Rear end weight and lift capacity on gasoline PT1430s

[BWSwamper]

So, I went ahead and purchased a PT1430 for my do-it-all home/residential machine/mower. This is a new machine with the 37 hp gasoline Kohler Command Pro engine (and green paint). The machine has the same specified lift capacity, lift height, and FEL as my PT1850 (1,200 lbs. to 6 ft.)

When I got the machine home I was unloading some pallets with implements from the trailer. The guys at PT had cautioned me about turning and backing with that load (54" Grapple Bucket and 60" Finish Mower) strapped together on a single pallet. Nonetheless, I was a little surprised when the rear wheels got light and the pallet tipped down lifting the rear end. I'm pretty sure those two implements aren't 1,200 lbs. and even out on a pallet that seems a bit wimpy.

I have been thinking about it and I believe the new machine with the gasoline engine may be "stronger than it can carry" due to the difference in engine weights. I looked at a couple of sources and the Kohler engine weighs 132 lbs. I found a range on the two-cylinder Deutz diesel, but it appears that engine as installed would be at least 400 lbs. So, we're looking at a difference of more than 250 lbs. at the very rear of the machine. That is significant.

No complaints here, the Deutz engine just isn't available. But, I've been thinking of adding a setup for standard tractor weights at the rear of the "tub".

On my PT1850 I have installed a plate with a standard 2 inch receiver which has proven very useful. I'm thinking I could do the same on the PT1430. Then set up a "suitcase weight" rack welded to a 2 inch mount carried low. I could then add rear weight just when doing loader work.

Any thoughts?

 

[MossRoad]

....

Any thoughts?

Yeah... I want one!

I'd talk to PT about the wheel motors and what kind of load they can carry before adding any weight. Side loads on the axles and bearings would be my main concern.

You could fill the rear tires and that wouldn't affect the wheel motors, but it's probably not that much weight, considering the size of the tires, and, you can't remove the weight easily as you could with a weight rack on a 2" like you're contemplating.

 

[BWSwamper]

I'll see what PT says. I was thinking that unless they changed the wheel motors used on the machine, I could add weight back up to the engine weight difference without issue.

Here's a link to a company that already makes what I was thinking of.

6 Weight Bracket for 2″ Receiver Hitch | Heavy Hitch - Compact Tractor Attachments

Enhance your tractor's performance with the 6 Weight Bracket for 2″ Receiver Hitch. Perfect for adding ballast and improving stability.

heavyhitch.com

 

[m5040]

IMHO I would try wheel weights and liquid ballast in the rear tires (beet juice, non corrosive). Think about the negative effects of rear ballast outside on the back of the machine, 1 clearance and backing issues, 2 the aforementioned stress on the wheel motors (not knowing if they lighten up the specs with the gas engine?). 3 like a kids seesaw, when you add weight to the rear of the tractor, you take some weight off the front. This will show up with implements like a mower rolling on the ground causes the front "axle" to get light. This is typically compensated with the DRAFT control, if utilized and set correctly. 4 is the framework on the back of the tractor engineered to take the stress of your stack of weights?
And further thoughts, the 250lbs you mentioned would be at the engine, not the rear. You would have to reduce it proportionally. And I believe, like most tractors, the loader lift spec is calculated at the lower (loader) pins, not 2' forward (like your situation), and most articulated machines list separate lift specs for a straight position vs full articulation.

 

[ponytug]

I'll see what PT says. I was thinking that unless they changed the wheel motors used on the machine, I could add weight back up to the engine weight difference without issue.

Here's a link to a company that already makes what I was thinking of.

6 Weight Bracket for 2″ Receiver Hitch | Heavy Hitch - Compact Tractor Attachments

Enhance your tractor's performance with the 6 Weight Bracket for 2″ Receiver Hitch. Perfect for adding ballast and improving stability.

heavyhitch.com

I think that @m5040 makes a number of good points. Given the distance from the axle, you probably won't need much more than half the weight difference. Rimguard's calculator suggests about 99lbs/tire for 26-12x12 tires;

Tire Fill Tools | Rim Guard

Find out how many gallons of beet juice tire ballast you need in your tires. Our Tire Fill Tool has data for over 2,200 different tire sizes.

www.rimguardsolutions.com

That would take you almost all the way there.

