Rotary Cutters, Medium Duty, Heavy Duty, Gearbox Sizing, etc.

I've spent this week looking at my local options for a shredder, as well as learning more about some of the ones I can buy and have shipped to me (especially the Tennessee River Implements cutters, as the price is quite nice).

Heavy duty to one person is medium to another
My father in law suggested I get a 6' heavy duty shredder. He was comparing it to his 5' heavy duty shredder. Most have said that a 6' heavy duty shredder is too my for my L with 29-30 PTO HP.

Turns out, after many more questions, he was primarily referring to the gearbox, that he's seen many people blow the gearboxes on those, especially ones bought at Tractor Supply, etc. His example of a good shredder was his Bush Hog Squealer SQ160. He says the gearbox is better, and the round design, with the top having less areas for water to pool, and hold grass are highly desirable. I ran his 5' Bush Hog behind my LDT, and it ran very well, with barely a slowdown, except in the thickest of the blue stem you can find on his property. Additionally, it cut through smaller mesquite trees with ease, which is something desireable at my place.

I find that his Bush Hog has the same deck thickness as the TRI medium duty cutters.

Gearbox Sizing isn't precise

I find that gearbox HP requirements aren't well explained by the manufacturers, and I find posts that say you can go with the bigger gearbox and it just gives you more leeway, but some manufacturers (like Bush Hog) list a HP range (with a minimum). The Bush Hog Squealer 172 (since I have a comparison with my father in law's 160) lists a range of 30-45 PTO HP. That seems like it is very much borderline, with the listed specs on my L showing either 29 or 30 PTO HP (I don't know what gear early versus late means, so I go with the late one. I guessed late meant at the PTO shaft on the back of the tractor).

Factors that are truly important

What you are cutting

If it's just pasture land, with nothing big, there is less risk of you bogging the engine. Cutting through thick, wet grass taxes it more. It seems to me that this is more a function of the size of the bite you are taking, on a 5' cutter, you are biting off less than a 6' cutter. I would assume the gearbox has no bearing here, unless you are undersized. So, for me, it seems that if I can get away with a 6' cutter with the output of my tractor, I'd like to go this way.

How heavy the cutter is

Primarily, this seems to affect the ability for you to lift the cutter. The TRI 6' cutter with the 45 HP gearbox has a listed weight of 708 lbs, and if you upgrade to the 90 HP gearbox, it adds 60 lbs. From this alone, I would opt for the cost of the 90 HP gearbox, because it feels like with me mowing with the FEL, the 60 pounds wouldn't be a problem. Tractordata says my tractor can lift at least pounds (without my understanding the difference between the two specifications listed, I picked the minimum). Given that, I assume it's only a matter of whether my front tires are going to come off the ground, so again, I doubt that 60 pounds is going to be the metaphorical straw that broke the camel's back, but I could be wrong. Current bush hog models (BH16) seem to weigh similar to that of TRI.

Matching the gearbox to the tractor size

This one as I mentioned above seems to have some voodoo involved. Nobody lists a minimum HP for the gearbox, but I would imagine having a heavier duty gearbox implies potentially more HP loss than a smaller model. Can I pick up the TRI model with a 90HP gearbox to attempt to future proof my purchase, and work with a bigger tractor later?

Other niceties

I find that the Bush Hog and Land Pride models have a rounded shape, and less channels for water/wet grass to get stuck on, reducing the likelihood of it rusting out. My father in law's old cutter had the deck rust out due to it collecting debris and not properly cleaned. I'm aware that if you are very good with taking care of it, it should not be a problem, but sometimes life intervenes, and it seems like a great feature.

Ability to get parts? I have dealers for Bush Hog as well as Land Pride around, so it seems relatively easy to get parts. If I pick a model not sold locally, parts may be less available.

My ultimate factors
I want the biggest shredder that I can get (seems like 6'), with the best gearbox and body design, to last me for the long haul, even if I spend a bit more money up front. Given that, I need it to work behind my Kubota L, or it's worthless.

I checked pricing on the Land Pride RCF locally, and was quoted $ (which turns into $ with tax). If I compare that to comparable pricing for a TRI cutter shipped to my property, I'm spending around $ less. I can see only the two main benefits, rounded design, and locally available parts. I'm tempted to save the $ and understand that the deck needs to be taken care of. At the moment, I can store the tractor in the barn, but I believe the shredder will stick out, so I have to assume it's going to see some rainfall.

Does anybody see anything wrong with my reasoning, after reading more threads, having seat time behind a 5' cutter, and getting pricing and options from local and online sellers?

Last but not least, I recorded some video of what I encounter on the property (I only have video from right now, with the grass not fully grown into summer, but it's still representative).

Thanks!

Mark

Features

• (1) brand new 45 horse power shearpin gearbox. This gearbox fits several different makes of 4',5' and some 6' rotary cutters. I sell a lot of these boxes every year for several different applications and carry ALL REPLACEMENT PARTS for this box, but hopefully you won't have to worry about that.
  

• Here are the specs on the box:

  If you want to learn more, please visit our website.

• *45 horse power gearbox

• *Standard 1-3/8" smooth input shaft(where the pto shaft hooks on). The pto shaft is held on by a 1/2 shearbolt.

• *length of the input shaft out of the gearbox is 3" long

• *bolt hole pattern for mounting is on the corners, 4-3/4 center of hole to center of hole. It takes a 5/8" bolt.

  GTM are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

• *12 splined output shaft(where the blade carrier hooks up on the bottom)

• *1-9/16 outside measurement over the output shaft splines- from the base of the output cap to the end of the splines is 2-3/4" long- overall length of the output shaft is 4-1/2" long.

• *takes a 1" threaded castle nut and a carter key on the bottom of the output shaft to secure blade pan(NUT is included - - BLADE PAN IS NOT!!)

• *overall height of the box from the top of the mower deck to the top of the box is 9-1/2"

• This is a fairly heavy item (47 lbs.) so freight is not cheap, but we do not make anything off of freight, whatever ups charges us we charge you.

  Contact us to discuss your requirements of 40 HP Rotary Cutter Gearbox. Our experienced sales team can help you identify the options that best suit your needs.

• 40 HP
• 1:1:47 Ratio
• 1-3/8" Smooth Input Shaft with Shear Pin Hole
• 1-1/2" 12-Spline Ouput Shaft
• Bolt Pattern: 6-1/2" (4) 5/8" Holes, 5" Center Hole Needed for Shaft Assembly
• The Input and Output Shafts Cannot be Purchased Serparately.
• They are Sold as a kit.
• The kit includes the following parts: input shaft, input gear, output shaft, output gear.
• The Shaft Kit Cannot Be Separated.