Traction Bobcat CT225 power and climbing issue

[bbse]

Problem 1. I call it a traction issue as I have a new Bobcat CT225 with loaded R4's and a HST transmission. As many may know, this is the same basic tractor as the Kioti CK27HST. I am having a power issue since new and I am looking for comparative opinions. One is that I can put the tractor with loader against a tree stump on solid grass covered Tennessee ground and in low range at 3000 rpm I cannot spin the tires. With 3000 lb tractor and loaded tires is it unreasonable to expect this tractor to break traction or is this normal with a HST tranny. BTW, I am just barely pressing the pedal to keep the gearing as low as possible. As I increase pedal pressure it eventually just stalls out.

Problem 2. The hill behind my house is about 16 to 20 degrees. I can climb the hill in mid range but I can barely make it up the hill, about 120 feet, and that is with the loader and bush hog on but not running. If I stop on the hill, I cannot take back off in mid range, I have to drop to low.

I do not believe this is normal but I am am only familiar with gear drive tractors of similar size. I can go up the same hill in the same spot with my Kioti LK3054 in 6th gear loaded. I can do in in 5th and accelerate. Just looking for experienced opinions as Bobcat says my tractor meets specs. I don't wish to accept that answer. I have a thread in the BC forum but I want a broader opinion base.

 

[Josh61513]

1) When you have the tractor in lowest range, be it a gear tractor or HST, and you demand maximum forward power but prevent movement (against a large tree, or tied to something) one of two things will happen, right? The tractor will either A) spin one or more tires, or B)if your traction exceeds your power output the tractor will stall. If you are able to stall the tractor than your traction exceeds your power output. This will happen with both an HST and gear tractor, and I don't see this as a problem at all.

Many of the higher horsepower per pound tractors (JD, Kubota, etc.) have more power than traction in low range so they will instead spin the tires in the same condition.

If you had said the tractor will not spin its tires and the engine will not stall, then that would mean the relief valve in the HST has met its maximum power output. That could be normal operation or potentially point to a relief valve out-of-spec. But since the tractor stalls this does not point to a problem with the transmission. It is possible that the engine is not making it's rated power, the best way to test would be to find a tractor dynomometer. The higher output (CT 230, CT 235) may spin its tires in this same condition, but then again it could exceed the power rating of the HST and engage the relief valve.

2) What does the engine do in this condition? Does it (nearly) maintain RPM or does it stall? If it stalls, again you have more traction than power. If the engine maintains RPM the HST relief valve has engaged which may or may not be as designed. Although, 16-20 degrees is significant. You may simply need to use low range in this condition. It's possible that a gear tractor may be better suited for this condition because it will likely have at least one range between "low" and "mid" so you could travel a bit faster, though it still wouldn't be easy to begin from a stop while using the clutch...

 

[bbse]

Thanks for your reply. I just brought the tractor home from Bobcat and it is still the same if not even a little worse. As to stalling. I can start at a touch of pedal to about 2/3rds before it starts to stall, applied slowly of course. The same on the hill side except on the hill as I give it just a little more than a touch it will shudder a bit but won't move. I just tried the tractor against a tree again and my fields are pretty soft right now. It has rained the last 2 days. I nearly stuck my truck and I left some bad ruts getting out. But the tractor will not spin a tire even on that soft ground. Either it is super weak or I have some super traction on near mud!

As to my Kioti being gear on that same hill, I have gone up it in 5th and 6th many times over the past 5 years and I agree I wouldn't want to drop the clutch in the middle but I have started at the bottom many times at idle and just drove right up that rise with no problems. That is what I meant by accelerate easily in fifth gear. I always line up straight first before I go up it if I have a lot of weight on the small Kioti.

 

[Sprocket]

I also have the CT225 (27hp) It's a real heavy tractor for it's HP rating and then the HST takes away some power. Mine will stall sometimes when working hard even in low range, but I can climb a pretty good grade at 2500 rpm in mid range and my tractor will spin all 4 at times in low when pushing dirt. It does take some fancy work on the HST pedal to get the most out of it. I have moved hundreds of tons of dirt with mine and I am completely satisfied with it. More HP would always be nice but I think my tractor does alot with only 27 to spite it's weight. I would suggest that you unload those tires, It will save alot of weight and give you more power and less traction. Make sure you don't have dragging brakes. Also make sure your loader valves are centered....When I tilt the bucket going up hill it robs ALOT of power.

 

[dfkrug]

Problem 1. I call it a traction issue as I have a new Bobcat CT225 with loaded R4's and a HST transmission. As many may know, this is the same basic tractor as the Kioti CK27HST. I am having a power issue since new and I am looking for comparative opinions. One is that I can put the tractor with loader against a tree stump on solid grass covered Tennessee ground and in low range at 3000 rpm I cannot spin the tires. With 3000 lb tractor and loaded tires is it unreasonable to expect this tractor to break traction or is this normal with a HST tranny. BTW, I am just barely pressing the pedal to keep the gearing as low as possible. As I increase pedal pressure it eventually just stalls out.

