Tractor front end geometry???

CTyler · May 18, 2004

I know tractors are not performance vehicle but why is the geometry so wacked? There is zero caster, lots of toe in and positive camber. The extra toe in is probably there to help it track better with the loose steering. Caster would help this as well. Its' kind of irritating that the tractor will not stay where you point it.

DaveNay · May 18, 2004

I would guess simplicity of manufacture? I am not an automotive engineer, but I would guess that much adjustability adds a whole lot of expense to the manufacturing, as well as lowering the reliability and strength due to the additional mounting points required.

Dave

Richard · May 18, 2004

CTyler...

Since you brought up front end geometry, I'll post this here /forums/images/graemlins/grin.gif

We have IH 444 and it needs a new kingpin assembley. As it currently stands, as you're driving down road, the front left wheel wobbles left/right in a VERY noticable jerky action. (would a 6 inch left/right wobble be "noticible"? /forums/images/graemlins/crazy.gif)

As I was watching the other day, just wondering what would happen if the wheel fell off... I noticed the kingpin was rotating counterclockwise inside the kingpin holder thingy. If I'd put a white mark on the pin itself, it was not going back/forth with wheel, but clearly was moving continuiously in a counterclockwise fashion. /forums/images/graemlins/crazy.gif

Ok..so now we need a kingpin assembley. When I get that replaced, how do I "align" the front wheels so they are pointing semi straight, or do I really need to worry about that?

I see the "alignment rod-a-matic thingy" is simply an arm connected to the steering cylinder (power steering) with an adjustable nut on the end.

Soundguy · May 18, 2004

Well.. then.. there you go.. that tells you that the draglink is the adjustment from wheel to wheel.

Soundguy

CTyler · May 18, 2004

I can see the ease of Mfg and less cost by eliminating adjustabilty. However loose/sloppy steering really is an area that could be improved upon dramticaly. It doesn't need to and I would not expect it to drive like a car or truck but jeeze...

What purpose does the positive camber(tops of tires tilting out) serve other than to ruin my conering speed? /forums/images/graemlins/tongue.gif

tc35dforme · May 18, 2004

I'm in now way an expert, but I wonder how things may change when you go to maximum load on the front end ( loader full ) ???

As for the sloppy steering, I can't complain on my TC35D. I find that most of the time, I'm making slight adjustments ( mowing ) or spinning the wheel like a nut ( loader work ). I think the short wheelbase and relatively fast turning ratio on the steering wheel combine to make it seem jittery.

If I were driving cross country on I-80 I'd probably want to tighten her up !! /forums/images/graemlins/grin.gif

slowrev · May 18, 2004

I also have a 444 with front end wobble in the right side. However mine is caused by a bad tie rod end. Just got a new one in the other day and need to install it.

To20Chris · May 18, 2004

Frankly, I have not experienced this on either my TO20 or the new LK3054. They are both quite different, with the Ferguson being 2WD, manual steering, and skinny tires, but they both pretty much go where pointed. The only time I've had trouble is when driving the TO20 on the road in 4th with the brush cutter raised up, but that is due to lack of weight. Maybe the toe is adjusted wrong? Adjustments for caster and camber would cost money, increase complexity, probably compromise strength, and provide an opportunity for misadjustment/failure. Beyond that, they really just aren't needed.

JimR · May 18, 2004

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First off they want you to keep your hands on the wheel where they belong. Other than that, I would have to say for ease of manufacturing and assembly. The least amount of parts, the less the cost is. As for setting the toe-in. You can make an easy tool out of wood and a nail to mark both tires. All you need is a base and a post. At the top of the post cut a notch in the post to put a horizontal piece of wood in that will pivot on a bolt or whatever. Bang a nail into the end of that board. Put a spring on the other end of the board using an electrical wire U nail and anchor the other end to the base. Jack your tractor up and mark each wheel in the center by spinning it downward. Have a friend help you with a tape measure to measure the two marks. Adjust the tie rod ends accordingly to get the right amount of toe-in.

normde2001 · May 18, 2004

"However loose/sloppy steering really is an area that could be improved upon dramticaly."

Sounds like your tractor needs some frontend work. My 25 year old Yanmar doesn't have loose/sloppy steering.