Front to Rear tire raito

[npalen]

This thread started by Blake13 was a quest to get better flotation using wider front tires if I understand correctly. I see dual front tires used extensively on farm tractors for better floatation and traction with FWA and 4WD. Some even use wide spacers between the front duals pair to fit row crop spacings. I'm wondering if anyone has tried using front duals on the compact tractors for the same reasons.

I understand that "the tractor isn't designed for front duals" and that "it would put too much load on the FWA" but I'm sure those same factors apply in some cases to the ag tractors as well. That doesn't keep people from doing it and probably tends to cause the manufacturers to take these things into account in designing FWA but doesn't necessarily mean that the manufacturer would warrant using front duals.

It would seem of value to keep the dual pair close together as possible to reduce axle overhang and turning stress. Just wondering if anyone has seen front duals on a compact tractor.




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[ovrszd]

There was a member on here that put duals on all fours of his BX. I thought maybe I'd saved a pic, but can't find it.

 

[aczlan]

There was a member on here that put duals on all fours of his BX. I thought maybe I'd saved a pic, but can't find it.

Milkman perhaps?
https://www.tractorbynet.com/forums/customization/74076-bx-whatyacallit.html

Aaron Z

 

[ovrszd]

Yes Aaron!!! Great job of researching as usual!!!! Thanks for adding the link!!!

 

[npalen]

Search Results - TractorByNet

Interesting stuff! I can see where adding duals to the front only wouldn't necessarily add stability but sure would add flotation and traction. Front duals would be a plus when moving heavy FEL loads on lawn grass to keep from damaging the turf. Dual REAR wheels for FEL operations always seem like some kind of silly. Perhaps if the loader was mounted on the rear...........

Front duals would not seem to add a whole lot more stress than overloading single fronts with a extremely heavy turning load on the FEL. Running reduced PSI in the outer dual tires to reduce loading on them is mentioned.

 

[ovrszd]

Understand, the width of the front tread doesn't do much to increase stability during FEL use.

The width of the rear tread dramatically changes stability during FEL use. Wider is better. So duals on an AG class tractor using an FEL is a huge bonus for stability.

The stress issue with duals on either end is when operating on uneven ground. At some point the outer most tire is carrying all of the load. The question is whether the bearings supporting that axle are designed to have that much leverage applied.

 

[npalen]

I was thinking more in terms of traction when mentioning rear duals not adding much when using an FEL. But how much stability do dual rears offer with an FEL? The pivoting front axle combined with the rear wheels form a tripod support and it seems like there wouldn't be much increase in stability with an FEL with duals. Any sidehill loading of the FEL would tend to reduce the support to only a bipod formed with the front axle pivot and the one rear dual which is lightly loaded. I don't really know, probably would take some testing to see the effect.

Edit: I don't recall ever seeing duals on an ag tractor with FEL but have seen them on sub compacts.

 

[WinterDeere]

Just look at a tractor catalog with similar tire sizes, then see the options they offer.You can by - 7-16 _ 12.4-24 or 8-16 _ 13.6-24 or 280/70r16 _380/70r24(340/85r24)

Just catching up, but I’ve been wondering since about post #10 when someone would suggest this. Look in your tractor manual, get the approved combinations, and do the math on their respective rolling circumferences. Then find a new tire combination that falls in this range of front/rear rolling circumference ratios.

 

[ovrszd]

I was thinking more in terms of traction when mentioning rear duals not adding much when using an FEL. But how much stability do dual rears offer with an FEL? The pivoting front axle combined with the rear wheels form a tripod support and it seems like there wouldn't be much increase in stability with an FEL with duals. Any sidehill loading of the FEL would tend to reduce the support to only a bipod formed with the front axle pivot and the one rear dual which is lightly loaded. I don't really know, probably would take some testing to see the effect.

Edit: I don't recall ever seeing duals on an ag tractor with FEL but have seen them on sub compacts.

You described the dynamics very well. And confirmed that duals on the rear will increase stability by changing the measurements of the triangle. Then add the weight and you have changed the dynamics a lot.

Most SCUTS and CUTS are FWA which minimizes the need for more traction by adding rear duals. They are also used in more confined spaces which makes duals awkward.

 

[dnw64]

Carlisle literature for their Farm Specialist 7-16 lists a rolling circumference of 86.8 inches. The Farm Specialist 11.2-24 rolling circumference is 129.1 inches.

I've only read the first page so far, but what am I missing? Doesn't this hold all the info you want right there? If you maintain that ratio, you will also maintain the mfr lead/lag.