Problem 2. The hill behind my house is about 16 to 20 degrees. I can climb the hill in mid range but I can barely make it up the hill, about 120 feet, and that is with the loader and bush hog on but not running. If I stop on the hill, I cannot take back off in mid range, I have to drop to low.

I do not believe this is normal but I am am only familiar with gear drive tractors of similar size.

This has been written about in numerous HST threads, incl the one you
mentioned in the Bobcat forum.

It is not a power issue if the engine does not stall out but the wheels do
not spin. The relief is opening, as stated by JOSH. Did you try the same
test in reverse?

Anyway, it is a feature (bug?) of these tractors that the RV opens in a high
traction situation in low range. I think 5000psi is a bit too low for the
RV setting, based on the fact that my JD955 would not do that and
it, as well as my JD4300, utilize 6000psi RVs in their HSTs. My B21's
engine would stall before the RV opened in the same hi-traction, low
range situation. It was an engineering decision to use an engine in
the B21 that was weaker than the RV, while the M27 tractors (CK30/35,
CT225/30/35) use an engine that is stronger than the RV. That means
a CT235 will be no more effective than a CT225 in this situation (RV-limited).

You mention a 16-20 degree hill. Don't you mean 16-20 percent?
Remember, a 45-degree hill has a 100% slope. Both are steep, but 16
degrees is hella-steep. I can not get up a 16 degree hill in my CK30
OR CT230 in anything other than L range. That kind of slope also starves
the hyd pumps (in forward).

I have had my CK in relief (I have excellent traction with a hoe mounted),
but fortunately this is rare, since it happens only trying to push an
essentially immovable object. This never happens just trying to climb
a steep hill.

If anyone is adventuresome, they may want to consider upping the HST
forward RV to maybe 5500. The tractor is built stoutly enough, IMO. It
would require another RV, or a modification to the existing one...they
are NOT adjustable.

 

[bbse]

Lets see, I can stall the engine if I ease the pedal past halfway while either pushing or stalled on a hill.

As to slope, I have never understood to percent to grade. I don't think it is just me, I have read some threads here that were very confusing about that subject. All I did was lay a 2x4 on the hillside and took my magnetic round angle gauge and it reads 16-20 degrees. Now if 45 degrees is 100% of grade then each degree between 45 and 0 would be 2% of grade. If I am understanding this then my hill is between 32% to 40% of grade....whatever that means. My angle gauge seems to work more like the side angle gauge that they used to (may still) here on this website. I think it shows yellow at 20 and red at 25 degrees on side slopes.

 

[biggerten]

As to slope, I have never understood to percent to grade. I don't think it is just me, I have read some threads here that were very confusing about that subject. All I did was lay a 2x4 on the hillside and took my magnetic round angle gauge and it reads 16-20 degrees. Now if 45 degrees is 100% of grade then each degree between 45 and 0 would be 2% of grade. If I am understanding this then my hill is between 32% to 40% of grade....whatever that means. My angle gauge seems to work more like the side angle gauge that they used to (may still) here on this website. I think it shows yellow at 20 and red at 25 degrees on side slopes.

Open the Windows calculator. (Start -> All Programs -> Accessories -> Calculator). Once it's open, click View and then Scientific. The Calculator will show a bunch more options. Now, for example, enter 18 (your 18 degrees) and click the button marked tan (tangent). The display will read 0.32491969623290632615587141221513. Multiply by 100 (just move the decimal point two places to the right in your head), the grade is 32.5%. It's not a linear function, 2% is not a degree. Just remember, take the tangent of an angle and multiply by 100. Try it with 45. Press 45 and then tan, display says 1, 1 * 100 = 100% grade.

 

[bbse]

Thanks for the trig lesson. I stopped after algebra 2 and I am afraid after 32 years I have forgotten most of that.

So, I guess the question the question is should 32.5 to 36.3 % to grade is too steep for mid range in a 27 hp, 3000lb HST tractor?

 

[Sprocket]

When I get back up to my property I will check how steep my driveway is. It's a great gauge for the CT225 power. My 225 will struggle at 2000rpm mid range but climb it fine at 2200-2500(with loader and 500lb BB)I think your tractor may be heavier than 3000 with Loader, BB and loaded tires.

When is the dealer going to do the comparison for you? I really want to know the outcome of that.

Respectfully
Mark

 

[bbse]

I have the same question. I picked up the tractor yesterday and I am waiting to hear from the salesman. If they really want to set me off they can take weeks to get to me. I am curious to see how well they deal with that.

As to the 3000lb mark you are right. With loader, BB, laded tires I am over 4000 lbs. But I hit this problem as soon as I got the unit home last fall. It will take off and go up the hill with no loader, no BB or cutter, unloaded tires but barely. just the unit alone can make it but it is struggling. Besides, a bare tractor is useless.

I am curious to see how steep your drive is too.