I can only buy one: B7800, TC30, JD790, or CK30

IslandTractor · Nov 12, 2005

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Interesting thought, so I looked up the specs on the tractors.
Kubota B7800 = 1741# which gives it an amazing 58# for each 1 HP
JD 790 = 2150# which gives it 79# of weight for each 1 HP
Kubota L2800 = 2600# which gives it 89# of weight for each 1 HP
CK 30 = 3042# which gives it 101# of weight for each 1 HP

All the weights are from the internet, none include FELs, which typically add another 850 to 1000# of weight. Obviously the less weight per horsepower a tractor has the more powerful it would feel. )

Not sure I would agree with the conclusion here. For motorcycles and hot rods the hp/lb is an important figure. Does anyone think the B7800 is almost twice as powerful "feeling" as the L2800 or CK30?? Seems to me that with tractors, while HP certainly is a factor, there is less than a direct correlation between power and HP. Think about some of the monster Ag tractors which likely have ratios well above 100. The B7800 might win a 5 yard sprint but is unlikely to grossly out pull the others and might well lose a tug of war to the heavier tractors. Right??

thcri · Nov 12, 2005

I found an article once on the web and I sure wish I could find it again as it explained the differences in tires.

Basically what they said in any tire weight was a major factor. I am talking about indents left in the soil not the turf. The different tires based on the same weight will leave pretty close to the same indent. Drive three tractors of the same across sand side by side. You would be surprised on how close the indent itself would be. I noticed this with my dad's L3000DT turfs and my TC29D with R4's. Now we can play with tire pressures and other things but the difference is not as big as would think it would be.

Why do we use turfs then, because turfs don't tear up the grass like a R1 or R4 does. R1's especially once they see a load will tend to dig in and start ripping, R4 will do the same but not as much. Turf once it sees a load it just starts to spin. The article also talked about how turfs are great on the straight, but very poor once turning. The R4's actually tear less than a turf does while turning. When I was buying I wanted turf's. My dealer talked me out of it and to this day I am don't regret it and the majority of my work is finish mowing. In fact 80% is finish mowing. My dealer took a TC18D with turfs and and TC21D with R4's out on the lot. Rainy day the TC18D while wheels are turned short would throw grass out all over the place while the R4's there was barely any signs of grass being ripped out. As far as golf courses, you won't ever see anything heavy out there.

If finish mowing is your task, weight is of more importance than having a turf or R4 tire. If your majority is loader work, then get a heavy tractor if the weight is distributed right.

murph

Bob_Skurka · Nov 12, 2005

Island . . . You are correct that a heavyweight will outpull a lightweight any time any day. But that is not the only way to measure a tractor's performance. A lighter tractor won't feel sluggish, will climb hills easier, etc. As for the big ag tractors, no doubt that they have more weight than modern CUTs however even with modern ag tractors the trend is moving toward somewhat lighter machines as farmers are becoming very concerned about soil compaction. I'm no farmer, so I have no experience in that class of equipment other than reading some articles on the trends. With a modern CUT you don't do too much pulling if most of the work is going to be mowing and that is the intent in the original post of this thread.

murph wrote 
If finish mowing is your task, weight is of more importance than having a turf or R4 tire. If your majority is loader work, then get a heavy tractor if the weight is distributed right.

Murph . . .I totally agree with most of what you wrote but will slighly argue with the concept that you need a heavier tractor for loader work. And I am really just nit-picking on this point, but a heavier tractor does not mean the tractor has more lift capacity, I know you know that, but some folks don't. You point about the weight being distributed right is spot on. A properly balanced tractor is more important than a heavy tractor for lifting and there are plenty of examples of lighter tractors than can lift more than heavier ones.

DrewL · Nov 13, 2005

. My dealer took a TC18D with turfs and and TC21D with R4's out on the lot. Rainy day the TC18D while wheels are turned short would throw grass out all over the place while the R4's there was barely any signs of grass being ripped out. As far as golf courses, you won't ever see anything heavy out there.

...................and as soon as I see a R4'ed machine mowing a fairway I'll be the first to report it. Turfs and slicks rule golf courses for turf management for years and for years to come. I have yet to see a Tri-Plex involved in rock removal.

never mind........................pounds per square inch is where it is judged, period

To20Chris · Nov 13, 2005

CUTs are general purpose devices, but as you are discovering they are optimized for different things, and that dictates how they are constructed. Tractors built in "conventional" fashion, where the structure is the gear case castings bolted together (L2800), will be heavier than those built with stamped steel welded chassis (B7800, etc.). In the end, you'll have to take a guess at what jobs you'll be doing most often, and pick the one that seems to fit best.

