What type of the trimmer is better and why, curved or straight shaft?
I prefer a straight shaft because it's easier for me to reach under bushes and under the edge of my storage building. Most curved shaft trimmers I've used force me to bend over too much.
Straight shaft. Gets under things better. Easier to use it as an edger. Puts the head a little farther from my feet.
You don't see the pro landscapers using curved shaft. All pro model trimmers are straight shaft. Only stating this to point out what is used when high performance is needed. Some do prefer the curved shaft. It works for them.
As stated, straight shafts tend to be better in regards to performance. Curved shafts can be useful for small/short folks, they also tend to be a bit lighter.
Straight shafts are nice for all of the above mentioned reasons, butt they also rotate in opposite directions, so the straight shafts tend to put a lot more trimmings on your feet. I use a curve most of the time for that reason, and break out the old staight shaft if I have a lot of reaching under things to do.
Straight shaft for all the above mention reasons. Also, being over 6 foot tall, the curved shafts are too short for my height.
I'll take the trimmings at my feet for being able to trim with a straight back - good posture.
eal51 in western CT
I have been manicuring my yard for almost 20 years with a simple Homelite Bandit curve shaft trimmer. I'm 6'1". The Homelite Bandit is at the end of it's road, it seems, still runs well for the age. I just finished fixing an new, but old, Homelite straight shaft trimmer that was stored in my garage for over a decade and although I have always been a fan of the curve shaft trimmer, I am leaning towards the straight shaft because of the reach, it seems to keep me cleaner, and also it seems as if it is easier to turn to do edging maintenance. I think today there are a lot of choices. Stihl makes the curve shaft FS 46 model which is a foot longer than regular curve shafts. It is a good option and provides the straight shaft reach and I'm currently considering for myself. One thing I should say on behalf of regular curve shaft trimmers is that in very tight spaces they are a lot easier to use than a longer shaft. So, each feature has an application. You will have to look at your stituation and decide what is the best fit.
Almost all professionals use straight shaft trimmers because the engineering and construction of the drive shaft system is better. A straight shaft has two ball bearing supporting either end of the gear box, and most have a solid steel shaft. However, some of the lower end Echo's use a flex shaft to drive the gear box.
Most curved shaft machines (except some of the more expensive Stihl and Tanaka) use a bushing at the bottom where the flex drive connects to the spindle for the string head. These tend to run hotter and do not have the longevity of the ball bearing systems. Those curved shaft Stihls and Tanakas will also cost you more than most "big box" straight shaft machines.
At the very lowest price points, maufacturers eliminate the centrifugal clutch and drive the engine directly to the shaft. Although common on cheaper Homelite, Weedeater, and some other curved shaft machines, I've never seen a modern straight shaft without a clutch.