If you go the route of weights, I would also check to see that your engine canopy can still open with the weights on, and that your "angle of attack" for starting slopes still works for you.

All the best,

Peter

 

[marrt]

Well, thinking about this for a second, if the front wheel motor can take the 1200 lb. rating, then adding 250 lbs to the rear would be nothing. PT uses the same motors front and rear. White (or whoever owns them now, I forgot) makes this series wheel motor with heavy duty bearings. I bought this style when upgrading my 425 to a 435 with 21.2 cc motors. I'm not sure which motor PT uses now, but if it's the HD version, you are fine. In any case, I don't' think it would be a problem, especially if you remove them when not needed.

 

[marrt]

BTW, can you PLEASE take some pictures of your engine compartment, from different angles if possible? I really want to see the layout. This sounds like a fantastic machine.

 

[BWSwamper]

Thanks for all of the issues to consider.

In the interim I had the chance to talk with Terry at PT about the new PT1430. The major takeaways from that conversation are 1) the lighter gas engine does impact loader performance, 2)it is okay to add a standard hitch at the back of the machine (2,000 lbs. max trailer, 200 lbs max tongue weight) - so adding a 2 inch receiver hitch weight bar is okay, and 3) due to the location of the weight rack behind the machine the suggested weights would be about 100 lbs (about 1/2 the weight difference in the engines).

On the wheel motors, I was surprised to learn that when they revised the 1430 to gasoline power, PT went to larger wheel motors. I can't remember the exact change, but Terry said they did that to get more torque. (I'd like to learn more about how that works - higher HP, lower torque engine but with larger volume wheel motors.)

I may be stuck with respect to the angle of attack/engine cover issue. If I modify the rack so that it is low enough to allow the cover to open with the rack in place, it would almost be dragging the weights. I'm planning to use an existing 2 inch hitch receiver compatible rack with suitcase style weights. So, even though it would be a bit of headache, it would still be pretty quick to unload the weights and slide out the rack if I need to get to the engine. I do expect to only use the weight setup when doing heavier loader work.

I will post photos once I get the components rounded up. Maybe a member with a Deutz powered 1430 can post similar shot for comparison.

 

[ponytug]

Thanks for an informative post!

On the wheel motors, switching to higher volume (per revolution) means more engine revs per wheel revolution. That increases the torque at the wheel for the same engine. I think of it as engine ignitions/rev. More engine ignitions per rev means more horsepower at the wheel.

There is the issue that diesel engines max out at about 3,600rpm, and gas engines go closer to 5,500rpm. So, back of the envelope, I would have expected PT to go to a wheel motor that was 5,500/3600=1.52 larger just to have ground performance match.

I suspect that it was the second point that pushed the change in wheel motors.

All the best,

Peter

 

[MossRoad]

My Kohler runs at 3600rpm. Don't most small gas engines also run at that?

 

[SpringHollow]

Yes

 

[CalG]

Do the math.
250# hanging out back can load the front axle HOW MUCH!!!!!???.

The front end can carry the full weight of the machine, ballast, and any load out front.

Like I said, do the math, it's a simple class 1 lever/ fulcrum.

Speaking from the experience of a broken front axle casting not 20 minutes after putting on the rear ballast weight and then getting under something heavy!

 

[ponytug]

Ok, I was not close on rpms. I don't know what I was thinking of. The Deutz diesel only goes to 2600rpm, so, 3600/2600=1.38

Sigh. Measure twice, cut once. Sorry.

All the best,

Peter

 

[m5040]

I attach a pic I had (not my tractor) of a diesel 1430 and a gas tractor. You will see how the back of the gas tractor is perforated for cooling. Since we haven't seen a gas 1430 it is hard to advise. But if PT is allowing you to ad weight, you should fill the rear tires. There is no downside to that except transport weight or when replacing a tire.

 

[BWSwamper]

Found this post and realized I never uploaded the photos I took of the gas 1430 engine compartment. Here they are. The gas 1430 has the perforations/air holes in the rear of the "tub" which are visible in the second photo down.

 

[m5040]

Nice and clean. In the fall when working with leaves, be careful the leaves don't clog up all the vents. I have had it happen to my PT180