Tilting the Tractor

[skgolfer]

All

I recently upgraded from a B7100hst to a B7500HST. I have relatively flat ground with a couple of modest hills (septic system and drainage trench). When I had the b7100 I could easily and quickly traverse the "hills" any which way. Now with the B7500, even with the FEL off, I often feel like I'm going to go over if I'm not real careful on these hills. I have the bar turf tires which are already out I believe as wide as I can get them.

My question is....would wheel weights help. If so would they be harder on my lawn and how much do they cost. Any other suggestions are very welcome.

Thanks,

sk

 

[Mike_Dumond]

Hi SK, just my opinion but, I think wheel weights actually don't do too much for side stability, considering you have as much weight above the axel as below. I would think partially filling your tires to the level of your center of gravity, if you know it, or to the axel level might be better. Keep the weight low as possible.

Also, off the record, unofficially, (Kubota might disagree with this), check if you can reverse your wheels. I did it on my b6100d and gained 3 inches. Doesn't sound like much, but it does make a difference.

OK, back on the record, if you don't have one, invest in a tilt-meter. Find out where you are comfortable, and operate in this area. R&B manufacturing puts out an exceptional one, check the main page for a link.

Keep the greasy side down.

Mike

 

[skgolfer]

Thanks Mike

I already have my order in for the tilt meter.

sk

 

[frank_f15]

sk: don't beleive wheel weights will help.lets suppose your rear wheels weigh 100 lbs now(just for argument) if u add 200 pounds to each the ratio woud be the same except, they just woud be heavier. the only way it would work is if the up hill wheel was heavier than the down hill and (that ain't practicle) so just learn to traverse slopes at a different angle. these are just my thoughts , but mabey more experienced users have a different slant(no pun intended)

 

[glennmac]

sk,

Whether you are talking about tractors or canoes or anything that can tip over, I think the general principle is that you will make it more stable if you add weight below the center of gravity (cg) and you will make it less stable if you add weight above the cg. So, the question is, how far up on your tractor is its cg. Certainly, it will be higher up on a bigger tractor, and its location will change depending on what implements you have on the tractor and how high you are carrying the implements and loads.

So, you cant exactly know where the cg is. However, perhaps unlike some of the others, I think its probably a safe bet that the cg is higher up than your axle because there isnt much total mass below the axle. Maybe the cg isnt up quite as high as the top of your rear tire.

In any event, I think metal wheel weights or a 75% liquid fill would be mostly below the cg, if not completely below it. Therefore, I am of the opinion that adding those weights should increase stability.

I also think it is important, as others have pointed out, that you travel at different angles on a higher tractor, widen your wheel spacing as much as possible, get a tiltmeter, wear your seatbelt, and be careful out there.

 

[JerryG]

skgolfer,
Yes, wheel weights will help. I put 400 lbs. on the rear of my MF 1250 and it was amazing. I can now brush hog on much steeper slopes with a very noticeable decrease in the pucker factor. The tractor is now much more stable. They also helped with loader stability.

 

[MReeter]

If you're going to add weight to the rear axle,I would stay away from the liquid or foam fill.With the constant changing of direction (especially with a Hydro) the weight of the fluid is working against the trans.The momentum of the liquid in the tires is still going foward,while you've already changed directions,and you're backing up,and visa versa. I would try steel wheel weights if at all possible.

 

[bmark]

Adding any weight to the rear tires whether it be liquid or other will help on side slopes unless more than half the weight is above the tractor's center of gravity. Since a tractor's mass is not evenly distributed, this center of gravity could change depending on the particular slope that you're transversing. When on a side slope, think of the tractor as a lever, with the downslope side of the tractor being the fulcrum. Since there is more mechanical advantage for weight added as you move away from the fulcrum (such as adding weight to the tire on the side of the upslope), you certainly add stability by adding equal weight to both tires. The weight on the side of the upslope is creating more force to hold the tractor down than the weight on the downslope side is creating. People have been adding weight to rear tires for years to add stability and traction, so it must work.

Mark

 

[BrentB]

Tip angle is a function of where the c.g. is relative to the "stability triangle". Its easiest to describe by comparing it it a 3 legged bar stool. Two of the legs represent the back tires, and third leg is where your front axle pivots (on the tractor centerline. How does a bar stool want to tip? It wants to rotate around one of the lines drawn from one let to the other on the floor. By connecting all three legs, you get the "triangle". As long as the c.g. is inside this triangle you won't tip. If you imagine the c.g. of the tractor is in the center of the seat of the bar stool, and you put the barstool on a slope, you can see that when the c.g. point "crosses over" that stability line, then the stool will tip.

Adding weight down low on the tractor lowers the tractor c.g., so you can go on a steeper slope before you tip.

Adding weight to the rear of the tractor moves the c.g. rearwards. If you imagine a top view of the stability triangle with the c.g. in the center, and then add rear weight, the c.g. moves rearward which puts it further away from the side legs of the stability triangle. You can also see how weight on the front hurts you.

Unlike a bar stool, the tractor tires can also flex sideways, which means you don't know exactly where the effective tip point is.

Wide front tires are better than the older tricycle tractors
because you have more weight down low, but the tractor still tips around the pivot point. When the tractor hits the front axle pivot stops, the stability triangle changes to a much more favorable shape, but by then you have tractor momentum working against you, and its too late. Ideally some sort of strut from tractor frame to front axle that could either prevent oscillation, or require lots of force to overcome it would greatly help stability.

Brent

 

[kerr]

I was convinced that filling the tires to axle level was the ticket.Never thought about the sloshin going on in there.So I would think either none or full " top of rim". Man ,I thought I was really cooking! O.K. wheel weights are the ticket. With the boxblade on my 4200 , an additional couple hundred lbs.on the rear would make using the F.E.L.on slopes a little more comfortable.