YEs...actually I DO miss that tight turning radius. I used to think that the gravely was really "awkward" working around all the trees, now it is my machine of choice when doing that (the BX being the other choice). The GR was hard to beat when it comes to getting in and out tight places. : )
4X4 downhill traction issue
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SPYDERLK
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They will fix the problem. Those turfs are almost like slicks on grass, esp if damp. He needs a sparser tread to link better with the ground.
larry
jenkinsph
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Yes,it's a K664 and near as I can tell it's working properly.If it had no holding power on the downhill the tractor would immediately start sliding after launch.I've tried rear drive machines on this hill in the past.Tire type or weight makes little difference.I'm no whiz either,but I think the solution is to keep the front tires from losing traction.So,We'll see.
A pic of the backside of the front drive.I notice there is a short link above the tie rod that moves a shaft inside.While in the air I can turn one wheel with no affect on the other,doesn't try to turn backwards like a normal open carrier.Can also grab both wheels and turn them forward,meaning loss of engine power and the front axle goes along for the ride.
I would block up the rear wheels and see if you can rotate the front wheels faster than the rears while they are turning forward slowly. That would answer alot of questions. I wouldn't make any assumptions rather I would verify this.
Just speculating that the lever in your picture controls the wheel speeds in turns similar to the k92, making the outside wheel in a turn go faster and the inside wheel slower.
OP
locknut
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Ok,jacked it up and tried it.The wheels can be turned faster than driven speed,lust as I thought.There must be some sort of over-running clutch in the hubs.You can hear a muffled clicking sound when you turn them manually.How's the front end work on your 749,is it one of those that have individual gear motors?
Here's a vid of the GR on the hill.You'll notice the hydro straining,and towards the end on the last run down is the part that's longest and steepest.Not much room to turn and nowhere for a runaway to go,except the briars, stumps and small trees.
jenkinsph
Super Star Member
So, if your front wheels will free wheel then they won't provide braking when driving down a hill. Hopefully the new atv tires will help with the rear tires traction.
My x749 is on a jobsite for a couple of days, I will jack it up and see what it does. So far it has held on some very steep grades for me.
My x749 is on a jobsite for a couple of days, I will jack it up and see what it does. So far it has held on some very steep grades for me.
jenkinsph
Super Star Member
Yes,it's a K664 and near as I can tell it's working properly.If it had no holding power on the downhill the tractor would immediately start sliding after launch.I've tried rear drive machines on this hill in the past.Tire type or weight makes little difference.I'm no whiz either,but I think the solution is to keep the front tires from losing traction.So,We'll see.
The rears may be holding but the fronts are not, that makes it react the same as a 2wd on a downwards slope.
I am not sure if I understand. If you turn a wheel on a hydro in gear it will click.
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locknut
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Yep,I guess you'd call it a hydraulic driven front wheel assist to the rear wheels.Of course,on the downhill you backpeddle the hydro and that puts a braking action on the front wheels as the gearmotor goes into reverse mode.You'll notice in the video I backpeddle the hydro on the GR a little to keep from overspeeding.These small tractors apparently don't have much holding power in the hydro neutral position.
jenkinsph
Super Star Member
I live in a mountain ski town (Ruidoso NM) and often have to deal with steep slopes. I can drive up or down the slopes at a low speed without using the brakes. Just back off the hydro pedals. It seems to maintain the speeds without much fluctuation, my older L130 couldn't make it up the hills muchless down the hills with any control. I try to be careful of the slopes I tackle though since it is so dry here it can be easy to slide at times.
jenkinsph
Super Star Member
What he means is when you turn the front wheels on his tractor in the forward direction faster he hears a light clicking sound. So the wheels can free wheel not providing the four wheel braking that you have with a mfwd.
I reread what you told him to do. I see you said have the wheels turning slowly and try turning the front faster. It make sense now. I thought he juat jacked up the front and tried turning it with the engine shut off, a clicking sound would be normal then.
I wonder if that hydro is supposed to perform like that? I think he needs more weight for sure now.
jenkinsph
Super Star Member
I don't know enough to determine whether adding more weight will help or not. Hopefully the new tires will help, other than that I suspect the machine is at its design limits.
I just think since he can make it up the hill with those tires they should be good enough to come down. I think it is the weight is transferring too much of the back. On the other hand the 4wd is not working coming down of the hill either. I guess we will find out.
jenkinsph
Super Star Member
That depends on the variable hydraulic valve which is tied to the steering linkage to adjust the wheel speeds. I don't know how accurate mine is but it works very well as I can make smooth turns without squirming on concrete or asphalt.
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locknut
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Got the rear tires today,mounted and 5 gal WW fluid in each one.With 12psi the circumference was 3 in larger than the turfs,so I aired them down down to 5psi and lost an inch.Still 2 in larger,but drove it around a bit and noticed no ill effects or gear wind-up or tire scuff in the grass.Hopefully,the new fronts will be a tad larger so the proportionality will be close to the original turf tires.The original outside wheel track is 37.5" and I do some sidehill spots,so I added some 1.5" wheel spacers.No hubcentrics to mess with so an easy install.Front tires will be here tomorrow.
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locknut
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One would think so,but in reality it doesn't appear to work.I do have a short 30 deg slope in the back yard and did back up it with no problem.The hydro seems to have equal grunt in reverse.From what I was told long ago on 4WD systems with open carriers as long as the machine is MOVING equal torque is applied to each wheel till such time as maximum resistance is met,then the differential decides which side has the least resistance and applies all the torque to that wheel.
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locknut
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Maxxis 938's for the back.Not quite as wide as the turfs,but should get a lot better bite.The lugs are about 5/8" tall.
Maxxis 938's for the back.Not quite as wide as the turfs,but should get a lot better bite.The lugs are about 5/8" tall.
i just serviced a 4 Wheeler last week. The minimum tire pressure was 3.2psi and the max was 4psi. So you may be able to go lower on your tire pressure.
