Another 2120 Turf to Ag switch

[smac]

How can I make the switch with out spending BIG $. I think I would like to go 13.6 x 28 rear and 8 x 16 front. I checked circumferences on Firestone's site and the front to rear ratio is very close to the turfs that are on now. Will a common 12 inch wide x 28 6 loop rim bolt up to the centers I would buy from my New Holland dealer (for about $375 each). And as for the fronts I see rims the right size and the 4.6" hub that I need but they say 6 bolt 6" pattern. My wheels have what looks like a 6 7/8" 6 bolt pattern.

any help would be great I am new to this and am trying to get educated
thanks smac

 

[farmerjim]

is that 2120 mfwd? if so i believe you will need to get new rims that are a "matched set" in order to keep the gear ratio w/ ag tires correct. if not i think that you can damage the mfwd. at least thats what i was told by a dealer when i was looking at purchasing a used jd 5200 utility mfwd which had turfs. in the long run it would have been almost the same price w/ new tires/rims as a new 2wd model would cost.

 

[shaley]

Welcome toTBN and join the "2120 I want different tires club".
All dimension are metric so none of the new TC rims will fit. The front bolt circle is 180mm x 6 ea.
Here is a print of the front dimensions and bolt pattern. I bought a set of 16" rims R4 with the thought of having the center removed and have a disk made to the print below and weld it back in. For the rear, I was going to make an adaptor for 200mm to 8in bolt circle so I could use the standard TC R4 rims. I'll have he prints finished in a couple of weeks.
View attachment 2120 front disc.pdf

 

[dogbreath108]

Shaley, thanks for the front rim print , I was looking to make one a ways back and you saved me some time.

Smac, there are a lot of us in the same boat. Dealer cost for the fronts are around $300 a pop, backs are $1000 each for the outer rim not including the center disc. If you find a aftermarket source, let us know!! What size rims and tires do you have on there now? I had 8x18 on the front so there is plenty of center to cut out and weld into a set of blank 8x16 rims that are about $50 each... (I used 8x16 rims for a 9.5x16 tire, if you are looking to use 8x16 tires, I think your rim size would be 6x16, check the tire catalog or maybe someone here can comment). If you have the small turf size rim and tire setup I'm not sure that there would be enough center material to cut out and use. If they are, you are probably better off selling the whole set anyway to finance your upgrade. As those are still a nice set. By the way, the 13.6x28 backs and 9.5x16 fronts (R-1) were a factory choice option on the tractor so the dimentions would be correct. I think the 8x16 R-1 tires on the front may still be ok as far as the 1-5% front axle lead. That what Farmerjim was mentioning.

Shaley, if you are looking to get some front centers made from one of the rim mfg. let me know, more is usually cheaper as the dim's are just put into a CNC. I would be interested in another set for my R-3's. Also, seems like a lot folks might be interested... I wonder how fast a set would sell on ebay???
And if you have the center discs for the 26 or 28 inch rears, the 26 and 28 inch rims are available blank. You then need to weld in the 8 loops... Thats always a choice. Let me know how you fair...

Thanks
Joe

 

[shaley]

Welcome Joe. I was going to email you last time but had too much going on. I can send you the DXF file so it can go directly into the CNC. The problem I'm running into is cutting the center from the rim in a concentric manner. Not technologically but cost wise. Looked at CNC Laser, abrasive jet, etc. I think I'll end up with just a mill and rotary table.
The rear adaptors are designed to allow a standard 8" BCD x 8 disc to fit. Standard R4 tire set from a kubota 5030 is 10-16.5 and 17.5L-24 gives the 5% lead req. Once you get the SAE 8x8 rear is adapted you could use R1's or R4's from a TC45 or 55. The new sets of tires and wheels are about $2300 total, 4 tires, 4 rims. They are made in the US by Titan so the cost is much lower than Japanese rims. The rears will bolt directly up but you will still need the front rim mod with the disc.
I'll try to finish the CAD print on the rear today.
I like the idea of multiple orders to the machine shop as it may save us some money.


Rear pattern looks like it will fit but the 2120 is 200mm BCD vs. 8in with a 151mm pilot hole.


Front will need the disc made


I bought these from a Kubota 5030 with R4's

 

[smac]

This is the kind of replies I was hoping for. I am sure We can nail this problem, as far as the fronts go I see a few low cost rims with 4.6" centers I was thinking about drilling 6 new holes between the old 6" pattern at the 180mm dimension. Does this sound good to anyone? Dogbreath the tires on the tractor now are 18.4 -16.1 (136.5" circ) rear and 27 - 8.5 (83" circ) fronts. When I divide the front circumfrence into the rear I get a 1.644 ratio. The Firestones that I listed in my origional post are 153" rear and 92" front circumfrences this is a 1.663 ratio. Is this close enough? Keep the thoughts coming. smac

 

[jimmysisson]

My 2120 has R1 tires, and even worn (rears are 15 years old, fronts 5) they can really tear up a lawn or soft pasture. Be sure you want to make the switch. Great in mud or the woods, not sure about the difference in snow, etc.
Jim

 

[shaley]

Here is the rear adaptor that attaches to the axle flange with 8 16mm socket head cap screws (SHCS). The SHCS will be in a counter bore as shown and the 8" bolt circle will then be available to mount a standard TC (SAE) rim. Then the original wheel bolts can be used to mount the new 8 x 8" BC rim disc. Made out of 1" Plate the OD could be flame cut as it is not critical on the OD.
The inner bore and holes need to be done on a lathe then mill index table.
The pilot boss (dwg 202) is then plug welded to the disc. See section (201) for assy. I'll get a quote from a machine shop next week.

 

[dogbreath108]

Again, thanks for the prints, you done a bang up job! Have you thought about going directly to US RIM, Unifirth (or whatever the heck the name is), or the other major rim mfg.? They do special orders, but only usually with good prints. And it looks like you have them! It probably would be worth a quote just to see.

As far as the rears go, I would probably like to stay with my 28" centers because I think they will size up to standard 28" outer rims by adding the 8 mounts. I am not sure on this yet though... I see your rears are "one piece" which would justify your adapter plate.. Pretty neat idea, I would like to see your final product! I am usually taken by other folks projects as much as my own... And that doesn't mean I wouldn't like to own a set also, as it opens up a lot of other possibilities.


Smac, as far as drilling different pattern bolt holes in other rims for the front goes, It may be a bit more difficult that you think. Even if you overlay both patterns before and know it will work, most of the centers that I have seen are a fairly thin stamped steel. Which have indents around the bolt holes for strength. Making drilling another pattern, well, probably not so easy. Hard for me to explain, but if you look at the advertised 16 and 16.5 rims available online you can probably see it. Maybe you would have a set where this does not apply.... I think, getting a custom set of centers to weld in a set a blank 16 or 16.5 or whatever might work better.

Joe

 

[shaley]

Joe, I talked to Unverfirth last summer about custom rims and disc centers. Unverfirth would make a flat disc with no dish for 6 clip (loop) rim for about $350 ea + S/H.
My new rears are two piece disc and loop (see bottom pic) it's just they are 8" bolt circle and my old turfs are one piece so yes, no disc with 200 mm bolt circle. Miller tire has flat base rims with weld on loops.
M.E. MIller Tire