If you're going to be mowing look into the PTO of the L2800. I am not familiar with HST variations, but the gear model does not have live PTO, which would be a disadvantage.

As far as weight goes, weight = traction. It's all well and good to say that you want "balance", but you're not going to feel like adding/removing wheel or suitcase weights very often. So if you're going to be doing jobs that require traction very often, you'll want a heavier tractor. My tractor is heavy, and I've never felt it was unbalanced. However, if you're going to be mowing with it a lot, obviously lighter is better.

Personally, if you are going with Kubota, I think you are wise to go with the L over the B. The B is highly optimized for mowing, and as such is extremely light, while the L is more general purpose.

thcri · Nov 13, 2005

DrewL,

I guess if you would read my post, my comment was in regards to turning is when the R4's did less damage, not on the straight. Since golf course machines mostly are running straight they stick with the turfs.

Also weight is weight and you would never see a large heavy tractor on a golf course. You can talk pounds per square inch all you want, the heavier the tractor the more pounds per square inch.

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RedRocker · Nov 13, 2005

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You can talk pounds per square inch all you want, the heavier the tractor the more pounds per square inch.

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Here's a 6200 pound skid steer with turf tread:
For the RC-60, ground pressure is 2.7 psi - about half the ground pressure of a person on foot.

daTeacha · Nov 13, 2005

The weight on a square inch of ground from a tractor is dependent on 3 things, just like a car. First, obviously, is the weight of the machine.

Secondly, the size of the tire's contact area with the ground. This varies with the type of tread. Using the two extremes A slick will use the entire "footprint" as area on which to spread the weight around whereas an Ag tire will put all its weight on the lugs until they sink deep enough to have the spaces between the lugs contact the ground. Then the weight gets spread to all the contact area, much like a slick.

The third factor is tire size, pressure and sidewall stiffness, which determine the general size of the flat area where the tire would contact a concrete slab or similar hard surface. On softer materials, this impacts how deeply the center of the tire sinks into the substrate. With a narrower tire, you will sink deeper in the middle but in a longer patch. A wider tire will have a wider footprint that is shorter front to back. Using a shoe or boot analogy, compare the track left by a wet hiking boot with that left by a street shoe or your bare foot. The hiking boot will have put your weight on fewer square inches of floor. On a soft surface, it will have left deeper dents and compacted the soil in those dents more while compacting the soil between the dents less. Changing your tire pressure can alter the shape of the footprint a bit, but mostly it exaggerates the characteristics already built into the tire tread and sidewalls.

The design of the lugs on Ag tires varies from one manufacturer to another and from one tire to another by the same manufacturer depending on the soil type in the area. A heavier soil more resistant to being displaced by lateral forces exerted by the lugs will make one type of lug work better than a tire designed for use in sandier soils that have less shear resistance.

Turfs have a lot of rubber contacting the ground at the same time and as such will sink less deeply into the ground. When they start to slip, they will remove the soil surface in thin layers, loading up the spaces between the tread blocks if the soil is sticky. Lugged tires will sink more deeply and are less likely to slip but when they do they will dig deeper divots than a turf spinning the same amount. My Ag tires on the Kubota will leave more marks on the lawn and dig ruts if I'm not careful, but the turfs on my Cadet 109 will leave large flat areas with the above ground parts of the grass torn loose and the roots intact if it spins the tires on a hill.

You've got to pick your tires based on your soil types, your primary use for the tractor, and your need for an award winning lawn. If you're really paranoid about your lawn, you'll stay off it with your tractor when the ground is soft and keep all turns as gentle as possible. The best looking lawns are mowed by reel mowers and not tractors with rotary mowers anyways. Look at a greens mower.

DK35vince · Nov 13, 2005

( You can talk pounds per square inch all you want, the heavier the tractor the more pounds per square inch. )

Why ???
A lighter machine with smaller diameter, narrower tires can have the same pounds per sqaure inch as a heavier machine with larger diameter, wider tires..

DrewL · Nov 14, 2005

( ( You can talk pounds per square inch all you want, the heavier the tractor the more pounds per square inch. )

Why ???
A lighter machine with smaller diameter, narrower tires can have the same pounds per sqaure inch as a heavier machine with larger diameter, wider tires.. )

That's my point exactly