic of interest for me at the moment.

I'm torn on investing in a Stihl-Kombi setup with a big powerhead for heavy duty stuff, or go with a cordless/battery setup for the light-duty weekly work. The real answer is "BOTH," but the immediate question is, which one first...?

I really want a trimmer with more torque for taking the guard off and letting out 20"+ of line for the bigger area trimming. My older Stihl FS80 is a great gas trimmer for daily stuff, but it does not have the torque for letting our more string than the guard allows.

I've often wondered how some of the small diameter (.080"?) "silent-twist" stuff would perform in lower-torque trimmers, without the guard.
.080 doesn't do to great when using a large swath over 20 inches because the line itself is flimsy. Even .095 is harder to whip without the guard than the .105 or .130 stuff imo. The problem is that while it weighs less and is easier to turn, it doesn't cut as well because it loses so much of its ridgdness.
 

Bootybaggins

LawnSite Member
Location
Ontario, Canada
I was pondering this the other day. It seems like for most situations trimmers are used for the torque gearing would be suitable. Im almost never at full throttle needing super high head speed anyways. It almost seems like torque gear ratios should be the norm and the taller gearing should be the special model.
 

Jashley73

LawnSite Member
Location
Louisville, KY
I'm getting more anxious about this.

Does anyone know if a high-torque head from Redmax, Shindaiwa, Maryuyama, Echo, etc... Will fit on a Stihl trimmer?

If so, I'm definitely going to get one and give it a shot...
 

Integrity-LC

LawnSite Member
Location
West Michigan
I'm getting more anxious about this.

Does anyone know if a high-torque head from Redmax, Shindaiwa, Maryuyama, Echo, etc... Will fit on a Stihl trimmer?

If so, I'm definitely going to get one and give it a shot...

If you get any of the bigger 4 mix power heads you will not need a high torque head. I have a KM130 and its by far the most powerful trimmer Ive ever run, nothing that Ive cut with the string trimmer attachment has ever bogged it down. The 4 mix heads have alot more TQ than the 2 stroke units.

My take on the high torque heads is mixed. Overall I like the one on my Maruyama but it takes some getting used to because you have to get it much higher in the RPM's to get the headspeed you need at times.
 

Jashley73

LawnSite Member
Location
Louisville, KY
If you get any of the bigger 4 mix power heads you will not need a high torque head. I have a KM130 and its by far the most powerful trimmer Ive ever run, nothing that Ive cut with the string trimmer attachment has ever bogged it down. The 4 mix heads have alot more TQ than the 2 stroke units.

My take on the high torque heads is mixed. Overall I like the one on my Maruyama but it takes some getting used to because you have to get it much higher in the RPM's to get the headspeed you need at times.

I would try the high-torque head on my existing FS80, for letting out more string without the guard. Provided that it fits, that is... I wonder how it would do.
 

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