Dirt Moving An understanding on the age old debate of geared/hydro

[Fallon]

Thanks for the response Troverman. Yes I am well aware that larger tractors have a live clutch that allows for continuous PTO operation but this is not the case with smaller lawn and garden tractors like my B6200. I was just comparing my experience HST vs geared drives on lawn/garden tractors.

What you say about the HP requirements of the HST pump makes sense, but in my case I don't think that is why I get stuck. I get stuck because of lack of traction not lack of HP. The wheels will spin and dig holes in the dirt road despite my use of the differential lock. So something else is to blame here. The tires on the HST are larger than the 6200 but I would think that would provide better traction, not less.

The generally accepted number is a HST is 15% less efficient than a gear transmission. Personally I think that 15% is worth it.

For those that complain about a HST not going up a hill in high range... Would your gear machine make it up in high? I'm quite sure the answer is no. You'd stall the machine. On a HST the relief valve will usually pop open before stalling the tractor.

Also on every HST I can recall I couldn't stall the machine in low range & full throttle without using the PTO. Just not enough traction.

 

[Crank Shaft]

For those that complain about a HST not going up a hill in high range... Would your gear machine make it up in high? I'm quite sure the answer is no. You'd stall the machine. On a HST the relief valve will usually pop open before stalling the tractor.Also on every HST I can recall I couldn't stall the machine in low range & full throttle without using the PTO. Just not enough traction.

I agree completely with Fallon, but I am not complaining about using high range (because I don't use high range on hills) and I am not complaining about stalling. I merely stated my observation that my HST does not have the same traction as my old geared drive despite both of them using LOW range. The HST simply spins its tires and gets stuck. Mind you the hill is steep but it surprised me that my 25 year old 15 HP geared tractor never got stuck on the same hill that my brand new 20 HP HST cannot climb reliably. Maybe it is tires, maybe it has a different centre of gravity. I don't know the reason, which I why I posted here. It may have nothing to do with HST or maybe it does.

 

[k0ua]

I agree completely with Fallon, but I am not complaining about using high range (because I don't use high range on hills) and I am not complaining about stalling. I merely stated my observation that my HST does not have the same traction as my old geared drive despite both of them using LOW range. The HST simply spins its tires and gets stuck. Mind you the hill is steep but it surprised me that my 25 year old 15 HP geared tractor never got stuck on the same hill that my brand new 20 HP HST cannot climb reliably. Maybe it is tires, maybe it has a different centre of gravity. I don't know the reason, which I why I posted here. It may have nothing to do with HST or maybe it does.

So your old tractor had narrow more aggressive AG tires and your new tractor has wider smoother R4 tires? Just guessing here, but that is my suspicion.

 

[Crank Shaft]

So your old tractor had narrow more aggressive AG tires and your new tractor has wider smoother R4 tires? Just guessing here, but that is my suspicion.

Good guess K0ua, but wrong. The old tractor and new one both have turf tires. And before anyone asks, neither tractor has loaded (brine-filled) tires and neither tractor has traction weights added. Thanks for all the comments guys. We might need to organize a hillclimb competition to sort this out.

 

[k0ua]

Good guess K0ua, but wrong. The old tractor and new one both have turf tires. And before anyone asks, neither tractor has loaded (brine-filled) tires and neither tractor has traction weights added. Thanks for all the comments guys. We might need to organize a hillclimb competition to sort this out.

So which tractor weighed the most, or had the most weight on the rear axle? Turf tire design the same? Turf tires covers a lot of ground in differences.

 

[Crank Shaft]

So which tractor weighed the most, or had the most weight on the rear axle? Turf tire design the same? Turf tires covers a lot of ground in differences.

The new tractor weighs 1477 lbs and the old one was 1100 lbs. I don't have any specs for weight on rear axle. Turf tire pattern is similar but not identical. I even left my winter chains on this year to see if that would help and it did seem to improve traction a bit, but when the wheels spin they quickly dig holes. One thing I have not done in a long while is to check the tire pressure. Do any of you run lower than factory pressure to gain traction? If so, by how much? Thanks for all the help!

 

[k0ua]

The new tractor weighs 1477 lbs and the old one was 1100 lbs. I don't have any specs for weight on rear axle. Turf tire pattern is similar but not identical. I even left my winter chains on this year to see if that would help and it did seem to improve traction a bit, but when the wheels spin they quickly dig holes. One thing I have not done in a long while is to check the tire pressure. Do any of you run lower than factory pressure to gain traction? If so, by how much? Thanks for all the help!

Many of the fellas, have noted better traction with lower pressure. Many run around 20 lbs or even a bit less. Tire lug design, can make a huge difference.

 

[pmsmechanic]

Many of the fellas, have noted better traction with lower pressure. Many run around 20 lbs or even a bit less.

Who runs that kind of pressure? I think my owners manual asks for around 12 when lightly loaded. I bump up to 16 when I have my counter weight on for any length of time like for two hours or so. The rest of the time I'm back down at 12 again. The ride so so much nicer and my back is worth something.

If I have my duals on then all rear tires are at 12 lbs.

 

[Fallon]

If your tractor can spin the tires on the hill the transmission is putting all the torque it can down. Well, technically max torque would be just be before it lost traction. A transmission isn't going to affect traction unless it can't pass enough torque.

A HST will eat up 15% of the avalible torque compared to a gear. But neither will affect the point it looses traction, unless you consider the minor differences in weight.

 

[LD1]

HST vs gear making difference in traction is one of the craziest things I have heard.